Serum Albumin Levels: A Biomarker to Be Repurposed in Different Disease Settings in Clinical Practice

Serum albumin (ALB), one of the most important proteins in human physiology, has the main functions of maintaining plasma oncotic pressure and plasma volume, transporting hormones, vitamins, oligominerals and drugs, and exerting a powerful antioxidant-anti-inflammatory role. Its prognostic value in liver and malabsorption syndromes is well known. In this narrative review, an analysis of the most important studies evaluating the prognostic significance of low serum ALB levels in hospitalized patients was performed. Specifically, the risk in emergency medicine, cardiovascular diseases, Coronavirus Disease 19 (COVID-19) infection, nephrology, oncology, and autoimmune rheumatic diseases has been examined to fully explore its clinical value. ALB is a negative acute-phase reactant and the reduction in its serum levels represents a threatening parameter for long-term survival in several clinical settings, and a strong biomarker for a poor prognosis in most diseases. Therefore, clinicians should consider serum ALB as a valuable tool to assess the efficacy of specific therapies, both in hospitalized patients and in chronic follow-up.

Peripheral blood CD4posCD25posFoxP3pos cells and inflammatory cytokines as biomarkers of response in rheumatoid arthritis patients treated with CTLA4-Ig

BACKGROUND

Prognostic biomarkers of treatment response to distinct biologic disease-modifying anti-rheumatic drugs (b-DMARDs) are still lacking within the management of rheumatoid arthritis (RA).

METHODS

Thirty-four b-DMARDs naive RA patients, divided by disease duration into early (cohort 1) and long standing (cohort 2), received CTLA4-Ig. At study entry, and every 3 months for 1 year, each patient underwent peripheral blood (PB)-derived CD4^pos cell subpopulation assessment by flow cytometry, STAT3 and STAT5 expression by RT-PCR and IL-6, IL-12p70, TGFβ, and IL-10 serum levels by ELISA. The DAS and CDAI remission was assessed at 6 and 12 months.

RESULTS

DAS- and CDAI-defined remission within 12 months was achieved by 16 (47.1%) and 8 (23.5%) RA patients, respectively. Considering the whole RA cohort, CTLA4-Ig induced a significant decrease of IL-6 serum levels from baseline to 6 and 12 months, as well as of PB CD4^posCD25^posFoxP3^pos cells at 6 and 12 months, and of CD4^posIL17^pos cells after 12 months. PB CD4^pos cells of RA patients showed higher STAT3 and STAT5 expression than healthy controls, which remained unchanged within 12 months of treatment. At study entry, RA patients achieving DAS remission had significantly lower IL-6 serum levels than RA patients not achieving this outcome. In particular, having baseline IL-6 serum levels ≤ 8.4 pg/ml, significantly identified naïve to b-DMARDs RA patients more likely to achieve DAS-remission under CTLA4-Ig at 6 months (66.7%) compared to RA patients with baseline IL-6 serum levels > 8.4 pg/ml [15.4%, OR (95%Cis) 11.00 (1.75-55.82)]. Moreover, having CD4^posCD25^posFoxP3^pos cells rate ≥ 6.0% significantly identifies naïve to b-DMARDs early RA patients more likely to achieve DAS remission at 6 months (83.3%) compared to RA patients with baseline CD4^posCD25^posFoxP3^pos cells < 6.0% [16.7%, OR (95% Cis) 25.00 (1.00-336.81)].

CONCLUSIONS

Baseline IL-6 serum levels and peripheral blood-derived CD4^pos subpopulations are putative novel prognostic biomarkers of CTLA4-Ig response in RA patients.

POS0316 SEMIQUANTITATIVE ASSESSMENT OF SYNOVITIS ON US-GUIDED SYNOVIAL MEMBRANE BIOPSIES IS CONTINGENT ON DISEASE PHASE AND PREDICTIVE OF TREATMENT RESPONSE IN NAIVE TO TREATMENT PSORIATIC ARTHRITIS

Background

Ultrasound (US)-guided minimally invasive Synovial Tissue (ST) biopsy serves as a safe and well tolerated procedure for basic and translational research on chronic inflammatory joint disease.

Objectives

(i) to assess the diagnostic value of the Krenn score (KSS) on ST samples obtained from US-guided biopsies in a large bio-samples dataset of patients with Psoriatic Arthritis (PsA) across different disease phases; (ii) to develop a multiparametric nomogram integrating clinical and histological characteristics enabling treatment response prediction in naïve to treatment PsA.

Methods

410 patients fulfilling the CASPAR criteria for PsA who underwent US-guided ST biopsy were enrolled. At baseline, patients were categorized based on their disease phase and treatment: n=207 naïve to DMARDs; n=101 resistant to c-DMARDs; n=48 resistant to b-DMARDs and n=54 in sustained clinical and ultrasound remission or in low disease activity (LDA) state (DAPSA ≤ 4 or among 4-14, respectively). Clinical, demographic, and immunological characteristics were recorded for each patient. All ST specimens were stained with H&E and classified by a pathologist, blinded to clinical characteristics, using the Krenn score to assess ST inflammation degree (1) implemented with the determination of lymphocytes, plasma cells, granulocytes and tissue oedema presence. Each naive to treatment PsA was treated according to the EULAR recommendations (2) and DAPSA remission rate at 6 months was recorded.

Results

Considering the whole enrolled cohort, the distribution of KSS was significantly different among patients across the different PsA phases (ANOVA p<0.001). In particular, among the different phases, KSS was significantly higher in b-DMARDs resistant (p<0.0001) and c-DMARDs resistant (p<0.0001) compared to remission/LDA disease patients as well as naive to treatment PsA (p<0.0001). Interestingly, regardless to the disease phase, KSS of the biopsied joint directly correlated to disease activity in terms of DAPSA (r=0.476, p<0.001) and DAS28 scores (r=0.476, p<0.001). Considering the naïve to treatment PsA cohort, patients achieving DAPSA defined-LDA/remission had, before treatment, significantly lower KSS (p<0.001), lower rate of ST plasmacells presence (p<0.001) and shorter symptoms duration (p=0.01) as compared to naïve to treatment PsA not achieving this clinical outcome. Moreover, considering distinct clinical phenotype domains, naive to treatment PsA patients with concomitant dactylitis and skin disease were less likely to achieve DAPSA LDA/remission (p<0.001), regardless of treatment scheme. On logistic regression, at baseline, having a KSS <5 [OR: 5.30 (95%CI:2.21-12.74) p<0.001], absence of plasma cells ST infiltrate [OR: 3.87 (2.11-7.10 95%CI) p<0.001], concomitant dactylitis [OR: 2.55 (95%CI:1.24-5.25) p=0.01] and skin involvement [OR: 2.06 (95%CI:1.17-3.62) p=0.01] were independent factors associated with DAPSA score-LDA/remission achievement at 6 months. Finally, a multiparametric nomogram integrating baseline clinical and histological characteristics of naïve PsA enabling to predict up to 75% of probability to achieve DAPSA remission at 6 months was developed.

Conclusion

KSS is a reliable tool for synovitis assessment in PsA, being contingent on disease phases, related to disease burden and included within a treatment response predictive multiparametric nomogram in naïve PsA.

References

[1]Krenn V, et al. Histopathology 2006

[2]Gossec L, et al. Annals of the Rheumatic Diseases 2020

Disclosure of Interests

None declared

OP0284 IMMUNOPHENOTYPIC CHARACTERIZATION OF PERIPHERAL BLOOD-DERIVED B LYMPHOCYTES OF PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS DURING B-CELL TARGETED THERAPY WITH ANTI-BLyS

Background

Belimumab, the first biological drug approved for the treatment of patients with Systemic Lupus Erythematosus (SLE), is a fully human IgG1λ monoclonal antibody directed against BlyS (B Lymphocyte Stimulator). BLyS inhibition is associated with a reduction in circulating B subsets and short-lived plasmacells

Objectives

The aim of this study was to characterize the B cell phenotype in SLE patients at baseline and after B-cell targeted therapy with Belimumab in a cohort of active SLE patients.

Methods

Fifty-four SLE patients diagnosed according to the 2012 SLICC criteria (49 females, mean age 40.6±13.2 years, disease duration 12.3±9.0 years, SLEDAI-2K 6.6±3.1) who received belimumab were enrolled. Phenotyping of peripheral blood (PB)- derived B lymphocytes (using as phenotypic markers IgD, CD27 and CD38) was performed at six (T6) and twelve (T12) months in 38 SLE patients, together with the expression of BAFF and BAFF- R by flow cytometry.

Results

In the whole SLE cohort, a reduction over time was observed in the percentage of CD19pos[T0:11.1±6.1% vs T6:6.4±3.4%,p<0.01;T12:4.2±3.4%,p<0.01] and naïve B cells (IgDposCD27neg) [T0:55.8±28.7% vs T6:34.9±22.2%,p<0.01;T12:30.0±19.4%;p=0.04] and an increase of switched memory B cells (IgDnegCD27pos)[T0:21.0±20.2% vs T6:37.5±21.4%,p<0.01;T12:42.2±21.%7,p=0.02] after B-cell targeted therapy with anti-BLyS. Moreover, a reduction of IgDnegCD27neg memory B cells at T6(p=0.01) was observed. Conversely, BAFF and BAFFR expression in peripheral blood-derived CD19pos cells remained unchanged during therapy with anti-BLyS. Stratifying SLE patients based on severe (renal and/or neurological) and mild (articular and/or cutaneous) organ involvement, a significant reduction of CD19pos percentage[T0:10.7±4.6% vs 6:6.8±2.4%,p=0.03;T12:4.5±3.5%,p=0.03] and naïve B cells[T0:61.0±24.6% vs T6:38.9±17.5%,p<0.01;T12:36.9±16.0%,p=0.03] was found in SLE patients with mild organ involvement and a significant increase of switched memory B cell subsets in both subgroups [(severe T0:24.1±25.0% vs T6:44.9±27.4%,p=0.01) (mild T0:18.9±18.3 vs T6:31.2±12.7%,p<0.01)]. Evaluating the B cell subsets regarding the response to treatment (based on the reduction of the SLEDAI-2K), a significant reduction of naïve B cells was observed at T6 in both SLE group,[(responders T0:55.4±29.3 vs T6:32.3±19.9,p<0.01)(no responders T0:63.1±41.3% vs T6:41.4±33.5%,p=0.05)] and switched memory B cells[(responders T0:22.4±21.2% vs T6:39.6±19.4%,p<0.01)(no responders T0:20.6±26.1% vs T6:38.6±35.3%,p<0.05)], with a significant higher percentage at baseline of switched memory B cells in responder SLE than in no-responder SLE group (22.4±21.2% vs 20.6±26.1%,p=0.02). ROC curve analysis of IgDnegCD27pos subset [AUC(95% CIs):0.761:(0.566-0.957)p=0.023] identified a cut-off of 9.94% associated with response at 6 months. Moreover, having a IgDnegCD27pos rate ≥9.94% [OR:4.5(95% CIs:0.9-17.2)]; and the presence of anti-dsDNA antibodies at baseline[OR:5.2(95%CIs:1.2-22.1)], identified SLE patients who achieved early response within 6 months from belimumab therapy initiation.

Conclusion

Anti BLyS therapy significantly impacts on the composition of peripheral blood B-cell subpopulations in SLE patients in relation with the distinct organ involvement. Moreover, baseline immunological features and IgDnegCD27pos B cell subset rate are novel putative biomarkers of response to anti-BLyS therapy in SLE patients.

References

[1]D. Ramsköld et al. B cell alterations during BAFF inhibition with belimumab in SLE. EBioMedicine. 2019 Feb;40:517-527.

[2]S. Piantoni et al. Characterization of B- and T-cell compartment and B-cell related factors belonging to the TNF/TNFr superfamily in patients with clinically active systemic lupus erythematosus: baseline BAFF serum levels are the strongest predictor of response to belimumab after twelve months of therapy. Front Pharmacol. 2021 May 21;12:666971.

Disclosure of Interests

None declared

POS0105 IMMUNOLOGICAL AND TISSUE DERIVED BIOMARKERS OF EARLY RESPONSE IN MODERATE-TO-SEVERE RHEUMATOID ARTHRITIS TREATED WITH JAK-INHIBITORS

Background

Among Janus kinase inhibitors (JAKi) approved for Rheumatoid Arthritis (RA) treatment, tofacitinib and baricitinib are considered as pan-JAKi (pJAKi) while upadacitinib and filgotinib as selective anti-JAK1 (sJAKi) drugs. To date, despite ≈30% of RA patients exposed to JAKi achieve DAS28-CRP remission at 12 weeks, there is still lack of predictive biomarkers of response in RA treated with distinct JAKi.

