Reduced prescription of TNF-inhibitors in chronic arthritis based on therapeutic drug monitoring: A randomized controlled trial

OBJECTIVE

Dosing of tumour necrosis factor-α inhibitors (TNFis) is not personalized causing interindividual variation in serum drug levels; however, dose optimization is not widely implemented. We hypothesized that some patients are overdosed; thus, drug prescription could be reduced by therapeutic drug monitoring (TDM).

METHOD

Independent of disease activity, 239 adults treated for rheumatoid arthritis (n = 99), psoriatic arthritis 15 (n = 48), or spondyloarthritis (n = 92) were recruited for a 48-week prospective, randomized open-label trial. Standard care alone or plus TDM was applied in chronic arthritis patients treated with infliximab (IFX), (n = 81), etanercept (ETN) (n = 79), or adalimumab (ADA) (n = 79). Serum TNFi trough levels assessed at inclusion and every 4 months determined patients within/outside predefined therapeutic intervals, supporting change in prescription or drug switch. The primary endpoint was reduced drug prescription.

RESULTS

Compared to standard care, TDM reduced prescribed IFX [-12% (95% confidence interval -20, -3); p = 0.001] and ETN (-15% (-29, 1); p = 0.01], and prolonged the interdosing intervals of ETN [+235% (38, 432); p = 0.02] and ADA [+28% (6, 51); p = 0.04]. Time to drug switch was accelerated (χ2 = 6.03, p = 0.01). No group differences in adverse events, disease activity, or self-reported outcomes were shown, indicating equally sustained remission.

CONCLUSIONS

TDM reduced prescription of IFX, ETN, and ADA and identified patients benefiting from accelerated drug switch, thereby minimizing treatment failure, risk of toxicity, and unnecessary adverse events.

Baseline serum levels of IgA anti-cyclic citrullinated protein antibodies in early rheumatoid arthritis predict radiographic progression after 11 years of treatment: a secondary analysis of the CIMESTRA study

OBJECTIVE

Smoking and periodontitis are risk factors for developing rheumatoid arthritis (RA), suggesting a break of tolerance on mucosal surfaces. Immunoglobulin A (IgA) antibodies are part of the mucosal immune system. The dominant autoantibodies in RA are anti-cyclic citrullinated protein antibodies (ACPAs), and IgG and IgA subclasses exist simultaneously. This study aimed to investigate the association of ACPA IgA subtypes with disease activity and long-term radiographic outcomes in RA, compared with ACPA IgG.

METHOD

Total ACPA IgG, IgA, IgA1, and IgA2 were quantified in serum from patients with early RA (n = 97). Patient characteristics, IgM rheumatoid factor (IgM-RF) status, clinical and biochemical disease activity scores, and radiographic status evaluated by total Sharp score (TSS), were assessed at baseline and after 2 and 11 years of treatment.

RESULTS

All patients with ACPA IgA also had ACPA IgG. ACPA IgA positivity was associated with IgM-RF and male gender. Both ACPA IgA and IgG levels at baseline were weakly associated with disease activity markers. Baseline ACPA IgA and IgG did not show a linear correlation with radiographic status after 10 years, but could predict radiographic progression (ΔTSS ≥ 5 from 0 to 11 years), with positive likelihood ratios of 3.7 and 4.0, respectively.

CONCLUSION

ACPA IgA and IgG were weakly associated with disease activity in early RA. RA patients with a ΔTSS ≥ 5 after 11 years of treatment had higher ACPA IgG and ACPA IgA levels at baseline; however, none of the ACPA subtypes was superior in predicting long-term radiographic progression.

Increased synovial galectin-3 induce inflammatory fibroblast activation and osteoclastogenesis in patients with rheumatoid arthritis

OBJECTIVE

Galectin-3 (Gal-3) has been suggested as a proinflammatory mediator in rheumatoid arthritis (RA). We aimed to study clinical and pathogenic aspects of Gal-3 in RA.

METHOD

Plasma samples from healthy controls (n = 48) and patients with newly diagnosed, early RA were assayed for soluble Gal-3. In patients with chronic RA (n = 18), Gal-3 was measured in both plasma and synovial fluid. Synovial fluid mononuclear cells were used to purify fibroblast-like synoviocytes (FLSs) and osteoclasts. Monocultures of FLSs and autologous co-cultures of FLSs and peripheral blood mononuclear cells were established and co-incubated with a Gal-3 inhibitor.

RESULTS

Patients with early and chronic RA had persistently increased plasma levels of Gal-3 compared with controls. However, changes in plasma Gal-3 at the level of individuals were associated with long-term disease activity. In seropositive early RA patients, all patients with decreasing plasma Gal-3 from 0 to 3 months had low disease activity after 2 years (p < 0.05). Gal-3 levels in synovial fluid were markedly elevated. In vitro, co-incubation with a Gal-3 inhibitor (GB1107, 10 µM) led to a significant reduction in both interleukin-1β and tumour necrosis factor-α secretion from FLS monocultures (both p < 0.05) and decreased monocyte-derived osteoclastogenesis compared with controls (both p < 0.05).

CONCLUSIONS

Our findings underscore the role of Gal-3 regarding disease activity and tissue destruction in RA. An initial decrease in plasma Gal-3 levels predicted decreased long-term disease activity. Correspondingly, a Gal-3 inhibitor decreased the activity of inflammatory FLSs and osteoclastogenesis in patients with RA.

POS0415 PLASMA GALECTIN-9 IS ASSOCIATED WITH CLINICAL DISEASE ACTIVITY IN TREATMENT NAÏVE EARLY RHEUMATOID ARTHRITIS, UNAFFECTED BY DMARD TREATMENT, AND IN VITRO MODULATES THE SECRETION OF MCP-1 AND IL-6 IN RHEUMATOID ARTHRITIS SYNOVIAL FIBROBLASTS

Background

Fibroblast-like synoviocytes (FLS) are pivotal mediators of rheumatoid synovitis expansive growth and invasiveness which respond insufficiently to disease-modifying antirheumatic drugs. Galectin-9 (Gal-9) is a lectin with well-conserved carbohydrate-recognition domains. Gal-9 has been reported to have both pro- and anti-inflammatory properties based on its ability to modulate RA FLS. Gal-9 levels are elevated in serum of rheumatoid arthritis (RA) patients, and high levels of Gal-9 have been identified in both the synovial fluid and in the inflamed synovial tissue of patients with RA.

Objectives

To investigate the role of Gal-9 as a biomarker for disease severity in treatment naïve patients with early RA and to study aspects of Gal-9 effects on inflammatory RA FLS.

Methods

Soluble plasma Gal-9 was measured in patients with newly diagnosed, treatment-naïve RA (n = 98) and in Healthy (HC) (n = 48) (Table 1). Over a 2-year period patients were randomized to either MTX alone or MTX and anti-TNF antibody treatments. Serial measurements of disease activity (DAS28CRP) were collected to evaluate the disease course. In another cohort of patients with established RA, plasma and synovial fluid samples were also examined for Gal-9 (n = 18) (Table 1). Synovial fluid mononuclear cells (SFMC) from established RA patients were used to harvest RA FLS (n=7). Osteoarthritis FLS were used as disease controls and obtained from patients with knee OA undergoing joint replacement surgery (n = 5). Monocultures of synovial fluid derived FLS (SF-FLS) (n= 6) and autologous co-cultures of SF-FLS and peripheral blood mononuclear cells (PBMC) were established (n=7) and subsequently analyzed by flow cytometry, MTT assay, and ELISA. In vitro, cultures were treated with a neutralizing anti-Gal-9 antibody.

Table 1.Patient characteristicsEarly RA (n=98)Established RA (n=18)HC (n=48)Time after treatment initiation (months)032484 (12-288)Disease activityDAS28CRP (0-10)5.7 (5.1-6.4)2.1 (1.8-3.2)2.0 (1.8-2.7)5.0 (3.2-5.5)-Gal-9 levels (pg/ml)Plasma3315 (2683-4421)3217 (2706-4250)2904 (2639-3411)2190 (1652-2852)Synovial fluid21246 (13832-34727)

Patient characteristics. Data are expressed as median with IQR range unless otherwise indicated.

Results

Patients with early and established RA had increased plasma levels of Gal-9 compared with HCs (P < 0.05) (Table 1) and levels of Gal-9 correlated positively with swollen joint counts at baseline (rho = 0.344, P < 0.05). The levels remained unaffected by treatment with MTX alone or by a combination of MTX and anti-TNF antibodies. Gal-9 levels were markedly elevated in the synovial fluid of chronic RA patients compared with the corresponding plasma samples (P < 0.05) (Table 1). In vitro, a neutralizing Gal-9 antibody mediated a 40% decrease in MCP-1 secretion (P < 0.05) and a 30% decrease in IL-6 secretion (P < 0.05) in RA FLS monocultures. In OA FLS, addition of anti-Gal-9 antibodies comparably decreased the production of both MCP-1 (P < 0.05) and IL-6 (P < 0.05). The changes in cytokine production were not attributable to reduction in the fraction of inflammatory FLS (CD34-PDPN+THY1+), decreased viability or proliferation. We further investigated if the effect of neutralizing Gal-9 persisted in co-cultures between FLS and autologous PBMC. Also in this setting, neutralization of Gal-9 mediated a 40% reduction in both MCP-1 and IL-6 (P < 0.05, P < 0.05).

Conclusion

Pretreatment plasma Gal-9 levels in patients with newly diagnosed RA were increased and correlated with baseline clinical disease activity but remained elevated during goal directed synovitis suppressive therapy. In addition, in vitro neutralization of Gal-9 decreased MCP-1 and IL-6 production in a subset of FLS linked to RA pathology. Collectively these findings indicate that Gal-9 overexpression is a co-player in the causation of acute and persistent RA synovitis by enhancing pro-inflammatory FLS pathways.

Acknowledgements

We thank Karin Skovgård Sørensen (Dept. of Biomedicine, Aarhus University) for technical assistance concerning the ELISA data and the FACS Core Facility (Aarhus University, Denmark) for technical assistant regarding Flow cytometry. We thank medical doctors and nurses at the Department of Rheumatology, Aarhus University Hospital for helping to collect the patient samples. We kindly acknowledge the generous grants from Aarhus University Research Foundation and the Danish Rheumatism Association.

Disclosure of Interests

None declared.

POS0761 TIME-DEPENDENT ANALYSES OF CLINICAL MANIFESTATIONS OF SYSTEMIC LUPUS ERYTHEMATOSUS IDENTIFY PATIENTS AT HIGH RISK OF INCIDENT PROTEINURIA

Background

Nephritis (LN) in systemic lupus erythematosus (SLE) is still a major determinant of poor prognosis[1].

