Exploring the Link between Plasma Levels of PCSK9, Immune Dysregulation and Atherosclerosis in Patients with Primary Sjögren's Syndrome

Proprotein convertase subtilisin/kexin type 9 (PCSK9) regulates lipid metabolism contributing to cardiovascular (CV) risk in the general population. The relationship between PCSK9 and CV risk in systemic autoimmune diseases has been poorly explored. We investigated the association between plasma PCSK9, measures of immune-inflammatory status and markers of atherosclerosis in 52 consecutive patients with primary Sjögren's syndrome (pSS) in comparison to healthy controls (HCs). Median plasma PCSK9 levels were significantly higher in pSS patients versus HCs (162 (79-255) vs. 53 (39-99) ng/mL). Significantly higher prevalence of subclinical atherosclerosis and lower of dyslipidaemia (61% vs. 85%, p = 0.042) characterized pSS patients versus HCs. In pSS, no significant correlation emerged between PCSK9 and disease activity, atherosclerosis and lipid levels. In HCs, PCSK9 significantly correlated with lipid levels and atherosclerosis. Interestingly, significantly higher PCSK9 levels were found in HCs with high-to-very-high as compared to low-to-moderate CV risk (p = 0.018) while a non-significant trend towards higher PCSK9 levels was detected in pSS patients with low-to-moderate as compared to high-to-very-high CV risk (p = 0.060). This is the first demonstration that pSS patients, despite lower prevalence of dyslipidaemia and higher CV risk profile, are characterized by a 3-fold increase in PCSK9 levels in comparison to HCs. As PCSK9 does not correlate with measures of CV risk, its role in CV morbidity in pSS needs further investigation.

Emerging of a new CD3+CD31HCD184+ tang cell phenothype in Sjögren’s syndrome induced by microencapsulated human umbilical cord matrix-derived multipotent stromal cells

Background

Sjögren’s syndrome (SS) is an autoimmune disease hallmarked by infiltration and destruction of exocrine glands. Currently, there is no therapy that warrants full recovery of the affected tissues. Umbilical cord-derived multipotent stromal cells, microincapsulated in an endotoxin-free alginate gel (CpS-hUCMS), were shown to modulate the inflammatory activity of PBMCs in SS patients in vitro, through release of soluble factors (TGFβ1, IDO1, IL6, PGE2, VEGF). These observations led us to set up the present study, aimed at defining the in vitro effects of CpS-hUCMS on pro- and anti-inflammatory lymphocyte subsets involved in the pathogenesis of SS.

Methods and results

Peripheral blood mononuclear cells (PBMCs) upon collection from SS patients and matched healthy donors, were placed in co-culture with CpS-hUCMS for five days. Cellular proliferation and T- (Tang, Treg) and B- (Breg, CD19+) lymphocyte subsets were studied by flow cytometry, while Multiplex, Real-Time PCR, and Western Blotting techniques were employed for the analysis of transcriptome and secretome. IFNγ pre-treated hUCMS were assessed with a viability assay and Western Blotting analysis before co-culture. After five days co-culture, CpS-hUCMS induced multiple effects on PBMCs, with special regard to decrease of lymphocyte proliferation, increase of regulatory B cells and induction of an angiogenic T cell population with high expression of the surface marker CD31, that had never been described before in the literature.

Conclusion

We preliminarily showed that CpS-hUCMS can influence multiple pro- and anti-inflammatory pathways that are deranged in SS. In particular, Breg raised and a new Tang phenothype CD3+CD31HCD184+ emerged. These results may considerably expand our knowledge on multipotent stromal cell properties and may open new therapeutic avenues for the management of this disease, by designing ad hoc clinical studies.

Dietary Supplementation with Boswellia serrata, Verbascum thapsus, and Curcuma longa in Show Jumping Horses: Effects on Serum Proteome, Antioxidant Status, and Anti-Inflammatory Gene Expression

Intense exercise can cause inflammation and oxidative stress due to the production of reactive oxygen species. These pathophysiological processes are interdependent, and each one can induce the other, creating a vicious circle. A placebo-controlled blind study was carried out in show jumping horses (n. 16) to evaluate the effects of a commercial dietary supplement (Dolhorse® N.B.F. Lanes srl, Milan, Italy) containing Verbascum thapsus leaf powder (1.42%), Curcuma longa (14.280 mg/kg), and Boswellia serrata (Roxb ex Colebr) (14.280 mg/kg) extracts. Before and after 10 days of dietary supplementation, blood samples were collected to evaluate the protein levels, antioxidants, and inflammatory responses by proteomic analysis or real-time Reverse Transcriptase-Polymerase Chain Reaction (real-time RT-PCR). A total of 36 protein spots, connected to 29 proteins, were modulated by dietary supplementation, whereas real-time RT-PCR revealed a significant downregulation of proinflammatory cytokines (interleukin 1α (p < 0.05) and interleukin-6 (0.005), toll-like receptor 4 (p < 0.05), and IKBKB (p < 0.05) in supplemented sport horses. Immunoglobulin chains, gelsolin, plasminogen, vitamin D binding protein, apolipoprotein AIV, and filamin B were overexpressed, whereas haptoglobin, α-2-HS-glycoprotein, α2-macroglobulin, afamin, amine oxidase, 60S acidic ribosomal protein, and complement fragments 3, 4, and 7 were reduced. No effect was observed on the antioxidant defense systems. The present results suggest this phytotherapy may reinforce the innate immune responses, thus representing a valid adjuvant to alleviate inflammation, which is a pathophysiological process in sport horses.

Characterization and Biological Activities of In Vitro Digested Olive Pomace Polyphenols Evaluated on Ex Vivo Human Immune Blood Cells

Olive pomace (OP) represents one of the main by-products of olive oil production, which still contains high quantities of health-promoting bioactive compounds. In the present study, three batches of sun-dried OP were characterized for their profile in phenolic compounds (by HPLC-DAD) and in vitro antioxidant properties (ABTS, FRAP and DPPH assays) before (methanolic extracts) and after (aqueous extracts) their simulated in vitro digestion and dialysis. Phenolic profiles, and, accordingly, the antioxidant activities, showed significant differences among the three OP batches, and most compounds showed good bioaccessibility after simulated digestion. Based on these preliminary screenings, the best OP aqueous extract (OP-W) was further characterized for its peptide composition and subdivided into seven fractions (OP-F). The most promising OP-F (characterized for its metabolome) and OP-W samples were then assessed for their potential anti-inflammatory properties in ex vivo human peripheral mononuclear cells (PBMCs) triggered or not with lipopolysaccharide (LPS). The levels of 16 pro-and anti-inflammatory cytokines were measured in PBMC culture media by multiplex ELISA assay, whereas the gene expressions of interleukin-6 (IL-6), IL-10 and TNF-α were measured by real time RT-qPCR. Interestingly, OP-W and PO-F samples had a similar effect in reducing the expressions of IL-6 and TNF-α, but only OP-W was able to reduce the release of these inflammatory mediators, suggesting that the anti-inflammatory activity of OP-W is different from that of OP-F.

AB0743 Biomarkers in systemic sclerosis: a 23-plex cytokine/chemokine analysis

Background

Systemic Sclerosis (SSc) is a rare inflammatory disease of unknown etiology associated with multi-organ involvement. Biomarkers remain urgently needed as tools for differential diagnosis, prognosis, disease progression, and as therapeutic response predictors in SSc. Ideally, for widespread utility, biomarkers should be easy to sample and analyse.

