Reed, Ann M.

Background/Purpose:Genome‐wide association studies have identified susceptibility loci for many autoimmune diseases, including rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA). About 5% of children with JIA have rheumatoid factor positive arthritis that is phenotypically similar to adult seropositive RA, thus representing childhood onset RA (CORA). To understand the genetic architecture of CORA risk relative to other autoimmune diseases, we genotyped CORA cases and controls on the Immunochip, a custom array designed by the Immunochip Consortium to fine map autoimmune disease‐associated loci shared across 11 autoimmune phenotypes.Methods:Genotyping was completed on 340 CORA cases (mean onset age: 10.2 ± 4.2 yrs) and 11624 controls. Standard SNP and sample QC was performed (e.g., removing samples with call rate <98%, admixture outliers). To test for SNP association with CORA a logistic regression model was computed with Caucasian admixture proportions (ADMIXTURE) as covariates (SNPLash). False discovery rate (FDR) adjusted p‐values (PFDR) are reported to account for the actual number of tests computed.Results:SNP rs3129769, near HLA DRB1 was the most significantly associated (PFDR <3×10‐25), and is in linkage disequilibrium with the HLA DRB1 SNP reported in RA (rs660895, PFDR <1×10‐24). Outside the HLA region, 28 regions had ≥1 SNP meeting genome‐wide significance (PFDR<0.05). The best signal of association was on 22q13 (rs9610687, OR = 0.57, PFDR < 0.0002) near IL2RB, followed by the PTPN22 locus (rs6679677, OR = 1.83, PFDR < 0.0005), an intergenic SNP on chromosome 4 (rs970036, OR = 1.78, PFDR < 0.002) and an intronic SNP (19p13, rs3787016 PFDR < 0.002) in the POLR2E gene, which encodes a subunit of RNA polymerase II. Some loci which have previously been implicated in RA had evidence of association including MMEL (rs751358 PFDR < 0.003), IRF5 (rs4731531 PFDR < 0.006) and CCR6 (rs11575078 PFDR < 0.03). In addition using the FDR‐based threshold we identified several potential SNPs (rs10918214, 1q23; rs28491312, 14q31) not previously implicated in RA.Conclusion:Immunochip analysis of the largest cohort of CORA investigated to date has confirmed the HLA DRB1 association and identified several other loci associated with CORA. Comparisons among loci associated with CORA and those identified in RA and other forms of JIA are underway and will help delineate the unique genetic factors for CORA susceptibility.

Objective: We investigated ADAMTS13 (a disintegrin-like and metalloprotease with thrombospondin type 1 motif, member 13) messenger RNA levels as a biomarker of disease features in systemic lupus erythematosus. Methods: We measured and compared messenger RNA (mRNA) levels of ADAMTS13 in peripheral blood cells in patients with systemic lupus erythematosus and healthy control subjects by whole-genome microarray. We retrospectively analyzed the correlations of ADAMTS13 mRNA expression with clinical features, laboratory parameters, therapeutic features, and disease activity (according to the Systemic Lupus Erythematosus Disease Activity Index). We also examined the association of three single nucleotide polymorphisms (rs4962145, rs2285467, and rs685523) of the ADAMTS13 gene with patient characteristics. Results: In 309 patients, the median ADAMTS13 mRNA expression levels were significantly higher in blood cells of systemic lupus erythematosus patients than in 23 healthy controls ( p = .03). Notably, ADAMTS13 mRNA expression levels were significantly higher in systemic lupus erythematosus patients with a history of stroke ( p = .02) or transient ischemic attack ( p = .02). Among the three single nucleotide polymorphisms analyzed, rs2285467 was significantly associated with stroke ( p = .03) and anticardiolipin antibodies ( p = .04). Conclusions: Increased expression of ADAMTS13 mRNA in blood cells is associated with the presence of ischemic cerebrovascular disease in systemic lupus erythematosus patients and suggests a potential role for ADAMTS13 in the pathogenesis of ischemic cerebrovascular disease in these patients.