The vast majority of LN occurs in proximity to the SLE diagnosis[2]. Identification of individuals at high risk, especially early onset SLE, is therefore warranted. Inclusion of risk factors prior to the SLE diagnosis may thus be of importance to enable sufficient risk factor profiling. SLE-patients seem to cluster according to clinical and serological phenotypes suggesting distinct disease trajectories[3-5].

Objectives

To determine if incident proteinuria associated with the debut age of non-renal SLE characteristics.

Methods

Data of SLE patients from six Danish centers were obtained from the Danbio-database from 2017 – 2020. The occurrence and timing of proteinuria was compared with first time onset of any non-renal manifestations as defined by the 1997 American College of Rheumatology Classification Criteria. Cox-regression models were used to identify risk factors for incident proteinuria. Time from first occurring non-renal manifestation to incident proteinuria or censoring defined time at risk. Covariates were eliminated if p >0.01 in a ‘backwards’ manner. After the model reduction process p-values <0.05 were considered statistically significant.

Results

586 SLE patients, mainly white (94%) women (88%), mean age at inclusion of 34.6 years (standard deviation, SD = 0.6 years) and observed for a mean of 14.9 years (SD =0.5 years), were recruited. The cumulative prevalence of proteinuria was 40%. Male gender hazard ratio, HR = 1.35 (range 0.77-2.35), p=0.009, lymphopenia HR = 1.77 (range 1.24-2.52), p=0.005 were associated with incident proteinuria. In contrast, patients with discoid rash had lower risk of incident proteinuria HR 0.42 (range 0.21-0.83), p=0.01. Male patients with lymphopenia had the highest risk of proteinuria with a one-, 5- and 10-year risk of proteinuria ranging from 9-27%, 34-75% and 51-89 %, depending on the age at presentation (debut at 20, 30, 40 or 50 years). The corresponding risk-profiles for women with lymphopenia were 3-9%, 8-34% and 12-58%, respectively, as illustrated in Figure 1.

Conclusion

The occurrences of lymphopenia and discoid rash were oppositely associated with risk of incident proteinuria and the risk effects varied according to gender and patient age at onset of these manifestations. Thus, the risk of proteinuria may not be constant but could vary according to presentation of non-renal manifestations that may call for a differentiated clinical follow-up. Based on these findings, we suggest that the debut age of known prognostic factors, even prior to the SLE diagnosis should be considered when designing prognostic statistical models.

References

[1]Faurschou, M., et al., Prognostic factors in lupus nephritis: diagnostic and therapeutic delay increases the risk of terminal renal failure. J Rheumatol, 2006. 33(8): p. 1563-9.

[2]Hanly, J.G., et al., The frequency and outcome of lupus nephritis: results from an international inception cohort study. Rheumatology (Oxford), 2016. 55(2): p. 252-62.

[3]Diaz-Gallo, L.M., et al., Four Systemic Lupus Erythematosus Subgroups, Defined by Autoantibodies Status, Differ Regarding HLA-DRB1 Genotype Associations and Immunological and Clinical Manifestations. ACR Open Rheumatol, 2022. 4(1): p. 27-39.

[4]Jacobsen, S., et al., A multicentre study of 513 Danish patients with systemic lupus erythematosus. II. Disease mortality and clinical factors of prognostic value. Clin Rheumatol, 1998. 17(6): p. 478-84.

[5]Leffers, H.C.B., et al., Smoking associates with distinct clinical phenotypes in patients with systemic lupus erythematosus: a nationwide Danish cross-sectional study. Lupus Sci Med, 2021. 8(1).

Disclosure of Interests

Martin Andersen Employee of: Novo Nordisk A/S: 2010-2014, Anders Stockmarr: None declared, Henrik Leffers: None declared, Anne Troldborg: None declared, Anne Voss: None declared, Salome Kristensen: None declared, Bent Deleuran: None declared, Lene Dreyer Speakers bureau: Speakers bureau: Eli Lilly, Galderma and Janssen, Grant/research support from: Grant from BMS outside the present work, Laura Johnsen: None declared, Ada Colic: None declared, Søren Jacobsen: None declared

POS0484 LUNG ORGANOIDS: A NOVEL APPROACH TO STUDY THE MOLECULAR PATHOLOGY OF PULMONARY FIBROSIS IN SYSTEMIC SCLEROSIS

Background

Pulmonary fibrosis is one of the major manifestations in Systemic Sclerosis (SSc) associated with high mortality. Mesenchymal transformation of the airway epithelial cells has been implicated as one of the causes for developing pulmonary fibrosis. Though several animal models shed light towards some of these aspects, an in vitro airway epithelial model would provide a novel experimental platform for the understanding and molecular and genetic changes that occur in SSc associated pulmonary fibrosis.

Objectives

To establish a functional model for airway epithelium from patient with diffuse cutaneous SSc (dSSc)and healthy volunteers derived nasal stem cells. Subsequently to induce Epithelial Mesenchymal transformation (EMT).

Methods

Nasal stem cells harvested from healthy volunteers(HV) and dSSc patients were differentiated into ciliated airway epithelium in an Air -Liquid Interface (ALI) using a transwell system. 4 HV cultures were then stimulated with TGF beta (5ug/ml) for 10 days at a basal stage and when differentiated. Markers of mesenchymal transformation including loss of E cadherin, and gain of N cadherin, fibronectin and vimentin were analysed by flow cytometry and image stream, and mean expression intensities given as (MFI). Secreted Type 1 collagen and fibronectin were measured by ELISA.

Results

Ciliated epithelial cultures could successfully be established from nasal stem cells (Figure 1).

TGF beta induced a phenotypic change in the epithelial cells towards a mesenchymal one in HV cultures. This was observed by significantly increased expression of fibronectin and vimentin and loss of expression of E cadherin on the ciliated cells with 7 days of stimulation with TGF beta at a basal stage (Figure 1b). When cells, stimulated with TGF beta for 7 days, were analysed at Day 35 a similar trend was seen in their Delta MFI (Figure 1c). Stimulating the ALI cultures with TGF beta for 20 days completely repressed epithelial cell growth and disrupted their microstructure.

Figure 1.

Conclusion

This novel ALI differentiated Airway epithelial model serves as a functional organoid to test various pulmonary manifestations of Systemic Sclerosis. The ability to induce Epithelial Mesenchymal Transformation of these cultures provides a proof of concept for TGF beta mediated fibrosis in dSSc. Moreover, this model can be utilized to explore, at the cell and molecular level, the impact of various autoantibodies and therapeutics on epithelial cells.

References

[1]Mehmet Kesimer,1 Sara Kirkham,2 Raymond J. Pickles,3 Ashley G. Henderson,4 Neil E. Alexis,5 Genevieve DeMaria,1 David Knight,2 David J. Thornton,2 and John K. Sheehan1 Tracheobronchial air-liquid interface cell culture: a model for innate mucosal defense of the upper airways?; Am J Physiol Lung Cell Mol Physiol 296: L92–L100, 2009

Disclosure of Interests

None declared.

AB0136 ELUCIDATING THE PATHOGENIC EFFECTS OF ANTI-TOPOISOMERASE-1 ANTIBODIES IN SYSTEMIC SCLEROSIS

Background

Prediction of the pattern of organ involvement in patients with diffuse cutaneous systemic sclerosis (dcSSc) is supported by the specificity of autoantibodies. These autoantibodies are generally mutually exclusive and highly specific for dcSSc1. The autoantibody reactivity allows patients to be stratified early in the disease course, leading to a tailored approach and management. Anti-topoisomerase I antibodies (ATA) are predictors of the development of interstitial lung disease (ILD) and digital ulcers but appear to be protective against pulmonary artery hypertension (PAH).

Objectives

The aim of this project was to elucidate the functioning of ATA and their role in the pathogenicity of the disease.

Methods

Sera from healthy volunteers (HV) and dcSSc patients with and without ATA were collected from Aarhus University Hospital. Total IgG was purified from the sera using a Protein G column. ATA was further purified from the total IgG fraction by passing it through a column packed with the functional domains of human topoisomerase-1 (TOP1) expressed from E.coli.

Sera, total IgG and purified ATA fractions were utilized in preliminary experiments. The ability of ATA to inhibit TOP1 was tested by a in house developed REEAD assay in which the generation of closed DNA circles, by the cleavage-ligation activity of TOP1, is monitored after rolling circle amplification2.

Results

Serum from patients with dcSSc, but not from HV, could inhibit TOP1 activity at various dilutions. Similarly, purified total IgG fractions from dcSSc patients could also inhibit TOP1 activity. ATA was successfully separated from IgG from dcSSc patients who were positive for ATA. This could inhibit TOP1 activity even at lower concentrations than total IgG. This was the case for both mitochondrial and nuclear TOP1 activity.

Fully in line with presence of ATA, PBMC’s from dcSSc patients contained a lower TOP1 activity compared to HVs PBMCs.

Conclusion

To our knowledge we are the first group to be able to successfully separate ATA from total IgG from dcSSc patients. our unique in house developed REEAD assay clearly demonstrates the function of ATA and provides the opportunity to better understand

References

[1]Role of autoantibodies in the diagnosis and prognosis of interstitial lung disease in autoimmune rheumatic disorders. Masataka Kuwana, Albert Gil-Vila and Albert Selva-O’Callaghan, Ther Adv Musculoskel Dis 2021, Vol. 13: 1–17 DOI: 10.1177/

[2]Rolling circle amplification based detection of human topoisomerase I activity on magnetic beads. Zuccaro, Laura; Tesauro, Cinzia; Cerroni, Barbara; Ottaviani, Alessio; Knudsen, Birgitta Ruth; Balasubramanian, Kannan; Desideri, Alessandro. Analytical Biochemistry, Bind 451, 15.04.2014, s. 42-44.

Disclosure of Interests

None declared

POS0166 POLYARTICULAR JIA HAS A DISTINCT CO-INHIBITOR RECEPTOR PROFILE AMONG OTHER JIA SUBTYPES

Background

Juvenile idiopathic arthritis (JIA) is the most common inflammatory joint disease in children, driven by continuous T-cell activation.[1] T cell activation is counter-balanced by signals generated by co-inhibitory receptors (co-IRs) such CTLA-4, PD-1, LAG-3, and TIM-3.[2]

Objectives

We aimed to identify the role of co-IRs in the pathogenesis of different subtypes of JIA.