Objectives

We aimed at evaluating potentially pathogenic circulating key cytokines/chemokines in a monocentric cohort of SSc patients.

Methods

Sera were drawn from SSc patients and 23 cytokines/chemokines (CCL2/MCP-1, IP-10/CXCL10, Flt3 Ligand, IFNa2, IL6, IL7, IL12, IL13, IL15, IL17A, TNFa, IL-1Ra, CXCL13, IL21, IL23, IL33, TSLP, IL-2RA, IL1RII, TNFRII, BAFF, CCL19/MIP-3B 66, MMP-8) were quantified using Luminex multiplex immunoassay (BioRad-BioPlex 200 System-Lumine x-Map technology R&D Systems, USA) following the manufacturer’s instructions and customized procedures. Data were acquired using Bioplex manager v 6.1. P value ≤ 0.05 was considered to be significant. Data were analyzed using GraphPad Prism V.8 (GraphPad Software, Inc.) software.

Results

Clinical and demographic features of 17 SSc (5 dcSSc, 12 lcSSc) patients are reported in Table 1. Mean±SD age was 55±14.68 years, mean±SD disease duration was 89.47±95.34 months. We found that MCP-1 levels inversely correlated with PAPs (r=-0.55, P=0.03) and IP10 with anti-Scl70 (r=-0.561, P=0.004), Figure 1. No other associations were found

Table 1.N%Sex2M/15F11.8/88.32Age (years, mean±SD)55±14.68Disease duration (months, mean±SD)89.47±95.34Cigarette smoke847Raynaud’s phenomenon17100Skin thickening1482.4Ulcers211.8Rodnan’s Skin Score (mean±SD)5.9±6.6Articular involvement211.8Heart involvement00Paps max (mmhg, mean±SD)28.3±5.9Pulmonary involvement529.4DLCO min (%, mean±SD)90.24±21.2Gastrointestinal involvement317.6ANA17100Rheumatoid factor423.5Anti-Scl70 (U/ml, mean±SD)33.2±59.3Anti-CENP(U/ml, mean±SD)55.9±48.9Anti-SSA211.8Anti-SSB15.9Anti-Sm15.9Anti-RNP15.9Elevated Blood Pressure423.5Obesity15.8Any DMARD529.4

Conclusion

We confirm a potential pathogenic role for MCP-1 in SSc. The -2518 promotor polymorphism in the MCP-1 gene has been already associated with disease susceptibility and an increased expression of the molecule both in peripheral blood and in the skin has been described. Intriguingly, MCP-1 seems to drive skin fibrosis while the role played in pulmonary involvement is more controversial. Indeed, similarly to our results, Scala et al. found an inverse correlation between pulmonary fibrosis and MCP-1 from T cell lines (1). At the same extent, the observation that IP-10 has an inverse correlation with anti-Scl70 levels is not novel and the usage of this chemokine as a marker of lcSSc has been already suggested. In this view, Zhu et al. found that Scl-70 negative patients have a higher expression of IP-10 than Scl-70 positive (1,878 (2,964) ng/L vs 1,030 (2,196.6) ng/L, P<0.05) (2). Finally, this is the first report on MMP8 in SSc and we suggest that MMP8 - a collagenase and marker of idiopathic pulmonary fibrosis involved in the migration of fibroblasts - can represent a promising biomarker for SSc diagnosis.

References

[1]Scala et al. Clin Exp Immunol 2004

[2]Beijing Da Xue Xue Bao Yi Xue Ban. 2019

Figure 1.

Disclosure of Interests

None declared

POS0788 DISTINCT CYTOKINE/CHEMOKINE PROFILE IN SJÖGREN’S SYNDROME IS ASSOCIATED WITH DISEASE ACTIVITY AND CLINICAL MANIFESTIONS

Background

Sjögren’s syndrome (SjS) is an autoimmune disease of unknown aetiology. Several cytokines, chemokines and collagenases have been implicated in the pathogenesis of the disease. Nonetheless, biomarkers of diagnosis, outcome and response to treatment are still lacking.

Objectives

We aimed at evaluating potentially pathogenic cytokines/chemokines in a monocentric cohort of SjS patients.

Methods

Sera were drawn from SjS patients classified according to 2016 ACR/EULAR criteria and 23 cytokines/chemokines (CCL2/MCP-1, IP-10/CXCL10, Flt3 Ligand, IFNa2, IL6, IL7, IL12, IL13, IL15, IL17A, TNFa, IL-1Ra, CXCL13, IL21, IL23, IL33, TSLP, IL-2RA, IL1RII, TNFRII, BAFF, CCL19/MIP-3B 66, MMP-8) were quantified using Luminex multiplex immunoassay (BioRad- BioPlex 200 System-Luminex-Map technology R&D Systems, USA) following the manufacturer’s instructions and customized procedures. Data were acquired using Bioplex manager v 6.1. P value ≤ 0.05 was considered significant. Data were analyzed using GraphPad Prism V.8 (GraphPad Software, Inc.) software.

Results

Clinical and demographic features of 21 SjS patients are reported in Table 1. Our main findings were that several cytokines positively correlated with indexes of disease activity. Particularly, we observed a correlation between IL-2RA and ESSDAI (r=0.602, P=0.005) and between IL-12p40 and ESSPRI (r=0.674, P=0.016) (Figure 1). Levels of IL-17A seem to be influenced by age (r=0.622, P=0.039) and showed a trend towards a positive correlation with labial salivary gland biopsy focus score (r=0.942, P=0.058). The only patient with cryoglobulins was the male who showed levels of BAFF/BLyS >20x higher than the remaining 20 females (43.4 ng/ml vs 1.8±1.6 ng/ml).

Table 1.N%Sex1M/20F4.8/95.2Age (years, mean±SD)53.43±12.27disease duration (months, mean±SD)30.29±10.47ESSDAI (mean±SD)2.20±2.40ESSPRI (mean±SD)4.18±2.12Global dryness VAS (0-10) (mean±SD)5.00±2.32VAS fatigue (0-10) mean±SD)4.00±2.39VAS pain (0-10) (mean± SD)3.48±3.28Dry mouth1571.40Dry eyes1781Parotid Gland Swelling419Articular involvement628 .6Skin Involvement14.7Raynaud’s Phenomenon523.8Other Organs314.3Lymphoma14.7Low Complement (C3 Or C4)314.3Low C3314.3Low C414.7Leukopenia733.3Hypergammaglobulinemia761.9Monoclonal Gammopathy210Ana1990.5Anti-SSA1990.5Anti-SSB1047.6Rheumatoid Factor942.9Cryoglobulins14.7Salivary Gland Biopsy Focus Score (Mean±SD)1.99±1.45Hydroxychloroquine523.8Immunosuppressant14.7Figure 1.

Conclusion

For the first time we suggest the potential usefulness of IL-2RA as a marker of disease activity in SjS. Notably, IL2RA has been used as a marker to identify CD4+FoxP3+ regulatory T cells. So far, it is known that T follicular helper (Tfh) cell differentiation is inhibited by IL-2 while regulatory T cell differentiation and survival depend on it. Nonetheless, Wing et al. (1) described a CD25- subpopulation within human PD1+CXCR5+Foxp3+ Tfh cells preferentially located in germinal centers which is reduced by the presence of IL-2, possibly explaining the association with disease activity. IL-12p40 is known to have a pathogenic role in SjS (2) and we suggest that it may represent a complementary tool in the evaluation of patients’ symptoms. The presence of high levels of IL-15 in SjS is not novel and associated with T cell migration and proliferation in germinal centers. Finally, the observation of very high BAFF/BLyS levels in the male with cryoglobulins will require further analysis.

