IL11-mediated stromal cell activation may not be the master regulator of pro-fibrotic signaling downstream of TGFβ

Fibrotic diseases, such as idiopathic pulmonary fibrosis (IPF) and systemic scleroderma (SSc), are commonly associated with high morbidity and mortality, thereby representing a significant unmet medical need. Interleukin 11 (IL11)-mediated cell activation has been identified as a central mechanism for promoting fibrosis downstream of TGFβ. IL11 signaling has recently been reported to promote fibroblast-to-myofibroblast transition, thus leading to various pro-fibrotic phenotypic changes. We confirmed increased mRNA expression of IL11 and IL11Rα in fibrotic diseases by OMICs approaches and in situ hybridization. However, the vital role of IL11 as a driver for fibrosis was not recapitulated. While induction of IL11 secretion was observed downstream of TGFβ signaling in human lung fibroblasts and epithelial cells, the cellular responses induced by IL11 was quantitatively and qualitatively inferior to that of TGFβ at the transcriptional and translational levels. IL11 blocking antibodies inhibited IL11Rα-proximal STAT3 activation but failed to block TGFβ-induced profibrotic signals. In summary, our results challenge the concept of IL11 blockade as a strategy for providing transformative treatment for fibrosis.

A genome-wide association study suggests new susceptibility loci for primary antiphospholipid syndrome

Objectives

Primary antiphospholipid syndrome (PAPS) is a rare autoimmune disease characterized by the presence of antiphospholipid antibodies and the occurrence of thrombotic events and pregnancy complications. Our study aimed to identify novel genetic susceptibility loci associated with PAPS.

Methods

We performed a genome-wide association study comprising 5,485 individuals (482 affected individuals) of European ancestry. Significant and suggestive independent variants from a meta-analysis of approximately 7 million variants were evaluated for functional and biological process enrichment. The genetic risk variability for PAPS in different populations was also assessed. Hierarchical clustering, Mahalanobis distance, and Dirichlet Process Mixtures with uncertainty clustering methods were used to assess genetic similarities between PAPS and other immune-mediated diseases.

Results

We revealed genetic associations with PAPS in a regulatory locus within the HLA class II region near HLA-DRA and in STAT4 with a genome-wide level of significance. 34 additional suggestive genetic susceptibility loci for PAPS were also identified. The disease risk allele in the HLA class II locus is associated with overexpression of HLA-DRB6 , HLA-DRB9 , HLA-DPB2 , HLA-DQA2 and HLA-DQB2 , and is independent of the association between PAPS and HLA-DRB1*1302 . Functional analyses highlighted immune and nervous system related pathways in PAPS-associated loci. The comparison with other immune-mediated diseases revealed a close genetic relatedness to neuromyelitis optica, systemic sclerosis, and Sjögren's syndrome, suggesting colocalized causal variations close to STAT4 , TNPO3 , and BLK .

Conclusions

This study represents a comprehensive large-scale genetic analysis for PAPS and provides new insights into the genetic basis and pathophysiology of this rare disease.

Multi-omics approach identifies PI3 as a biomarker for disease severity and hyper-keratinization in psoriasis

BACKGROUND

Psoriasis is an immune-mediated inflammatory skin disease. Psoriasis severity evaluation is important for clinicians in the assessment of disease severity and subsequent clinical decision making. However, no objective biomarker is available for accurately evaluating disease severity in psoriasis.

OBJECTIVE

To define and compare biomarkers of disease severity and progression in psoriatic skin.

METHODS

We performed proteome profiling to study the proteins circulating in the serum from patients with psoriasis, psoriatic arthritis and ankylosing spondylitis, and transcriptome sequencing to investigate the gene expression in skin from the same cohort. We then used machine learning approaches to evaluate different biomarker candidates across several independent cohorts. In order to reveal the cell-type specificity of different biomarkers, we also analyzed a single-cell dataset of skin samples. In-situ staining was applied for the validation of biomarker expression.

RESULTS

We identified that the peptidase inhibitor 3 (PI3) was significantly correlated with the corresponding local skin gene expression, and was associated with disease severity. We applied machine learning methods to confirm that PI3 was an effective psoriasis classifier, Finally, we validated PI3 as psoriasis biomarker using in-situ staining and public datasets. Single-cell data and in-situ staining indicated that PI3 was specifically highly expressed in keratinocytes from psoriatic lesions.

CONCLUSION

Our results suggest that PI3 may be a psoriasis-specific biomarker for disease severity and hyper-keratinization.

Pyruvate metabolism controls chromatin remodeling during CD4+ T cell activation

Upon antigen-specific T cell receptor (TCR) engagement, human CD4+ T cells proliferate and differentiate, a process associated with rapid transcriptional changes and metabolic reprogramming. Here, we show that the generation of extramitochondrial pyruvate is an important step for acetyl-CoA production and subsequent H3K27ac-mediated remodeling of histone acetylation. Histone modification, transcriptomic, and carbon tracing analyses of pyruvate dehydrogenase (PDH)-deficient T cells show PDH-dependent acetyl-CoA generation as a rate-limiting step during T activation. Furthermore, T cell activation results in the nuclear translocation of PDH and its association with both the p300 acetyltransferase and histone H3K27ac. These data support the tight integration of metabolic and histone-modifying enzymes, allowing metabolic reprogramming to fuel CD4+ T cell activation. Targeting this pathway may provide a therapeutic approach to specifically regulate antigen-driven T cell activation.

Identification of Novel Associations and Localization of Signals in Idiopathic Inflammatory Myopathies Using Genome-Wide Imputation

OBJECTIVE

The idiopathic inflammatory myopathies (IIMs) are heterogeneous diseases thought to be initiated by immune activation in genetically predisposed individuals. We imputed variants from the ImmunoChip array using a large reference panel to fine-map associations and identify novel associations in IIM.

METHODS

We analyzed 2,565 Caucasian IIM patient samples collected through the Myositis Genetics Consortium (MYOGEN) and 10,260 ethnically matched control samples. We imputed 1,648,116 variants from the ImmunoChip array using the Haplotype Reference Consortium panel and conducted association analysis on IIM and clinical and serologic subgroups.

RESULTS

The HLA locus was consistently the most significantly associated region. Four non-HLA regions reached genome-wide significance, SDK2 and LINC00924 (both novel) and STAT4 in the whole IIM cohort, with evidence of independent variants in STAT4, and NAB1 in the polymyositis (PM) subgroup. We also found suggestive evidence of association with loci previously associated with other autoimmune rheumatic diseases (TEC and LTBR). We identified more significant associations than those previously reported in IIM for STAT4 and DGKQ in the total cohort, for NAB1 and FAM167A-BLK loci in PM, and for CCR5 in inclusion body myositis. We found enrichment of variants among DNase I hypersensitivity sites and histone marks associated with active transcription within blood cells.