Methods

In total, we included 107 patients with oligoarticular JIA (n=67), polyarticular JIA (n=12), enthesitis related arthritis (n=17), systemic JIA (n=11) and healthy controls (HC, n=10). We collected plasma samples from the patients during the active phase of their disease. We measured the soluble plasma levels of co-IRs by commercial pre-defined cytometric bead array kits and their cellular expression by flow cytometry in blood mononuclear cells. We compared the plasma levels and cellular expressions of different coIRs within different JIA subgroups.

Results

IL-2 levels were lower than HC in all JIA subgroups. The polyarticular JIA group distinguished from the four different JIA subgroups, by having different co-IR pattern. In this specific subgroup, CTLA4, PD-1 and 4-1BB levels were higher than other groups. Polyarticular JIA is the more chronic and severe form of JIA, especially when compared to oligoarticular JIA. (Figure 1).

Figure 1.

We investigated the correlations between disease activity markers and plasma co-IRs. Plasma TIM3 levels correlated with erythrocyte sedimentation rate, C-reactive proteins and JADAS in the polyarticular JIA group. In oligoarticular JIA group, JADASs correlated with plasma PD-1 levels, C-reactive protein with PD-L1 plasma levels. Erythrocyte sedimentation rates correlated with IL-2, CD86, PD-L1 and PD-1 plasma levels. There was no correlation between disease activity markers and co-IRs levels in the systemic JIA group and enthesitis related arthritis group.

Finally, we analysed the cellular surface expression of different co-IRs on the PBMCs of different JIA subtypes. Similar to plasma levels, both the percentage and the MFI (mean fluorescence intensity) of CTLA4 expression was higher in polyarticular JIA subgroup.

Conclusion

This is the first report studying the effects of different co-IRs in different subtypes of JIA. Polyarticular JIA patients had a different coIR profile, having more CTLA-4, PD-1 and 4-1BB in their plasma than the other subtypes of JIA

References

[1]Wedderburn, L.R., et al., Int Immunol, 2001. 13(12): p. 1541-50.

[2]Wherry, E.J. and M. Kurachi, Nat Rev Immunol, 2015. 15(8): p. 486-99.

Acknowledgements

This work was supported by a research grant from FOREUM Foundation for Research in Rheumatology

Disclosure of Interests

None declared

AB0006 ESTABLISHED RISK LOCI FOR SYSTEMIC LUPUS ERYTHEMATOSUS AT NCF2, STAT4, TNPO3, IRF5 AND ITGAM ASSOCIATE WITH DISTINCT CLINICAL MANIFESTATIONS: A DANISH GENOME-WIDE ASSOCIATION STUDY

Background

Systemic lupus erythematosus (SLE) has been associated with more than 100 genetic loci. This parallels positively to the clinical diversity that is reflected by the classification of SLE.

Objectives

We aimed to investigate associations between disease manifestations of SLE and risk gene variants relevant to Danish subjects of European ancestry.

Methods

We included 427 SLE patients of European ancestry similar to previous reports.[1] We also included 89,699 controls from the Danish Blood Donor Study Genomic Cohort. SLE risk loci in this population were identified by genome-wide association methodology and hereafter correlated to cumulative occurrence of SLE classification items.

Results

Fourteen variants mapped to the following genes: NCF2, STAT4, TNPO3/TPI1P2, IRF5, and ITGAM, were significantly associated (p<5E-8) with SLE.

The five lead variants were associated (p<0.05) with the following manifestations; NCF2: proteinuria and anti-phospholipid antibodies, STAT4: arthritis, serositis, neurologic disorder, lymphopenia, and anti-Smith antibodies, IRF5: seizures and proteinuria, TNPO3: proteinuria, and ITGAM: photosensitivity (Table 2).

Conclusion

Our findings support the future use of select, relevant genetic markers in predicting various SLE phenotypes.

References

[1]Leffers HCB, Troldborg A, Voss A, et al. Smoking associates with distinct clinical phenotypes in patients with systemic lupus erythematosus: a nationwide Danish cross-sectional study. Lupus Sci Med 2021;8(1).

Table 1.

Associations between five SLE risk loci and specific disease manifestations in 427 Danish patients with SLE*.

NCF2STAT4IRF5TNPO3ITGAMrs17849502_Trs7574865_Trs4728142_Ars13239597_Ars11860650_TN (%)Malar rash233 (55%)1.28 (0.84-1.96)0.83 (0.62-1.11)1.01 (0.74-1.38)1.44 (0.97-2.12)1.14 (0.80-1.61)Discoid rash46 (11%)1.49 (0.81-2.73)0.90 (0.56-1.45)1.01 (0.62-1.66)1.16 (0.63-2.12)0.76 (0.42-1.41)Photosensitivity219 (51%)0.96 (0.63-1.46)1.09 (0.81-1.47)0.98 (0.71-1.34)0.84 (0.57-1.25)0.67 (0.47-0.97)Oral ulcers132 (31%)0.96 (0.61-1.50)0.90 (0.65-1.23)0.83 (0.60-1.16)1.30 (0.87-1.96)1.43 (0.99-2.05)Non-erosive Arthritis342 (80%)0.84 (0.52-1.37)1.49 (1.02-2.18)0.93 (0.63-1.36)1.04 (0.64-1.68)1.16 (0.74-1.80)Serositis-Pleuritis124 (29%)0.63 (0.38-1.05)1.38 (1.01-1.89)1.22 (0.87-1.72)0.85 (0.56-1.29)0.84 (0.57-1.24)-Pericarditis72 (17%)0.75 (0.41-1.40)1.35 (0.93-1.96)1.05 (0.70-1.58)1.15 (0.70-1.89)1.09 (0.70-1.72)Persistent proteinuria158 (37%)1.63 (1.07-2.49)1.08 (0.80-1.46)0.68 (0.49-0.94)1.74 (1.16-2.61)1.09 (0.76-1.57)Neurologic disorder-Seizures23 (5%)1.58 (0.75-3.35)1.49 (0.80-2.76)2.10 (1.04-4.25)0.61 (0.26-1.44)0.93 (0.42-2.06)-Psychosis8 (2%)0.76 (0.097-5.87)2.77 (0.94-8.15)0.35 (0.10-1.23)0 (0)2.96 (0.85-10.3)Haematologic disorder-Haemolytic anaemia38 (9%)0.78 (0.34-1.76)1.37 (0.85-2.22)0.75 (0.44-1.29)1.11 (0.57-2.19)1.24 (0.70-2.20)-Leukopenia130 (30%)1.04 (0.67-1.61)1.19 (0.87-1.63)1.00 (0.72-1.39)0.90 (0.60-1.37)0.94 (0.64-1.37)-Lymphopenia228 (53%)0.95 (0.63-1.44)1.35 (1.01-1.81)0.95 (0.70-1.29)1.16 (0.79-1.70)1.09 (0.77-1.54)-Thrombocytopenia102 (24%)1.42 (0.91-2.22)0.84 (0.60-1.18)0.83 (0.58-1.18)1.35 (0.86-2.11)0.91 (0.60-1.37)Immunologic disorder-anti-DNA ab.330 (77%)0.69 (0.44-1.09)1.02 (0.72-1.44)0.94 (0.65-1.35)0.97 (0.62-1.53)1.08 (0.71-1.65)-anti-Smith ab.44 (10%)1.44 (0.79-2.64)1.58 (1.00-2.49)1.23 (0.73-2.07)1.47 (0.80-2.69)1.07 (0.61-1.84)-anti-phospholipid ab.183 (43%)1.63 (1.07-2.49)1.05 (0.79-1.41)0.84 (0.61-1.14)1.14 (0.77-1.68)1.14 (0.80-1.62)

* Logistic regression models for each manifestation included all five lead variants (multivariate) and were adjusted for age and sex

Disclosure of Interests

Henrik Leffers: None declared, David Westergaard: None declared, Saedis Saevarsdottir: None declared, Ingileif Jonsdottir: None declared, Ole Birger Pedersen: None declared, Anne Troldborg: None declared, Anne Voss: None declared, Salome Kristensen: None declared, Jesper Lindhardsen: None declared, Prabhat Kumar: None declared, Asta Linauskas: None declared, Lars Juul: None declared, Niels Steen Krogh: None declared, Bent Deleuran: None declared, Lene Dreyer Speakers bureau: Speakers bureau: Eli Lilly, Galderma and Janssen, Grant/research support from: from BMS outside the present work, Michael Schwinn: None declared, Lise wegner Thørner: None declared, Lotte Hindhede: None declared, Christian Erikstrup: None declared, Henrik Ullum: None declared, Søren Brunak Shareholder of: SB has ownerships in Intomics A/S, Hoba Therapeutics Aps, Novo Nordisk A/S, Lundbeck A/S, Kari Stefansson: None declared, Karina Banasik: None declared, Søren Jacobsen: None declared

OP0106 SOLUBLE PD-1 PROMOTES LOCAL IL-17A PRODUCTION IN THE INFLAMED MICROENVIRONMENT IN SpA

Background

Programmed death 1 (PD-1) is an immune checkpoint receptor expressed by activated T-cells. Activation of the PD-1 pathway reduces T cell activation and inflammation. Targeting PD-1 in cancer can result in autoimmune disease, which highlights the importance of this pathway in balancing inflammation. Both PD-1 and its ligands are present in soluble (s) forms, and we have previously showed that sPD-1 is associated to bone erosions in rheumatoid arthritis. Spondyloarthritis (SpA) is characterized by both bone erosions and bone formation. Current evidence suggests an important interaction between the PD-1 pathway and the proinflammatory cytokine IL-17A. IL-17A is central in promoting inflammation in SpA and direct osteoclast activation leading to bone erosion. We have previously demonstrated that the PD-1 ligand, PD-L2, reduces osteoclast formation under inflammatory conditions.

Objectives

We aimed at investigating the interplay between the PD-1 pathway and IL-17A in relation to inflammation and bone homeostasis in patients with SpA.

Methods

From early SpA patients, plasma was collected at baseline and after 1 year of treatment with Adalimumab. From chronic SpA patients, plasma, synovial fluid (SF), peripheral blood mononuclear cells (PBMCs) and synovial fluid mononuclear cells (SFMCs) were collected. Plasma and PBMCs were also collected from healthy controls (HC) for comparison. Disease activity was measured by ASDAS and progression by inflammation and new bone formation in the total spine.

Facet joint biopsies were collected from SpA patients during surgery for correction of rigid hyperkyphosis. Levels of sPD-1 and sPD-L2 were measured in plasma and SF. Surface expression of PD-1 and CCR6 was evaluated on PBMCs and SFMCs. Levels of IL-17A were measured in the supernatant from stimulated PBMC cultures with recombinant human (rh)PD-1. Facet joint biopsies were stained for the presence of PD-1, PD-L1, PD-L2 and CCR6.