References

[1]Wing et al. Proc Natl Acad Sci USA. 2017

[2]Mathsson L, et al. Clin Exp Immunol. 2007

Disclosure of Interests

None declared

Methotrexate improves endothelial function in early rheumatoid arthritis patients after 3 months of treatment

Background

Endothelial dysfunction contributes to increased cardiovascular (CV) disease in rheumatoid arthritis (RA). Angiogenic T cells (Tang) are a key regulator of vascular function via their interaction with endothelial progenitor cells (EPCs). Methotrexate (MTX) has been associated to reduced CV disease risk, but its effects on endothelial homeostasis have been poorly explored. We investigated MTX effects on endothelial homeostasis in early, treatment-naïve RA patients.

Methods

Fifteen untreated, early RA patients and matched healthy controls (HC) were enrolled. RA patients with long-standing disease in remission or low disease activity treated with MTX for at least 6 months were selected as controls. Circulating CD28⁺ and CD28^null Tang cell, endothelial microparticle (EMP), EPC and soluble vascular cell adhesion molecule (sVCAM)-1 levels were measured.

Results

Tang percentage was higher in early RA than in HCs and significantly increased after 3-month MTX treatment. Tang cells in RA were characterized by higher percentage of CD28^null and lower CD28-positive cells than HCs. MTX restored a Tang cell phenotype similar to HCs. Altered sVCAM-1, EMP and EPC were restored to levels similar to HCs after a 3-month MTX. Biomarker levels after 3 months of MTX were not different to those of patients with long-standing treatment.

Conclusions

MTX has a positive effect on Tang, sVCAM-1, EPCs and EMPs in RA. Restoration of imbalance between CD28 + and CD28^null Tang by MTX may be one of the mechanisms underlying its favourable effects on endothelial dysfunction. These effects seem to be long-lasting and independent from systemic inflammation reduction, suggesting a direct effect of MTX on the endothelium.

POS0755 PREVALENCE AND RELEVANCE OF ANTIBODIES AGAINST CITRULLINATED ALPHA ENOLASE (ANTI-CEP1) IN CONNECTIVE TISSUE DISEASES

Background:

Anti-citrullinated alpha enolase antibodies have been investigated in rheumatoid arthritis and associated with bone erosion and interstitial lung disease but little is known about their prevalence and role in connective tissue diseases (CTDs).

Objectives:

The aim of this study was to investigate the prevalence and relevance of anti-CEP1 antibodies in CTDs.

Methods:

Serum samples from five independent patient cohorts were assessed: 1) established (est) primary Sjogren’s syndrome (pSS) N=78, 2) est-systemic lupus erythematosus (SLE) N=52, 3) est-systemic sclerosis (SSc) N=71, 4) pSS at disease onset N=30, 5) SLE at disease onset N=46 (cohorts 4 and 5 had at least 3 years of follow-up). Samples from ninety sex and age matched healthy donors (HD) and 200 patients with est-RA (disease controls) were also tested. Anti-CEP1 IgG antibodies were measured with a commercially available ELISA kit (Euroimmun, Luebeck, Germany).

Results:

Anti-CEP1 titer was significantly higher in est-pSS, est-SLE and est-SSc compared to HD, significantly lower in est-pSS and est-SSc compared to est-RA and comparable in est-SLE versus est-RA. We divided patients in every CTD group based on whether their anti-CEP1 titer was below or above the 25th, 50th and 75th percentile. In est-SLE anti-CEP1 values over the 25th percentile were associated with articular involvement (odds ratio, OR (95% confidence interval, CI)=11.5; 1.9-70.6, p=0.008). In est-pSS, no relationship between anti-CEP1>25th percentile and articular involvement was found but rather an association with rheumatoid factor positivity (OR (95% CI)=4.8, 1.6-14.1, p=0.004) and salivary gland swelling (OR (95% CI)=6.2, 1.3-29.1, p=0.021). In est-SSc no difference could be detected across the 3 groups. Anti-CEP-1 titers in pSS and SLE at onset did not differ from each other, were comparable also to those of HD and significantly lower than those of est-pSS, est-SLE and est-RA patients (all p<0.0001).). Of interest, we could retrieve a serum sample collected at the time of diagnosis for 5 patients from the cohort of established pSS and we observed that anti-CEP1 titers were significantly lower at pSS onset than during follow up (at least 12 months after the diagnosis, p=0.0024). No difference was observed in the clinical presentation at disease onset according to different anti-CEP1 titer and they did not predict the development of new clinical manifestations during follow-up.

Conclusion:

Anti-CEP-1 antibodies can be detected in CTDs at different title during the disease course and may increase overtime, at least in pSS. Although anti-CEP1 antibodies are associated with specific clinical manifestation in est-CTDs, such as articular involvement in est-SLE, they seem to lack a predictive value for future manifestations when measured at disease onset.

References:

[1]Alunno A, Bistoni O, Pratesi F et al Rheumatology (Oxford) 2018.

[2]Manca ML, Alunno A, D’Amato C et al. Joint Bone Spine 2018.

Disclosure of Interests:

None declared

Frequency and clinical correlates of antiphospholipid antibodies arising in patients with SARS-CoV-2 infection: findings from a multicentre study on 122 cases

OBJECTIVES

COVID-19 features include disseminated intravascular coagulation and thrombotic microangiopathy indicating a hypercoagulable state. We aimed to investigate antiphospholipid antibodies (aPL) prevalence and clinical relationships in a large cohort of COVID-19 patients.

METHODS

We analysed the prevalence and titres of serum aPL in 122 patients with COVID-19 and 157 with primary antiphospholipid syndrome (PAPS) and 91 with other autoimmune rheumatic diseases (oARD) for comparison. IgG/IgM anticardiolipin (aCL) and IgG/IgM anti-beta2glycoprotein I (β2GPI) were assayed using homemade ELISA, IgA aCL and anti-β2GPI by commercial ELISA kits and lupus anticoagulant (LAC) by multiple coagulation tests following updated international guidelines.

RESULTS

Prevalence of IgG and IgM aCL and of IgG and IgM anti-β2GPI across COVID-19 patients were 13.4%, 2.7%, 6.3% and 7.1%, being significantly lower than in PAPS (p<0.0001 for all). Frequency of IgG aCL and IgM anti-β2GPI was comparable to oARD (13.4% vs. 13.2% and 7.1% vs. 11%, respectively), while IgG anti-β2GPI and IgM aCL were lower (p<0.01). IgA aCL and IgA anti-β2GPI were retrieved in 1.7% and 3.3% of COVID-19 patients, respectively. Positive LAC was observed in 22.2% COVID-19 vs. 54.1% of PAPS (p<0.0001) and 14.6% of oARD (p=0.21). Venous or arterial thromboses occurred in 18/46 (39.1%) COVID-19 patients and were not associated with positive aPL (p=0.09).