Objectives

To determine whether pre-treatment immunological and synovial tissue features can predict clinical improvement in moderate-to-severe RA treated with JAKi.

Methods

Among 174 RA patients treated with JAKi, 84 underwent peripheral blood (PB) drawing and US-guided synovial tissue (ST) biopsy. Demographic, clinical and immunological features were collected for each patient at baseline and after 12 weeks. The distribution of PB-derived B lymphocytes subsets was assessed by flow cytometry, using CD27/IgD classification. Synovitis degree assessment was determined using Krenn score (KSS) by trained pathologist, blinded to clinical characteristics.

Results

Among enrolled RA patients, 82.7% was treated with pJAKi and 17.3% with sJAKi. Moreover, 35.6% of RA patients was b/ts-DMARDs naïve, 18.4% b/ts-DMARDs non-responder and 46.0% was difficult-to-treat (D2T) RA. In the whole cohort, 49.2% and 50.8% of RA patients achieved DAS28-CRP and CDAI low disease activity (LDA), respectively, after 12 weeks of JAKi treatment. Moreover, 37.7% and 5.9% of RA patients achieved DAS28-CRP and CDAI remission (REM), respectively, after 12 weeks of JAKi treatment regardless to JAKi category. Considering the immunological profile, RA patients achieving CDAI LDA were more likely rheumatoid factor (60.0%) and ACPA positive (60.5%) compared to RA patients not achieving this outcome (RF: 40.0%, p= 0.03 and ACPA: 39.5%, p= 0.02). Considering PB-derived B cell phenotype, b/ts-DMARDs naïve RA achieving DAS28-CRP LDA at 12 week had pre-treatment lower unswitched memory B (IgDposCD27pos) cell rate (6.91±7.70%) compared to b/ts-DMARDs naïve RA not achieving the same outcome (13.21±5.68%, p= 0.009). ROC analysis identified a cut-off value of 6.89% for IgDposCD27pos cells discriminating b/ts-DMARDs naïve RA achieving DAS28-CRP LDA at 12 week [AUC: 0.174±0.086; p= 0.008; OR(95%CIs): 18.20 (1.761-188.069)]. Furthermore, b/ts-DMARDs naïve RA achieving DAS28-CRP REM at 12-week follow up visit, had PB enrichment of naïve B cells (IgDposCD27neg: 68.08±17.38%) and lower percentage of unswitched memory B lymphocytes (5.10±4.29%) compared to RA not achieving the same outcome (IgDposCD27neg: 54.68±16.16%, p= 0.05; IgDposCD27pos: 13.96±8.34%, p= 0.001) [IgDposCD27neg cut-off: 62.6%, AUC:0.727±0.101, p=0.05; OR(95%CIs): 7.33(1.272-42.294); IgDposCD27pos cut-off: 6.89%, AUC: 0.139±0.073, p= 0.002; OR(95%CIs): 12.37 (1.828-83.767)]. Interestingly, considering the D2T RA subgroup, patients achieving DAS28-CRP LDA at 12 week follow up had lower rates of PB-derived IgDnegCD27neg B cells (3.83±0.96%) compared to RA not achieving the same outcome (7.25±2.83%, p= 0.04; cut-off: 5.46%, AUC: 0.083±0.095, p=0.041). Considering the pre-treatment synovitis degree, b/ts-DMARDs naïve RA achieving CDAI LDA status had significantly higher KSS at baseline (3.8±2.2) compared to RA not achieving the same outcome [1.7±1.4, p= 0.02; KSS cut-off: 3.00, AUC: 0.795±0.097; p=0.018; OR(95%CIs): 14.0 (1.39-141.49)]. Finally, no significant associations were observed between PB-derived B cell subpopulations rate and synovitis degree both in the whole RA cohort as well as stratifying patients for disease phase.

Conclusion

Pre-treatment immunological profile, peripheral blood-derived B cell phenotype and synovitis degree are associated with the early achievement of at least DAS28-CRP/CDAI LDA in RA patients receiving JAKi despite their selectivity.

References

[1]Gremese E et. J Leukoc Biol. 2019

[2]Alivernini S et al. Pharmacol Res. 2019

[3]Alivernini S et al. Arthritis Rheumatol. 2021

Disclosure of Interests

None declared

OP0084 DIGITAL SPATIAL PROFILING REVEALS DISTINCT SYNOVIAL TISSUE MACROPHAGE TRANSCRIPTOMIC SIGNATURE OF SUSTAINED REMISSION IN RHEUMATOID ARTHRITIS PATIENTS AT RISK OF DISEASE FLARE AFTER TREATMENT CESSATION

Background

Sustained remission is the treatment goal for Rheumatoid Arthritis (RA) and once achieved patients are eligible to treatment tapering or discontinuation. However, this exposes patients to the occurrence of unpredictable disease flare, and to date there are no definitive predictive biomarkers of flare for RA in remission that could be used in clinical practice.

Objectives

To assess the impact of clinical classification of remission on synovial tissue (ST) features of RA in sustained remission and to identify predictive biomarkers of disease flare.

Methods

200 RA in sustained clinical (102 RA with DAS<1.6 and 98 RA fulfilling Boolean remission criteria for at least 9 months, respectively) and ultrasound (US) remission (PD negative) under Methotrexate with or without biological-Disease Modifying Anti-Rheumatic Drugs (bDMARDs) were enrolled and underwent to US guided ST biopsy. 373 naive RA were included as comparison. For each patient, synovitis degree was determined using a H&E-based semiquantitative score1. Some ST samples of remission RA were used for synovial tissue macrophage (STMs)(CD206/MerTK) FACS phenotyping and digital spatial profiling (GeoMx DSP, Nanostring) to quantitate transcript abundance of CD68pos cells in 138 spatially distinct ST regions of interest (ROI). After study entry, RA were randomly assigned to tapering/discontinuation (TAP/DISC) (tapering c- or b-DMARD treatment for 6 months and discontinuing c- or bDMARD afterwards) or maintaining the same therapeutic scheme (CONT). Each RA was followed every 3 months to assess flare rate after treatment modifications for 24 months.

Results

Regardless of either DAS- or Boolean-defined, remission patients had significantly lower KSS than naive RA (p<0.0001 for both). However, ST of RA in Boolean remission had lower KSS (p<0.0001) and was enriched in CD206posMerTKpos STMs (p=0.0012) as compared to DAS-defined remission RA. 73(36.5%) RA experienced a disease flare regardless of the treatment change during 24 months follow-up. Stratifying RA in remission based on remission definition and treatment group, DAS-defined remission RA who had a disease flare within at least 6 months follow-up had, at study entry, significantly higher KSS (p<0.0001) than RA who maintained a sustained remission, regardless of the treatment change (CONT:p=0.0027 and TAP/DISC:p=0.0011). Logistic regression analysis revealed that baseline KSS≥3 [AUC:0.748(95%CI:0.649-0.846)p<0.0001] was an independent predictive factor of disease flare [OR:6.9(95%CI:2.82-16.81)] within 24 months follow-up in DAS-defined remission RA. Conversely, RA in Boolean remission did not differ for KSS at study entry in both the CONT (p>0.05) and the TAP/DISC (p>0.05) group in relation to disease flare. However, considering STMs phenotype, RA in Boolean remission in the TAP/DISC group who had low levels of CD206posMerTKpos (<38.1%), experienced more likely a disease flare compared to RA in the CONT subgroup with CD206posMerTKpos≥38.1% (p=0.0014). Logistic regression analysis confirmed that, before treatment change, STMs phenotype (CD206posMerTKpos <38.1%) in RA in remission is an independent predictor of disease flare [OR:6.25(95%CI:1.33-29.43)] within 24 months. Finally, DSP analysis using CD68 morphology marker, revealed that lining and sublining layer CD68pos spatial transcriptomics distinguished, at baseline, remission RA who flared after treatment modification from those who did not.

Conclusion

Disease flare is a common event in RA in sustained remission after treatment modification. KSS and STMs phenotype identified by flow cytometry or by tissue spatial transcriptomic can identify RA in remission at higher risk of flare after treatment modification. Thus, spatial transcriptomic with defined panel of markers on histological biopsy tissues could be a way forward in predicting disease flare.

References

[1]Alivernini S, et al. Arthritis & Rheumatology 2021

Disclosure of Interests

Simone Perniola: None declared, Barbara Tolusso: None declared, Aziza Elmesmari: None declared, Marco Gessi: None declared, Clara Di Mario: None declared, Maria Rita Gigante: None declared, Luca Petricca: None declared, Dario Bruno: None declared, Domenico Somma: None declared, Annamaria Paglionico: None declared, Valentina Varriano: None declared, Laura Bui: None declared, Maria Antonietta D’Agostino: None declared, Mariola Kurowska-Stolarska Grant/research support from: Pfizer, GSK, Novartis, Eli Lilly, Elisa Gremese Speakers bureau: Abbvie, BMS, Novartis, GSK, Galapagos, Eli Lilly, Pfizer., Grant/research support from: Abbvie, BMS., Stefano Alivernini Speakers bureau: Abbvie, BMS, Novartis, Galapagos, Eli Lilly, Pfizer., Grant/research support from: Pfizer, Novartis, GSK.

POS0777 STUDY OF PERIPHERAL BLOOD B CELL IMMUNO-PHENOTYPING IN PATIENTS WITH LUPUS NEPHRITIS: PARAMETERS OF DISEASE ACTIVITY, REMISSION AND FLARE

Background

B cells play a central role in systemic lupus erythematosus (SLE) pathogenesis connecting innate with adaptative immunity.

Objectives

To investigate the peripheral blood B cell phenotype in a cohort of SLE patients with renal involvement (LN-SLE) in relation to disease activity and renal histological lesions compared to healthy controls.

Methods

One hundred LN-SLE patients with active renal involvement, 40 at disease onset (Early) and 60 in whom LN occurred after the disease onset (Long) were enrolled. Thirty-seven healthy controls were included. Clinical, laboratory and demographic data were collected at baseline and at 6 and 12 month of follow-up. Disease activity was recorded using SLEDAI-2K. Ultrasound-guided renal biopsy has been performed for the definition of the nephritic class according to the ISN/RPS classification. The memory B cells immunophenotyping (IgD/CD27 classification) was analyzed in peripheral blood through flow cytometry. To clarify the role of key molecules in the B cells activation, IL-6 and BAFF serum levels were assayed by Enzyme-linked immunosorbent assay (ELISA).

Results

According to the onset of renal symptoms, there were no differences in the distribution of the renal classes and in activity and chronicity indices in the two groups. A direct correlation was observed between chronicity index score and creatinine in the whole cohort (R=0.342;p<0.01) and in LN-SLE Early (R=0.528;p=0.01) and Long (R=0.337;p=0.02). The disease activity index was found to be significantly higher in anti-dsDNA positive than in negative ones (6.6±4.8 vs 2.8±3.5;p=0.01), and in patients with at least one antiphospholipid antibody-APL positivity (6.8±4.8 vs 5.1±4.8;p=0.05). Considering predictive biomarkers of the remission within 12 months, the presence of histological lesions (glomerulosclerosis and fibrocellular crescents) and the positivity for at least one of the APL antibodies were associated to the failure in achieving clinical remission, while baseline 24h-UP levels ≤2750mg were associated to remission achievement [OR:2.6(95%CIs:1.1-5.8)]. Studying the B cells subset, a lower percentage of CD19pos and unswitched memory (IgDposCD27pos) in LN-SLE compared to controls (6.8±5.5% vs 10.5±3.5%;p<0.01 and 11.1±12.0% vs 15.3±8.0%;p<0.01,respectively) was observed. In addition, we found higher levels of double-negative memory B cells (IgDnegCD27neg) and plasmablasts (CD27posCD38pos) in LN-SLE than in controls [(CD27negIgDneg 10.0±8.7% vs 4.1±1.9%;p<0.01)(CD27posCD38pos 4.4±5.3% vs 1.0±0.5%;p<0.01)]. Furthermore, CD19pos and IgDposCD27pos negatively correlated with BAFF [(R=-0.327;p=0.03 and R=-0.305;p=0.04) respectively] while a direct correlation was observed between IgDnegCD27neg B cells and IL-6 serum levels (R=0.302;p<0.01). No correlation was found between B cells subsets and the disease activity parameters. Considering the remission status achievement within 12 months both LN-SLE groups had significantly lower frequencies of IgDposCD27pos than controls [(Remission:10.7±12.4% vs 15.3±8.0%;p<0.01)(No-Remission:9.8±9.5% vs 15.3±8.0%;p<0.01)] conversely had a significantly higher rate of IgDnegCD27neg than controls [(Remission:11.5±10.0% vs 4.1±1.9%;p<0.01;NoRemission:9.6±6.7% vs 4.1±1.9%;p<0.01] and plasmablasts [(Remission 5.2±6.7% vs 1.0±0.5;p=0.05;NoRemission:4.1±3.4 vs 1.0±0.5;p<0.01)]

Conclusion

This study suggests that the active injury and chronic damage histological features of LN do not depend on the SLE duration per se, but could be associated to the failure in achieving clinical remission within 12 months. Furthermore, data on memory B cells immunophenotyping reveals a distinct B cells subset of SLE patients when compared to healthy controls, confirming an alteration of B cells subsets in SLE patients and strengthening the hypothesis of the pathogenetic role played by B lymphocytes in the course of LN.