Results

Plasma levels of sPD-1 and sPD-L2 were equally increased in both early and chronic SpA compared to HC. Plasma levels of sPD-1 and sPD-L2 did not change following one year of treatment. In chronic SpA patients, sPD-1 levels were higher in SF than in plasma. Levels of sPD-1 and sPD-L2 in plasma and SF did not correlate with any disease activity scores or progression. Expression of PD-1 on the cell surface of PBMCs from SpA patient was comparable to healthy controls. On SFMCs, PD-1 expression was increased, supporting continuous T-cell activation in the local microenvironment. After stimulation with anti CD3/CD28, SpA PBMCs produced more IL-17A when cultured with rhPD-1 compared to healthy control PBMCs.

PD-1 and CCR6 were highly present in facet joint biopsies, but PD-L2 and PD-L1 could not be detected. This supports the PD-1 pathway to play a role at the actual site of pathology.

Conclusion

Plasma levels of the PD-1 family is unaffected by addition of anti-TNFα antibody treatment in SpA. The early SpA cohort had a low degree of progression in structural changes in the observation period, which could explain the lack correlation with sPD-1 and sPD-L2 and disease progression. Soluble PD-1 is high in the inflamed microenvironment, where it may result in increased IL-17A production. Collectively, these data suggest that the PD-1 pathway could play a role in the pathogenesis of SpA, acting in the inflamed microenvironment.

Disclosure of Interests

None declared

AB0100 PHENOTYPIC AND FUNCTIONAL CHARACTERIZATION OF SYNOVIAL FLUID-DERIVED FIBROBLAST-LIKE SYNOVIOCYTES IN RHEUMATOID ARTHRITIS

Background:

Fibroblast-like synoviocytes (FLS) are central cellular components in persistent inflammatory joint diseases such as rheumatoid arthritis (RA). Pathological subsets of FLS have been identified from synovial tissue. However, the synovial tissue obtained from arthroplasty procedures is acquired at late disease stages and the cellular yield obtained from synovial tissue biopsies is fairly low. Collectively, challenging the robustness of human RAin vivoandin vitromodels. FLS obtained from the synovial fluid (SF-FLS) are proposed as an alternative source of FLS, but a detailed phenotypical and functional characterization of FLS subsets from the synovial fluid has not been performed.

Objectives:

The aim of this study was to determine the phenotypical and functional characteristics of synovial fluid-derived fibroblast-like synoviocytes in rheumatoid arthritis.

Methods:

In the present study, paired peripheral blood mononuclear cells (PBMC) and SF-FLS from patients with RA were obtained (n=7). FLS were isolated from the synovial fluid by a strict trypsinization protocol1and their cellular characteristics and functionality were evaluated at passage 4. Monocultures (SF-FLS) and autologous co-cultures (SF-FLS and PBMC) were established from five patients with RA and subsequently evaluated by flow cytometry, Western blotting and multiplex immunoassays. Human cartilage-sponges (n=3) with SF-FLS and without SF-FLS (n=3) were co-implanted subcutaneously in SCID mice (n=15), mice with only cell-free human cartilage-sponges were used as controls (n=12). After 45 days, the implants were evaluated using stained sections to determine the SF-FLS invasion score based on perichondrocytic cartilage degradation. Data are expressed as median (25-75 percentile). P-values <0.05 were considered statistically significant.

Results:

The homogeneous subpopulations of FLS, isolated from the synovial fluid, were negative for CD34 and CD45 [98.9%, (97.5-99.7]) and positive for Thy-1 and PDPN [94.6%, (79.9-97.4]). Without stimulation, RA SF-FLS showed high and comparable levels of NFκB related pathway proteins and secreted multiple pro-inflammatory cytokines and chemokines dominated by IL-6 [2648 pg/mL, (1327-6116)] and MCP-1 [2458 pg/mL, (692-8719)]. SF-FLS increased their ICAM-1 and HLA-DR expression after encountering autologous PBMCs (p<0.01), (p<0.05). Further, SF-FLS and PBMC interacted synergistically in a co-culture model of RA and significantly increasing the secretion of several cytokines (IL-1β, IL-2, IL-6, (p<0.01)) and a chemokine (MCP-1, (p<0.01)). The invasion score of the human SF-FLSin vivowas at primary site, [1.6, (1.3-1.7)] and contralateral implantation site [1.5, (1.1-2.2)]. The invasion score of the human SF-FLS-containing implants both at primary and contralateral site were significantly higher compared with cartilage-sponges evaluated from SF-FLS-free control mice (p<0001).

Conclusion:

This phenotypical and functional characterization of SF-FLS, acquired and activated at the site of pathology, lays a foundation for establishingin vivoandin vitroFLS models. These FLS models will be beneficial in our understanding of the role of this cellular subset in arthritis and for characterization of drugs specifically targeting this pathological RA FLS subset.

References:

[1]Nielsen M. A. et al. Responses to Cytokine Inhibitors Associated with Cellular Composition in Models of Immune-Mediated Inflammatory Arthritis. ACR Open Rheumatology, 2(1):3-10.http://doi.org/10.1002/acr2.11094

Disclosure of Interests:

Ditte Køster: None declared, Johanne Hovgaard Egedal: None declared, Malene Hvid: None declared, Martin Roelsgaard Jakobsen: None declared, Ulf Müller-Ladner Speakers bureau: Biogen, Bent Deleuran: None declared, Tue Wenzel Kragstrup Shareholder of: iBio Tech ApS, Consultant of: Bristol-Myers Squibb, Speakers bureau: TWK has engaged in educational activities talking about immunology in rheumatic diseases receiving speaking fees from Pfizer, Bristol-Myers Squibb, Eli Lilly, Novartis, and UCB., Elena Neumann: None declared, Morten Aagaard Nielsen: None declared

AB0151 PRELIMINARY RESULTS SHOW AN INCREASED EXPRESSION OF COINHIBITORY RECEPTORS IN SYSTEMIC SCLEROSIS

Background:

Recent studies suggest dysregulation in T cell activation in systemic sclerosis (SSc). Co-inhibitory-receptors (Co-IRs) such as TIM-3, PD-1 and LAG-3 play a crucial role in controlling excessive T cell activation and in maintaining immune homeostasis. Engagement of these receptors by their ligand’s limits cytokine production in response to TCR or activating NK receptor stimulation and hence limit tissue damage from excessive immune activation. However, chronically increased expression of multiple Co-IRs is a hallmark of immune exhaustion. We evaluate the role of these soluble Co-IRs in diffuse SSc (dcSSc).

Objectives:

Establish the role of CiR and their ligands in diffuse systemic sclerosis.

Understand how immune regulatory mechanisms influence the development of fibrosis.

Provide a better understanding of the disease and fibrosis in general.

Methods:

PBMC’s(Peripheral blood mononuclear cells) and dermal fibroblasts from SSc patients were isolated and investigated for markers of T cell inhibition. These cells were analysed using flow cytometry in a 10 colour panel. Cells were stained for PD1, TIM3, TIGIT, LAG3, CD3, CD8, CD4 and CD19 along with a Live/dead marker. Co-cultures of fibroblasts and PBMCs will be setup, and treated with various drugs that act on the Co-IRs.

Results:

The proportion of CD4+ T cells expressing PD1 were markedly increased in SSc patients compared to healthy volunteers and Rheumatoid Arthritis patients.

There was increased expression of both TIGIT and TIM3 in the CD4+ T cells. (Figure 1)

Similarly, the co-expression of these receptors on the CD4+ T cell population was elevated compared to healthy volunteers. (figure 2)

Conclusion:

Soluble co-inhibitors are differentially expressed in early dcSSc compared to healthy volunteers and other autoimmune diseases. Our preliminary data indicates that these co inhibitors could play an important role in unravelling the pathogenesis of systemic sclerosis. Inhibition or activation of these receptors through different treatment modalities can be utilized as a novel patient centric treatment strategy.

References:

[1]Fukasawa, T., Yoshizaki, A., Ebata, S., Nakamura, K., Saigusa, R., Miura, S., … Sato, S. (2017). Contribution of Soluble Forms of Programmed Death 1 and Programmed Death Ligand 2 to Disease Severity and Progression in Systemic Sclerosis.Arthritis & Rheumatology,69(9), 1879–1890.

[2]Greisen S, Rasmussen T, Stengaard-Pedersen K, Hetland M, Hørslev-Petersen K, Hvid M, et al. Increased soluble programmed death-1 (sPD-1) is associated with disease activity and radiographic progression in early rheumatoid arthritis. Scand J Rheumatol 2014; 43:101-8.

[3]de Paoli, F., Nielsen, B., Rasmussen, F., Deleuran, B., & Søndergaard, K. (2014). Abatacept induces clinical improvement in patients with severe systemic sclerosis.Scandinavian Journal of Rheumatology,43(4), 342–345.

[4]Kwon, B. (2010). Intervention with costimulatory pathways as a therapeutic approach for graft-versus-host disease.Experimental and Molecular Medicine. Nature Publishing Group.

Acknowledgments:

FOREUM: Foundation of Research in Rheumatology

Disclosure of Interests:

None declared

AB0091 PD-1 AND GAL3 REGULATE OSTEOCLAST DEVELOPMENT IN RHEUMATOID ARTHRITIS

Background:

Bone erosions in rheumatoid arthritis (RA) is a major complication. Despite improved treatment, erosions still occur and progress. Therefore, a continuous investigation of the interplay between bone regulation and immune activity is needed.

Co-inhibitory receptors, like CTLA-4, participate in modulating osteoclast activity1, and blocking these receptors in cancer treatment results in autoimmune disease2. Programmed death 1 (PD-1) is a central co-inhibitory receptor, also present in a soluble (s) form. We have previously shown that sPD-1 is associated with disease activity and reduced bone erosions in RA3. PD-1 and its ligands are glycosylated and the glycosylation affects signaling through the PD-1 pathway4,5. Galectins (GAL) bind to specific glycosylation patterns on glycoproteins by their carbonrecognition domain. Gal-3 can bind to multiple immune receptors shaping the immunological response6.

Objectives:

We aimed to investigate if PD-1 and GAL-3 modulate osteoclastogenesis in RA.