CONCLUSIONS

Thrombosis is a frequent manifestation during COVID-19 infection. However, prevalence and titres of aPL antibodies or LAC were neither consistently increased nor associated with thrombosis when measured at a single timepoint, therefore not representing a suitable screening tool in the acute stage of disease.

FRI0565 PREVALENCE AND SIGNIFICANCE OF ANTIBODIES AGAINST CITRULLINATED ALPHA-ENOLASE (ANTI-CEP1) IN CONNECTIVE TISSUE DISEASES

Background:

Anti-cyclic citrullinated peptide (anti-CCP) auto-antibodies represent the current gold standard for the diagnosis of rheumatoid arthritis (RA). However, growing evidence suggests that a variety of other citrullinated self-proteins may act as autoantigens and lead to the production of autoantibodies (1). Furthermore, autoantibodies believed to be RA-specific have been detected also in patients with connective tissue diseases (CTDs). We recently demonstrated that antibodies against citrullinated alpha-enolase (anti-CEP1) are a biomarker of erosive disease and RA-associated interstitial lung disease (2).

Objectives:

The purpose of this study was to investigate the prevalence and possible prognostic value of anti-CEP-1 in patients with CTDs.

Methods:

Two hundred and twelve consecutive patients with CTDs (51 systemic lupus erythematosus (SLE), 85 primary Sjogren’s syndrome (pSS) and 76 systemic sclerosis (SSc)) were studied and compared to 97 sex and age matched normal controls (NC) and 267 patients with RA. Anti-CEP1 IgG were detected in serum samples with a commercial ELISA kit (Euroimmun).

Results:

The overall prevalence of anti-CEP1 in CTDs was 7% (15/212 patients). In detail, these antibodies were detectable in 4 out of 85 pSS (5%), 5 out of 51 SLE (10%) and 6/76 SSc (8%). The prevalence and the titer of anti-CEP1 in CTDs was significantly higher compared to NC and significantly lower compared to RA. Anti-CEP1 positive patients did not display a specific clinical and serological picture. Unlike in RA, anti-CEP1 did not correlate with CTD-associated ILD.

Conclusion:

This is the first study assessing anti-CEP1 in a large cohort of patients with CTDs. We demonstrated that the association of these autoantibodies with ILD is specific for RA since it is not observed in SLE, pSS and SSc. Furthermore, although being significantly more prevalent and at higher titer compared to NC, anti-CEP1 do not allow to discriminate different patient subsets displaying peculiar clinical or serological phenotypes. Based on our results, the application of anti-CEP1 in CTDs is not advisable, however larger studies may possibly identify correlations not evident in our cohort.

References:

[1] Bonifacio AF, Alunno A, La Paglia GMC, Valentini E, Leone MC, Bartoloni E, Gerli R. Novel autoantibodies in rheumatoid arthritis. Reumatismo 2019;71(1):1-12

[2] Alunno A, Bistoni O, Pratesi F, La Paglia GMC, Puxeddu I, Migliorini P, Gerli R. Anti-citrullinated alpha enolase antibodies, interstitial lung disease and bone erosion in rheumatoid arthritis. Rheumatology (Oxford). 2018;57(5):850-855

Disclosure of Interests:

Alessia Alunno: None declared, Francesco Carubbi Speakers bureau: Francesco Carubbi received speaker honoraria from Abbvie and Celgene outside this work., Onelia Bistoni: None declared, Matteo Antonucci: None declared, Elena Bartoloni Bocci: None declared, Roberto Giacomelli Grant/research support from: Actelion, Pfizer, Speakers bureau: Abbvie, Roche, Actelion, BMS, MSD, Ely Lilly, SOBI, Pfizer, Roberto Gerli: None declared

A Platelet's Guide to Synovitis

Platelets have the ability to influence the immune system and the inflammatory process and may be strongly involved in the whole pathogenic process of chronic inflammatory joint diseases, such as rheumatoid arthritis. They may play a significant role even before the clinical onset of the disease, contributing to the loss of tolerance of the immune system and the induction of autoimmunity. Subsequently, they can interact with the most important cellular players involved in autoimmunity and inflammation, namely innate immunity cells and T cells and eventually contribute to the building of inflammation in the synovium, thus inducing the activation, migration, and proliferation of fibroblasts that eventually lead to joint damage. Due to their peculiar features, studying the behavior of platelets is a challenging task; however, platelets may prove to be valuable therapeutic targets in the future.

Angiogenic T cells in primary Sjögren's syndrome: a double-edged sword?

OBJECTIVES

The mechanisms underlying increased cardiovascular risk in primary Sjögren's syndrome (pSS) remain unclear. Since the recently discovered angiogenic T cells (Tang) may participate in endothelial repair by cooperating with endothelial progenitor cells (EPC), we aimed to quantify and characterise Tang in the peripheral blood and minor salivary glands (MSG) of pSS patients.

METHODS

Tang (CD3+CD31+CXCR4+) and EPC (CD34+CD133+VEGFR-2+) were quantified by flow cytometry in peripheral blood samples from 36 pSS patients and 20 healthy donors. Tang subsets were assessed on the basis of CD4, CD8 and CD28 expression. Labial MSG sections from 10 pSS patients and 12 non-pSS sicca syndrome controls were subjected to immunofluorescence staining to investigate the presence of Tang and the expression of the CXCR4-ligand stromal cell-derived factor-1 (SDF-1)/CXCL12.

RESULTS

Circulating Tang cells were expanded and directly correlated to EPC in pSS. Both Tang and EPC directly correlated with disease activity as calculated with the EULAR Sjögren's syndrome disease activity index (ESSDAI). In pSS, the majority of Tang cells were CD4-CD8- double negative (DN) and lacked CD28 revealing a senescent phenotype. A subset of CD4+, CD8+ and DN Tang cells produced interleukin-17. Immunohistology revealed the exclusive presence of periductal and perivascular infiltrating Tang cells along with increased SDF-1/CXCL12 expression in pSS MSG compared to non-pSS sicca syndrome controls.

CONCLUSIONS

In pSS, Tang cells are expanded in peripheral blood and infiltrate MSG. Tang may be novel actors in pSS-related endothelial dysfunction and glandular neo-angiogenesis and inflammation.

Celiac Disease Prevalence is Increased in Primary Sjögren's Syndrome and Diffuse Systemic Sclerosis: Lessons from a Large Multi-Center Study

Association of celiac disease (CD) with systemic autoimmune diseases (ADs) remains controversial. Awareness of CD in these patients is important to prevent complications, including lymphoproliferative disorders. We evaluated previously diagnosed CD prevalence in systemic lupus erythematosus (SLE), primary Sjögren’s syndrome (pSS) and systemic sclerosis (SSc) patients in comparison to 14,298 matched controls. All patients were screened for subclinical CD. Data from 1458 unselected consecutive SLE (580), pSS (354) and SSc (524) patients were collected. Previously biopsy-proven CD diagnosis and both CD- and AD-specific features were registered. All patients without previous CD were tested for IgA transglutaminase (TG). Anti-endomysium were tested in positive/borderline IgA TG. Duodenal biopsy was performed in IgA TG/endomysium+ to confirm CD. CD prevalence in AD was compared to that observed in 14,298 unselected sex- and age-matched adults who acted as controls. CD was more prevalent in pSS vs controls (6.78% vs 0.64%, p < 0.0001). A trend towards higher prevalence was observed in SLE (1.38%, p = 0.058) and SSc (1.34%, p = 0.096). Higher CD prevalence was observed in diffuse cutaneous SSc (4.5%, p ≤ 0.002 vs controls). Subclinical CD was found in two SLE patients and one pSS patient. CD diagnosis usually preceded that of AD. Primary SS and SSc–CD patients were younger at AD diagnosis in comparison to non-celiac patients. Autoimmune thyroiditis was associated with pSS and CD. CD prevalence is clearly increased in pSS and diffuse SSc in comparison to the general population. The association of CD with diffuse but not limited SSc may suggest different immunopathogenic mechanisms characterizing the two subsets. CD screening may be considered in pSS and diffuse SSc in young patients, particularly at the time of diagnosis.