References

[1]Obris că et al. Int J Mol Sci 2021;22(7):3766.

[2]Zhu L et al. Clin Rheumatol 2018;37(1):205-212.

Disclosure of Interests

None declared

Prevalence of dyslipidemia and hypercholesterolemia awareness: results from the Lookup 7+ online project

Background

Cardiovascular disease still represents the leading cause of death worldwide. Management of risk factors remains crucial; despite this, hypercholesterolemia, which is one of the most important modifiable cardiovascular risk factor, is still high prevalent in general population. The aim of this study is to determine the prevalence of dyslipidemia and hypercholesterolemia awareness in a very large population.

Methods

More than 65 000 users completed the online, self-administered survey. It was structured like a ‘journey’ where each stage corresponded to a cardiovascular risk factor: blood pressure, body mass index, cholesterol, diet, physical exercise, smoke and blood sugar. At the end, the user received a final evaluation of his health status.

Results

The mean age was 52.5 years (SD 13.9, range 18–98), with 35 402 (53.7%) men. About 56% of all participants believed to have normal cholesterol values, when only 40% of them really showed values <200 mg/dl. Only about 30% of all participants self-predicted to have abnormal cholesterol values whereas we found high cholesterol levels in about 60% of people.

Conclusions

Dyslipidemia is very prevalent and half of the people with high cholesterol is not aware of having high values.

Durable renal response and safety with add-on belimumab in patients with lupus nephritis in real-life setting (BeRLiSS-LN). Results from a large, nationwide, multicentric cohort

BACKGROUND

Belimumab was recently approved for treatment of lupus glomerulonephritis (LN).

AIM

To evaluate renal response and its predictors in LN patients receiving belimumab in real-life.

PATIENTS AND METHODS

We considered all patients fulfilling the SLEDAI-2K renal items and/or having estimated glomerular filtration rate (eGFR)≤60 ml/min/1.73 m², with positive anti-dsDNA and/or low C3/C4 enrolled in the multicentre Italian lupus cohort BeRLiSS (BElimumab in Real LIfe Setting Study), treated with monthly IV Belimumab 10 mg/kg over standard treatment. Primary efficacy renal response (PERR), defined as proteinuria ≤0.7 g/24 h, eGFR≥60 ml/min/1.73 m² without rescue therapy, was considered as primary outcome. Complete renal response (CRR; proteinuria <0.5 g/24 h, eGFR≥90 ml/min/1.73 m²) was considered as secondary outcome. Prevalence and predictors of PERR were evaluated at 6, 12, 24 months by multivariate logistic regression.

RESULTS

Among the 466 SLE patients of BeRLiSS, 91 fulfilled the inclusion criteria, 79 females, median age 41.0 (33.0-47.0) years, median follow-up 22.0 (12.0-36.0) months. Sixty-four (70.3%) achieved PERR, of whom 38.4% reached CRR. Among patients achieving PERR at 6 months, 86.7% maintained response throughout the follow-up. At multivariable analysis, hypertension (OR [95%CI]: 0.28 [0.09-0.89], p = 0.032), high baseline serum creatinine (0.97 [0.95-0.99], p = 0.01) and high baseline proteinuria (0.37, [0.19-0.74], p = 0.005) negatively predicted PERR. Positive predictors of PERR at 12 and 24 months were baseline anti-Sm positivity (OR [95%CI]: 6.2 [1.21-31.7], p = 0.029; 19.8 [2.01-186.7], p = 0.009, respectively) and having achieved PERR at 6 months (14.4 [3.28-63.6]; 11.7 [2.7-48.7], p = 0.001 for both).

CONCLUSIONS

Add-on therapy with belimumab led to durable renal response in patients with LN in a real-life setting.

Haemophilus parasuis (Glaesserella parasuis) as a Potential Driver of Molecular Mimicry and Inflammation in Rheumatoid Arthritis

Background:Haemophilus parasuis (Hps; now Glaesserella parasuis) is an infectious agent that causes severe arthritis in swines and shares sequence similarity with residues 261–273 of collagen type 2 (Coll_261−273), a possible autoantigen in rheumatoid arthritis (RA).

Objectives/methods: We tested the presence of Hps sequencing 16S ribosomal RNA in crevicular fluid, synovial fluids, and tissues in patients with arthritis (RA and other peripheral arthritides) and in healthy controls. Moreover, we examined the cross-recognition of Hps by Coll_261−273-specific T cells in HLA-DRB1^*04^pos RA patients, by T-cell receptor (TCR) beta chain spectratyping and T-cell phenotyping.

Results:Hps DNA was present in 57.4% of the tooth crevicular fluids of RA patients and in 31.6% of controls. Anti-Hps IgM and IgG titers were detectable and correlated with disease duration and the age of the patients. Peripheral blood mononuclear cells (PBMCs) were stimulated with Hps virulence-associated trimeric autotransporter peptide (VtaA10_755−766), homologous to human Coll_261−273 or co-cultured with live Hps. In both conditions, the expanded TCR repertoire overlapped with Coll_261−273 and led to the production of IL-17.

Discussion: We show that the DNA of an infectious agent (Hps), not previously described as pathogen in humans, is present in most patients with RA and that an Hps peptide is able to activate T cells specific for Coll_261−273, likely inducing or maintaining a molecular mimicry mechanism.

Conclusion: The cross-reactivity between VtaA10_755−766 of a non-human infectious agent and human Coll_261−273 suggests an involvement in the pathogenesis of RA. This mechanism appears emphasized in predisposed individuals, such as patients with shared epitope.

Prevalence and Predictors of Persistence of COVID-19 Symptoms in Older Adults: A Single-Center Study

Objectives

Symptom persistence weeks after laboratory-confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) clearance is a relatively common long-term complication of Coronavirus disease 2019 (COVID-19). Little is known about this phenomenon in older adults. The present study aimed at determining the prevalence of persistent symptoms among older COVID-19 survivors and identifying symptom patterns.

Design

Cross-sectional study.

Setting and Participants

We analyzed data collected in people 65 years and older (n = 165) who were hospitalized for COVID-19 and then admitted to the Day Hospital Post-COVID 19 of the Fondazione Policlinico Universitario "Agostino Gemelli" IRCCS (Rome, Italy) between April and December 2020. All patients tested negative for SARS-CoV-2 and met the World Health Organization criteria for quarantine discontinuation.

Measures

Patients were offered multidisciplinary individualized assessments. The persistence of symptoms was evaluated on admission using a standardized questionnaire.

Results

The mean age was 73.1 ± 6.2 years (median 72, interquartile range 27), and 63 (38.4%) were women. The average time elapsed from hospital discharge was 76.8 ± 20.3 days (range 25−109 days). On admission, 137 (83%) patients reported at least 1 persistent symptom. Of these, more than one-third reported 1 or 2 symptoms and 46.3% had 3 or more symptoms. The rate of symptom persistence was not significantly different when patients were stratified according to median age. Compared with those with no persistent symptoms, patients with symptom persistence reported a greater number of symptoms during acute COVID-19 (5.3 ± 3.0 vs 3.3 ± 2.0; P < .001). The most common persistent symptoms were fatigue (53.1%), dyspnea (51.5%), joint pain (22.2%), and cough (16.7%). The likelihood of symptom persistence was higher in those who had experienced fatigue during acute COVID-19.

Conclusions and Implications

Persistent symptoms are frequently experienced by older adults who have been hospitalized for COVID-19. Follow-up programs should be implemented to monitor and care for long-term COVID-19–related health issues.

COVID-19 and RA share an SPP1 myeloid pathway that drives PD-L1+ neutrophils and CD14+ monocytes

We explored the potential link between chronic inflammatory arthritis and COVID-19 pathogenic and resolving macrophage pathways and their role in COVID-19 pathogenesis. We found that bronchoalveolar lavage fluid (BALF) macrophage clusters FCN1+ and FCN1+SPP1+ predominant in severe COVID-19 were transcriptionally related to synovial tissue macrophage (STM) clusters CD48hiS100A12+ and CD48+SPP1+ that drive rheumatoid arthritis (RA) synovitis. BALF macrophage cluster FABP4+ predominant in healthy lung was transcriptionally related to STM cluster TREM2+ that governs resolution of synovitis in RA remission. Plasma concentrations of SPP1 and S100A12 (key products of macrophage clusters shared with active RA) were high in severe COVID-19 and predicted the need for Intensive Care Unit transfer, and they remained high in the post-COVID-19 stage. High plasma levels of SPP1 were unique to severe COVID-19 when compared with other causes of severe pneumonia, and IHC localized SPP1+ macrophages in the alveoli of COVID-19 lung. Investigation into SPP1 mechanisms of action revealed that it drives proinflammatory activation of CD14+ monocytes and development of PD-L1+ neutrophils, both hallmarks of severe COVID-19. In summary, COVID-19 pneumonitis appears driven by similar pathogenic myeloid cell pathways as those in RA, and their mediators such as SPP1 might be an upstream activator of the aberrant innate response in severe COVID-19 and predictive of disease trajectory including post-COVID-19 pathology.

Retention rate of a second line with a biologic DMARD after failure of a first-line therapy with abatacept, tocilizumab, or rituximab: results from the Italian GISEA registry

OBJECTIVES

EULAR recommendations do not suggest which biologic disease-modifying anti-rheumatic drug (bDMARD) should be preferred after failure of a first bDMARD in the treatment of rheumatoid arthritis (RA). In particular, few data are available regarding the effectiveness of a second-line bDMARD after failure of abatacept (ABA), tocilizumab (TCZ), and rituximab (RTX). The aim of this study was to analyze the retention rate of a second line with tumor necrosis factor inhibitors (TNFi) or other mechanisms of action (MoAs), after the failure of either RTX, TCZ, or ABA.

METHODS

Two hundred and seventy-eight RA patients from the Italian GISEA registry were included in the study. RTX was the first bDMARD in 18% of patients, ABA in 45.7%, and TCZ in 36.3%, while the second bDMARD was a TNFi (group 1) in 129 patients and an agent with a different MoA (group 2) in 149.

RESULTS

During a median follow-up of 22 months (IQR 68), 129 patients discontinued their treatment; patients of group 1 discontinued the treatment more frequently than patients of group 2 (p<0.001) with retention rates of 33.6±5.7% and 63.6±4.6% after 104 weeks for group 1 and group 2, respectively (p<0.001). At multivariate analysis, the mechanism of action was the only predictor for the maintenance in therapy.

CONCLUSIONS

According to our data, ABA, RTX, and TCZ seem to maintain a good retention rate also when used as a second-line therapy, suggesting their use after the failure of a non-TNFi as first-line therapy. However, specifically designed studies are needed to evaluate the more appropriate therapeutic strategies in RA, according to the first-line drug, including new targeted synthetic DMARDs. Key Points • A large proportion of rheumatoid arthritis patients fail the first biologic DMARD. • Few data are available about the efficacy of biologic DMARD after the failure of a non-TNF inhibitor. • Abatacept, rituximab, or tocilizumab seem to maintain a good retention rate after the failure of a first-course therapy with a non-TNF inhibitor.

Inclusion of Synovial Tissue-Derived Characteristics in a Nomogram for the Prediction of Treatment Response in Treatment-Naive Rheumatoid Arthritis Patients

Objective

This study applied a synovitis score obtained during routine care from ultrasound (US)–guided biopsies of synovial tissue (ST) in patients with rheumatoid arthritis (RA) and patients with other inflammatory and noninflammatory joint diseases to identify pretreatment synovial biomarkers associated with disease characteristics, and to integrate the findings into a multiparameter nomogram for use in baseline prediction of diagnosis and treatment response in treatment‐naive rheumatoid arthritis (RA) patients.