Methods:

Plasma and synovial fluid (SF) samples were collected from patients with chronic (c) RA (>8 years of disease, n=14) SF and blood samples were obtained when patients presented with disease flare. Soluble PD-1 and GAL-3 were investigated by ELISA. GAL-3:PD-1 complexes were captured in an optimized ELISA using both GAL-3 and PD-1 antibodies. Surface plasmon resonance was used to evaluate on the binding properties between GAL-3 and PD-1, on a Biacore 3000. Lactose was used to block the potential binding. Cells from the synovial fluid (SFMC) were differentiated into osteoclasts with M-CSF and RANKL, recombinant human (rh) PD-1 and rhGAL-3 were added and osteoclast formation evaluated by TRAP in the supernatant.

Results:

Soluble PD-1 and GAL-3 were present in both plasma and SF from cRA patient, and the ratio (PD-1/GAL-3) was increased in SF. PD-1:GAL-3 complexes were detected in both plasma and SF, with the highest concentration in SF. The binding between PD-1 and GAL-3 was confirmed by surface plasmon resonance analyses, with an estimated Kd of 5uM. Binding could be blocked by addition of lactose, confirming the binding to be glycan dependent. In SFMC osteoclast cultures, rhPD-1 and rhGAL-3 slightly decreased osteoclast formation evaluated by TRAP. However, combining rhPD-1 and rhGAL3 further potentiated the reduction in osteoclast formation by 37%.

Conclusion:

We confirm glycan depended binding between the co-inhibitory receptor PD-1 and GAL-3. Both sPD-1 and Gal-3, and the PD-1:GAL-3 complexes, are upregulated in the inflamed joint at site of erosions. In vitroRA culture demonstrates that GAL-3 potentiate the functions of PD-1 and reduces osteoclastogenesis. These findings indicate that the binding between Gal-3 and PD-1 could provide a novel target to control erosions in RA. Futurein vivostudies on this interaction is needed.

References:

[1]Axmann, R.et al.CTLA-4 directly inhibits osteoclast formation.Ann Rheum Dis67,1603–1609 (2008).

[2]Friedman, C. F., Proverbs-Singh, T. A. & Postow, M. A. Treatment of the Immune-Related Adverse Effects of Immune Checkpoint Inhibitors.JAMA Oncol2,1346–8 (2016).

[3]Greisen, S.et al.Increased soluble programmed death-1 (sPD-1) is associated with disease activity and radiographic progression in early rheumatoid arthritis.Scand J Rehabil Med43,101–108 (2013).

[4]Verdura, S.et al.Resveratrol targets PD-L1 glycosylation and dimerization to enhance antitumor T-cell immunity.Aging (Albany NY)12,8–34 (2020).

[5]Wang, M.et al.Identification of a monoclonal antibody that targets PD-1 in a manner requiring PD-1 Asn58 glycosylation.Com Biol1–10 (2019). doi:10.1038/s42003-019-0642-9

[6]de Oliveira, F. L.et al.Galectin-3 in autoimmunity and autoimmune diseases.Exp Biol Med (Maywood)240,1019–1028 (2015).

Disclosure of Interests:

None declared

Increased interleukin (IL)-20 and IL-24 target osteoblasts and synovial monocytes in spondyloarthritis

The pathogenesis of spondyloarthritis (SpA) involves activation of the innate immune system, inflammation and new bone formation. The two cytokines interleukin (IL)-20 and IL-24 have been shown to link innate immune activation and tissue homeostasis. We hypothesized that these two cytokines are secreted as part of activation of the innate immune system and affect bone homeostasis in SpA. IL-20 and IL-24 were measured in plasma from axial SpA patients (n = 83). Peripheral SpA patients (n = 16) were included for in-vitro cell culture studies. The plasma IL-20 and IL-24 levels were increased in SpA patients compared with healthy controls (HCs) by 57 and 83%, respectively (both P < 0·0001). The Toll-like receptor 4-induced secretion of the two cytokines was greater in SpA peripheral blood mononuclear cells (PBMCs) compared with HC PBMCs. IL-20 and IL-24 increased the production of monocyte chemoattractant protein-1 by activated SpA synovial fluid monocytes, decreased the production of Dickkopf-1 by SpA fibroblast-like synovial cells and induced mineralization in human osteoblasts. Taken together, our findings indicate disease-aggravating functions of IL-20 and IL-24 in SpA.

Interleukin-23 in early disease development in rheumatoid arthritis

OBJECTIVES

To investigate the levels of interleukin (IL)-23 in patients with early rheumatoid arthritis (eRA) and the effect of anti-tumour necrosis factor (anti-TNF)-α treatment on IL-23 levels.

METHOD

Treatment-naïve eRA patients from the OPERA cohort were included (n = 151). Patients were randomized to methotrexate (MTX) plus adalimumab (ADA; n = 75) or MTX plus placebo-ADA (PLA; n = 76). Plasma samples were obtained at baseline and at months 3, 6, and 12 together with values for C-reactive protein (CRP), the 28-joint Disease Activity Score based on CRP (DAS28CRP), scores on the Clinical Disease Activity Index (CDAI) and the Simplified Disease Activity Index (SDAI), visual analogue scale (VAS) for pain/fatigue/physician global and total Sharp/van der Heijde score (TSS). IL-23 was measured at each time point.

RESULTS

IL-23 levels decreased significantly in the ADA group from 20.6 pg/mL (IQR 13.1-32.7 pg/mL) at baseline to 18 pg/mL (IQR 7.2-25.0 pg/mL) at 12 months (p < 0.01). No significant decrease in IL-23 level was observed in the PLA group. No associations between baseline IL-23 levels and measures of disease activity (DAS28CRP, CRP, CDAI, or SDAI) at 12 or 24 months were present in the treatment groups. Baseline IL-23 correlated inversely with changes in TSS and symptom duration before diagnosis.

CONCLUSIONS

Our data show increased baseline levels and a significant decrease in IL-23 levels in eRA patients treated with anti-TNF-α. The inverse correlation with duration of symptoms before diagnosis supports the importance of IL-23 in the preclinical disease development of RA.

Collectin liver 1 and collectin kidney 1 and other complement-associated pattern recognition molecules in systemic lupus erythematosus

The objective of this study was to explore the involvement of collectin liver 1 (CL-L1) and collectin kidney 1 (CL-K1) and other pattern recognition molecules (PRMs) of the lectin pathway of the complement system in a cross-sectional cohort of systemic lupus erythematosus (SLE) patients. Concentrations in plasma of CL-L1, CL-K1, mannan-binding lectin (MBL), M-ficolin, H-ficolin and L-ficolin were determined in 58 patients with SLE and 65 healthy controls using time-resolved immunoflourometric assays. The SLE patients' demographic, diagnostic, clinical and biochemical data and collection of plasma samples were performed prospectively during 4 months. CL-L1, CL-K1 and M-ficolin plasma concentrations were lower in SLE patients than healthy controls (P-values < 0.001, 0.033 and < 0.001, respectively). H-ficolin concentration was higher in SLE patients (P < 0.0001). CL-L1 and CL-K1 plasma concentrations in the individuals correlated in both patients and controls. Patients with low complement component 3 (C3) demonstrated a negative correlation between C3 and CL-L1 and CL-K1 (P = 0.022 and 0.031, respectively). Patients positive for anti-dsDNA antibodies had lower levels of MBL in plasma than patients negative for anti-dsDNA antibodies (P = 0.02). In a cross-sectional cohort of SLE patients, we found differences in the plasma concentrations of CL-L1, CL-K1, M-ficolin and H-ficolin compared to a group of healthy controls. Alterations in plasma concentrations of the PRMs of the lectin pathway in SLE patients and associations to key elements of the disease support the hypothesis that the lectin pathway plays a role in the pathogenesis of SLE.

Toll-like receptor 2 and 4 induced interleukin-19 dampens immune reactions and associates inversely with spondyloarthritis disease activity

Spondyloarthritis (SpA) is a group of immune mediated inflammatory diseases affecting joints, gut, skin and entheses. The inflammatory process involves activation of Toll-like receptor (TLR)-2 and TLR-4 and production of cytokines and chemokines such as monocyte chemoattractant protein 1 (CCL2/MCP-1). This proinflammatory chemokine recruits monocytes to sites of inflammation and is central in the development of several immune-mediated inflammatory diseases. Interleukin (IL)-19 is a member of the IL-10 family of cytokines. IL-19-deficient mice are more susceptible to innate-mediated colitis and develop more severe inflammation in response to injury. In this work, we studied inducers of IL-19 production and effect of IL-19 on the production of CCL2/MCP-1 and proinflammatory cytokines in peripheral blood mononuclear cells (PBMCs) from healthy controls (HCs) and in PBMCs and synovial fluid mononuclear cells (SFMCs) from SpA patients. Further, we measured IL-19 in plasma from HCs and in plasma and synovial fluid from SpA patients. Constitutive IL-19 expression was present in both PBMCs and SFMCs and the secretion of IL-19 was increased by TLR-2 and TLR-4 ligands. Neutralizing IL-19 in HC PBMCs and SpA SFMCs resulted in increased production of CCL-2/MCP-1. IL-19 concentrations were decreased in synovial fluid compared with plasma and associated inversely with disease activity in SpA. SpA SFMCs produced less IL-19 in response to LPS compared with HC PBMCs. These findings indicate that IL-19 production is diminished in SpA. Taken together, impaired IL-19 control of the innate immune system might be involved in the pathogenesis of SpA.

Flow cytometry detection of vitamin D receptor changes during vitamin D treatment in Crohn's disease

Crohn's disease (CD) is a chronic inflammatory disease associated with a dysregulated T cell response towards intestinal microflora. Vitamin D has immune modulatory effects on T cells through the nuclear vitamin D receptor (VDR) in vitro. It is unclear how oral vitamin D treatment affects VDR expression. The aim of this study was to establish a flow cytometry protocol, including nuclear and cytoplasmic VDR expression, and to investigate the effects of vitamin D treatment on T cell VDR expression in CD patients. The flow cytometry protocol for VDR staining was developed using the human acute monocytic leukaemia cell line (THP-1). The protocol was evaluated in anti-CD3/CD28-stimulated peripheral blood mononuclear cells (PBMCs) from vitamin D3- (n = 9) and placebo-treated (n = 9) CD patients. Anti-VDR-stained PBMCs were examined by flow cytometry, and their cytokine production was determined by cytokine bead array. VDR, CYP27B1 and RXRα mRNA expression levels in CD4(+) T cells were measured by quantitative reverse transcriptase polymerase chain reaction. The flow cytometry protocol enabled detection of cytoplasmic and nuclear VDR expression. The results were confirmed by confocal microscopy and supported by correlation with VDR mRNA expression. VDR expression in CD4(+) T cells increased following stimulation. This VDR up-regulation was inhibited with 30% by vitamin D treatment compared to placebo in CD patients (P = 0027). VDR expression was correlated with in-vitro interferon-γ production in stimulated PBMCs (P = 0.01). Flow cytometry is a useful method with which to measure intracellular VDR expression. Vitamin D treatment in CD patients reduces T cell receptor-mediated VDR up-regulation.