Subclinical Atherosclerosis in Primary Sjögren's Syndrome: Does Inflammation Matter?

Sjögren's syndrome (SS) is a systemic autoimmune disease mainly characterized by inflammatory involvement of exocrine gland. Atherosclerosis is a complex process leading to plaque formation in arterial wall with subsequent cardiovascular (CV) events. Recently, numerous studies demonstrated that SS patients bear an increased CV risk. Since activation of immune system is a key element in atherosclerosis, it is interesting to analyze whether and how the autoimmune and inflammatory events characterizing SS pathogenesis directly or indirectly contribute to atherosclerosis risk in these patients. An increase in circulating endothelial microparticles and integrins, which may be a consequence of endothelial damage and impaired repair mechanisms, has been demonstrated in SS. Increased endothelial expression of adhesion molecules with subsequent infiltration of inflammatory cells into arterial wall is also a critical event in atherosclerosis. The early inflammatory events taking place in the atherosclerotic plaque cause an increase in alarmins, such as S100A8/A9, which seems to be associated with SS disease activity and, in turn, induce up-regulation of interleukin (IL)-1β and other pro-atherogenic cytokines. Interestingly, increased IL-1β levels were also detected in tertiary lymphoid structures developing in vessel adventitia adjacent to the atherosclerotic plaque, suggesting a direct role of IL-1β in this process. Similar to these structures, germinal center-like structures arising in SS exocrine glands are also tertiary lymphoid systems where T-helper (Th) cell subsets govern the adaptive immune response. Th1 cells are the most prevalent subtype and have been shown to be strongly involved in both SS pathogenesis and atherosclerosis. Th17 cells are attracting great interest and few studies showed its importance in SS development. Albeit in low amounts, a Th17 signature was also detected in atherosclerotic plaques and some animal models demonstrated a significant pro-atherogenic role and positive effects of IL-17A blockade. Despite the fact that T cells have a pivotal role in the inflammatory process that ultimately leads to atherosclerosis, B cells have also been detected in atherosclerotic plaques, although their exact role is still mostly unknown with studies showing contrasting results. In this scenario, the role of inflammation in atherosclerosis pathogenesis in patients with SS needs to be further explored.

Laboratory Assessment of Patients with Suspected Rheumatic Musculoskeletal Diseases: Challenges and Pitfalls

Current patient care in rheumatology relies primarily on a combination of traditional clinical assessment and standard laboratory tests. Investigators seek to discover new biomarkers and novel technologies to boost the research in this field. Mechanistic biomarkers such as cytokines, cell types, antibodies, signaling molecules, are rooted in the mechanism underlying the disease and can guide the clinical management of the disease. Conversely, descriptive biomarkers are byproducts of the disease process, depict the state of a disease but are not involved in its pathogenesis. In this article, we reviewed the field of common laboratory biomarkers in rheumatology, highlighting both their descriptive or mechanistic value as well as their role in clinical practice.

Maraviroc Intensification Modulates Atherosclerotic Progression in HIV-Suppressed Patients at High Cardiovascular Risk. A Randomized, Crossover Pilot Study

Background

Experimental CCR5 antagonism with maraviroc in atherosclerosis-prone mice and preliminary data in humans suggest an anti-atherosclerotic effect of the drug. We assessed the impact of maraviroc treatment in persons living with HIV on subclinical indicators of atherosclerosis.

Methods

Persons living with HIV on effective antiretroviral therapy (ART) including only protease inhibitors were recruited if they had a Framingham risk score >20% and brachial flow-mediated dilation (bFMD) <4%, as indices of high cardiovascular risk. Maraviroc (300 mg per os for 24 weeks) was administered, in addition to ongoing ART, to all patients using a crossover design. Brachial FMD, carotid-femoral pulse wave velocity (cfPWV), and carotid intima-media thickness (cIMT) were measured as markers of atherosclerosis. Vascular competence—as expressed by the ratio of circulating endothelial microparticles (EMPs) to endothelial progenitor cells (EPCs)—and markers of systemic inflammation and monocyte and platelet activation were assessed.

Results

Maraviroc treatment significantly improved bFMD, cfPWV, and cIMT by 66%, 11%, and 13%, respectively (P = .002, P = .022, P = .038, respectively). We also found a beneficial effect of maraviroc on the EMP/EPC ratio (P < .001) and platelet/leucocyte aggregates (P = .013). No significant changes in markers of systemic inflammation, monocyte activation, and microbial translocation were observed.

Conclusions

Maraviroc led to significant improvements in several markers for cardiovascular risk, endothelial dysfunction, arterial stiffness, and early carotid atherosclerosis, which was accompanied by an increase of vascular competence, without seeming to affect systemic inflammation. Our data support the need for larger studies to test for any effects of maraviroc on preventing atherosclerosis-driven pathologies.

Different operators and histologic techniques in the assessment of germinal center-like structures in primary Sjögren's syndrome minor salivary glands

Objective

A standardization of minor salivary gland (MSG) histopathology in primary Sjögren’s syndrome (pSS) has been recently proposed. Although there is strong agreement that germinal center (GC)-like structures should be routinely identified, due to their prognostic value, a consensus regarding the best protocol is still lacking. Aim of this study was to compare the performance of different histological techniques and operators to identify GC-like structures in pSS MSGs. MSG biopsies from 50 pSS patients were studied.

Methods

Three blinded operators (one pathologist and two rheumatologists with different years of experience in pSS MSG assessment) assessed 50 MSGs of which one slide was stained with haematoxylin and eosin (H&E) and consecutive slides were processed to investigate CD3/CD20, CD21 and Bcl-6 expression.

Results

By assessing 225 foci, the best agreement was between H&E-stained sections evaluated by the rheumatologist with more years of experience in pSS MSG assessment and CD3/CD20 segregation. In the foci with CD21 positivity, the agreement further increased. Bcl-6^- foci could display a GC, detected with other staining, but not vice versa.

Conclusion

GC assessment on H&E-stained sections should be performed with caution, being operator-dependent. The combination of H&E with CD3/CD20 and CD21 staining should be recommended as it is reliable, feasible, able to overcome the bias of operator experience and easily transferrable into routine practice.

Association between anti-citrullinated alpha enolase antibodies and clinical features in a cohort of patients with rheumatoid arthritis: a pilot study

In recent years several antibodies against citrullinated peptides (ACPAs) have been identified in patients with rheumatoid arthritis (RA) and their pathogenic, diagnostic and prognostic significance is under intense investigation. Among ACPAs, those targeting citrullinated alpha enolase (anti-CEP1) have been identified in RA but data about their ability to predict the development of erosive disease are conflicting. Furthermore, no data are currently available concerning their possible association with extra-articular manifestations (EAMs) in RA. The aim of this study was to investigate the prevalence and significance of anti-CEP1 from a prognostic point of view. In this pilot study we confirmed that anti-CEP1 Abs are associated with higher prevalence of bone erosions, but we also provided the first evidence of an association between anti-CEP1 Abs and RA interstitial lung disease (ILD). These results provide the basis to investigate the association between anti-CEP1 Abs and EAMs in larger cohorts of RA patients to possibly confirm its role as biomarker for RA-ILD.