CONCLUSION

We found novel and strong associations in IIM and PM and localized signals to single genes and immune cell types.

Efficacy and Safety of ABBV-3373, a Novel Anti-Tumor Necrosis Factor Glucocorticoid Receptor Modulator Antibody Drug Conjugate, in Adults with Moderate to Severe Rheumatoid Arthritis Despite Methotrexate Therapy: a Randomized, Double-Blind, Active-Controlled Proof-of-Concept Phase 2a Trial

OBJECTIVE

To assess the efficacy and safety of ABBV-3373, a novel antibody drug conjugate (ADC) composed of the anti-tumor necrosis factor (TNF) monoclonal antibody adalimumab linked to a glucocorticoid receptor modulator (GRM), versus adalimumab in patients with rheumatoid arthritis (RA).

METHODS

In this randomized, double-blind, active-controlled proof-of-concept trial (NCT03823391), adults with moderate/severe RA on background methotrexate received intravenous ABBV-3373 100 mg every other week (EOW) for 12 weeks, followed by placebo for 12 weeks, or subcutaneous adalimumab 80 mg EOW for 24 weeks.

PRIMARY ENDPOINT

change from baseline in DAS28(CRP) at week 12 with two pre-specified primary comparisons of ABBV-3373 versus historical adalimumab (80 mg EOW or equivalent dose) and versus combined in-trial/historical adalimumab. Secondary endpoints: change from baseline in CDAI, SDAI, and DAS28(ESR); proportion of patients achieving DAS28(CRP) ≤3.2 and ACR50.

RESULTS

48 patients were randomized to ABBV-3373 (n=31) or adalimumab (n=17). At week 12, ABBV-3373 reduced DAS28(CRP) versus historical adalimumab (-2.65 versus -2.13; P=0.022) and combined in-trial/historical adalimumab (-2.65 versus -2.29; probability=89.9%), with numerically greater improvement than in-trial adalimumab (-2.51). For secondary endpoints, greater efficacy was observed with ABBV-3373 versus historical adalimumab; ABBV-3373 was predicted with 79.3-99.5% probability to be better than adalimumab based on combined in-trial/historical adalimumab data. Of the ABBV-3373-treated patients that achieved DAS28(CRP) ≤3.2 at week 12, 70.6% maintained this response at week 24 despite switching to placebo. Four serious adverse events (SAEs) were reported with ABBV-3373 (non-cardiac chest pain, pneumonia, upper respiratory tract infection, and anaphylactic shock) and two SAEs with adalimumab (breast abscess and bronchitis). After increasing the duration of ABBV-3373 IV administration from 3 min to 15-30 min, no similar events of anaphylactic shock were reported.

CONCLUSION

Data from this proof-of-concept trial support the continued development of a TNF-GRM-ADC for the treatment of RA, with the potential to achieve superior outcomes compared to currently available therapies.

Multi-omics integration reveals a core network involved in host defence and hyperkeratinization in psoriasis

OBJECTIVES

The precise pathogenesis of psoriasis remains incompletely explored. We aimed to better understand the underlying mechanisms of psoriasis, using a systems biology approach based on transcriptomics and microbiome profiling.

METHODS

We collected the skin tissue biopsies and swabs in both lesional and non-lesional skin of 13 patients with psoriasis, 15 patients with psoriatic arthritis and healthy skin from 12 patients with ankylosing spondylitis. To study the similarities and differences in the molecular profiles between these three conditions, and the associations between the host defence and microbiota composition, we performed high-throughput RNA-sequencing to quantify the gene expression profile in tissues. The metagenomic composition of 16S on local skin sites was quantified by clustering amplicon sequences and counted into operational taxonomic units. We further analysed associations between the transcriptome and microbiome profiling.

RESULTS

We found that lesional and non-lesional samples were remarkably different in terms of their transcriptome profiles. The functional annotation of differentially expressed genes showed a major enrichment in neutrophil activation. By using co-expression gene networks, we identified a gene module that was associated with local psoriasis severity at the site of biopsy. From this module, we found a 'core' set of genes that was functionally involved in neutrophil activation, epidermal cell differentiation and response to bacteria. Skin microbiome analysis revealed that the abundances of Enhydrobacter, Micrococcus and Leptotrichia were significantly correlated with the genes in core network.

CONCLUSIONS

We identified a core gene network that associated with local disease severity and microbiome composition, involved in the inflammation and hyperkeratinization in psoriatic skin.

POS0365 ANTI-TNF GLUCOCORTICOID RECEPTOR MODULATOR ANTIBODY DRUG CONJUGATE FOR THE TREATMENT OF AUTOIMMUNE DISEASES

Background:

Glucocorticoids (GC) are potent drugs used for treating many inflammatory diseases. While GCs are effective in many immune diseases, dose and duration of administration is limited due to significant side effects. Resting immune cells have very little TNF expression on the cell surface and it is only in an activated state that TNF expression is upregulated. Upon immune cell stimulation, TNF is upregulated and although a significant amount of TNF is cleaved from an activated cell, a portion remains on the cell surface. We have observed that anti-TNF antibodies bind to transmembrane TNF (tmTNF) and undergo endocytosis to the lysosome (1). We have developed a stable antibody drug conjugate (ADC), ABBV-3373, that has a proprietary, highly potent, glucocorticoid receptor modulator (GRM) payload linked to an anti-TNF monoclonal antibody (mAb) that is able to deliver the GC payload to activated immune cells.

Objectives:

We hypothesized that a TNF ADC with a GRM payload would be able to deliver increased efficacy through both TNF inhibition and targeted GRM payload delivery to activated immune cells while sparing systemic glucocorticoid side effects.

Methods:

A mouse surrogate TNF GRM ADC was characterized in an acute in vivo contact hypersensitivity model of inflammation (CHS) and in a mouse model of collagen induced arthritis (mCIA). Additionally, the human anti-TNF GRM ADC, ABBV-3373 has been characterized in healthy volunteers.

Results:

In the CHS model the anti-TNF GRM ADC significantly inhibited the inflammatory response with minimal effect on systemic GC biomarkers. In mCIA a single dose of an anti-TNF GRM ADC, administered at disease onset, was able to completely inhibit arthritis for greater than 30 days while an anti-TNF mAb only partially inhibited disease. ABBV-3373, a human anti-TNF GRM ADC with a GC payload, was evaluated in a Phase 1 study in healthy volunteers. ABBV-3373 demonstrated antibody-like PK profile and ABBV-3373 did not impact cortisol levels at predicted efficacious doses while control subjects that received a single oral dose of 10 mg prednisone demonstrated expected decreases in cortisol levels.

Conclusion:

These data suggest that an anti-TNF ADC delivering a GRM payload into activated immune cells may provide improved efficacy in immune mediated diseases, while minimizing systemic side effects associated with standard GC treatment.