Increased soluble programmed death-1 (sPD-1) is associated with disease activity and radiographic progression in early rheumatoid arthritis

OBJECTIVES

Programmed death-1 (PD-1) is an immunoregulatory molecule functioning by down-regulating immune responses. PD-1 is present on follicular helper T cells (TFH) and is important in the formation of plasma cells. PD-1 exists in a bioactive soluble form (sPD-1) and is thought to be implicated in disease activity in chronic rheumatoid arthritis (RA).

METHOD

We measured sPD-1 at baseline and 9 months after treatment initiation in plasma from early RA patients (n = 34). We tested for correlations with the Disease Activity Score using 28 joint counts (DAS28), the Health Assessment Questionnaire (HAQ) score, immunoglobulin M rheumatoid factor (IgM-RF), anti-cyclic citrullinated peptide (anti-CCP) antibodies, C-reactive protein (CRP), interleukin-21 (IL-21), and total Sharp score (TSS). We also measured sPD-1 in plasma from healthy volunteers (HV) (n = 20) and in plasma and synovial fluid (SF) from patients with chronic RA (> 8 years of disease, n = 30). We further investigated the cellular expression of PD-1 and its ligand PD-L1.

RESULTS

sPD-1 concentrations in early [median 0.421 ng/mL, interquartile range (IQR) 0.04-2.560 ng/mL] and chronic (median 0.239 ng/mL, IQR 0.184-0.584 ng/mL) RA were increased compared with HV (median 0.04 ng/mL, IQR 0.04-0.04 ng/mL) (all p < 0.005). In early RA the change in sPD-1 was associated with DAS28 (r = 0.363, p < 0.05) and HAQ score (r = 0.554, p < 0.05) and inversely with TSS at 3-5 years (r = -0.468, p < 0.05). sPD-1 concentration correlated with IgM-RF, anti-CCP antibodies, and IL-21 (all p < 0.05). PD-1 was primarily expressed by synovial memory T cells whereas PD-L1 was mainly expressed by synovial monocytes.

CONCLUSIONS

The significantly elevated plasma levels of sPD-1 in early RA, the association with core disease parameters, and the inverse correlation with TSS suggest that sPD-1 is an important mediator in inflammatory and radiographic disease progression.

Levels of lectin pathway proteins in plasma and synovial fluid of rheumatoid arthritis and osteoarthritis

The innate immune system contributes to the development of rheumatoid arthritis (RA). A potent contributor to such processes is the complement system. The complement system is known to be activated in the inflammatory phases of osteoarthritis (OA). The lectin pathway of the complement system is activated through the recognition of pathogens or altered self-structures by mannan-binding lectin (MBL) or one of the three ficolins in collaboration with MBL-associated serine proteases (MASPs). We assessed the lectin pathway in plasma and synovial fluid (SF) of 27 RA patients and 30 OA patients by measuring MBL, MASP-2, MASP-3, M-ficolin, and H-ficolin. The concentration for all 5 proteins was significantly higher in plasma than in SF (P < 0.001) and the concentration in paired plasma and SF samples correlated in both RA and OA (significance levels between <0.001 and 0.02). The ratio of SF/plasma concentration was for all proteins significantly elevated in RA compared with OA patients (all P < 0.001). The M-ficolin concentration correlated with the neutrophils in both plasma (P = 0.01) and SF (P < 0.001) of RA, and in plasma of 78 controls (P = 0.03). To our knowledge, this is the first report on these proteins in SF, except for MBL where our results are in contrast to the one previous publication. The results support an important physiological role of the neutrophils in determining the M-ficolin levels in both RA and healthy adults. We suggest that quantifications of white blood cells should be included in future clinical investigations of M-ficolin.

Soluble macrophage-derived CD163 is a marker of disease activity and progression in early rheumatoid arthritis

OBJECTIVES

To investigate the expression of the soluble form of the resident macrophage marker CD163 (sCD163) and its association with core parameters for disease activity, including radiographic progression in early rheumatoid arthritis (RA).

METHODS

In a longitudinal sample set from early RA patients (n=34) we measured plasma levels of sCD163 at initiation of treatment and after 9 months of treatment and correlated levels with disease activity in 28 joints (DAS28), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and total Sharp score (TSS). We also measured plasma levels of sCD163 in 55 healthy volunteers (HV) and in a transverse sample set of chronic (>8 years of disease) RA patients (n=24) and OA patients (n=24) with paired plasma and joint fluid.

RESULTS

Early RA patients had significantly higher plasma levels of sCD163 (1.69mg/l (1.42-2.10)) (median (IQR)) at baseline than after 9 months of treatment (1.28mg/l (0.963-1.66), p=0.001), but not significantly changed compared with HV (1.66mg/l (1.22-2.02)). In early RA patients, baseline levels of sCD163, correlated with DAS28, CRP and ESR. Interestingly, sCD163 at 9 months was associated with radiographic progression (TSS) between year 0 and 5 (r=0.468, p=0.02). Levels of sCD163 were higher in RA patients, than in OA patients and higher in SF than in plasma.

CONCLUSIONS

Plasma levels of macrophage derived sCD163 are associated with disease activity and predict radiographic progression in early RA patients, supporting that sCD163 may have a role as a biomarker of disease activity and that resident macrophages are important for joint destruction.

Monocyte chemoattractant protein 1 (MCP-1) in temporal arteritis and polymyalgia rheumatica

OBJECTIVE

To examine the localisation of monocyte chemoattractant protein 1 (MCP-1) in the inflamed vessel wall in temporal arteritis (TA) and to measure MCP-1 in plasma both in patients with TA and patients with polymyalgia rheumatica (PMR).

METHODS

By immunohistochemical techniques MCP-1 was localised to the vessel wall in patients with TA. In TA, PMR, and healthy controls MCP-1 was quantified by enzyme linked immunosorbent assay (ELISA) in plasma.

RESULTS

MCP-1 was localised to the majority of mononuclear cells, some smooth muscle cells, and giant cells in the arterial biopsy specimens from 12 patients with histologically verified TA. In all sections, including the vasa vasorum, the endothelium stained positive. In the intima 73% (range 57-91%), in the media 49% (range 32-67%), and in the adventitia 74% (range of 62-91%) of all cells stained positive. In plasma MCP-1 was significantly raised in untreated TA (n=33) and untreated PMR (n=27) compared with healthy controls (n=12). Untreated TA plasma levels of MCP-1 (mean 391 pg/ml (range 82-778 pg/ml)) were similar to untreated PMR plasma levels (mean 402 pg/ml (range 29-1153 pg/ml)), and no significant difference was found between the two groups of patients. In both patients with TA and patients with PMR no correlation was found between the plasma level of MCP-1 and the erythrocyte sedimentation rate, haemoglobin concentration, and CD4/CD8 ratio.

CONCLUSIONS

These results show that MCP-1 plays a part in the disease processes of TA and PMR.

Intracutaneous injection of lysophosphatidylcholine induces skin inflammation and accumulation of leukocytes

Various cell stimuli act through activation of phospholipase A2, which hydrolyses fatty acids from membrane phospholipids, resulting in the formation of fatty acids and lysophospholipids. One of the lysophospholipid classes, lysophosphatidylcholine, is a chemoattractant for monocytes and T-lymphocytes and induces the expression of adhesion molecules on cultured endothelial cells. The purpose of the present study was to determine whether lysophosphatidylcholine possesses proinflammatory properties in vivo. This was assessed clinically and histologically by intracutaneous injection of 200-800 nmol lysophosphatidylcholine in healthy volunteers. Lysophosphatidylcholine elicited a dose- and time-dependent local erythema and oedema. The erythema disappeared within 4 h, while the induration lasted for up to 48 h. HE-stained biopsies taken after 24 h showed a leukocytoclastic vasculitis in 2 of the 6 subjects. Microscopic examination of immunohistochemically stained biopsies taken 24 h after the injection showed a significant increase in the number of T-lymphocytes, monocytes and neutrophils, whereas the number of Langerhans' cells was unchanged after lysophosphatidylcholine injection. In addition, the number of intercellular cell adhesion molecule-1 and -3-positive cells was increased approximately 3-fold after injection of lysophosphatidylcholine. In conclusion, the phospholipase A2 hydrolysis product lysophosphatidylcholine can induce erythema, oedema, a mixed cellular infiltrate and the expression of adhesion molecules.

Graded experimental acute pancreatitis: monitoring of a renewed rabbit model focusing on the production of interleukin-8 (IL-8) and CD11b/CD18

OBJECTIVE

To establish and monitor a rabbit model of graded severity of acute pancreatitis to test the hypothesis that interleukin-8 (IL-8) and the adhesion molecule complex CD11b/CD18 are involved in the development of systemic complications in severe acute pancreatitis.

METHODS

Acute pancreatitis induction in rabbits by duct ligation with or without infusion of 5.0% or 0.5% chenodeoxycholic acid or 0.9% saline. Control animals underwent laparotomy. The animals were monitored biochemically, histologically and immunohistochemically.

RESULT

Increased serum levels of IL-8, tumour necrosis factor alpha (TNF-alpha), amylase and lipase were found in the chenodeoxycholic acid groups when compared with the saline, duct-ligated or control groups. Leukopenia, hypocalcaemia, and hyperglycaemia were marked in the 5.0% chenodeoxycholic acid group as compared to the saline, duct-ligated and control groups. Histologically, the 5.0% chenodeoxycholic acid group manifested a significant degree of pancreatic necrosis and neutrophil infiltration. The lungs of these animals showed acute lung injury and a significant up-regulation of CD11b/CD18. IL-8 was produced in pancreatic acinar and ductal cells. A significantly large output of ascitic fluid was seen in the 5.0% chenodeoxycholic acid group.

CONCLUSION

The rabbit models of acute pancreatitis are reliable in that enzymatic and histological evidence of acute pancreatitis with or without systemic complications developed. IL-8 is produced locally in pancreatic acinar and ductal cells and significantly increased in peripheral blood during severe but not mild pancreatitis. The expression of the adhesion molecule complex CD11b/CB18 is significantly increased in lung tissue during severe acute pancreatitis with acute lung injury. IL-8 and CD11b/CB18 are involved in the pathogenesis of severe acute pancreatitis but not of mild oedematous pancreatitis.

