Analysis of the ImmunoChip single nucleotide polymorphism (SNP) array in 2816 individuals, comprising the most common subtypes (oligoarticular and RF negative polyarticular) of juvenile idiopathic arthritis (JIA) and 13056 controls strengthens the evidence for association to three known JIA-risk loci (HLA, PTPN22 and PTPN2) and has identified fourteen risk loci reaching genome-wide significance (p < 5 × 10-8) for the first time. Eleven additional novel regions showed suggestive evidence for association with JIA (p < 1 × 10-6). Dense-mapping of loci along with bioinformatic analysis has refined the association to one gene for eight regions, highlighting crucial pathways, including the IL-2 pathway, in JIA disease pathogenesis. The entire ImmunoChip loci, HLA region and the top 27 loci (p < 1 × 10-6) explain an estimated 18%, 13% and 6% risk of JIA, respectively. Analysis of the ImmunoChip dataset, the largest cohort of JIA cases investigated to date, provides new insight in understanding the genetic basis for this childhood autoimmune disease.

Twenty-eight patients with refractory rheumatoid arthritis completed a randomized 24-week double-blind crossover trial comparing oral methotrexate (2.5 to 5 mg every 12 hours for three doses weekly) with placebo. The methotrexate group had significant reductions (P less than 0.01 as compared with the placebo group) in the number of tender or painful joints, the duration of morning stiffness, and disease activity according to physician and patient assessments at the 12-week crossover visit; reductions in the number of swollen joints (P less than 0.05) and 15-m walking time (P less than 0.03) also occurred. These variables, as well as the grip strength and erythrocyte sedimentation rate, showed significant (P less than 0.01) improvement at 24 weeks in the population crossed over to methotrexate. A significantly increased frequency (P less than 0.03) of the HLA-DR2 haplotype occurred in the eight patients with the most substantial response to methotrexate. Adverse reactions during methotrexate therapy included transaminase elevation (21 per cent), nausea (18 per cent), and diarrhea (12 per cent); one patient was withdrawn from the trial because of diarrhea. One patient died while receiving the placebo. Methotrexate did not affect measures of humoral or cellular immunity. We conclude that this trial provides evidence of the short-term efficacy of methotrexate in rheumatoid arthritis, but the mechanism of action is unknown. Longer trials will be required to determine the ultimate safety and effectiveness of this drug.

The germline repertoire of variable genes for the TCR-gamma/delta is limited. This, together with the availability of several V delta-specific and a C delta-specific mAbs, has made it possible to assess differences in the TCR-gamma/delta repertoire in man. TCR-gamma/delta cells expressing particular V gene segments have been previously shown to be localized in different anatomical sites. In this study, analysis of TCR-gamma/delta V gene segment usage performed on subjects from the time of birth through adulthood revealed striking age-related changes in the TCR-gamma/delta repertoire in peripheral blood. V delta 1+ gamma/delta T cells predominated in thymus as well as in peripheral blood at birth and then persisted as a relatively constant proportion of CD3+ PBL. However, V delta 2+ gamma/delta T cells that constitute a small proportion of the CD3+ cells in thymus and in peripheral blood at birth, then expand and account for the major population of gamma/delta T cells in PBL in adults. No parallel postnatal expansion of V delta 2+ cells in the thymus was observed, even when paired thymus-peripheral blood specimens were obtained on subjects between the ages of 3 d and 8 yr. The subset of V delta 2+ lymphocytes that was expanded in peripheral blood expressed high levels of CD45RO suggesting prior activation of these cells, consistent with the possibility that their expansion might have resulted from exposure to foreign antigens or superantigens. In contrast, V delta 1+ T cells in PBL showed no comparable increase in relative numbers and were either negative or expressed only low levels of CD45RO. Consistent with evidence for extrathymic peripheral expansion of selective TCR-gamma/delta subsets, no link between MHC haplotype and differences in the TCR-gamma/delta V gene usage between individuals was apparent, and identical twins displayed TCR-gamma/delta variable gene segment phenotypes that were strikingly different from one another. The elements that determine the TCR-gamma/delta repertoire in individuals are not known. It is possible that both thymic selection and extrathymic factors may influence the peripheral repertoire. Recently, TCR-gamma/delta+ lymphocytes have been shown to expand markedly in peripheral lymphoid tissues and infectious lesions in response to mycobacterial antigens, and a correlation between mycobacterial responses and TCR-gamma/delta V gene usage has been shown in mice. The data presented here demonstrated peripheral age-related changes in the gamma/delta repertoire and point to the importance of extrathymic expansion of specific gamma/delta subsets in generating the human TCR-gamma/delta repertoire.