Methods

The study enrolled a total of 1,015 patients with various autoimmune diseases (545 patients with RA, 167 patients with psoriatic arthritis [PsA], 199 patients with undifferentiated peripheral inflammatory arthritis [UPIA], 18 patients with crystal‐induced arthritis, 26 patients with connective tissue diseases, and 60 patients with osteoarthritis [OA] [as part of the SYNGem cohort]). All patients underwent a US‐guided ST biopsy at baseline, and patients were then stratified according to disease phase. The KSS, along with disease characteristics and clinical outcomes, were incorporated into a nomogram for prediction of achievement of clinical remission in RA patients who were previously naive to treatment. In patients in whom a treat‐to‐target strategy was applied, remission was defined as change in the Disease Activity Score in 28 joints (DAS28) at 6 months after treatment initiation.

Results

The KSS significantly differed among RA patients, as well as PsA patients and UPIA patients, when compared to OA patients. In RA, the KSS directly correlated with the DAS28 and was related to autoantibody positivity in treatment‐naive RA patients. Moreover, at baseline, treatment‐naive RA patients achieving 6‐month remission according to DAS28 had a lower KSS, shorter duration of symptoms (very early RA [VERA]), and lower disease activity than treatment‐naive RA patients not achieving remission according to DAS28. Results of logistic regression analysis identified the following synergistic predictive factors of achievement of DAS28‐based disease remission at 6 months: having a short disease duration (VERA), not having high disease activity, and having a KSS of <5 at baseline. A nomogram integrating these baseline clinical and histologic characteristics in treatment‐naive RA patients yielded an up to 81.7% probability of achieving 6‐month remission according to the DAS28.

Conclusion

The KSS is a reliable tool for synovitis assessment on US‐guided ST biopsy, contingent on the phase of the disease and the autoimmune profile of each patient. This tool could be integrated within a therapeutic response–predictive nomogram for the prediction of treatment response in RA patients who were previously naive to treatment.

Systemic Bone Density at Disease Onset Is Associated With Joint Erosion Progression in Early Naive to Treatment Rheumatoid Arthritis: A Prospective 12-Month Follow-Up Open-Label Study

Objectives: Osteoporosis and bone erosions are hallmarks of rheumatoid arthritis (RA) since disease onset is underpinned by the inflammatory burden. In this observational study, we aimed to dissect the putative RA-related parameters and bone-derived biomarkers associated with systemic and focal bone loss at disease onset and with their progression.

Methods: One-hundred twenty-eight patients with early rheumatoid arthritis (ERA) were recruited at disease onset. At study entry, demographic, clinical, and immunological parameters were recorded. Each ERA patient underwent plain X-rays of the hands and feet at study entry and after 12 months to assess the presence of erosions. After enrollment, each patient was treated according to the recommendations for RA management and followed up based on a treat-to-target (T2T) strategy. At baseline, blood samples for soluble biomarkers were collected from each patient, and plasma levels of osteoprotegerin (OPG), receptor activator of nuclear factor κB ligand (RANKL), Dickkopf-1 (DKK1), and interleukin 6 (IL-6) were assessed by enzyme-linked immunosorbent assay (ELISA). Seventy-one ERA patients underwent bone mineral density (BMD) measurement at the left femoral neck and second to fourth lumbar spine vertebrae (L2–L4) by dual-energy X-ray absorptiometry (DXA).

Results: Among the whole cohort, 34 (26.6%) ERA patients with bone erosions at study entry had a higher disease activity (p = 0.02) and IL-6 plasma levels (p = 0.03) than non-erosive ones. Moreover, at DXA, 33 (46.5%) ERA patients had osteopenia, and 16 (22.5%) had osteoporosis; patients with baseline bone erosions were more likely osteopenic/osteoporotic than non-erosive ones (p = 0.03), regardless of OPG, RANKL, and DKK1 plasma levels. Obese ERA patients were less likely osteopenic/osteoporotic than normal weight ones (p = 0.002), whereas anti-citrullinated protein antibodies (ACPA) positive ERA patients were more likely osteopenic/osteoporotic than ACPA negative ones (p = 0.034). At logistic regression analysis, baseline Disease Activity Score measured on 44 joints (DAS44) [OR: 2.46 (1.11–5.44)] and osteopenic/osteoporosis status [OR: 7.13 (1.27–39.94)] arose as independent factors of erosiveness. Baseline osteopenic/osteoporotic status and ACPA positivity were associated with bone damage progression during the follow-up.

Conclusions: Bone erosions presence is associated with systemic bone loss since the earliest phases of RA, suggesting that the inflammatory burden and autoimmune biology, underpinning RA, represent crucial enhancers of bone remodeling either locally as at systemic level.

Rituximab Followed by Belimumab Controls Severe Lupus Nephritis and Bullous Pemphigoid in Systemic Lupus Erythematosus Refractory to Several Combination Therapies

Systemic lupus erythematosus (SLE) and bullous pemphigoid (BP) are chronic autoimmune diseases in which B cells play an important pathogenic role in the different stages of the disease. B cell-targeted therapies have been suggested as a new rational approach for treating SLE. Rituximab (RTX), an anti-CD20 chimeric monoclonal antibody, failed to achieve primary endpoints in two clinical trials (EXPLORER and LUNAR) despite multiple observational and retrospective studies showing its beneficial effect on SLE. Moreover, RTX is recommended in cases of BP that is unresponsive to conventional treatments. Belimumab (BLM), a human immunoglobulin G1 λ monoclonal antibody that inhibits soluble B-lymphocyte stimulator (BlyS)/B-cell activating factor (BAFF), is the only biological treatment approved for standard therapy of refractory autoantibody-positive active SLE. Animal models and a few case reports have supported the efficacy of the combined use of RTX followed by BLM as maintenance therapy in severe lupus nephritis (LN), suggesting that their combined use may be more effective than their single use, without compromising safety. In this study, we describe the clinical case of a SLE patient with predominant renal involvement in overlap with BP, refractory to conventional therapy including RTX alone, achieving significant steroid sparing and clinical remission under sequential treatment of RTX-BLM. Moreover, we describe the first case of BP successfully treated with BLM. This case report may encourage further clinical research studies in B lymphocyte targeted combination therapy in patients affected by SLE with major organ involvement or with refractory disease, suggesting that RTX and BLM sequential therapy may be a valid option for the treatment of SLE manifestations, including conventional therapy and RTX-resistant LN.

Sarilumab use in severe SARS-CoV-2 pneumonia

BACKGROUND

Interleukin-6 signal blockade showed preliminary beneficial effects in treating inflammatory response against SARS-CoV-2 leading to severe respiratory distress. Herein we describe the outcomes of off-label intravenous use of Sarilumab in severe SARS-CoV-2-related pneumonia.

METHODS

53 patients with SARS-CoV-2 severe pneumonia received intravenous Sarilumab; pulmonary function improvement or Intensive Care Unit (ICU) admission rate in medical wards, live discharge rate in ICU treated patients and safety profile were recorded. Sarilumab 400 mg was administered intravenously on day 1, with eventual additional infusion based on clinical judgement, and patients were followed for at least 14 days, unless previously discharged or dead.

FINDINGS

Of the 53 SARS-CoV-2pos patients receiving Sarilumab, 39(73·6%) were treated in medical wards [66·7% with a single infusion; median PaO2/FiO2:146(IQR:120-212)] while 14(26·4%) in ICU [92·6% with a second infusion; median PaO2/FiO2: 112(IQR:100-141.5)].Within the medical wards, 7(17·9%) required ICU admission, 4 of whom were re-admitted to the ward within 5-8 days. At 19 days median follow-up, 89·7% of medical inpatients significantly improved (46·1% after 24 h, 61·5% after 3 days), 70·6% were discharged from the hospital and 85·7% no longer needed oxygen therapy. Within patients receiving Sarilumab in ICU, 64·2% were discharged from ICU to the ward and 35·8% were still alive at the last follow-up. Overall mortality rate was 5·7%.

INTERPRETATION

IL-6R inhibition appears to be a potential treatment strategy for severe SARS-CoV-2 pneumonia and intravenous Sarilumab seems a promising treatment approach showing, in the short term, an important clinical outcome and good safety.

Nailfold capillaroscopy findings in patients with coronavirus disease 2019: Broadening the spectrum of COVID-19 microvascular involvement

Objective

Increasing evidence points to endothelial dysfunction as a key pathophysiological factor in coronavirus disease-2019 (COVID-19). No specific methods have been identified to predict, detect and quantify the microvascular alterations during COVID-19. Our aim was to assess microvasculature through nailfold videocapillaroscopy (NVC) in COVID-19 patients.

Methods

We performed NVC in patients with a confirmed diagnosis of COVID-19 pneumonia. Elementary alterations were reported for each finger according to a semi-quantitative score. Capillary density, number of enlarged and giant capillaries, number of micro-hemorrhages and micro-thrombosis (NEMO score) were registered.

Results

We enrolled 82 patients (mean age 58.8 ± 13.2 years, male 68.3%) of whom 28 during the hospitalization and 54 after recovery and hospital discharge. At NVC examination we found abnormalities classifiable as non-specific pattern in 53 patients (64.6%). Common abnormalities were pericapillary edema (80.5%), enlarged capillaries (61.0%), sludge flow (53.7%), meandering capillaries and reduced capillary density (50.0%). No pictures suggestive of scleroderma pattern have been observed. Acute COVID-19 patients, compared to recovered patients, showed a higher prevalence of hemosiderin deposits as a result of micro-hemorrhages (P = .027) and micro-thrombosis (P < .016), sludge flow (P = .001), and pericapillary edema (P < .001), while recovered patients showed a higher prevalence of enlarged capillaries (P < .001), loss of capillaries (P = .002), meandering capillaries (P < .001), and empty dermal papillae (P = .006).

Conclusion

COVID-19 patients present microvascular abnormalities at NVC. Currently ill and recovered subjects are characterized by a different distribution of elementary capillaroscopic alterations, resembling acute and post-acute microvascular damage. Further studies are needed to assess the clinical relevance of NVC in COVID-19.

•

We assessed and accurately described peripheral microvasculature in COVID-19 patients through nailfold videocapillaroscopy.

•

Capillary alterations at the nailfold bed suggest a broad COVID-related microvascular involvement.

•

Different alterations in acutely-ill and recovered patients resemble a transition from acute to post-acute injury.

Factors Predicting Early Failure of Etanercept in Rheumatoid Arthritis: An Analysis From the Gruppo Italiano di Studio sulla Early Arthritis (Italian Group for the Study of Early Arthritis) Registry

Objectives

This study aims to investigate the factors associated with early discontinuation (within one year) of etanercept (ETA) in rheumatoid arthritis (RA) patients who began ETA as first biologic disease-modifying antirheumatic drug (bDMARD) and who were entered into the Gruppo Italiano di Studio sulla Early Arthritis (Italian Group for the Study of Early Arthritis; GISEA) registry.

Patients and methods

This registry-based cohort study included 477 RA patients (95 males, 382 females; median age 53 years; range 18 to 83 years) who began ETA as first bDMARD. Patient demographics, disease features and drugs were re-evaluated after 12 months. Baseline predictors of ETA discontinuation were estimated by univariate and multivariate analyses using Cox regression model.

Results

Seventy patients (14.7%) discontinued ETA during the first year (for inefficacy in 55.8%, adverse events in 28.6%, and other reasons in 6.5%). Concurrent conventional synthetic DMARDs (csDMARDs) were reported in 54.3% of patients, mainly methotrexate (MTX), while 52.4% of subjects took low doses of glucocorticoids. Patients stopping ETA more frequently showed one or more comorbidities, mainly cardiovascular diseases (28.6% vs. 15.7% in patients stopping and continuing ETA, respectively, p=0.009). The presence of comorbidities and a combination therapy with csDMARDs other than MTX were independent factors associated with early discontinuation of ETA at multivariate Cox analysis.

Conclusion

Although ETA demonstrated a high persistence in biologic-naïve RA patients, about 15% of patients discontinued the treatment within 12 months. The presence of comorbidities and a combination therapy with csDMARDs other than MTX were the main factors for an early withdrawal of the drug.

Distinct synovial tissue macrophage subsets regulate inflammation and remission in rheumatoid arthritis

Immune-regulatory mechanisms of drug-free remission in rheumatoid arthritis (RA) are unknown. We hypothesized that synovial tissue macrophages (STM), which persist in remission, contribute to joint homeostasis. We used single-cell transcriptomics to profile 32,000 STMs and identified phenotypic changes in patients with early/active RA, treatment-refractory/active RA and RA in sustained remission. Each clinical state was characterized by different frequencies of nine discrete phenotypic clusters within four distinct STM subpopulations with diverse homeostatic, regulatory and inflammatory functions. This cellular atlas, combined with deep-phenotypic, spatial and functional analyses of synovial biopsy fluorescent activated cell sorted STMs, revealed two STM subpopulations (MerTKposTREM2high and MerTKposLYVE1pos) with unique remission transcriptomic signatures enriched in negative regulators of inflammation. These STMs were potent producers of inflammation-resolving lipid mediators and induced the repair response of synovial fibroblasts in vitro. A low proportion of MerTKpos STMs in remission was associated with increased risk of disease flare after treatment cessation. Therapeutic modulation of MerTKpos STM subpopulations could therefore be a potential treatment strategy for RA.