References:

[1]Deora, A. et al. MABs. 2017;9(4):680-695.

Disclosure of Interests:

Bob Stoffel Shareholder of: AbbVie, Grant/research support from: AbbVie, Employee of: AbbVie, Michael McPherson Shareholder of: AbbVie, Grant/research support from: AbbVie, Employee of: AbbVie, Axel Hernandez Shareholder of: AbbVie, Grant/research support from: AbbVie, Employee of: AbbVie, Christian Goess Shareholder of: AbbVie, Grant/research support from: AbbVie, Employee of: AbbVie, Suzanne Mathieu Shareholder of: AbbVie, Grant/research support from: AbbVie, Employee of: AbbVie, Wendy Waegell Shareholder of: AbbVie, Grant/research support from: AbbVie, Employee of: AbbVie, Shaughn Bryant Shareholder of: AbbVie, Grant/research support from: AbbVie, Employee of: AbbVie, Adrian Hobson Shareholder of: AbbVie, Grant/research support from: AbbVie, Employee of: AbbVie, Melanie Ruzek Shareholder of: AbbVie, Grant/research support from: AbbVie, Employee of: AbbVie, Yinuo Pang Shareholder of: AbbVie, Grant/research support from: AbbVie, Employee of: AbbVie, Hartmut Kupper Shareholder of: AbbVie, Grant/research support from: AbbVie, Employee of: AbbVie, Ronilda D’Cunha Shareholder of: AbbVie, Grant/research support from: AbbVie, Employee of: AbbVie, Julie Parmentier Shareholder of: AbbVie, Grant/research support from: AbbVie, Employee of: AbbVie, Timothy Radstake Shareholder of: AbbVie, Grant/research support from: AbbVie, Employee of: AbbVie

OP0115 EFFICACY AND SAFETY OF ABBV-3373, A NOVEL ANTI-TNF GLUCOCORTICOID RECEPTOR MODULATOR ANTIBODY DRUG CONJUGATE, IN PATIENTS WITH MODERATE TO SEVERE RHEUMATOID ARTHRITIS DESPITE METHOTREXATE THERAPY: A PHASE 2A PROOF OF CONCEPT STUDY

Background:

ABBV-3373 is a novel antibody drug conjugate composed of adalimumab (ADA) linked to a proprietary and highly potent glucocorticoid receptor modulator (the anti-inflammatory payload) currently evaluated for the treatment of rheumatoid arthritis (RA).

Objectives:

To assess the efficacy and safety of ABBV-3373 vs ADA in RA patients (pts).

Methods:

This was a 24-week (wk) randomized, double-blind, double-dummy, active-controlled Phase 2a study of intravenously (IV)-administered ABBV-3373 100 mg (for 12 wks followed by placebo [PBO] for 12 wks) vs subcutaneous injections of ADA 80 mg every other wk (for 24 wks) in pts on background methotrexate. The primary endpoint was the change from baseline (BL) in DAS28(CRP) at Wk 12. Pre-planned statistical methods incorporating pre-specified historical ADA data both alone (pre-specified success criterion, 2-sided P ≤0.1) and supplemented with in-trial ADA data (pre-specified success criterion, probability >95%) were used to achieve adequate statistical power with a reduced trial size. Assay sensitivity was evaluated through construction of a synthetic PBO arm by propensity score matching, using individual pt-level PBO data from 3 recent sponsor-run trials of similar populations and trial settings. Secondary endpoints at Wk 12 included 1) mean change from BL in CDAI, SDAI, DAS28(ESR), HAQ-DI; 2) proportion of pts achieving DAS28(CRP)≤3.2, ACR20/50/70 responses, HAQ-DI≤-0.22. Continuous and categorical efficacy variables were analyzed using mixed effect model repeated measurements and Cochran-Mantel-Haenszel test, respectively; non-responder imputation was applied to missing categorical data. Treatment-emergent adverse events were summarized through Wk 12.

Results:

A total of 48 pts were randomized and treated (ABBV-3373: 31; ADA: 17); 46 pts (96%) completed 12 wks of study treatment. BL demographics and disease characteristics were indicative of established RA and similar among the 2 treatment arms and the synthetic PBO arm. ABBV-3373 demonstrated significant improvement in mean DAS28(CRP) at Wk 12 vs the pre-specified historical ADA (-2.65 vs -2.13; P=0.022) and numerically greater improvement vs the combined in-trial and historical ADA arm (-2.65 vs -2.29; probability 90%; Figure). Comparable improvements in disease activity and targets were observed for ABBV-3373 and in-trial ADA. Assay sensitivity was supported by the fact that both ABBV-3373 and ADA arms were superior to synthetic PBO (P<0.001). For secondary endpoints, greater efficacy was observed with ABBV-3373 vs historical ADA; ABBV-3373 was predicted with 79-99% probability to be better than ADA based on the combined in-trial and historical ADA data. 2 serious infections were reported with ABBV-3373 (pneumonia, upper respiratory tract infection) and none with ADA through Wk 12 (Table). 1 event of anaphylactic shock reaction was reported with ABBV-3373. After increasing the duration of IV administration from 3 min to 15-30 min, no similar events were observed.

Table 1.

Treatment Emergent Adverse Events up to Week 12

Event, n (%)ADA(N = 17)ABBV-3373(N = 31)Adverse event (AE)12 (70.6)11 (35.5)AE with reasonable possibility of being drug related$3 (17.6)2 (6.5)Severe AE01 (3.2)Serious AE04 (12.9) #AE leading to Discontinuation of Study Drug1 (5.9)1 (3.2)Serious infections02 (6.5)Opportunistic infection excluding Tuberculosis00Allergic Reactions Including Hypersensitivity, Angioedema, and Anaphylaxis2 (11.8) &1 (3.2) ^Systemic glucocorticoid events00All deaths00

$As assessed by investigator. #Serious AEs: 1 non-cardiac chest pain, 1 pneumonia, 1 upper respiratory tract disease and 1 anaphylactic shock. &1 Type I hypersensitivity, 1 Pruritus ^1 Anaphylactic shock

Conclusion:

These data demonstrate the clinical efficacy of ABBV-3373 and its potential to provide improved outcomes for RA pts compared to ADA. The safety profile of ABBV-3373 was generally similar to ADA.

Acknowledgements:

AbbVie and the authors we thank the patients, trial sites, and investigators who participated in this clinical trial. AbbVie, Inc was the trial sponsor, contributed to trial design, data collection, analysis & interpretation, and to writing, reviewing, and approval of final version. No honoraria or payments were made for authorship. The authors thank Yang Yang of AbbVie Inc for supporting the statistical analysis and data reporting. Medical writing support was provided by Ramona Vladea, PhD of AbbVie, Inc.