IT 9302, a synthetic interleukin-10 agonist, diminishes acute lung injury in rabbits with acute necrotizing pancreatitis

BACKGROUND

Proinflammatory cytokines (eg, tumor necrosis factor [TNF]-alpha, interleukin [IL]-1 and Il- 8) are believed to play an important role in the pathogenesis of acute necrotizing pancreatitis (ANP) and its systemic complications. Recently, IL-10 has emerged as a major anti-inflammatory cytokine, inhibiting the secretion and activities of inflammatory cytokines. Further, a protective effect of IL-10 has recently been shown in experimental acute pancreatitis. The purpose of this study was to test the potential role of a newly developed IL-10 agonist, IT 9302, in a model of ANP in rabbits.

METHODS

ANP was induced in 18 rabbits by retrograde injection of 5% chenodeoxycholic acid in the pancreatic duct, followed by duct ligation. The rabbits were allocated to pretreatment with intravenous physiologic saline solution or IT 9302 (200 micrograms/kg) 30 minutes before the induction of ANP.

RESULTS

Injection of IT 9302 resulted in a significant reduction in the blood levels of TNF-alpha and IL-8 from 3 to 6 hours. IT 9302 also reduced the amount of ascitic fluid and significantly inhibited neutrophil infiltration and margination, as well as the number of CD11b- and CD18-positive cells in the lung tissues. By contrast, the local pancreatic necrosis, as well as the biochemical changes such as serum amylase, lipase, and calcium, was sever and similar in both groups. Survival was improved significantly after treatment with IT 9302.

CONCLUSIONS

As expected, IT 9302 cannot change the degree of ANP induced by 5% bile acid but does reduce mortality rates and the development of acute lung injury, probably through the inhibition of circulating levels of TNF-alpha, IL-8, and the expression of the adhesion molecule complex CD11b/CD18.

IT 9302, a synthetic interleukin-10 agonist, diminishes acute lung injury in rabbits with acute necrotizing pancreatitis

BACKGROUND

Proinflammatory cytokines (eg, tumor necrosis factor [TNF]-alpha, interleukin [IL]-1 and Il- 8) are believed to play an important role in the pathogenesis of acute necrotizing pancreatitis (ANP) and its systemic complications. Recently, IL-10 has emerged as a major anti-inflammatory cytokine, inhibiting the secretion and activities of inflammatory cytokines. Further, a protective effect of IL-10 has recently been shown in experimental acute pancreatitis. The purpose of this study was to test the potential role of a newly developed IL-10 agonist, IT 9302, in a model of ANP in rabbits.

METHODS

ANP was induced in 18 rabbits by retrograde injection of 5% chenodeoxycholic acid in the pancreatic duct, followed by duct ligation. The rabbits were allocated to pretreatment with intravenous physiologic saline solution or IT 9302 (200 micrograms/kg) 30 minutes before the induction of ANP.

RESULTS

Injection of IT 9302 resulted in a significant reduction in the blood levels of TNF-alpha and IL-8 from 3 to 6 hours. IT 9302 also reduced the amount of ascitic fluid and significantly inhibited neutrophil infiltration and margination, as well as the number of CD11b- and CD18-positive cells in the lung tissues. By contrast, the local pancreatic necrosis, as well as the biochemical changes such as serum amylase, lipase, and calcium, was sever and similar in both groups. Survival was improved significantly after treatment with IT 9302.

CONCLUSIONS

As expected, IT 9302 cannot change the degree of ANP induced by 5% bile acid but does reduce mortality rates and the development of acute lung injury, probably through the inhibition of circulating levels of TNF-alpha, IL-8, and the expression of the adhesion molecule complex CD11b/CD18.

A monoclonal anti-interleukin 8 antibody (WS-4) inhibits cytokine response and acute lung injury in experimental severe acute necrotising pancreatitis in rabbits

BACKGROUND

Interleukin 8 (IL-8) has recently been proposed to have an important role in mediating the development of the systemic sequelae associated with severe acute pancreatitis.

AIMS

To define the role of IL-8 in acute pancreatitis by neutralising its effects with a monoclonal anti-IL-8 antibody (WS-4), in a rabbit model of severe acute pancreatitis.

METHODS

Acute pancreatitis was induced by retrograde injection of 5% chenodeoxycholic acid into the pancreatic duct and duct ligation. Twenty rabbits were divided equally into two groups: acute pancreatitis controls received physiological saline and the treated group received WS-4, 30 minutes before induction of acute pancreatitis.

RESULTS

Pretreatment of animals with WS-4 resulted in significant down regulation of serum IL-8 and tumour necrosis factor alpha (TNF-alpha) from three to six hours after induction of acute pancreatitis (p = 0.011 and 0.047 for IL-8 and 0.033 and 0.022 for TNF-alpha, respectively). In addition, a significant reduction in the CD11b and CD18 positive cells and the amount of interstitial neutrophil infiltration in the lungs from WS-4 treated animals was seen. In contrast, WS-4 did not alter the amount of pancreatic necrosis and the serum concentrations of amylase, lipase, calcium, and glucose.

CONCLUSION

WS-4 cannot change the amount of pancreatic necrosis induced by injection of 5% bile acid, but does reduce the acute lung injury, presumably through inhibition of circulating IL-8 and TNF-alpha, and CD11b/CD18 in lung tissue. Therefore, a role of IL-8 in the progression of acute pancreatitis and the development of its systemic complications is suggested.

Soluble intercellular adhesion molecule-1 (sICAM-1) and soluble interleukin-2 receptors (sIL-2R) in scleroderma skin

In order to investigate whether soluble intercellular adhesion molecule-1 (sICAM-1) and soluble interleukin-2 receptors (sIL-2R) were present in scleroderma skin, and to compare their levels to concentrations measured in plasma and clinical parameters, we examined suction blister fluid and plasma from 13 patients with systemic sclerosis and 11 healthy volunteers. Suction blisters and biopsies were from the transition zone between normal skin and scleroderma, and uninvolved abdominal skin. The levels of sICAM-1 and sIL-2R were significantly increased in both plasma and suction blister fluid from systemic sclerosis patients compared with healthy volunteers. ICAM-1 was localized to vessels and perivascular mononuclear infiltrates by immunohistochemical methods. IL-2R was expressed by CD3-positive cells. The elevated levels of sICAM-1 and sIL-2R in suction blister fluid point towards activation of endothelial cells and T cells in both the transition zone and uninvolved skin of systemic sclerosis patients.

CD19-selected B lymphocytes synthesize, secrete and migrate in the presence of IL-8. TNF-alpha and gammaIP-10 are also B lymphocyte migratory factors

B lymphocytes are responsible for antigen uptake and presentation, as well as antibody production. These reactions require close cell-to-cell contact between B lymphocytes and monocytes. In this study we demonstrate that interleukin 8 (IL-8), gamma-immune protein 10 (gammaIP-10) and tumour necrosis factor alpha (TNF-alpha) all induce a significant chemokinetic response of human B lymphocytes. Among the cytokines tested, rIL-8 was the strongest B lymphocyte migratory factor with a migratory index (MI) of 2.03+/-0.32, (P<0.002), followed by rTNF-alpha (MI=1.89+/-0.17, P<0.001) and rgammaIP-10 (MI=1.63+/-0.17, P<0.001). We did not observe B lymphocyte migration towards rIL-1alpha, rIL-2, rIL-4, rIL-10, interferon gamma (rINF-gamma) or transforming growth factor beta (rTGF-beta). Furthermore, we report that human B lymphocytes have a constitutive IL-8 mRNA expression and protein secretion in vitro. Resting as well as stimulated B lymphocytes secrete on average 1.5 ng IL-8/ml medium/24 h (2x10(6) B lymphocytes). Our data indicate a possible mechanism by which B lymphocytes make contact with other cells, during immuno-inflammatory processes.

Increased levels of type I and III collagen and hyaluronan in scleroderma skin

The aminoterminal propeptide of type III procollagen (PIIINP) and the carboxyterminal propeptide of type I procollagen (PICP) and hyaluronan (HA) were measured in plasma and suction blister fluid from 13 systemic sclerosis patients and 11 healthy volunteers. Suction blisters and skin biopsies were from the transition zone between normal skin and scleroderma, and uninvolved abdominal skin of patients. The median value of suction blister PIIINP from the transition zone was 38% higher than suction blister PIIINP from uninvolved skin. PIIINP was localized to the dermis by immunohistochemical techniques. PICP and HA levels in blisters from the transition zone were 87% and 53%, respectively, above the levels measured in uninvolved skin. Furthermore, PICP and HA blister levels from the transition zone were 67% and 63%, respectively, higher than the levels measured in healthy volunteers. In plasma from scleroderma patients levels of PIIINP and HA were 38% and 127% higher, respectively, than in plasma of healthy volunteers. The plasma PICP level was not significantly higher in scleroderma patients. Finally, PICP, PIIINP and HA levels were several times higher in suction blister fluid than in plasma. The data indicate that a fibrogenetic process takes place in the transition zone of scleroderma. The method may be used to monitor the progression of scleroderma skin lesions in vivo.

Localization of monocyte chemotactic and activating factor (MCAF/MCP-1) in psoriasis

The monocyte chemotactic protein-1 (MCAF) also termed MCP-1, a strong chemotactic factor towards monocytes, is produced by several cell types present in the skin. The in situ presence of MCAF/MCP-1 protein in the skin has, however, not yet been established. Using immunohistochemical techniques we have investigated the distribution of MCAF in skin from patients with different types of psoriasis and normal healthy volunteers. We report the novel finding that psoriasis has strong positive immunostaining for MCAF located to all the layers of the epidermis, except the stratum granulosum, in pustular, guttate and chronic plaque psoriasis. In the dermis, infiltrating cells in the perivascular aggregates and the blood vessels stained positive for MCAF. No significant differences were observed between the different subtypes of psoriasis except that strongly positive infiltrating cells were observed in the epidermal pustules in pustular psoriasis. In normals positive staining was observed in all the layers of the epidermis and in a few perivascular cells and blood vessels in the dermis. Where present in normal and diseased skin, eccrine ducts of sweat glands and sebaceous glands stained positive for MCAF. Arrector pili muscles were in all cases negative. These findings are consistent with a role for MCAF in attracting inflammatory cells, including monocytes, into the skin in psoriasis.