AB0102 SPECIALIZED PRO-RESOLVING MEDIATOR RECEPTORS AS INFLAMMATORY RESOLUTION BIOMARKERS IN RHEUMATOID ARTHRITIS

Background:

The regulation of inflammation is a dynamic process involving several molecules as lipid mediators. The Specialized Pro-resolving Mediators (SPMs), such as Resolvin (RvD and RvE), Protectins, Maresins and Lipoxin A4 (LXA4), are bioactive metabolites of omega-3 and omega-6 fatty acids which drive inflammatory resolution phase and promote tissue repair. ERV, ALX/FPR2 and BLT1 are SPM receptors. Although in Rheumatoid Arthritis (RA) lipid mediators role within pathophysiology is under definition, studies on SPMs receptors role are still lacking in this disease.

Objectives:

Purpose of this study is to define ERV, ALX/FPR2 and BLT1 expression in blood derived leukocytes and synovial cells and to correlate it to disease activity to define SPM receptors ad inflammatory resolution biomarkers in RA patients.

Methods:

A cohort of 52 RA patients was enrolled in the study of which 40 with active disease (DAS28= 5,35 (5,18-6,40)) and 12 in sustained remission status (DAS28= 2,1 (1,83-2,42)). Each enrolled patient underwent peripheral blood (PB) drawing and 46 of them underwent US-guided synovial tissue (ST) biopsy. FACS gating strategy was used for PB and ST processing to evaluate percentage of positive cells and the mean fluorescence intensity (MFI) of ERV+, ALX/FPR2+and BLT1+in CD45+CD3+, CD45+CD19+for PB and ST, CD45+CD14+and neutrophils for PB only and CD45-CD90+, CD45+CD64+CD11b+macrophages (distinct in CD206+and CD206-subpopulations) for ST only. Each included ST was stained with haematoxylin/eosin and categorized by a pathologist, blinded to clinical characteristics, using the Krenn Score (KS) to assess ST inflammation degree. As control group, 11 undifferentiated peripheral inflammatory arthritis (UPIA) patients were enrolled in the study.

Results:

Considering the whole RA cohort, DAS28 inversely correlated with BLT1+positive cells on ST-derived CD45+(r= -0.48; p= 0.048), CD3+(r= -0.56; p= 0.019) and CD19+(r= -0.49; p= 0.042) cells, in contrast with CD90+(r= 0.50; p= 0.041) cells. Similarly, both DAS28 and KS inversely correlated with ALX/FPR2+positive cells in ST-derived CD45+(r= -0.42, p= 0.050 and r= -0,41, p= 0,046 respectively) cells. Evaluating the MFI levels of the SPM receptors along all RA stages (naïve-to-treatment, resistant-to-treatment, sustained remission) compared with UPIA control group, interestingly ST-derived CD45+cells of remission RA were depleted of ERV1 compared to naïve-to-treatment RA (p=0.04), despite comparable ST inflammation. Furthermore, highest ERV1 expression was found in ST-derived CD45+CD3+and CD45+CD19+cells in naïve-to-treatment RA compared with UPIA patients (p= 0,045 and p= 0,012 respectively). Moreover, the lowest BLT1 level was found in remission RA CD3+cells compared with UPIA and naïve-to-treatment RA patients (p= 0,008 and p= 0,023 respectively).

Conclusion:

SPM receptors expression seem to be tightly related to disease activity in the synovial tissue, suggesting an important involvement in the inflammatory process in RA patient.

References:

[1]Serhan CN. Nature, 2014.

[2]Alivernini S, et al. Arthritis Res Ther 2016

[3]Krenn V et al. Histopathology, 2006.

Disclosure of Interests:

Simone Perniola: None declared, Stefano Alivernini: None declared, Barbara Tolusso: None declared, Maria Rita Gigante: None declared, Marco Gessi: None declared, Clara Di Mario: None declared, Luca Petricca: None declared, Annunziata Capacci: None declared, Anna Laura Fedele: None declared, Gianfranco Ferraccioli: None declared, Elisa Gremese Speakers bureau: Abbvie, BMS, Celgene, Jannsen, Lilly, MSD, Novartis, Pfizer, Sandoz, UCB

FRI0574 RENAL TISSUE EPIGENETIC BIOMARKERS’ CHARACTERIZATION IN PATIENTS WITH LUPUS NEPHRITIS AS PARAMETERS OF DISEASE ACTIVITY, REMISSION AND FLARE

Background:

Epigenetic factors such as non-coding RNA (miRNA) have been shown to be deregulated in Systemic Lupus Erythematosus (SLE). In particular, in mouse model (1), different miRNAs have been associated with lupus nephritis (LN), one of the most severe manifestations of the disease.

Objectives:

The aim of the study was to evaluate the expression of miR-155 and miR-34a in renal tissue as biomarkers of organ involvement and inflammatory tissue activity in patients with LN.

Methods:

Thirty-two LN patients with active renal involvement were enrolled (age: 32.2 ± 9.2 years). The nephritic onset of the disease (early-SLE) was present in 13 patients (41%), while 19 patients (59%) showed a renal involvement during the follow-up (long-SLE). Clinical, laboratory and demographic data were collected for each patient. Disease activity was recorded using SLEDAI-2K and renal activity, using the total SLEDAI-2K fraction including the items related to the renal involvement. Ultrasound-guided renal biopsy has been performed for each patients for the definition of the nephritic class according to the ISN / RPS classification of 2003 revised in 2018(2). The expression of miR-155 and miR-34a in renal tissue was carried out by extraction of total RNA from paraffin-preserved biopsies and after a retrotrascription protocol was evaluated using SYBR® Green-based real-time PCR by relative quantification considering the ΔCt (Ct miRNA- Ct housekeeping gene)(3).

Results:

Mir-155 and miR-34a expression in renal tissue were comparable in the different histological classes. Dividing patients on the base of nephritic onset, patients with early SLE showed lower expression of miR-155 (ΔCt 12.8 ± 10.8) and miR-34a (ΔCt 14.6 ± 9.9) than patients with long-SLE (miR-155: ΔCt 6.1 ± 8.7 p = 0.02; miR-34a: ΔCt 7.1 ± 9.0 p = 0.03). Furthermore, a direct correlation was observed between the expression of miR-155 and miR-34a (r = 0.91, p <0.001). Considering patients with early-SLE, the expression of miR-34a was slightly significant in patients who had relapsed (ΔCt 8.2 ± 11.4 vs ΔCt 18.4 ± 7.9 p = 0.08), although no correlation emerged between the expression of miR-155 and miR-34a both at the time of the biopsy and with the disease activity indices. At the histological evaluation, miR-155 and miR-34a were more expressed in Early-SLE patients who had wire loop lesions (miR-155: ΔCt 19.5 ± 7.7 vs ΔCt 7.3 ± 9.6 p = 0.05; miR-34a: ΔCt 21,7 ± 1.1 vs ΔCt 8,8 ± 9.7 p= 0.05) possibly associated with a greater activation of the inflammatory component.

Conclusion:

MiR-155 and miR-34a may represent tissue biomarkers of inflammatory activation in patients with LN in particular the higher expression of these miRNA in Long-SLE patients could indicate a possible role of these biomarkers in renal involvement in patients with SLE with later renal onset. The increased expression of miR-34a could give indications of a disease recurrence suggesting a closer monitoring of the patient.

References:

[1] Leiss H et al. Plosone 2017

[2] Bajema IM et al Kidney Int. 2018

[3] Alivernini S et al. Nat Commun 2018

Disclosure of Interests:

None declared

THU0193 CLINICO-DEMOGRAPHIC, IMMUNOLOGIC AND SYNOVIAL HISTOLOGIC FEATURES INFLUENCING RESPONSE TO JAK-INHIBITORS IN RHEUMATOID ARTHRITIS: A MONOCENTRIC COHORT

Background:

Janus kinase Inhibitors (JAKis) are approved for the treatment of Rheumatoid Arthritis (RA) in over 40 countries. The updated EULAR recommendations for RA treatment revised the preference of bDMARDs over tsDMARDs based on the new data related to JAKis long-term efficacy and safety. [1].

Objectives:

To evaluate the efficacy and safety of JAKis molecules in an observational single center cohort of RA patients in a real life outpatient clinical setting.

Methods:

76 RA patients [mean age: 55.7±12.5 years, 64(84.2%) female, disease duration: 120.7±97.2 months, 43 (61.4%) seropositive (AB+) for ACPA and/or IgM-RF, 34(44.7%) with BMI ≥25.0 kg/m2] were followed after starting JAKis treatment monotherapy or in combination with conventional synthetic DMARDs (csDMARDs). At study entry, and every 3 months, the ACR/EULAR core data set variables were recorded for each patient. Clinical improvement and remission rate were evaluated according to Disease Activity Score (DAS) and Clinical Disease Activity Index (CDAI) and any therapy-related adverse effect was reported. Among the whole RA cohort, 20 patients underwent US-guided synovial tissue (ST) biopsy before JAKis treatment and classified using the Krenn score for the semiquantitative assessment of ST inflammation[2].

Results:

Among the whole RA cohort who started JAKis [mean follow-up (FU) duration: 6.1±3.7 months], 22(28.9%) showed DAS-defined high disease activity. 54(71.1%) patients were previously treated with at least 1 csDMARD and 33(43.4%) were naive to biologic DMARDs (bDMARDs). Among RA previously exposed to b-DMARDs, 23(30.3%) were using anti-TNF and 14(18.4%) anti-IL6R, whereas 6(7.9%) patients received other bDMARD. In particular, 11(14.5%) patients were previously treated only with one bDMARD.

During the FU, 12(15.8%) patients discontinued JAKis [7 due to treatment failure and 5 to adverse events (1 anemia, 2 gastrointestinal intolerance, 2 H.Zoster infection)]. All RA who discontinued JAKis for incomplete or no-response were previously exposed to bDMARDs.

DAS Remission was achieved in 29 of 65(44.6%) patients during the FU, of whom 21(32.5%) achieved remission at 3 months. Similarly, 16(24.6%) patients reached CDAI remission of whom 12(18.5%) patients achieved remission at 3 months.

At baseline, there were no differences of DAS-remission rate based on age, gender, disease duration, BMI and high disease activity. Similarly, concomitant steroid and csDMARDs therapy did not impact on the rate of DAS and CDAI Remission. However, RA reaching DAS remission during FU had more likely a shorter disease duration (p=0.01) and were less previously exposed to bDMARDs (p=0.001) than patients not achieving DAS remission. Conversely, the DAS Remission rate was higher in AB+ (55.3%) than in AB- RA patients (27.3%, p=0.04).

Furthermore, bDMARDs naive RA showed higher probability to reach remission compared to bDMARD previously exposed RA [DAS remission: 66.7% vs 28.9%, respectively, p=0.003; OR(95%): 4.90 (1.69-14.3) and CDAI-remission: 37.0% vs 15.8%, p=0.05; OR(95%CIs): 3.12(0.97-10.10)], regardless to the type of the previous bDMARDs used.Finally, considering the baseline ST features, RA achieving clinical improvement did not differ in terms of Krenn score and microanatomical organization compared to RA not achieving the clinical improvement.

Conclusion:

The efficacy rate of JAKis therapy is not influenced by BMI and baseline high disease activity. Previous exposure to bDMARDs impacts both on the clinical response and on the rate of JAKis therapy discontinuation. Therapy-related adverse effects mainly occurred in bDMARD previously exposed RA patients.

References:

[1]Smolen JS, et al. Ann Rheum Dis 2020

[2]Krenn V, et al. Histopathology 2006

Disclosure of Interests:

Dario Bruno: None declared, Maria Rita Gigante: None declared, Luca Petricca: None declared, Anna Laura Fedele: None declared, Simone Perniola: None declared, Marco Gessi: None declared, Barbara Tolusso: None declared, Stefano Alivernini: None declared, Elisa Gremese Speakers bureau: Abbvie, BMS, Celgene, Jannsen, Lilly, MSD, Novartis, Pfizer, Sandoz, UCB

CO0002 LOSS OF SELF-TOLERANCE IN SARS-COV-2 INFECTION: IMMUNOLOGICAL ASSESSMENT OF A CONVALESCENT COHORT

Background:

Some infectious agents may act as inducers of autoimmune conditions1. Despite SARS-CoV-2 infection can induce autoimmune phenomena in infected people2, individual risk factors or underlining mechanisms leading to loss of immunological tolerance are still unknown.