Disclosure of Interests:

Frank Buttgereit Consultant of: AstraZeneca, AbbVie, Grünenthal, Horizon Pharma, Pfizer, and Roche, Grant/research support from: AbbVie, Horizon Pharma, Pfizer, and Roche, Jacob Aelion Grant/research support from: AbbVie, Amgen, AstraZeneca, BMS, Celgene, Eli Lilly, Galapagos/Gilead, Genentech, GlaxoSmithKline, Horizon, Janssen, Mallinckrodt, Nektar, Nichi-Iko, Novartis, Pfizer, Regeneron, Roche, Sanofi-Aventis, Selecta, UCB, Bernadette Rojkovich: None declared, Anna Zubrzycka-Sienkiewicz Consultant of: Astellas and Roche, Grant/research support from: AbbVie, Astellas, Galapagos NV, Gilead Sciences, Janssen, Lilly, Mabion, Pfizer, Roche, and UCB SA, Timothy Radstake Shareholder of: AbbVie, Employee of: AbbVie, Su Chen Shareholder of: AbbVie, Employee of: AbbVie, Dilek Arikan Shareholder of: AbbVie, Employee of: AbbVie, Hartmut Kupper Shareholder of: AbbVie, Employee of: AbbVie, Howard Amital Consultant of: Abbvie, Janssen, Novartis, Roche, Perrigo, Pfizer, Neopharm, Elly Lilly, Gilead, Sanofi, Teva and Rafa, Grant/research support from: Yansen, Pfizer

POS0920 TARGETED SERUM PROTEOMIC ANALYSIS FOLLOWING UPADACITINIB TREATMENT IN ANKYLOSING SPONDYLITIS SHOWS ROBUST SUPPRESSION OF INNATE AND ADAPTIVE IMMUNE PATHWAYS WITH TISSUE REPAIR MODULATION

Background:

Upadacitinib (UPA), an oral JAK inhibitor selective for JAK1, demonstrated efficacy in patients with active ankylosing spondylitis (AS) with an inadequate response (IR) to nonsteroidal anti-inflammatory drugs (NSAID) therapy in the SELECT-AXIS 11 trial.

Objectives:

To identify pathways modulated by UPA in AS patients with emphasis on those associated with response to treatment.

Methods:

A subgroup of patients from the SELECT-AXIS 1 study, with available baseline and at least one follow up plasma sample during the placebo-controlled period, were selected for analysis (PBO, n= 65; UPA 15 mg QD, n=63). The levels of 92 inflammation related protein biomarkers (BioMs) were analyzed using the Olink® platform; change from baseline were expressed as Log2 Fold Change; a repeated measure mixed linear model identified BioMs differentially modulated by UPA. Relationship between change in BioMs and change in clinical disease activity measures were derived using Pearson’s correlation (ASDAS-CRP, BASDAI, and CRP) and Spearman’s correlation (MRI Spine SPARCC). Pathway analysis was performed with Ingenuity® Pathway Analysis (Qiagen Inc.).

Results:

Treatment with UPA 15 mg QD reduced the levels of BioMs associated with IFN, IL6, T Cells, M1 or “inflammatory” Macrophages, and Dendritic Cells (DC); and increased those of BioMs associated with tissue repair and hematopoiesis. The type of pathways, inferred in silico based on BM data, suggests that UPA exerts broad inhibitory activity directly on multiple JAK1-dependent (IFNα/β, IFNγ, IL6, IL2, IL5, IL7, and OSM) and indirectly on JAK1-independent upstream pathways (IL1, IL23, IL17, IL18, and TNFα), resulting in the inhibition of key functional pathways such as leukocyte activation and mobility, inflammatory response, and damage to connective tissue. Improvement in ASDAS-CRP, BASDAI, and MRI spine SPARCC correlated with increase in BioMs associated with tissue repair (FGF5, DNER [Delta/Notch Like EGF Repeat Containing]) and hematopoiesis (FLT3LG,and SCF/KITLG), while improvement in ASDAS-CRP and CRP correlated with decrease in CCL23, CSF1, IL-6, and MMP1; and reduction in only CRP correlated with decrease in IFN- and of TNFα-related BioMs (Data tables will be presented).

Conclusion:

Treatment of NSAID-IR AS patients with UPA 15 mg QD resulted in the coordinated decrease in multiple BioMs associated with the innate and adaptive immune responses, and in the increase in BioMs generally associated with tissue repair and hematopoiesis. In silico pathway prediction indicates that treatment with UPA directly inhibits JAK1-dependent and indirectly JAK1-independent pathways, resulting in the down modulation of functional pathways related to inflammation and tissue damage which are known to be dysregulated in AS2. Based on this observation and on the correlation of change in BioMs with change in clinical measures, we hypothesize that both increase in BioMs associated with tissue repair and hematopoiesis, and decrease in BioMs associated with inflammation may contribute to the clinical activity of UPA in AS patients.

References:

[1]van der Heijde, D. et al. Lancet 394, 2108-2117 (2019).

[2]Stoll, M.L. Clin Exp Rheumatol 29, 322-330 (2011).

Acknowledgements:

AbbVie, Inc was the study sponsor, contributed to the study design, data collection, analysis & interpretation, and to writing, reviewing, and approval of the final version

Disclosure of Interests:

Thierry Sornasse Shareholder of: AbbVie, Employee of: AbbVie, In-Ho Song Shareholder of: AbbVie, Employee of: AbbVie, Timothy Radstake Shareholder of: AbbVie, Employee of: AbbVie, Dennis McGonagle Speakers bureau: AbbVie, Grant/research support from: AbbVie

Broad proteomic screen reveals shared serum proteomic signature in patients with psoriatic arthritis and psoriasis without arthritis

OBJECTIVE

To identify novel serum proteins involved in the pathogenesis of PsA as compared with healthy controls, psoriasis (Pso) and AS, and to explore which proteins best correlated to major clinical features of the disease.

METHODS

A high-throughput serum biomarker platform (Olink) was used to assess the level of 951 unique proteins in serum of patients with PsA (n = 20), Pso (n = 18) and AS (n = 19), as well as healthy controls (HC, n = 20). Pso and PsA were matched for Psoriasis Area and Severity Index (PASI) and other clinical parameters.

RESULTS

We found 68 differentially expressed proteins (DEPs) in PsA as compared with HC. Of those DEPs, 48 proteins (71%) were also dysregulated in Pso and/or AS. Strikingly, there were no DEPs when comparing PsA with Pso directly. On the contrary, hierarchical cluster analysis and multidimensional scaling revealed that HC clustered distinctly from all patients, and that PsA and Pso grouped together. The number of swollen joints had the strongest positive correlation to ICAM-1 (r = 0.81, P < 0.001) and CCL18 (0.76, P < 0.001). PASI score was best correlated to PI3 (r = 0.54, P < 0.001) and IL-17 receptor A (r = -0.51, P < 0.01). There were more proteins correlated to PASI score when analysing Pso and PsA patients separately, as compared with analysing Pso and PsA patients pooled together.