Anti-citrullinated alpha enolase antibodies, interstitial lung disease and bone erosion in rheumatoid arthritis

Objectives

RA is an articular chronic inflammatory disease that in a subgroup of patients can also present with extra-articular manifestations (EAMs). Despite intense investigation on this topic, reliable biomarkers for EAMs are lacking. In recent years several ACPAs, including those targeting anti-citrullinated alpha enolase peptide-1 (anti-CEP-1), have been identified in patients with RA. Data about the ability of anti-CEP-1 to predict the development of erosive disease are confliciting and no evidence concerning their possible association with EAMs in RA is currently available. The aim of this study was to investigate the prevalence and significance of anti-CEP-1 with regard to the association with erosive disease and EAMs in a large cohort of patients with RA.

Methods

Anti-CCP and anti-CEP-1 antibodies have been assessed on serum samples of RA patients, healthy donors and patients with SpA using commercially available ELISA kits.

Results

Anti-CEP-1 antibodies are detectable in over 40% of RA patients and are associated with erosive RA and with RA-associated interstitial lung disease (ILD).

Conclusion

Anti-CEP-1 antibodies may represent a useful biomarker for RA-associated ILD and erosive disease to be employed in clinical practice.

Prevalence and significance of anti-saccharomyces cerevisiae antibodies in primary Sjögren's syndrome

OBJECTIVES

Saccharomyces cerevisiae is a common yeast used in the food industry. IgG and IgA antibodies against the phosphopeptidomannan of the S. cerevisiae cell wall (ASCA) are a well known marker of disease severity in Crohn's disease. Moreover, a number of studies assessed ASCA in several systemic and organ-specific autoimmune diseases postulating molecular mimicry as a possible link between ASCA and autoimmunity. However, since they have never been tested in primary Sjögren's syndrome (pSS), the purpose of this study was to investigate these antibodies in a large cohort of pSS patients, compared to healthy donors (HD), and their significance as potentially helpful biomarker in a clinical setting.

METHODS

ASCA IgG+IgA were assessed with ASCA screen dot for Blue Diver instrument (Alphadia sa/nv, Belgium). The comparison between the aminoacid sequence of mannan of S. cerevisiae and well characterised auto-antigens peculiar to pSS (52kD and 60kD Ro/SSA, La/SSB) was performed with the Basic Local Alignment Search Tool (BLAST).

RESULTS

The prevalence of ASCA in our pSS cohort was 4.8%. We also reported that the ASCA target protein has a high similarity with Ro60/SSA protein further supporting the molecular mimicry hypothesis. Finally, we observed that ASCA positivity is associated with pSS specific clinical and serological features. ASCA+ pSS patients displayed a triple combination of circulating anti-Ro52/SSA, anti-Ro60/SSA and anti-La/SSB antibodies, associated with low complement and cutaneous involvement.

CONCLUSIONS

Our data suggest a possible pathogenic/prognostic significance of ASCA in pSS.

Novel Therapeutic Strategies in Primary Sjögren's Syndrome

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disease mainly affecting exocrine glands. However, a subgroup of patients experiences extraglandular manifestations which worsens disease prognosis. To date evidence based guidelines for the management of pSS are lacking, hence the therapeutic approach is mainly based on expert opinion and data from other connective tissue diseases. In recent years, several studies have explored the efficacy and safety of biologic agents in pSS and after the failure of tumor necrosis factor inhibitors, the attention has been focused on compounds directly targeting B or T lymphocytes. The aim of this review article is to provide an overview of available data about B and T cell targeting in pSS and of future directions based on ongoing trials.

Role of Inflammatory Diseases in Hypertension

Chronic inflammatory diseases (CID) are characterized by an increased risk of cardiovascular (CV) morbidity and mortality. Several mechanisms, including early acceleration of subclinical atherosclerotic damage, inflammatory markers and immune system deregulation factors, have been demonstrated to strictly interplay for development and progression of atherosclerosis. Moreover, traditional CV risk factors are likely to explain at least some of the excess of CV risk in these patients. Among traditional CV risk factors, compelling evidence suggests a higher incidence and prevalence of hypertension in patients with CID in comparison to the general population. Moreover, hypertension represents an important predictor of CV events in these patients. Pathogenic mechanisms underlying the rise of blood pressure in CID are multifactorial and still poorly investigated. Indeed, multiple disease-related factors may affect blood pressure control in these patients and hypertension may affect disease prognosis and increase CV risk. Better knowledge of the complex interplay between hypertension and CID will be important to elucidate pathogenic mechanisms and to improve CV outcome in these patients. Aim of this review is to highlight available evidence on the relationship between hypertension and CID and to elucidate the multiple factors that may affect blood pressure control in these disorders.

Insulin-Like Growth Factor Binding Protein 6 in Rheumatoid Arthritis: A Possible Novel Chemotactic Factor?

Objectives

Immune cell migration from the bloodstream to target tissues is a hallmark of rheumatoid arthritis (RA) pathogenesis. The role of chemoattractants, mainly chemokines, and their possible targeting for therapeutic purposes have been under intense investigation over the last few years but the results were not as satisfactory as expected. The insulin-like growth factor binding protein 6 (IGFBP6), a direct inhibitor of insulin-like growth factor (IGF)-II, also exerts IGF-independent effects including tumor cell migration in vitro. We aimed to assess the expression of this protein in serum, synovial fluid, and synovial tissue (ST) of RA patients and to identify its possible chemotactic role in this disorder.

Methods

IGFBP6 was measured in RA patients and healthy donors (HD) sera by Luminex xMAP^® technology and in ST of RA patients and osteoarthritis (OA) controls by immunofluorescence. The identification of circulating IGFBP6⁺ cells was evaluated by flow cytometry and an in vitro migration assay was arranged.

Results

We demonstrated that IGFBP6 is able to induce greater in vitro migration of RA as compared to HD and OA T lymphocytes and is overexpressed in serum and ST of RA patients. This in vitro chemotactic activity can be partially inhibited by dexamethasone.

Conclusion

Our findings suggest a pathogenic role of IGFBP6 in RA and support its possible targeting for therapeutic purposes.

Functional Profiles of Human Umbilical Cord-Derived Adult Mesenchymal Stem Cells in Obese/Diabetic Versus Healthy Women

BACKGROUND

Adult human mesenchymal stem cells retrieved, from the post-partum human umbilical cord Wharton jelly (hUCMS), have recently gained growing interest due to their morphological and functional properties.

OBJECTIVE

The main purpose of our work was to examine morphology and functional properties of hUCMS retrieved from healthy women as compared to those with obesity, or gestational or type 2 diabetes mellitus, under fair metabolic control. Possible differences between groups could shed light into the potential use of these cells for the cell therapy of a variety of diseases, regardless of the obesity/diabetes status of the donor mothers. Additionally, information on how the maternal disease may affect the cord-derived stem cells, hence possibly newborn children would be important.