Objectives:

To assess the rate of development of autoantibodies in convalescent SARS-CoV-2 patients and their relation on infection clinical course and disease parameters.

Methods:

One-hundred and nine convalescent SARS-CoV-2 patients were studied and underwent multidisciplinary assessment in a Day Hospital clinical setting. For each patient, demographic, clinical and immunological data were collected and, at study entry, autoimmune profile [antinuclear antibodies (ANAs), antibodies reacting with extractable nuclear antigens (anti-ENA), antineutrophil cytoplasmic antibodies (ANCAs), Lupus anticoagulant (LA), anticardiolipin antibodies (aCL) IgM and IgG, anti-β2 glycoprotein I (anti-β2GPI) IgM and IgG] was assessed by Fluorescent immunoassay. Moreover, IL-6 plasma levels were assessed by ELISA (ELLA).

Results:

After a median time from hospitalization for SARS-CoV-2 infection of 53.3 ± 0.9 days, 55(50.5%) SARS-CoV-2 convalescent patients showed the positivity (ABpos) of at least one autoantibody. In particular, 31(28.4%) were positive for LA, 11(10.1%) for IgM-RF, 8(7.3%) for ANA and 6(5.5.%) for IgG-aCL whilst less than 2% showed other autoantibody positivities (IgM-aCL, IgG-anti-β2GPI, ENA, ACPA, c-ANCA, Scl70 and RNP). Analyzing the patient-related characteristics associated with the development of autoimmunity, convalescent male patients were more likely characterized by the development of antiphospholipid antibodies (aPL) (37.3%) than female (16.7%; p=0.02). Considering the disease-related characteristics, convalescent SARS-CoV-2 patients who experienced severe pneumonia (i.e., oxygen support need) during hospitalization, more likely received IL-6R-inhibitor administration (47.3%) and developed more than one autoantibody (87.5%) (aPL + another AB) than convalescent SARS-CoV-2 patients who did not need oxygen support [(12.5%; p=0.02) (OR95%IC: 9.5(1.4-109.1)] or IL-6R-inihibitor (1.9%; p<0.001). Finally, assessing cytokines plasma levels in convalescent SARS-CoV-2 patients stratified based on the development of autoantibodies we found that, despite a significant reduction of IL-6 plasma levels from hospitalization, convalescent SARS-CoV-2 patients who developed autoantibody positivity had higher IL-6 plasma levels (8.5 ± 2.5 pg/ml) than convalescent SARS-CoV-2 ABnegpatients (5.6 ± 1.5 pg/ml; p=0.07), mostly if considered autoantibodies other than aPL (15.4 ± 7.7 pg/ml)(p=0.01).

Conclusion:

Loss of self-tolerance is a common phenomenon in the medium-term follow-up of SARS-CoV-2 convalescent patients whose occurrence is dependent by a severe disease course and by an aberrant host inflammatory response. Long-term follow-up will reveal AB persistency and their clinical impact.

References:

[1]Barzilai O, et al. Current Opinion in Rheumatology 2007.

[2]Zhou Y, et al. Clin Transl Sci. 2020.

Disclosure of Interests:

None declared

THU0287 EVALUATION OF PREDICTIVE FACTORS OF WORSE PROGNOSIS IN LUPUS NEPHRITIS: FOCUS ON NEW PATHOGENETIC PATHWAYS

Background:

cytokine dysregulation plays an important role in the pathogenesis of Lupus Nephritis (LN) representing an attractive field of research aiming to find new pathways for new targeted therapies. IL-17, IL-23 axis seems to have a great influence in the development of LN.

Objectives:

to evaluate the strongest prognostic factors in a cohort of patient with LN focusing on of the impact of IL-17, IL 23 axis as new pathogenetic pathway on renal outcome.

Methods:

91 patients with active LN at disease onset or disease flare were enrolled. Laboratory, immunological and disease activity data were collected at the baseline and at 6(T6),12(T12),24(T24) months and at the last follow-up(FU). 84 renal biopsies were evaluated according to ISN/RPS classification, assessing the activity and chronicity indexes and the active interstitial infiltrate using the BANFF score system. Baseline serum levels of IL-17 and IL-23 were assessed by ELISA in 37 patients.

Results:

among the 84 renal biopsies evaluated 77% belonged to class III and IV according to ISN/RPS; 41,8% of patients had an active interstitial infiltrate<5%, 35.2% between 5% and 25% and 15,4% above 25%. Regarding immunological data 35,2% of patients revealed a seropositivity for antiphospholipid antibodies(APL+). The median serum level of IL-17 and IL-23 were 0.12±0.15 pg/ml and 27.7±9.12 pg/ml respectively. Using the ROC curves analysis we found a cut off value of 25.89 pg/ml for IL-23 for remission at T6. Among the 10 patients with a IL-23 level above this cut-off none achieved remission at T6 and the univariate analysis shows that a serum level of IL-23 above the defined cut-off was associated with an active interstitial infiltrate>5% at renal biopsy and with the development of persistent proteinuria. The analysis of IL-17 could not let us to find a cut off value for renal damage progression since a too much high number of patients had a null value. Nevertheless patients with more elevated serum levels of IL-17 at the baseline showed more elevated level of interstitial infiltrate at renal biopsy and a worse renal outcome overall. Finally we conducted an univariate and multivariate analysis for each renal outcome considered. We found that an inflammatory interstitial infiltrate>5% at renal biopsy and APL+ were associated with worse renal outcome in terms of early and persistent remission, chronic damage, persistent proteinuria, and renal flare both in univariate and multivariate analysis. Higher serum level of IL-23 was associated with persistent proteinuria, renal flare and tended to be associated to chronic renal damage and persistent renal activity.

Conclusion:

interstitial inflammatory infiltrate and APL+ represent in our study the strongest predictors of worse renal outcome. An higher serum level of IL-23 was found to be a negative prognostic factor pointed out the possibility to consider the IL-17-IL 23 axis as a biomarkers of a more aggressive renal disease.

Disclosure of Interests:

None declared

SAT0224 ANTIPHOSPHOLIPID ANTIBODIES AND VASCULAR RENAL LESIONS AS PROGNOSTIC FACTORS IN LUPUS NEPHRITIS

Background:

Several studies have showed that antiphospholipid antibodies (aPL) positivity represents a predictor of worse renal outcome in patients with Lupus Nephritis (LN). In addition, an association between aPL positivity and the histological data of vascular lesions on the renal biopsies has been reported.

Objectives:

To determine the prognostic role of aPL and vascular renal lesions in the assessment of clinical outcome during the follow up period, in terms of time to achieve remission, number of renal flares and development of chronic renal damage in patients affected by LN.

Methods:

Among 120 patients affected by LN from our Rheumatology Unit, 91 patients (age 43.8 ± 12 years, 74 (81.3%) female, disease duration 7.1 ± 7.9 years) have been evaluated and the follow-up data have been collected at the baseline and at 6, 12, 24 months and at the last follow-up visit. Histopathological data of 41 patients were evaluated according to the 2016 revision of ISN/RPS classification.

Results:

Among the 91 LN patients, 31 (34.1%) were aPL positive (aPL+), 10 (32.2%) of them were affected by Antiphospholipid Antibodies Syndrome (APS), 53.3% showed a single aPL positivity, 23.1% double aPL positivity and 15.4% triple aPL positivity. At the last follow up visit a significant higher number of aPL+ patients showed a persistent complement consumption than aPL negative (aPL-) patients (p=0.001). Evaluating clinical outcome, we observed that aPL- patients showed a remission achievement time slightly earlier than aPL+ patients (13.6 ± 1.0 months vs 16.5 ± 1.5 months; log-rank test: p=0.06, Breslow test: p=0.08) and as expected, patients with a persistent complement consumption achieve remission later (18.2 ± 1.5 months vs 13.0 ± 1 months; log-rank test: p=0.002, Breslow test: p=0.003). Furthermore at the last follow up, a significant higher percentage of aPL+ patients developed persistent proteinuria (p=0.02) and chronic renal failure (p=0.04). Considering histologic features (activity and chronicity index, glomerulonephritis class, presence of mesangiolysis, glomerular wrinkling, glomerular thrombi, interstitial inflammatory infiltrates, interstitial fibrosis and tubular atrophy,tubulitis and vascular lesions) we didn’t observe significant differences between aPL+ and aPL- patients but we found two typical vascular lesions (mesangiolysis and vascular thrombi) only in aPL + patients.

Conclusion:

aPL positivity is a predictor of worse renal outcome but in our cohort of LN patients we didn’t find an association between aPL positivity and vascular renal lesions at renal biopsy. The worse renal outcome and the late time to achieve remission in aPL+ group can be related to a cumulative vascular damage over time as observed in other organ and systems.

Disclosure of Interests:

None declared

SAT0027 DEVELOPMENT AND VALIDATION OF A NOMOGRAM COMBINING CLINICAL AND HISTOPATHOLOGICAL SYNOVIAL FEATURES FOR PREDICTING EARLY TREATMENT RESPONSE IN NAIVE TO TREATMENT RHEUMATOID ARTHRITIS

Background:

Rheumatoid Arthritis (RA) is characterized by synovial tissue (ST) heterogeneity at disease onset in terms of inflammatory degree and microanatomical organization being related to treatment response.

Objectives:

To develop a multiparametric tool for baseline treatment response prediction including disease characteristics and histopathologic features of ST biopsies, using a large single center (SYNGem Unit) naive to treatment RA cohort.

Methods:

240 naive to treatment RA who underwent US-guided ST biopsy, at the first clinical evaluation, were enrolled. Clinical and immunological characteristics were recorded for each patient. All ST FFPE specimens were stained with H&E and classified by a pathologist, blinded to clinical characteristics, using the Krenn score [1] to assess the degree of ST inflammation. All naive to treatment RA were treated according to the T2T scheme and DAS remission rate at 6-12 months was recorded. On the basis of the regression analysis, a nomogram was constructed that incorporated the significant factors predicting the “achievement of DAS-Remission at 6 months follow-up” in naive RA. The performance of the nomogram was assessed by discrimination and calibration.

Results:

Univariate analysis showed that RA who achieved early (6 months) DAS-remission had, at baseline, significantly lower total Krenn score (p<0.001), shorter symptoms duration (p=0.005) and lower disease activity (p<0.001) than RA not achieving this clinical outcome. ROC curve analysis revealed that RA having, at baseline, a total Krenn score <4.5 [(AUC)95%C.I.: 0.67(0.60-0.74),p<0.001] achieved more likely DAS-remission at 6 months (53.1%) than RA with total Krenn score ≥4.5(28.9%,p<0.001). Interestingly, RA whose ST was biopsied within 3 months from joint symptoms beginning showed significantly lower ST inflammation as total Krenn score than RA whose ST was analyzed among 3-12 months (p=0.04) or after 12 months (p=0.002) since symptoms beginning. However, in terms of follicular structure presence, the microanatomical organization of the synovial inflammatory infiltrate did not differ comparing RA whose ST was biopsied within 3 months from joint symptoms beginning (44.4%) and RA whose ST was biopsied among 3-12 months (47.6%, p=0.74) or after 12 months (52.7%,p=0.33) since symptoms beginning.

Logistic regression analysis revealed that, at baseline, being VERA, not having HDA and having a total Krenn score <4.5 were synergistic factors of DAS-remission achievement at 6 months [OR:10.5(95%IC:2.28-48.01);p<0.05]. Based on the regression analysis, a nomogram integrating baseline clinical (disease activity and duration) and histological (total Krenn score) characteristics was developed in which the value of each of the variables was given a point score. A total score was calculated by adding each single point score and, by projecting the value of the “total points” score to the “probability” line up to 87.5%.

Conclusion:

Krenn score is a reliable tool for the semi-quantitative assessment of ST inflammation on US-guided ST biopsies being contingent to baseline disease characteristics and can be integrated within a nomogram to better predict the therapeutic response in naive to treatment RA.