CONCLUSION

PsA and Pso patients share a serum proteomic signature, which supports the concept of a single psoriatic spectrum of disease. Future studies should target skin and synovial tissues to uncover differences in local factors driving arthritis development in Pso.

FRI0026 PROTEOMICS ANALYSIS COMPARING THE MODE OF ACTION OF UPADACITINIB AND ADALIMUMAB HEAD TO HEAD IN RA IDENTIFIES NOVEL, DISCRETE EARLY IMMUNE PATHWAY MODULATION IN THE SELECT-COMPARE PHASE 3 STUDY

Background:

Upadacitinib (UPA), an oral JAK1 selective inhibitor, showed greater efficacy compared to adalimumab (ADA) in patients with active rheumatoid arthritis (RA) despite treatment with methotrexate (MTX) in the SELECT-COMPARE phase 3 study1. The regulatory immune networks affected by JAK1 inhibition compared with TNF-blockade have not been explored previously in a head-to-head trial.

Objectives:

To infer the relative immunological pathway modulation of UPA compared with ADA in patients with RA via the evaluation of a pre-defined set of plasma proteins associated with inflammation.

Methods:

Patients from the SELECT-COMPARE studies were randomly selected (PBO, n=100; UPA 15 mg QD, n=100; ADA 40 mg EOW, N = 100). The levels of 184 inflammation related proteins were analyzed using the Olink® platform; change from baseline in protein levels were expressed as Log2 Fold Change; a Repeated Measure Mixed Linear Model identified proteins differentially modulated by UPA and ADA compared to PBO, and between Responders (R defined as achieving Low Disease Activity [LDA] based on CDAI [≤ 10] at week 12) and Non Responders (NR defined asnotachieving LDA at week 12) for the UPA and ADA groups. Pathway analysis were performed with Ingenuity® Pathway Analysis (Qiagen Inc.); selection criteria: mean |Log2 FC| ≥ 0.1 AND a FDR ≤ 0.05 → n = 88 out of 184 proteins; the top 10% pathways based on Z score for the ADA and UPA groups, and each visit (Week 2 and Week 8) were selected for comparison.

Results:

Both UPA and ADA inhibited protein biomarkers (pBM) associated with Neutrophil / Macrophage biology. However, UPA preferentially inhibited pBM associated with T cells and ADA preferentially inhibited pBM associated with M1 or ‘inflammatory’ Macrophages. The pathways implicatedin silicoby these pBM changes in response to UPA and ADA tended to be similar except for T cell activity related pathways that were preferentially modulated by UPA.

In the ADA group, clinical response was mainly associated withlowerlevels of pBMs such as IL6, TNFRSF1A, MMP10, IL2RA, PLAUR, CCL2, TNFRSF10C, and SERPINE1, suggesting that control of these pathways may be important for response to ADA in RA.

In the UPA treated group, clinical response was mainly associated with slightlyhigherlevels of the pBM IL17A, IL17C, CCL11, CCL20, and TIMP4.

Analysis of the reciprocal changes in the above showed that IL6, TNFRSF1A, IL2RA, NPPB, and SERPINE1 were downregulated similarly in UPA R and NR patients. By comparison, IL17A was modestly upregulated similarly in ADA R and NR patients; CCL20 was downregulated similarly in ADA R and NR patients; and IL17C, IL22RA1, TIMP4, and CCL11 were not modulated by ADA. Finally, taken together, among the 184 inflammation-related pBM tested, none were associated with clinical response for both ADA and UPA.

Conclusion:

We detected common but also discrete alterations in pBMs upon exposure to ADA and UPA overall and further distinctions when we examined pathway changes associated with achievement of a low disease clinical status achieved by each patient population. Whereas both drugs exhibit inhibition of macrophages and granulocyte associated pathways, ADA appears to preferentially affect M1 macrophages and UPA appears to preferentially affect T cells. This modulatory pattern by UPA is consistent with its broad cytokine receptor inhibition profile compared with highly specific TNF inhibition and could account at least in part, for the greater efficacy of UPA over ADA in the SELECT-COMPARE study.

References:

[1]Fleischmann, R., et al. (2019).Arthritis Rheumatol71(11): 1788-1800.

Disclosure of Interests:

Thierry Sornasse Shareholder of: AbbVie Inc, Employee of: AbbVie Inc, In-Ho Song Shareholder of: AbbVie Inc., Employee of: AbbVie Inc., Timothy Radstake Shareholder of: AbbVie Inc, Employee of: AbbVie Inc, Iain McInnes Grant/research support from: Bristol-Myers Squibb, Celgene, Eli Lilly and Company, Janssen, and UCB, Consultant of: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly and Company, Gilead, Janssen, Novartis, Pfizer, and UCB

AB0062 CHARACTERIZATION OF IL-12 AND IL-23 REDUCTION BY TOFACITINIB IN MDCS

Background:

Psoriatic arthritis (PsA) is a chronic inflammatory auto-immune disease characterized by an excessive production of pathogenic mediators that cause inflammation of the skin, peripheral joints, entheses and the spine. Among these, interleukin (IL)-23, IL-12, the IL-17 family and TNF constitute key players in PsA pathogenesis.1,2IL-23, consisting of IL23A (IL-23p19) and IL12B (IL-12p40) subunits, is predominantly produced by myeloid dendritic cells (mDCs). While the p19 subunit is unique to IL-23, the p40 subunit is shared with IL-12. Together, IL-12 and IL-23 play a crucial role in promoting the differentiation of naïve T lymphocytes into T helper (Th) interferon (IFN)-γ-producing Th1 or IL17-producing Th17 cells, respectively.3

Small-molecule inhibitors, such as the JAK/STAT inhibitor Tofacitinib, have recently shown promising therapeutic potential in PsA clinical trials.4The inhibition of JAKs by Tofacitinib results in the direct suppression of multiple intracellular signaling pathways which constitute key hubs in the cytokine network.5However, whether Tofacitinib is able directly target IL-12/IL-23 production by mDCs has not yet been documented. Suppression of these canonical inflammatory pathways would provide further evidence that Tofacitinib is an effective drug in halting both innate and adaptive immune responses.

Objectives:

To evaluate the transcriptional and molecular events underlining IL-12 and IL-23 regulation by Tofacitinib in mDCs.

Methods:

Peripheral blood mononuclear cells from healthy donors were isolated by Ficoll gradient. Monocytes and myeloid dendritic cells (mDCs) were isolated by using magnetic beads on autoMACS. Monocytes were cultured for 6 days in the presence of IL-4 and granulocyte-macrophage colony-stimulating factor (GM-CSF) to generate monocyte-derived dendritic cells (moDCs). MoDCs were harvested, washed and put to rest for 1 day prior to stimulation, while mDCs were stimulated on the same day of isolation. Both moDCs and mDCs were pre-treated with Tofacitinib and then stimulated with either lipopolysaccharide (LPS) or combination of LPS with IFN-γ for 4 hours. Cytokines were measured using enzyme-linked immunosorbent assay (ELISA) and gene expression was assessed using quantitative polymerase chain reaction (qPCR).