METHOD

We have studied obese/diabetic or normal donor post-partum umbilical cord-derived hUCMS, either in basal or during differentiation protocols into several cell phenotypes and the definitive endoderm. Immunomodulatory properties of these cells, in terms of inhibition of activated lymphocyte proliferation, also was examined.

RESULTS

According to our preliminary results, there are functional differences, as assessed by cell and molecular assays, in terms of both, differentiation and immunomodulatory potential, between the cells derived from normal as compared to obese/diabetic mothers.

CONCLUSION

The findings seemingly indicate that the uterine environment of obese/diabetic mothers is quite distant from normal, regardless of metabolic control. Hence hUCMS extracted from obese/diabetic mothers do not appear to be suitable for cell therapy clinical protocols but more studies are required.

Interleukin (IL)-17-producing pathogenic T lymphocytes co-express CD20 and are depleted by rituximab in primary Sjögren's syndrome: a pilot study

Compelling evidence suggests that interleukin (IL)-17 and IL-17-producing cells play a pivotal role in the pathogenesis of primary Sjögren's syndrome (pSS). We investigated phenotypical and functional effects of the anti-CD20 antibody rituximab (RTX) on circulating and glandular IL-17-producing T cells in pSS. RTX is able to deplete glandular IL-17(+) CD3(+) CD4(-) CD8(-) double-negative (DN) and CD4(+) Th17 cells as well as circulating IL-17(+) DN T cells. A fraction of glandular and circulating IL-17(+) DN cells and CD4(+) T helper type 17 (Th17) cells co-expresses CD20 on the cell surface explaining, at least in part, such depletive capacity of RTX. The exposure to RTX does not rescue the in-vitro corticosteroid resistance of IL-17(+) DN T cells. Our results support further the therapeutic role in pSS of RTX that, despite its B cell specificity, appears able to also hamper IL-17-producing T cells in this disease.

Mobilization of lymphatic endothelial precursor cells and lymphatic neovascularization in primary Sjögren's syndrome

Although lymphatic neovascularization may be a key feature of chronic inflammation, it is almost unexplored in primary Sjögren's syndrome (pSS). A recent study revealed a pro‐lymphangiogenic function of interleukin (IL)‐17, a leading player in pSS pathogenesis. The aims of the study were to investigate lymphangiogenic mediators and lymphatic vasculature in pSS, as well as their possible association with IL‐17. Circulating lymphatic endothelial precursor cells (LEPCs) and Th17 cells were enumerated in pSS patients and healthy donors. VEGF‐C and IL‐17 levels were assessed in paired serum samples. Lymphatic vasculature, VEGF‐C/VEGF receptor (VEGFR)‐3 and IL‐17 were evaluated in pSS minor salivary glands (MSGs) and compared with normal and non‐specific chronic sialadenitis (NSCS) MSGs. Circulating LEPCs were expanded in pSS and correlated with circulating Th17 cells, IL‐17 and VEGF‐C. In pSS MSGs, a newly formed lymphatic capillary network was found within periductal inflammatory infiltrates and the number of interlobular lymphatic vessels was significantly increased compared with normal and NSCS MSGs. Strong VEGF‐C expression was detected in pSS ductal epithelial cells and periductal inflammatory cells. Numerous VEGFR‐3⁺ infiltrating mononuclear cells were exclusively observed in pSS MSGs. VEGFR‐3 expression was strongly increased in lymphatic capillaries of pSS MSGs. IL‐17⁺ inflammatory cells were preferentially observed around lymphatic vessels in pSS MSGs. This study supports the notion that lymphvasculogenesis and lymphangiogenesis are active in pSS, thereby unmasking a novel aspect of disease pathogenesis. In addition, our results suggest another possible pathogenic role of IL‐17 in pSS, further supporting its therapeutic targeting in this disease.

Blue honeysuckle fruit (Lonicera caerulea L.) from eastern Russia: phenolic composition, nutritional value and biological activities of its polar extracts

We conducted a chemical and biological investigation of blue honeysuckle growing in eastern Russia.

Interferon gamma-inducible protein 16 (IFI16) and anti-IFI16 antibodies in primary Sjögren's syndrome: findings in serum and minor salivary glands

The interferon (IFN) signature, namely the overexpression of IFN-inducible genes is a crucial aspect in the pathogenesis of primary Sjögren's syndrome (pSS). The IFN-inducible IFI16 protein, normally expressed in cell nuclei, may be overexpressed, mislocalized in the cytoplasm and secreted in the extracellular milieu in several autoimmune disorders including pSS. This leads to tolerance breaking to this self-protein and development of anti-IFI16 antibodies. The aim of this study was to identify pathogenic and clinical significance of IFI16 and anti-IFI16 autoantibodies in pSS. IFI16 and anti-IFI16 were assessed in the serum of 30 pSS patients and one-hundred healthy donors (HD) by ELISA. IFI16 was also evaluated in 5 minor salivary glands (MSGs) of pSS patients and 5 MSGs of non-pSS patients with sicca symptoms by immunohistochemistry. Normal MSGs do not constitutively express IFI16. Conversely, in pSS-MSGs a marked expression and cytoplasmic mislocalization of IFI16 by epithelial cells was observed with infiltrations in lymphocytes and peri/ intra-lesional endothelium. pSS patients display higher serum levels of both IFI16 and anti-IFI16 autoantibodies compared to HD. Our data suggest that IFI16 protein may be involved in the initiation and perpetuation of glandular inflammation occurring in pSS.

Restoration of t cell substes of patients with type 1 diabetes mellitus by microencapsulated human umbilical cord Wharton jelly-derived mesenchymal stem cells: An in vitro study

Human umbilical cord Wharton jelly-derived mesenchymal stem cells (hUCMS) might apply to treating chronic autoimmune disorders, as already shown for Sjögren's syndrome, including type 1 diabetes mellitus (T1D). Since naked hUCMS grafts encountered restraints, we enveloped hUCMS, within immunoisolatory microcapsules (CpS-hUCMS), made of our endotoxin-free, clinical grade alginate. We then examined the vitro effects of interferon (IFN)-γ-pretreated CpS-hUCMS on Th17 and Treg of T1D patients (n=15) and healthy controls (n=10). Peripheral blood mononuclear cells (PBMCs) were co-cultured with PBMC/CpS-hUCMS: lymphocyte proliferation was assessed by carboxyfluorescein succinimidyl esther (CFSE) dilution assay, and phenotypic analysis of regulatory and effector Tc was also performed. Cytokine expression was performed by bead array and qPCR on IFN-γ-pretreated hUCMS before PBMCs co-culture. CpS-hUCMS restored a correct Treg/Th17 ratio, relevant to the T1D disease process. In summary, we have preliminarily developed a new biohybrid system, associated with immunoregulatory properties, that is ready for in vivo application.

Interferon gamma-inducible protein 16 in primary Sjögren's syndrome: a novel player in disease pathogenesis?

Introduction

There is evidence that interferon is involved in the pathogenesis of primary Sjögren’s syndrome (pSS). The interferon-inducible IFI16 protein, normally expressed in cell nuclei, may be overexpressed, mislocalized in the cytoplasm and secreted in the extracellular milieu in several autoimmune disorders. This leads to tolerance breaking to this self-protein with consequent development of anti-IFI16 antibodies. The aim of this study was to identify the pathogenic and clinical significance of IFI16 and anti-IFI16 in pSS.