Objective To identify the clinical and laboratory predictors of clinical improvement in a cohort of myositis patients treated with rituximab. Methods We analyzed data for 195 patients with myositis (75 with adult polymyositis [PM], 72 with adult dermatomyositis [DM], and 48 with juvenile DM) in the Rituximab in Myositis trial. Clinical improvement was defined as 20% improvement in at least 3 of the following 6 core set measures of disease activity: physician's and patient's/parent's global assessment of disease activity, manual muscle testing, physical function, muscle enzymes, and extramuscular disease activity. We analyzed the association of the following baseline variables with improvement: myositis clinical subgroup, demographics, myositis damage, clinical and laboratory parameters, core set measures, rituximab treatment, and myositis autoantibodies (antisynthetase, anti–Mi‐2, anti–signal recognition particle, anti–transcription intermediary factor 1γ [TIF‐1γ], anti‐MJ, other autoantibodies, and no autoantibodies). All measures were univariately assessed for association with improvement using time‐to‐event analyses. A multivariable time‐dependent proportional hazards model was used to evaluate the association of individual predictive factors with improvement. Results In the final multivariable model, the presence of an antisynthetase, primarily anti–Jo‐1 (hazard ratio [HR] 3.08, P < 0.01), anti–Mi‐2 (HR 2.5, P < 0.01), or other autoantibody (HR 1.4, P = 0.14) predicted a shorter time to improvement compared to the absence of autoantibodies. A lower physician's global assessment of damage (HR 2.32, P = 0.02) and juvenile DM (versus adult myositis) (HR 2.45, P = 0.01) also predicted improvement. Unlike autoantibody status, the predictive effect of physician's global assessment of damage and juvenile DM diminished by week 20. Rituximab treatment did not affect these associations. Conclusion Our findings indicate that the presence of antisynthetase and anti–Mi‐2 autoantibodies, juvenile DM subset, and lower disease damage strongly predict clinical improvement in patients with refractory myositis.

Morphea and systemic sclerosis are fibrosing disorders of the skin that share common inflammatory and immunologic pathways that are responsible for the vascular changes, increased collagen production, and extracellular matrix proliferation seen in both conditions. Recent advances in molecular biology techniques have furthered our knowledge of the potential underlying pathogenic mechanisms and offer new and provocative areas of research for novel diagnostic and therapeutic interventions. This review focuses on the role of vascular injury in the development of morphea, the use of ultrasonography as a diagnostic modality, and well-established and newly proposed treatments.

ObjectiveTo identify new genetic associations with juvenile and adult dermatomyositis (DM).MethodsWe performed a genome‐wide association study (GWAS) of adult and juvenile DM patients of European ancestry (n = 1,178) and controls (n = 4,724). To assess genetic overlap with other autoimmune disorders, we examined whether 141 single‐nucleotide polymorphisms (SNPs) outside the major histocompatibility complex (MHC) locus, and previously associated with autoimmune diseases, predispose to DM.ResultsCompared to controls, patients with DM had a strong signal in the MHC region consisting of GWAS‐level significance (P < 5 × 10–8) at 80 genotyped SNPs. An analysis of 141 non‐MHC SNPs previously associated with autoimmune diseases showed that 3 SNPs linked with 3 genes were associated with DM, with a false discovery rate (FDR) of <0.05. These genes were phospholipase C–like 1 (PLCL1; rs6738825, FDR = 0.00089), B lymphoid tyrosine kinase (BLK; rs2736340, FDR = 0.0031), and chemokine (C‐C motif) ligand 21 (CCL21; rs951005, FDR = 0.0076). None of these genes was previously reported to be associated with DM.ConclusionOur findings confirm the MHC as the major genetic region associated with DM and indicate that DM shares non‐MHC genetic features with other autoimmune diseases, suggesting the presence of additional novel risk loci. This first identification of autoimmune disease genetic predispositions shared with DM may lead to enhanced understanding of pathogenesis and novel diagnostic and therapeutic approaches.

ObjectiveCD8+ T cells lacking CD28 were originally reported to be a characteristic feature of juvenile idiopathic arthritis (JIA), but the relevance of these unusual cells to this disease remains to be elucidated. Because of recent evidence that loss of CD28 cells is typical of terminally differentiated lymphocytes, the aim of this study was to examine functional subsets of CD8+ T cells in patients with JIA.MethodsBlood and/or waste synovial fluid samples were collected from children with a definite diagnosis of JIA (n = 98). Deidentified peripheral blood (n = 33) and cord blood (n = 13) samples from healthy donors were also collected. CD8+ and CD4+ T cells were screened for novel receptors, and where indicated, bioassays were performed to determine the functional relevance of the identified receptor.ResultsJIA patients had a naive T cell compartment with shortened telomeres, and their entire T cell pool had reduced proliferative capacity. They had an overabundance of CD31+CD28nullCD8+ T cells, which was a significant feature of oligoarticular JIA (n = 62) as compared to polyarticular JIA (n = 36). CD31+ CD28nullCD8+ T cells had limited mitotic capacity and expressed high levels of the senescence antigens histone γH2AX and/or p16. Ligation of CD31, which was independent of the T cell receptor (TCR), sufficiently induced tyrosine phosphorylation, vesicle exocytosis, and production of interferon‐γ and interleukin‐10.ConclusionThese data provide the first evidence of cell senescence, as represented by CD31+CD28null CD8+ T cells, in the pathophysiology of JIA. Activation of these unusual cells in a TCR‐independent manner suggests that they are maladaptive and could be potential targets for immunotherapy.