LTA4 hydrolase in human skin: decreased activity, but normal concentration in lesional psoriatic skin. Evidence for different LTA4 hydrolase activity in human lymphocytes and human skin

Leukotriene A4 (LTA4) hydrolase which transforms LTA4 into the proinflammatory compound LTB4 has been identified in human epidermis. The purpose of this study was to investigate the potential role of this enzyme in psoriasis, in which LTB4 is present in biologically active concentrations. The concentration and activity of LTA4 hydrolase was determined in normal skin and in matched samples of involved and uninvolved psoriatic skin. The enzyme content was determined using an affinity-purified antibody. This antibody was also used for immunohistochemical staining of skin biopsies. Immunohistochemically LTA4 hydrolase was localized predominantly in the basal and spinous layers in normal skin and in involved and uninvolved psoriatic skin. The LTA4 hydrolase content varied between 2.8 and 3.1 micrograms enzyme/mg protein and was found to be similar in normal and psoriatic skin, involved as well as uninvolved. In contrast, the activity of the enzyme was decreased significantly in involved psoriatic skin (9.9 +/- 2.1 micrograms LTB4/mg enzyme per min) compared with matched uninvolved psoriatic skin (16.4 +/- 3.5 micrograms LTB4/mg enzyme per min), but was decreased only insignificantly compared with normal skin (12.4 +/- 1.8 micrograms LTB4/mg enzyme per min). It was found that the conversion of LTA4 to LTB4 results in inactivation of LTA4 hydrolase activity. This finding is compatible with the idea that the decreased LTA4 hydrolase activity in involved psoriatic skin reflects transcellular LTB4 formation in vivo. In peripheral lymphocytes the enzyme content was 1.3 +/- 0.3 microgram enzyme/mg protein in normal lymphocytes and 1.4 +/- 0.3 microgram enzyme/mg protein in psoriatic lymphocytes, which was significantly lower than in the skin. In contrast, the specific LTA4 hydrolase activities in normal and psoriatic lymphocytes (23.4 +/- 1.3 and 21.3 +/- 1.7 micrograms LTB4/mg enzyme per min) were significantly higher than in normal skin. These findings may indicate the existence of LTA4 hydrolase isoforms in human lymphocytes and human skin.

Polyethylene particles stimulate monocyte chemotactic and activating factor production in synovial mononuclear cells in vivo. An immunohistochemical study in rabbits

We report that polyethylene particles can activate mononuclear cells within the joint to produce the monocyte chemotactic and activating factor (MCAF) and to a lesser degree interleukin 8 (IL-8) as judged by immunohistological staining. Polyethylene particles suspended in hyaluronic acid were injected weekly for 12 weeks into the right knee joint of New Zealand white rabbits. The average size of the particles was 7 (3-12) microns in diameter. The left knee joint was injected with hyaluronic acid as the control. The animals were killed after 13 weeks. On the control side, the synovial membrane was histologically normal, without signs of inflammation. In the knees that were injected with polyethylene particles, histological analysis showed a weak inflammatory response, consisting of mononuclear cells, multi-nucleated giant cells and polyethylene particles. In the vicinity of the particles, the presence of mononuclear cells that were highly positive for MCAF was noted, whereas IL-8 was present in endothelial cells and in the lining layer, but not in cells in the vicinity of polyethylene particles, suggesting that polyethylene particles are able to activate cytokine metabolism in a differentiated way in the synovial monocytes.

Chemotaxis of human osteoblasts. Effects of osteotropic growth factors

The in vitro chemotactic response of human osteoblasts was investigated towards the following growth factors: TGF-beta, PDGFs, FGFs and IGFs. Human osteoblasts grown from trabecular bone after enzymatic digestion were studied. TGF-beta stimulated the migration of human osteoblasts in a dose-dependent manner with a four-fold increase in migrated cells at 100 pg/ml, which was the optimum concentration. PDGF-BB also stimulated migration four-fold in a dose-dependent manner with a maximum response at 10 ng/ml. PDGF-AA, IGF-I and IGF-II stimulated migration two-fold at 100 ng/ml. The results show that TGF-beta and PDGF-BB are important regulators of human osteoblast migration, but other growth factors IGF-I, IGF-II and PDGF-AA may also stimulate osteoblast migration. Our results additionally suggest that TGF-beta and PDGF-BB may participate in the recruitment of osteoblasts during bone remodeling since both TGF-beta and PDGF-BB are found in bone matrix and could be released during osteoclastic bone resorption. They furthermore support a possible use of TGF-beta and PDGF-BB in growth factor-induced osteogenesis.

Interleukin-8 induces its own production in CD4+ T lymphocytes: a process regulated by interleukin 10

The neutrophil and T cell chemotactic factor interleukin 8 (IL-8) is believed to play a pathophysiological role in the development of various inflammatory disorders. So far no other effects of IL-8 on T cells have been observed. We observed that purified CD4+ T cells in particular, but also CD8+ T cells, spontaneously synthesize IL-8 mRNA and secrete IL-8 protein. The culture supernatants of CD4+ T cells contained T cell chemotactic activity as well as IL-8 protein. In addition, we confirmed the ability of CD4+ T cells to produce IL-8 by double immunofluorescence staining and by the demonstration of IL-8 mRNA expression. Further, IL-8 induced its own production in CD4+ T cells, while its synthesis by CD8+ T cells was low and not always auto-stimulatory. Both the spontaneous, as well as the IL-8 induced IL-8 production, could be inhibited in the presence of human interleukin 10 (100 ng/ml). This observation suggests that IL-10 plays a homeostatic role in regulating the IL-8 circuit in CD4+ T cells.

Cetirizine inhibits the in vitro and ex vivo chemotactic response of T lymphocytes and monocytes

We have studied the effect of a nonsedating antihistamine, cetirizine dihydrochloride, on the in vitro chemotaxis of leukocytes from human peripheral blood. We observed that 0.25 microgram/ml of cetirizine dihydrochloride in vitro significantly inhibited the chemotaxis of monocytes toward N-formyl-methionyl-leucyl-phenylalanine and leukotriene B4. Higher concentrations of cetirizine, 1.0 and 2.5 micrograms/ml, completely inhibited monocyte chemotaxis without affecting cell viability. T-lymphocyte migration was also significantly depressed but not abolished. Pyrilamine (mepyramine) was not inhibitory in equimolar concentrations. According to these in vitro observations, we extended our studies to measure monocyte and T-lymphocyte chemotaxis in an open study, where four healthy volunteers and six patients with atopic dermatitis took 10 and 20 mg/day cetirizine 3 days. We observed a reduction in ex vivo monocyte and T-lymphocyte chemotaxis toward N-formyl-methionyl-leucyl-phenylalanine and leukotriene B4 without a reduction of the blood cell count. The results were confirmed in an ensuing double-blind, placebo-controlled study of 16 healthy subjects and 14 adult patients with atopic dermatitis, where ex vivo monocyte chemotaxis was reduced or abolished during cetirizine therapy. Serum levels of the two eosinophil-derived granule proteins, eosinophilcationic protein P and eosinophil protein X, were not changed during the treatment period of 7 days. The results show that cetirizine dihydrochloride has an inhibitory effect on monocytes and T lymphocytes in vitro and ex vivo. Our findings support the clinical observations that cetirizine dihydrochloride has an antiinflammatory effect besides its H1-blocking activity.

Interleukin 13 suppresses cytokine production and stimulates the production of 15-HETE in PBMC. A comparison between IL-4 and IL-13

We examined the ability of rIL-13 to regulate rIL-l alpha induced IL-1 beta, IL-1 receptor antagonist (IL-1ra) and IL-8 production in cultured peripheral blood mononuclear cells (PBMC), endothelial cells and fibroblasts. Furthermore we examined whether rIL-13 could influence the production of the arachidonic acid products LTB4, 12-HETE and 15-HETE by PBMC. rIL-1 alpha-stimulated PBMC cultures secreted high levels of IL-1 beta and IL-8; this could be inhibited to the level of unstimulated control cells by co-incubation with rIL-13 (10 ng/ml). IL-13 induced a 3-fold increase of the IL-1ra secretion which was inhibited by rIFN-gamma. In the presence of both rIL-1 alpha and rIL-13, endothelial cells increased IL-8 secretion, whereas dermal fibroblasts remained unchanged. Of the arachidonic acid metabolites examined, the greatest change was observed in the formation of 15-HETE. In unstimulated PBMC cultures the amount of 15-HETE was less than 4 ng/10(6) cells, whereas after addition of rIL-13 we measured a formation of 139 +/- 6.2 ng/10(6) cells. The effect of rIL-13 on the 15-HETE formation in PBMC was abolished by addition of 100 U/ml rIFN-gamma. rIL-13 only induced minor changes in the LTB4 and 12-HETE formation. Compared to IL-4, IL-13 induced a similar alteration of the cytokine cascade and arachidonic acid metabolism, supporting the hypothesis that the two cytokines use a common receptor complex or signal pathway.

Regulation of human T lymphocyte chemotaxis in vitro by T cell-derived cytokines IL-2, IFN-gamma, IL-4, IL-10, and IL-13

There has been a number of conflicting reports regarding the T lymphocyte chemotactic activities of several cytokines. IL-2 and IFN-gamma are known to promote augmentation of immune inflammation, whereas IL-4, IL-10, and IL-13 display immunomodulatory effects on inflammatory cells including inhibition of cytokine production. Their effects on chemotaxis of inflammatory cells are unknown. We observed that IL-1 alpha could induce chemotaxis both in overnight cultured and anti-CD3 mAb-activated T lymphocytes and that overnight culture and anti-CD3 activation increase the number of IL-1R on T lymphocytes. In contrast, IL-8 selectively attracts freshly isolated T lymphocytes. Staurosporine inhibits freshly isolated T lymphocyte chemotaxis toward IL-8, whereas tyrphostin 23 inhibits chemotaxis of overnight cultured and anti-CD3-activated T lymphocytes toward IL-1 alpha. We have found that IL-2 and IL-13 inhibit the chemotactic migration of both CD4+ and CD8+ T lymphocytes toward IL-8, and RANTES. IL-4 inhibits only CD8+ T lymphocyte chemotaxis toward RANTES, IL-8 and IL-10. IL-10 inhibits only CD4+ T lymphocytes in their chemotactic response toward RANTES and IL-8. IFN-gamma does on the other hand augment the sensitivity of human T lymphocytes to chemotactic stimuli. Thus, our results demonstrate that different proinflammatory cytokines will induce chemotactic migration of T lymphocytes under different circumstances acting through different signaling pathways. The T cell-derived cytokines IL-2, IL-4, IL-10, and IL-13 are able to block further T lymphocyte chemotaxis, thus leading to a focusing of T lymphocytes in an area of T lymphocyte activation. These mechanisms seem relevant in our understanding of the specific and continuous localization of T lymphocytes in allergic and autoimmune disorders.