Methods

IFI16 and anti-IFI16 were assessed in the serum of 67 pSS patients and over 100 healthy donors by enzyme-linked immunosorbent assay. IFI16 was also evaluated by immunohistochemistry in minor salivary glands of 15 pSS patients and 10 subjects with sicca symptoms but without any clinical, serological or histological features of pSS.

Results

pSS patients display higher serum levels of both IFI16 and anti-IFI16 compared to healthy donors. IFI16 concentration was directly correlated with disease duration and focus score and inversely correlated with age at diagnosis. Moreover, IFI16 positivity was associated with concurrent positivity for rheumatoid factor. Interestingly, the direct correlation between IFI16 positivity and focus score was independent of disease duration and age at diagnosis. pSS minor salivary glands display marked expression and cytoplasmic mislocalization of IFI16 by acinar and ductal epithelial cells as well as infiltrating lymphocytes and peri/intralesional endothelium compared to minor salivary glands with normal architecture or nonspecific chronic sialadenitis. Within the mononuclear cell infiltrate, IFI16 expression appears to parallel the distribution of T lymphocytes.

Conclusion

Our data suggest that the IFI16 protein may be involved in the pathogenesis of glandular inflammation occurring in pSS.

T Regulatory and T Helper 17 Cells in Primary Sjögren's Syndrome: Facts and Perspectives

Historically, primary Sjögren's syndrome (pSS) was thought to be a T helper (h) 1 driven disease due to the predominance of CD4(+)T lymphocytes and their products in target organs and peripheral blood of patients. In the last decades, the identification of a number of T cell subsets, including Th17, T regulatory (Treg), and follicular helper T cells, challenged this long-standing paradigm and prompted to identify their role in pSS pathogenesis. In addition the impact of abnormal proinflammatory cytokine production, such as IL-6, IL-17, IL-22, and IL-23, has also attracted considerable attention. However, although several studies have been carried out in experimental models and patients with pSS, many aspects concerning the role of Treg cells and IL-17/Th17 cell system in pSS pathogenesis are not fully elucidated. In particular, the role played by different IL-17-producing T cell subsets as well as the effects of pharmacological therapies on Treg/Th17 cell balance represents an intriguing issue. The aim of this review article is to provide an overview of current knowledge on Treg cells and IL-17-producing T cells in pSS pathogenesis. We believe that these insights into pSS pathogenesis may provide the basis for successful therapeutic intervention in this disease.

Telocytes in minor salivary glands of primary Sjögren's syndrome: association with the extent of inflammation and ectopic lymphoid neogenesis

It has been recently reported that telocytes, a stromal (interstitial) cell subset involved in the control of local tissue homeostasis, are hampered in the target organs of inflammatory/autoimmune disorders. Since no data concerning telocytes in minor salivary glands (MSGs) are currently available, aim of the study was to evaluate telocyte distribution in MSGs with normal architecture, non-specific chronic sialadenitis (NSCS) and primary Sjögren's syndrome (pSS)-focal lymphocytic sialadenitis. Twelve patients with pSS and 16 sicca non-pSS subjects were enrolled in the study. MSGs were evaluated by haematoxylin and eosin staining and immunofluorescence for CD3/CD20 and CD21 to assess focus score, Tarpley biopsy score, T/B cell segregation and germinal center (GC)-like structures. Telocytes were identified by immunoperoxidase-based immunohistochemistry for CD34 and CD34/platelet-derived growth factor receptor α double immunofluorescence. Telocytes were numerous in the stromal compartment of normal MSGs, where their long cytoplasmic processes surrounded vessels and encircled both the excretory ducts and the secretory units. In NSCS, despite the presence of a certain degree of inflammation, telocytes were normally represented. Conversely, telocytes were markedly reduced in MSGs from pSS patients compared to normal and NSCS MSGs. Such a decrease was associated with both worsening of glandular inflammation and progression of ectopic lymphoid neogenesis, periductal telocytes being reduced in the presence of smaller inflammatory foci and completely absent in the presence of GC-like structures. Our findings suggest that a loss of MSG telocytes might have important pathophysiological implications in pSS. The specific pro-inflammatory cytokine milieu of pSS MSGs might be one of the causes of telocyte loss.

Expansion of regulatory GITR+CD25 low/-CD4+ T cells in systemic lupus erythematosus patients

Introduction

CD4⁺CD25^low/-GITR⁺ T lymphocytes expressing forkhead box protein P3 (FoxP3) and showing regulatory activity have been recently described in healthy donors. The objective of the study was to evaluate the proportion of CD4⁺CD25^low/-GITR⁺ T lymphocytes within CD4⁺ T cells and compare their phenotypic and functional profile with that of CD4⁺CD25^highGITR⁻ T lymphocytes in systemic lupus erythematosus (SLE) patients.

Methods

The percentage of CD4⁺CD25^low/-GITR⁺ cells circulating in the peripheral blood (PB) of 32 patients with SLE and 25 healthy controls was evaluated with flow cytometry. CD4⁺CD25^low/-GITR⁺ cells were isolated with magnetic separation, and their phenotype was compared with that of CD4⁺CD25^highGITR⁻ cells. Regulatory activity of both cell subsets was tested in autologous and heterologous co-cultures after purification through a negative sorting strategy.

Results

Results indicated that CD4⁺CD25^low/-GITR⁺ cells are expanded in the PB of 50% of SLE patients. Expansion was observed only in patients with inactive disease. Phenotypic analysis demonstrated that CD4⁺CD25^low/-GITR⁺ cells display regulatory T-cell (Treg) markers, including FoxP3, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), transforming growth factor-beta (TGF-β), and interleukin (IL)-10. In contrast, CD4⁺CD25^highGITR⁻ cells appear to be activated and express low levels of Treg markers. Functional experiments demonstrated that CD4⁺CD25^low/-GITR⁺ cells exert a higher inhibitory activity against both autologous and heterologous cells as compared with CD4⁺CD25^highGITR⁻ cells. Suppression is independent of cell contact and is mediated by IL-10 and TGF-β.

Conclusions

Phenotypic and functional data demonstrate that in SLE patients, CD4⁺CD25^low/-GITR⁺ cells are fully active Treg cells, possibly representing peripheral Treg (pTreg) that are expanded in patients with inactive disease. These data may suggest a key role of this T-cell subset in the modulation of the abnormal immune response in SLE. Strategies aimed at expanding this Treg subset for therapeutic purpose deserve to be investigated.

Unmasking the pathogenic role of IL-17 axis in primary Sjögren's syndrome: a new era for therapeutic targeting?

Compelling evidence suggests that the IL-17 axis plays a pivotal role in the pathogenesis of several autoimmune disorders including primary Sjögren's syndrome (pSS). However, although several studies have been carried out in experimental models and patients with pSS, many aspects of this field are not fully elucidated. In particular, the role played by different Th17 cell subsets as well as the effects of pharmacological therapies on IL-17 balance represent an intriguing issue. Furthermore, the understanding of IL-17 axis pathogenic role in pSS may be of interest for therapeutic purposes as a variety of compounds targeting IL-17, IL-17 receptor and other related cytokines and transcription factors involved in Th17 cell commitment are under intense investigation. The aim of this review article is to provide an overview of current knowledge in IL-17/Th17 cells in pSS and discuss their potential therapeutic targeting in this disease.