Results:

Treatment of both mDCs and moDCs with Tofacitinib led to a decreased mRNA expression of IL-12 p40 (IL12B) in the presence of TLR4 and IFNγ co-stimulation. The decreasedIL12BmRNA expression also resulted in lower production of IL-12 p40 and IL-23 proteins in mDCs.

Conclusion:

In this work, we demonstrated for the first time that Tofacitinib can suppress the production of IL-23/IL-12 p40 subunit in mDCs, upon the condition that an active type II IFN signalling is also present in these cells. This observation indicates that specific factors, such as endogenous IFN-γ levels in the serum of PsA patients, can possibly predict differential responses to Tofacitinib treatment.

References:

[1]Gaffen SL. et al. The IL-23-IL-17 immune axis: from mechanisms to therapeutic testing. Nat Rev Immunol. 2014 Sep;14(9):585-600

[2]Bravo A, Kavanaugh A. Bedside to bench: defining the immunopathogenesis of psoriatic arthritis. Nat Rev Rheumatol. 2019 Nov;15(11):645-656

[3]Floss DM. et al. Insights into IL-23 biology: From structure to function. Cytokine Growth Factor Rev. 2015 Oct;26(5):569-78

[4]Berekmeri A. et al. Tofacitinib for the treatment of psoriasis and psoriatic arthritis. Expert Rev Clin Immunol. 2018 Sep;14(9):719-730

[5]T Virtanen A. et al. Selective JAKinibs: Prospects in Inflammatory and Autoimmune Diseases. BioDrugs. 2019 Feb;33(1):15-32

Disclosure of Interests:

None declared

Current status of use of big data and artificial intelligence in RMDs: a systematic literature review informing EULAR recommendations

Objective

To assess the current use of big data and artificial intelligence (AI) in the field of rheumatic and musculoskeletal diseases (RMDs).

Methods

A systematic literature review was performed in PubMed MEDLINE in November 2018, with key words referring to big data, AI and RMDs. All original reports published in English were analysed. A mirror literature review was also performed outside of RMDs on the same number of articles. The number of data analysed, data sources and statistical methods used (traditional statistics, AI or both) were collected. The analysis compared findings within and beyond the field of RMDs.

Results

Of 567 articles relating to RMDs, 55 met the inclusion criteria and were analysed, as well as 55 articles in other medical fields. The mean number of data points was 746 million (range 2000–5 billion) in RMDs, and 9.1 billion (range 100 000–200 billion) outside of RMDs. Data sources were varied: in RMDs, 26 (47%) were clinical, 8 (15%) biological and 16 (29%) radiological. Both traditional and AI methods were used to analyse big data (respectively, 10 (18%) and 45 (82%) in RMDs and 8 (15%) and 47 (85%) out of RMDs). Machine learning represented 97% of AI methods in RMDs and among these methods, the most represented was artificial neural network (20/44 articles in RMDs).

Conclusions

Big data sources and types are varied within the field of RMDs, and methods used to analyse big data were heterogeneous. These findings will inform a European League Against Rheumatism taskforce on big data in RMDs.

A pilot study of CXCL8 levels in crystal proven gout patients during allopurinol treatment and their association with cardiovascular disease

OBJECTIVES

Gout is associated with cardiovascular diseases, and systemic inflammation has a role in this. CXCL8 (interleukin-8) levels were increased in synovial fluid of gout patients, and in serum in gout patients irrespective of their disease activity. We hypothesized that the well-known cardiovascular protective effects of allopurinol could be related to effects of this drug on CXCL8 levels.

METHODS

Patients with a crystal proven gout diagnosis, who newly started allopurinol treatment, were included in this prospective cohort study. After evaluation at baseline for cardiovascular diseases, tophi, uric acid, CRP and CXCL8 serum levels, patients were followed for changes in uric acid and CXCL8 levels. A subgroup analysis was performed in 10 patients with the longest follow-up period and at least 4 assessments of serum uric acid and CXCL8.

RESULTS

Sixty patients were included, and patients known with cardiovascular diseases at baseline had significantly higher CXCL8 and uric acid levels (P<0.01). In the whole group, median CXCL8 levels had not decreased after a median (IQR) follow-up of 27 (12-44) weeks (P=0.66). In the subgroup analysis in 9 out of 10 patients, CXCL8 levels showed a slight decrease, sometimes after an initial increase after a median (IQR) follow-up of 51 (45-60) weeks.

CONCLUSIONS

This pilot study indicates that higher CXCL8 levels were associated cardiovascular diseases in gout patients. Short-term use of allopurinol does not decrease CXCL8 levels in gout patients, but longer use possibly does. Further studies are warranted to establish the potential mechanisms of treatment and effects on CXCL8 levels.

B cell depleting therapy regulates splenic and circulating T follicular helper cells in immune thrombocytopenia

B cells are involved in immune thrombocytopenia (ITP) pathophysiology by producing antiplatelet auto-antibodies. However more than a half of ITP patients do not respond to B cell depletion induced by rituximab (RTX). The persistence of splenic T follicular helper cells (TFH) that we demonstrated to be expanded during ITP and to support B cell differentiation and antiplatelet antibody-production may participate to RTX inefficiency. Whereas it is well established that the survival of TFH depends on B cells in animal models, nothing is known in humans yet. To determine the effect of B cell depletion on human TFH, we quantified B cells and TFH in the spleen and in the blood from ITP patients treated or not with RTX. We showed that B cell depletion led to a dramatic decrease in splenic TFH and in CXCL13 and IL-21, two cytokines predominantly produced by TFH. The absolute count of circulating TFH and serum CXCL13 also decreased after RTX treatment, whatever the therapeutic response. Therefore, we showed that the maintenance of TFH required B cells and that TFH are not involved in the inefficiency of RTX in ITP.

Dense genotyping of immune-related loci in idiopathic inflammatory myopathies confirms HLA alleles as the strongest genetic risk factor and suggests different genetic background for major clinical subgroups

OBJECTIVES

The idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of rare autoimmune diseases characterised by muscle weakness and extramuscular manifestations such as skin rashes and interstitial lung disease. We genotyped 2566 IIM cases of Caucasian descent using the Immunochip; a custom array covering 186 established autoimmune susceptibility loci. The cohort was predominantly comprised of patients with dermatomyositis (DM, n=879), juvenile DM (JDM, n=481), polymyositis (PM, n=931) and inclusion body myositis (n=252) collected from 14 countries through the Myositis Genetics Consortium.