References:

[1] Krenn V, et al. Histopathology 2006

Disclosure of Interests:

Stefano Alivernini: None declared, Barbara Tolusso: None declared, Marco Gessi: None declared, Maria Rita Gigante: None declared, Alice Mannocci: None declared, Luca Petricca: None declared, Simone Perniola: None declared, Clara Di Mario: None declared, Anna Laura Fedele: None declared, Laura Bui: None declared, Annunziata Capacci: None declared, Dario Bruno: None declared, Giuseppe La Torre: None declared, Francesco Federico: None declared, Gianfranco Ferraccioli: None declared, Elisa Gremese Speakers bureau: Abbvie, BMS, Celgene, Jannsen, Lilly, MSD, Novartis, Pfizer, Sandoz, UCB

O14 Semi-quantitative assessment of synovial inflammation on US guided synovial membrane biopsy is contingent to disease phase, autoimmune profile and treatment response in RA: a large single center experience

Background

Ultrasound (US)-guided minimally-invasive synovial tissue (ST) biopsy is a well-tolerated procedure for basic and translational studies on chronic inflammatory joint diseases as rheumatoid arthritis (RA), psoriatic arthritis (PsA) and spondyloarthritis (SpA). The aim of the study was to evaluate the utility of histopathologic criteria to differentiate US-guided ST biopsies in daily clinical care in relation to diagnosis, disease characteristics, US parameters and treatment response in a large single center ST biopsy unit.

Methods

1,064 patients [545 RA, 167 PsA, 75 SpA, 199 undifferentiated peripheral inflammatory arthritis (UPIA), 18 crystal arthritis, 26 connective tissue diseases and 34 osteoarthritis (OA) respectively] who underwent US-guided ST biopsy were enrolled. US parameters (Synovial Hyperthrophy and Power Doppler signal respectively) were recorded for each biopsied joint. RA, PsA and SpA patients were stratified based on disease activity phase (naive to DMARDs, DMARDs resistant and in sustained remission, respectively). Clinical, demographic and immunological characteristics were recorded for each patient. All ST FFPE specimens were routinely processed and stained with H&E and classified by a pathologist, blinded to clinical characteristics, using the Krenn score to assess the degree of ST inflammation. Moreover, the presence/absence of lymphocytes, plasmacells, granulocytes and oedema was assessed for each ST. All naive to treatment RA were treated according to the T2T scheme and followed for at least 12 months and DAS remission rate was recorded.

Results

In the cohort, the distribution of synovitis score was significantly different among patients with inflammatory chronic diseases (RA, PsA, SpA and UPIA respectively) compared to OA (ANOVA Test p &lt; 0.001). Moreover, Krenn score directly correlated with synovial hyperthrophy (R = 0.36; p &lt; 0.001) and Power Doppler signal (R = 0.40;p&lt;0.001) of the biopsied joint. Considering the RA cohort, naive RA showed a higher Krenn score compared to resistant RA (p &lt; 0.001) and RA in sustained clinical and US remission (p &lt; 0.001), directly correlating with DAS28 (R = 0.51; p &lt; 0.001). Moreover, ACPA and RF positivity was related to the Krenn score and to ST plasmacells presence at RA onset (p &lt; 0.05 and p &lt; 0.001, respectively) but not at the time of DMARDs-failure or sustained remission achievement (p &gt; 0.05 for both). Stratifying naive RA based on disease duration at ST biopsy, naive RA with symptoms duration &gt;1 year, showed higher Krenn score compared to those with symptoms duration &lt;3 months (p &lt; 0.001). Finally, logistic regression analysis revealed that Krenn score higher or equal to 4.5 at baseline is an independent factor of no DAS remission achievement within 12 months [OR(95%CI):0.37(0.20-0.67)p&lt;0.001] in naive RA.

Conclusion

Krenn score is a reliable tool for the semi-quantitative assessment of ST inflammation on US-guided ST biopsies being differentially distributed among various chronic inflammatory joint diseases and contingent to disease phase, autoimmune profile and therapeutic response in RA.

Disclosures

S. Alivernini None. B. Tolusso None. M. Gessi None. M. Gigante None. L. Petricca None. C. Di Mario None. S. Perniola None. A. Fedele None. G. Peluso None. L. Bui None. A. Capacci None. F. Federico None. G. Ferraccioli None. E. Gremese None.

Laboratory Monitoring of Biological Therapies in Rheumatology: The Role of Immunogenicity

Biological drugs, such as proteins and immunogens, are increasingly used to treat various diseases, including tumors and autoimmune diseases, and biological molecules have almost completely replaced synthetic drugs in rheumatology. Although biological treatments such as anti-tumor necrosis factor (TNF) drugs seem to be quite safe, they cause some undesirable effects, such as the onset of infections due to weakening of the immune system. Given the biological nature of these drugs, they might be recognized as extraneous; this would induce an immune reaction that neutralizes their effectiveness or lead to more serious consequences. Laboratories play a pivotal role in appropriate therapeutic management. The aim of this review was to underline the production of anti-drug antibodies during treatment with biological drugs and highlight the role of laboratories in ensuring appropriate use of these drugs.

Differential synovial tissue biomarkers among psoriatic arthritis and rheumatoid factor/anti-citrulline antibody-negative rheumatoid arthritis

Background

Differential diagnosis among psoriatic arthritis (PsA) and seronegative rheumatoid arthritis (Ab^neg RA) can be challenging particularly in the clinical setting of peripheral phenotype and autoantibodies seronegativity. The aim of the study was to identify synovial tissue (ST) biomarkers differentially expressed in PsA and Ab^neg RA and test their predictive value of therapeutic response.

Methods

Thirty-four PsA patients [12 DMARD naive and 22 non-responder to methotrexate (MTX-IR)] with peripheral joint involvement and 55 Ab^neg RA (27 DMARD naive and 28 MTX-IR) underwent US-guided ST biopsy and immunohistochemistry (IHC) for CD68⁺, CD3⁺, CD20⁺, CD21⁺, CD117⁺, and CD138⁺ cells. After study entry, each DMARD-naive patient started MTX therapy and was followed in an outpatient setting for at least 6 months to define the achievement of Minimal Disease Activity (PsA) and DAS remission (Ab^neg RA) status respectively. Each IR-MTX patient was treated according to EULAR recommendations.

Results

At study entry, IHC analysis revealed that PsA patients had comparable levels of lining and sublining CD68⁺ and sublining CD21⁺, CD20⁺, and CD3⁺ cells than Ab^neg RA, despite the therapeutic regimen. Moreover, regardless of the therapeutic scheme, PsA patients showed higher IHC score of CD117⁺ cells (p = 0.0004 and p = 0.0005 for naive and MTX-IR patients respectively) compared to Ab^neg RA patients. Conversely, Ab^neg RA patients showed higher IHC score of CD138⁺ cells, irrespective to the therapeutic scheme (p = 0.04 and p = 0.002 for naive and MTX-IR patients respectively). Analyzing the response rate to the therapeutic scheme, naive PsA patients reaching MDA status at 6 months follow-up, showed, at the study entry, lower IHC score of CD3⁺ cells compared to PsA patients not reaching this outcome (p = 0.02); conversely, naive Ab^neg RA patients reaching DAS remission status at 6 months follow-up, showed, at the study entry, lower IHC score of sublining CD68⁺ cells compared to Ab^neg RA patients not reaching this outcome (p < 0.001).

Conclusions

CD117⁺ and CD138⁺ cells are differentially distributed among PsA and Ab^neg RA. Histological analysis of ST may help to solve the clinical overlap between the two diseases and provides prognostic data about the therapy success.

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1898-7) contains supplementary material, which is available to authorized users.

Anti-Müllerian hormone serum levels in systemic lupus erythematosus patients: Influence of the disease severity and therapy on the ovarian reserve

PURPOSE

Systemic lupus erythematosus (SLE) mainly affects childbearing age women and pharmacological treatments may negatively influence the ovarian reserve. Anti-Müllerian hormone (AMH) could be a good biomarker for ovarian reserve.

METHODS

AMH serum levels were assessed in 86 consecutive SLE female patients with regular menstrual cycle compared with 44 aged matched healthy controls. Clinical and demographic characteristics, disease duration, pattern of organ involvement, and previous and current therapies were recorded.

RESULTS

AMH levels were comparable between patients and controls (4.2 ± 3.1 ng/ml vs. 5.0 ± 3.1 ng/ml, p = 0.21). According to disease severity, AMH levels were lower in SLE patients with major organ involvement than in controls (3.8 ± 2.7 ng/ml vs. 5.0 ± 3.1 ng/ml, p = 0.08); no difference was found between SLE patients with mild organ involvement (4.5 ± 3.4 ng/ml) and controls (p = 0.43). Grouping patients based on the pharmacological treatments, AMH serum levels did not differ among SLE patients treated with antimalarials only (4.7 ± 3.3 ng/ml), conventional disease-modifying antirheumatic drugs (cDMARDs) only (4.8 ± 3.2 ng/ml), cDMARDs and antimalarials (3.9 ± 2.9 ng/ml) or cyclophosphamide (CYC) only (4.9 ± 3.9 ng/ml), compared to controls, but patients sequentially treated with cDMARDs and CYC, had significantly lower AMH serum levels than controls (p = 0.01).

CONCLUSIONS

SLE patients showed comparable AMH levels than controls, however, a reduction of the ovarian reserve was associated with sequentially therapy with CYC and cDMARDs and with the disease severity. AMH could be a sensitive and specific biomarker of ovarian reserve in SLE and it could be useful for therapeutic strategy and family planning.

Correction to: Anti-Müllerian hormone serum levels in systemic lupus erythematosus patients: influence of the disease severity and therapy on the ovarian reserve

The original version of this article unfortunately contained a mistake in given and family names of all the authors.

Anti-LL37 Antibodies Are Present in Psoriatic Arthritis (PsA) Patients: New Biomarkers in PsA

Psoriatic arthritis (PsA) is a chronic inflammatory arthritis associated with psoriasis. A third of psoriatic patients develop PsA via unknown mechanisms. No reliable diagnostic markers are available for PsA, or prognostic biomarkers for PsA development in psoriasis. We previously uncovered a pro-inflammatory role for cathelicidin LL37 in lesional psoriasis skin. LL37 binds nucleic acids and stimulates plasmacytoid/myeloid dendritic cells (pDC, mDCs) to secrete type I interferon (IFN-I) and pro-inflammatory factors. LL37 becomes an autoantigen for psoriatic Th1-Th17/CD8 T cells. Anti-LL37 antibodies were detected in systemic lupus erythematosus, an autoimmune disease characterized by neutrophil-extracellular-traps release (NETosis) in target organs. LL37 can be substrate of irreversible post-translational modifications, citrullination or carbamylation, linked to neutrophil activity. Here we analyzed inflammatory factors, included LL37, in PsA and psoriasis plasma and PsA synovial fluids (SF)/biopsies. We show that LL37 (as a product of infiltrating neutrophils) and autoantibodies to LL37 are elevated in PsA, but not OA SF. Anti-LL37 antibodies correlate with clinical inflammatory markers. Anti-carbamylated/citrullinated-LL37 antibodies are present in PsA SF/plasma and, at lower extent, in psoriasis plasma, but not in controls. Plasma anti-carbamylated-LL37 antibodies correlate with PsA (DAS44) but not psoriasis (PASI) disease activity. Ectopic lymphoid structures, and deposition of immunoglobulin-(Ig)G-complexes (IC) co-localizing with infiltrating neutrophils, are observed in PsA and not OA synovial tissues (ST). Activated complement (C5a, C9), GM-CSF and IFN-I are up-regulated in PsA and not OA synovia and in PsA and psoriasis plasma but not in HD. C9 and GM-CSF levels in PsA SF correlate with clinical inflammatory markers and DAS44 (C9) and with anti-carbamylated/citrullinated-LL37 antibodies (GM-CSF and IFN-I). Thus, we uncover a role for LL37 as a novel PsA autoantibody target and correlation studies suggest participation of anti-LL37 antibodies to PsA pathogenesis. Notably, plasma antibodies to carbamylated-LL37, which correlate with DAS44, suggest their use as new disease activity markers. GM-CSF and complement C5a and C9 elevation may be responsible for autoantigens release by neutrophils and their modification, fueling inflammation and autoreactivity establishment. Finally, targeting GM-CSF, C5a, C9 can be beneficial in PsA.

Chemerin and PEDF Are Metaflammation-Related Biomarkers of Disease Activity and Obesity in Rheumatoid Arthritis

Objective: Obesity is a risk factor for Rheumatoid Arthritis (RA) being associated to low grade inflammation. This study aimed to determine whether PEDF and Chemerin are biomarkers of inflammation related to fat accumulation in RA and to investigate whether weight loss associates with clinical disease improvement through the modification of fat-related biomarkers in overweight/obese RA with low-moderate disease.