RESULTS

The human leucocyte antigen (HLA) and PTPN22 regions reached genome-wide significance (p<5×10(-8)). Nine regions were associated at a significance level of p<2.25×10(-5), including UBE2L3, CD28 and TRAF6, with evidence of independent effects within STAT4. Analysis of clinical subgroups revealed distinct differences between PM, and DM and JDM. PTPN22 was associated at genome-wide significance with PM, but not DM and JDM, suggesting this effect is driven by PM. Additional suggestive associations including IL18R1 and RGS1 in PM and GSDMB in DM were identified. HLA imputation confirmed that alleles HLA-DRB1*03:01 and HLA-B*08:01 of the 8.1 ancestral haplotype (8.1AH) are most strongly associated with IIM, and provides evidence that amino acids within the HLA, such as HLA-DQB1 position 57 in DM, may explain part of the risk in this locus. Associations with alleles outside the 8.1AH reveal differences between PM, DM and JDM.

CONCLUSIONS

This work represents the largest IIM genetic study to date, reveals new insights into the genetic architecture of these rare diseases and suggests different predominating pathophysiology in different clinical subgroups.

The IRF5-TNPO3 association with systemic lupus erythematosus has two components that other autoimmune disorders variably share

Exploiting genotyping, DNA sequencing, imputation and trans-ancestral mapping, we used Bayesian and frequentist approaches to model the IRF5-TNPO3 locus association, now implicated in two immunotherapies and seven autoimmune diseases. Specifically, in systemic lupus erythematosus (SLE), we resolved separate associations in the IRF5 promoter (all ancestries) and with an extended European haplotype. We captured 3230 IRF5-TNPO3 high-quality, common variants across 5 ethnicities in 8395 SLE cases and 7367 controls. The genetic effect from the IRF5 promoter can be explained by any one of four variants in 5.7 kb (P-valuemeta = 6 × 10(-49); OR = 1.38-1.97). The second genetic effect spanned an 85.5-kb, 24-variant haplotype that included the genes IRF5 and TNPO3 (P-valuesEU = 10(-27)-10(-32), OR = 1.7-1.81). Many variants at the IRF5 locus with previously assigned biological function are not members of either final credible set of potential causal variants identified herein. In addition to the known biologically functional variants, we demonstrated that the risk allele of rs4728142, a variant in the promoter among the lowest frequentist probability and highest Bayesian posterior probability, was correlated with IRF5 expression and differentially binds the transcription factor ZBTB3. Our analytical strategy provides a novel framework for future studies aimed at dissecting etiological genetic effects. Finally, both SLE elements of the statistical model appear to operate in Sjögren's syndrome and systemic sclerosis whereas only the IRF5-TNPO3 gene-spanning haplotype is associated with primary biliary cirrhosis, demonstrating the nuance of similarity and difference in autoimmune disease risk mechanisms at IRF5-TNPO3.

Toll-like receptor 4 signaling augments transforming growth factor-β responses: a novel mechanism for maintaining and amplifying fibrosis in scleroderma

Because recent studies implicate Toll-like receptors (TLRs) in the pathogenesis of fibrosis, we sought to investigate the in vitro and in vivo role and mechanism of TLR4-mediated fibroblast responses in fibrogenesis. We found that TLR4 was constitutively expressed, and accumulation of endogenous TLR4 ligands significantly elevated, in lesional skin and lung tissues from patients with scleroderma. Activation of TLR4 signaling in explanted fibroblasts resulted in enhanced collagen synthesis and increased expression of multiple genes involved in tissue remodeling and extracellular matrix homeostasis. Moreover, TLR4 dramatically enhanced the sensitivity of fibroblasts to the stimulatory effect of transforming growth factor-β1. These profibrotic responses were abrogated by both genetic and pharmacological disruption of TLR4 signaling in vitro, and skin fibrosis induced by bleomycin in vivo was attenuated in mice harboring a mutated TLR4. Activation of TLR4 in fibroblasts augmented the intensity of canonical Smad signaling, and was accompanied by suppression of anti-fibrotic microRNA expression. Together, these results suggest a novel model to account for persistent fibrogenesis in scleroderma, in which activation of fibroblast TLR4 signaling, triggered by damage-associated endogenous TLR4 ligands, results in augmented transforming growth factor-β1 sensitivity with increased matrix production and progressive connective tissue remodeling. Under these conditions, fibroblast TLR4 serves as the switch for converting self-limited tissue repair into intractable fibrosis.

Independent replication and meta analysis of association studies establish TNFSF4 as a susceptibility gene preferentially associated with the subset of anticentromere-positive patients with systemic sclerosis

OBJECTIVE

Independent replication with large cohorts and metaanalysis of genetic associations are necessary to validate genetic susceptibility factors. The known tumor necrosis factor (ligand) superfamily, member 4 gene (TNFSF4) systemic lupus erythematosus (SLE) risk locus has been found to be associated with systemic sclerosis (SSc) in 2 studies, but with discrepancies between them for genotype-phenotype correlation. Our objective was to validate TNFSF4 association with SSc and determine the subset with the higher risk.

METHODS

Known SLE and SSc TNFSF4 susceptibility variants (rs2205960, rs1234317, rs12039904, rs10912580, and rs844648) were genotyped in 1031 patients with SSc and 1014 controls of French white ancestry. Genotype-phenotype association analysis and meta analysis of available data were performed, providing a population study of 4989 patients with SSc and 4661 controls, all of European white ancestry.

RESULTS

Allelic and genotypic associations were observed for the 5 single-nucleotide polymorphisms (SNP) with the subset of patients with SSc who are positive for anticentromere antibodies (ACA) and only a trend for association with SSc and limited cutaneous SSc. Rs2205960 exhibited the strongest allelic association in ACA+ patients with SSc [p = 0.0015; OR 1.37 (1.12-1.66)], with significant intra-cohort association when compared to patients with SSc positive for ACA. Metaanalysis confirmed overall association with SSc but also raised preferential association with the ACA+ subset and strongest effect with rs2205960 [T allele p = 0.00013; OR 1.33 (1.15-1.54) and TT genotype p = 0.00046; OR 2.02 (1.36-2.98)].

CONCLUSION

We confirm TNFSF4 as an SSc susceptibility gene and rs2205960 as a putative causal variant with preferential association in the ACA+ SSc subphenotype.

Replication of the tumor necrosis factor receptor-associated factor 1/complement component 5 region as a susceptibility locus for rheumatoid arthritis in a European family-based study

OBJECTIVE

We recently showed, using a candidate gene approach in a case-control association study, that a 65-kb block encompassing tumor necrosis factor receptor-associated factor 1 (TRAF1) and C5 is strongly associated with rheumatoid arthritis (RA). Compared with case-control association studies, family-based studies have the added advantage of controlling potential differences in population structure and are not likely to be hampered by variation in population allele frequencies, as is seen for many genetic polymorphisms, including the TRAF1/C5 locus. The aim of this study was to confirm this association in populations of European origin by using a family-based approach.