Participants and Methods: Two-hundred and thirty RA patients were enrolled, of whom 176 at disease onset treated according to a treat-to-target strategy (T2T) and 54 overweight/obese RA in stable therapy and low-moderate disease activity. Gene expression of adipokines, interleukin-6 and their receptors were examined in adipose tissue from obese RA. Obese RA with low-moderate disease activity underwent low-calories diet aiming to Body Mass Index (BMI) reduction >5%, maintaining RA therapy unchanged. Chemerin, PEDF and Interleukin-6 plasma values were assessed by ELISA and disease activity was evaluated.

Results: At RA onset, PEDF and Chemerin plasma values correlated with BMI (p < 0.001) but only Chemerin plasma values correlated with disease activity (p < 0.001). After adopting a T2T strategy, Chemerin arose as an independent factor associated with remission in early RA [OR(95%CIs):0.49(0.25–0.97)]. Moreover, after low-calories diet, RA with low-moderate disease activity reaching BMI reduction ≥5% (62.6%) at 6 months had significant decrease of PEDF (p < 0.05) and Chemerin (p < 0.05) plasma values, in parallel with the improvement in disease activity.

Conclusions: PEDF and Chemerin arose as biomarkers of obesity and metaflammation respectively, providing a link between chronic inflammation and excess of body weight in RA. Therefore, BMI reduction of at least 5% in obese RA allowed better disease control without modifying RA treatment.

Synovial Predictors of Differentiation to Definite Arthritis in Patients With Seronegative Undifferentiated Peripheral Inflammatory Arthritis: microRNA Signature, Histological, and Ultrasound Features

Objectives: To examine synovial tissue (ST) predictors of clinical differentiation in patients with seronegative undifferentiated peripheral inflammatory arthritis (UPIA).

Methods: Fourty-two patients with IgA/IgM-Rheumatoid Factor and anti-citrullinated peptide antibodies negative UPIA, naive to Disease-Modifying Anti-Rheumatic Drugs, underwent Gray Scale (GSUS) and power Doppler (PDUS) evaluation and Ultrasound (US) guided ST biopsy. CD68, CD3, CD21, CD20, and CD31 synovial expression was evaluated by immunohistochemistry. Whole ST microRNA expression was assessed using miScript miRNA PCR Array. Peripheral blood (PB) and synovial fluid (SF) IL-6, VEGF-A, and VEGF-D levels were measured by ELISA and ST TNF expression was assessed by RT-PCR. Each patient was prospectively monitored and classified at baseline and within 1 year as UPIA, Rheumatoid Arthritis (RA), Spondyloarthritis (SpA) or Psoriatic Arthritis (PsA), respectively.

Results: At baseline, CD68⁺ cells were the most common cells within the lining layer (p < 0.001) in seronegative UPIA, directly correlating with GSUS (R = 0.36; p = 0.02) and PDUS (R = 0.55; p < 0.001). Synovial CD31⁺ vessels count directly correlated with GSUS (R = 0.41; p = 0.01) and PDUS (R = 0.52; p < 0.001). During the follow-up, 6 (14.3%) UPIA reached a definite diagnosis (2 RA, 2 SpA and 2 PsA, respectively). At baseline, UPIA who differentiated had higher GSUS (p = 0.01), PDUS scores (p = 0.02) and higher histological scores for CD68⁺ (p = 0.005 and p = 0.04 for lining and sublining respectively), sublining CD3⁺ cells (p = 0.002), CD31⁺ vessels count (p < 0.001) and higher IL-6 PB levels (p = 0.01) than patients who remained as UPIA. MiRNA PCR Array showed that among the 86 tested miRNA species, at baseline, miR-346 and miR-214 were significantly down-regulated (p = 0.02 for both) in ST of UPIA who differentiated than in patients who remained as UPIA, inversely correlating with the lining CD68⁺ cells IHC score (R = −0.641; p = 0.048) and CD31⁺ vessels count (R = −0.665; p = 0.036) and with higher baseline ST expression of TNF (p = 0.014). Finally, logistic regression analysis demonstrated that baseline GSUS and PDUS scores ≥1.5 [OR:22.93 (95%CI:0.98–534.30)] and CD31⁺ vessels count ≥24.3 [OR:23.66 (95%CI:1.50–373.02)] were independent factors associated with the development of definite arthritis.

Conclusions: MiRNA signature, histological and US features of ST may help in the identification of seronegative UPIA with high likelihood of clinical differentiation toward definite seronegative arthritis.

Paradoxical arthritis occurring during anti-TNF in patients with inflammatory bowel disease: histological and immunological features of a complex synovitis

OBJECTIVE

Paradoxical arthritis under tumour necrosis factor inhibitor (TNF-i) for inflammatory bowel disease (IBD) has been described. This study aims to evaluate the histological features of paired synovial tissue (ST) and colonic mucosa (CM) tissue in patients with IBD developing paradoxical arthritis under TNF-i.

METHODS

Patients with IBD without history of coexisting joint involvement who developed arthritis under TNF-i were enrolled. Each patient underwent ST biopsy and ileocolonoscopy with CM biopsies. ST and CM paired samples were stained through immunohistochemistry (IHC) for CD68, CD21, CD20, CD3 and CD117. Clinical and immunological parameters (anticitrullinated peptides antibodies (ACPA)-immunoglobulin (Ig)M/IgA rheumatoid factor (RF)) were collected. Psoriatic arthritis (PsA) and ACPA/IgM-RF/IgA-RF negative rheumatoid arthritis (RA) were enrolled as comparison.

RESULTS

10 patients with IBD (age 46.0±9.7 years, 13.2±9.9 years of disease duration, 2.5±1.6 years of TNF-i exposure, six with Crohn's disease and four with ulcerative colitis, respectively) were studied. At ST level, IHC revealed that patients with IBD with paradoxical arthritis showed more similar histological findings in terms of synovial CD68+, CD21+, CD20+, CD3+ and CD117+ cells compared with PsA than ACPA/IgM-RF/IgA-RF negative RA. Analysing the CM specimens, patients with IBD showed the presence of CD68+, CD3+, CD117+ and CD20+ cells in 100%, 70%, 60% and 50% of cases, respectively, despite endoscopic remission. Finally, addition of conventional disease-modifying antirheumatic drugs and switch to ustekinumab were more effective than swapping into different TNF-i in patients with IBD with paradoxical arthritis.

CONCLUSION

Patients with IBD may develop histologically proven synovitis during TNF-i, comparable to PsA. The inhibition of inflammatory pathways alternative to TNF (IL12/1L23) may be an effective therapeutic option for severe paradoxical articular manifestations.

Interleukin-6 and IgA-rheumatoid factor are crucial for baseline erosiveness, and anti-citrullinated peptide antibodies for radiographic progression in early rheumatoid arthritis treated according to a treat-to-target strategy

OBJECTIVES

To define baseline clinical and immunological characteristics [anti-citrullinated peptide antibodies (ACPAs), immunoglobulin M (IgM)- and IgA-rheumatoid factor (RF), and interleukin-6 (IL-6) levels] involved in determining baseline erosiveness, outcome, and radiographic progression among seropositive and seronegative early rheumatoid arthritis (ERA) patients.

METHOD

The 408 ERA patients enrolled in the study were monitored every 3 months according to the treat-to-target strategy. At baseline and after 12 months, hand and foot radiographs were evaluated using the Sharp/van der Heijde erosion score.

RESULTS

At diagnosis, seronegative patients were older and had higher Disease Activity Scores (DASs) than seropositive patients. A higher risk of erosiveness at baseline was conferred by IgA-RF positivity and IL-6 plasma levels ≥7.6 pg/mL, particularly when simultaneously present. In multivariate analysis, disease duration and IL-6 plasma levels ≥7.6 pg/mL arose as independent variables associated with presence of erosions at onset. Radiographic progression at 1 year follow-up, which occurred in 11.1% of ERA patients, was predicted by ACPA positivity, together with higher age at diagnosis. Despite similar percentages of good European League Against Rheumatism response, DAS and Boolean remission being observed over time among seropositive and seronegative patients and between erosive and non-erosive subjects, ERA patients who were erosive at onset, IgA-RF seropositive, and simultaneously having high baseline IL-6 plasma levels (≥7.6 pg/mL) were treated to a greater extent with tumour necrosis factor blockers after 12 months.

CONCLUSION

IgA-RF positivity and IL-6 plasma levels are crucial for baseline erosiveness, while ACPA positivity represents the strongest risk factor for developing radiographic progression in ERA.

MicroRNA-34a dependent regulation of AXL controls the activation of dendritic cells in inflammatory arthritis

Current treatments for rheumatoid arthritis (RA) do not reverse underlying aberrant immune function. A genetic predisposition to RA, such as HLA-DR4 positivity, indicates that dendritic cells (DC) are of crucial importance to pathogenesis by activating auto-reactive lymphocytes. Here we show that microRNA-34a provides homoeostatic control of CD1c⁺ DC activation via regulation of tyrosine kinase receptor AXL, an important inhibitory DC auto-regulator. This pathway is aberrant in CD1c⁺ DCs from patients with RA, with upregulation of miR-34a and lower levels of AXL compared to DC from healthy donors. Production of pro-inflammatory cytokines is reduced by ex vivo gene-silencing of miR-34a. miR-34a-deficient mice are resistant to collagen-induced arthritis and interaction of DCs and T cells from these mice are reduced and do not support the development of Th17 cells in vivo. Our findings therefore show that miR-34a is an epigenetic regulator of DC function that may contribute to RA.

Synovial features of patients with rheumatoid arthritis and psoriatic arthritis in clinical and ultrasound remission differ under anti-TNF therapy: a clue to interpret different chances of relapse after clinical remission?

Objective

To define the synovial characteristics of patients with rheumatoid arthritis (RA) and psoriatic arthritis (PsA) in clinical and ultrasound remission achieved by combination therapy with methotrexate (MTX) and tumour necrosis factor (TNF) blockers.

Methods

Patients with RA in remission (n=25) (disease activity score (DAS)<1.6 for at least 6 months), patients with RA in low disease activity (LDA) (n=10) (1.6<DAS<2.4 for at least 6 months) and patients with PsA in remission (n=18) (DAS<1.6 and Psoriasis Area Severity Index (PASI)=0 for at least 6 months) achieved by MTX+anti-TNF (adalimumab 40 mg or etanercept 50 mg) with power Doppler (PDUS)-negative synovial hypertrophy underwent synovial tissue biopsy. Patients with RA with high/moderate disease naïve to treatment (n=50) were included as a comparison group. Immunostaining for cluster designation (CD)68, CD21, CD20, CD3, CD31 and collagen was performed.

Results

PDUS-negative patients with RA in remission showed lower histological scores for synovial CD68⁺, CD20⁺, CD3⁺ cells and CD31⁺ vessels and collagen deposition (p<0.05 for both lining and sublining) compared with PDUS-positive patients with RA with high/moderate disease. In addition, there was no significant difference in terms of lining and sublining CD68⁺, CD20⁺, CD3⁺, CD31⁺ cells and collagen comparing PDUS-negative patients with RA in remission and in LDA, respectively. On the contrary, PDUS-negative patients with PsA in remission showed higher histological scores for sublining CD68⁺ (p=0.02) and CD3⁺ cells (p=0.04) as well as CD31⁺ vessels (p<0.001) than PDUS-negative patients with RA in remission.

Conclusions

PDUS-negative patients with RA in remission have comparable synovial histological features than PDUS-negative patients with RA in LDA. However, patients with PsA in remission are characterised by a higher degree of residual synovial inflammation than patients with RA in remission, despite PDUS negativity under TNF inhibition.

MicroRNA-155 influences B-cell function through PU.1 in rheumatoid arthritis

MicroRNA-155 (miR-155) is an important regulator of B cells in mice. B cells have a critical role in the pathogenesis of rheumatoid arthritis (RA). Here we show that miR-155 is highly expressed in peripheral blood B cells from RA patients compared with healthy individuals, particularly in the IgD^-CD27^- memory B-cell population in ACPA⁺ RA. MiR-155 is highly expressed in RA B cells from patients with synovial tissue containing ectopic germinal centres compared with diffuse synovial tissue. MiR-155 expression is associated reciprocally with lower expression of PU.1 at B-cell level in the synovial compartment. Stimulation of healthy donor B cells with CD40L, anti-IgM, IL-21, CpG, IFN-α, IL-6 or BAFF induces miR-155 and decreases PU.1 expression. Finally, inhibition of endogenous miR-155 in B cells of RA patients restores PU.1 and reduces production of antibodies. Our data suggest that miR-155 is an important regulator of B-cell activation in RA.

MiR-155 is thought to inhibit PU.1 and thereby drive antigen-induced B-cell maturation. Here the authors show that patients with rheumatoid arthritis have high B-cell miR-155 expression and that an antagomir can rescue PU.1 expression, suggesting potential therapeutic avenues to treat rheumatoid arthritis.