METHODS

A total of 1,356 western European white individuals from 452 "trio" families were genotyped for the rs10818488 polymorphism, using the TaqMan allelic discrimination assay.

RESULTS

We observed evidence for association, demonstrating departure from Mendel's law, with an overtransmission of the rs10818488 A allele (A = 55%; P = 0.036). By taking into consideration parental phenotypes, we also observed an increased A allele frequency in affected versus unaffected parents (A = 64%; combined P = 0.015). Individuals carrying the A allele had a 1.2-fold increased risk of developing RA (allelic odds ratio 1.24, 95% confidence interval 1.04-1.50).

CONCLUSION

Using a family-based study that is robust against population stratification, we provide evidence for the association of the TRAF1/C5 rs10818488 A allele and RA in populations of European descent, further substantiating our previous findings. Future functional studies should yield insight into the biologic relevance of this locus to the pathways involved in RA.

Influence of anti-tumour necrosis factor therapy on cardiovascular risk factors in patients with active rheumatoid arthritis

BACKGROUND

Tumour necrosis factor (TNF) is known to increase the concentrations of interleukin (IL) 6 and C reactive protein (CRP) and to induce proatherogenic changes in the lipid profile and may increase the cardiovascular risk of patients with rheumatoid arthritis (RA) and other inflammatory disorders.

OBJECTIVE

To assess whether anti-TNF therapy modifies the cardiovascular risk profile in patients with RA.

METHODS

The lipoprotein spectrum and the inflammation markers CRP and IL6 were investigated in 33 patients with RA treated with human anti-TNF monoclonal antibodies (D2E7, adalimumab, Humira) and 13 patients with RA given placebo, before and after 2 weeks' treatment.

RESULTS

In the anti-TNF treated group, the mean (SD) concentrations of HDL-cholesterol were significantly higher after 2 weeks' treatment (0.86 (0.30) mmol/l v 0.98 (0.33) mmol/l, p<0.01), whereas LDL and triglyceride levels were not significantly changed. Additionally, a significant decrease in CRP (86.1 (54.4) mg/l v 35.4 (35.0) mg/l, p<0.0001), and IL6 (88.3 (60.5) pg/ml v 42.3 (40.7) pg/ml, p<0.001) concentrations was seen in this group. No changes in lipid profile, IL6, or CRP levels were seen in the placebo group.

CONCLUSIONS

TNF neutralisation with monoclonal anti-TNF antibodies increased HDL-cholesterol levels and decreased CRP and IL6 levels after 2 weeks. Therefore this treatment may improve the cardiovascular risk profile of patients with RA.

Salmonella septicemia in rheumatoid arthritis patients receiving anti-tumor necrosis factor therapy: association with decreased interferon-gamma production and Toll-like receptor 4 expression

OBJECTIVE

Patients treated with antibodies to tumor necrosis factor alpha (TNFalpha) have an increased susceptibility to intracellular infections. We describe 2 patients with rheumatoid arthritis (RA) who developed Salmonella septicemia during anti-TNF treatment. The aim of this study was to identify the mechanisms involved in the increased susceptibility of anti-TNF-treated patients to intracellular microorganisms.

METHODS

We evaluated an additional 6 RA patients receiving anti-TNF antibodies, 5 RA patients not receiving anti-TNF therapy, and 6 age- and sex-matched healthy volunteers. The in vitro production of cytokines (interleukin-1beta [IL-1beta], IL-6, interferon-gamma [IFNgamma], and IL-10) upon bacterial stimulation of whole blood and the expression of Toll-like receptor 4 (TLR-4) on dendritic cells from RA patients treated with infliximab, RA patients not treated with infliximab, and healthy controls were compared.

RESULTS

Stimulation with heat-killed Salmonella typhimurium or Candida albicans led to a significantly decreased production of IFNgamma, but not to a decreased production of IL-10, IL-beta, or IL-6, in anti-TNF-treated RA patients compared with RA patients who were not receiving anti-TNF antibodies and compared with healthy controls. TNF-blocking treatment ex vivo significantly inhibited TLR-4 expression on dendritic cells from RA patients and healthy controls.

CONCLUSION

Since recognition of microorganisms by TLR-4 and activation of phagocytes by IFNgamma are essential mechanisms for the defense against intracellular and fungal pathogens, we propose that this pathway is crucial for the increased susceptibility to these microorganisms in patients receiving anti-TNF therapy.

Noninherited maternal antigens do not increase the susceptibility for familial rheumatoid arthritis. European Consortium on Rheumatoid Arthritis Families (ECRAF)

OBJECTIVE

It has been proposed that noninherited maternal HLA-DR antigens (NIMA) might play a role in the susceptibility for rheumatoid arthritis (RA). This hypothesis has not been thoroughly tested in patients with familial RA, in whom genetic factors, either inherited or not, might have stronger influence than in patients with sporadic RA. We investigated the NIMA hypothesis in a large cohort of European patients with familial RA.

METHODS

The distribution of NIMA, noninherited paternal antigens (NIPA), and inherited HLA-DR antigens was assessed in patients with familial RA from all family sets collected from 1996 onwards by the ECRAF. HLA-DRB1 oligotyping from patients and all available nonaffected siblings and parents was carried out. Familial RA was defined by the presence of at least 2 affected first-degree relatives in the same family. The frequencies of HLA-DR NIMA and NIPA were compared using odds ratios after stratification for HLA-DR*04, *0401, and/or *0404 and shared epitope (SE) status. NIMA/NIPA that coincided with inherited parental HLA-DR antigens were considered redundant and were excluded from analysis.

RESULTS

NIMA and NIPA could be analyzed in 165 RA patients with familial RA and 84 nonaffected siblings. Patients were predominantly female, rheumatoid factor positive, and had erosive disease (81, 75, and 84%, respectively). Possession of HLA-DR*04 and *0401/*0404 alleles tended be more frequent in patients than in nonaffected siblings but this did not reach statistical significance. SE possession was similar in patients and healthy siblings, although the former had a double dose SE more often (37.6 vs 17.8%; p = 0.002). Transmission of SE encoding alleles from parents to offspring was skewed only in patients [OR (95% CI) 3.56 (2.55-4.95) vs 1.16 (0.75-1.79) in nonaffected siblings]. Using the NIPA as control, the frequencies of HLA-DRB1*04, *0401/*0404, and SE positive NIMA were not increased in patients lacking these susceptibility alleles. The frequencies of NIMA encoding susceptibility alleles in DR*04 and *0401/*0404 negative patients were lower than in nonaffected siblings.

CONCLUSION

Our results corroborate the association between RA and inherited SE alleles and do not support a role for noninherited HLA-DR maternal antigens in the susceptibility for familial RA.