Objective. Systemic juvenile idiopathic arthritis (JIA) is frequently associated with the development of macrophage activation syndrome. This study was undertaken to better understand the relationship between systemic JIA and macrophage activation syndrome.Methods. Gene expression profiles were examined in 17 patients with untreated new-onset systemic JIA, 5 of whom showed evidence of subclinical macrophage activation syndrome (of whom 2 eventually developed overt macrophage activation syndrome). Peripheral blood mononuclear cells (PBMCs) were separated on Ficoll gradients, and purified RNA was analyzed using Affymetrix GeneChip expression arrays. A fraction of the PBMCs were used for flow cytometry to define the cellular composition of the samples.Results. Two hundred twenty-five differentially expressed genes (P < 0.05) that distinguished patients with systemic JIA from healthy controls (n ‫؍‬ 30) were identified. Clustering analysis indicated that expression patterns correlated with serum ferritin levels. Three main clusters distinguished systemic JIA patients with highly elevated ferritin levels (including those with subclinical macrophage activation syndrome) from those with normal or only moderately elevated ferritin levels. The first cluster comprised genes involved in the synthesis of hemoglobins and structural proteins of erythrocytes. This transcriptional profile was consistent with immature nucleated red blood cells, likely reflective of high red blood cell turnover. Also included were transcripts indicating immature granulocytes. The second cluster was enriched for genes involved in cell cycle regulation. The third cluster was enriched for genes involved in innate immune responses, including those involved in the negative regulation of Toll-like receptor/ interleukin-1 receptor-triggered inflammatory cascades and markers of the alternative pathway of macrophage differentiation. Additional differentially expressed genes of interest were those involved in the cytolytic pathway, including SH2D1A and Rab27a. Conclusion. These data indicate that gene expression profiling can be a useful tool for identifying early macrophage activation syndrome in patients with systemic JIA.At onset, systemic juvenile idiopathic arthritis (JIA), which constitutes ϳ10% of all cases of JIA, is distinguished from other forms of JIA by the prominence of extraarticular features, such as spiking fevers,

The nuclear DNA-binding protein DEK is an autoantigen that has been implicated in the regulation of transcription, chromatin architecture, and mRNA processing. We demonstrate here that DEK is actively secreted by macrophages and is also found in synovial fluid samples from patients with juvenile arthritis. Secretion of DEK is modulated by casein kinase 2, stimulated by interleukin-8, and inhibited by dexamethasone and cyclosporine A, consistent with a role as a proinflammatory molecule. DEK is secreted in both a free form and in exosomes, vesicular structures in which transcription-modulating factors such as DEK have not previously been found. Furthermore, DEK functions as a chemotactic factor, attracting neutrophils, CD8؉ T lymphocytes, and natural killer cells. Therefore, the DEK autoantigen, previously described as a strictly nuclear protein, is secreted and can act as an extracellular chemoattractant, suggesting a direct role for DEK in inflammation.DEK is a mammalian oncoprotein and putative autoantigen whose primary biological function has not been previously elucidated, despite literature linking it to the regulation of transcription, chromatin architecture, and mRNA processing (1,2,11,15,16,24,35,51,65). The DEK protein is widely conserved among species and is transcribed at high levels, especially in hematopoietically derived cells (14,(62)(63)(64). DEK was first characterized as part of the protein product of the DEK-CAN fusion oncogene, resulting from a t(6;9) translocation found in a subset of patients with acute myelogenous leukemia (64). DEK is overexpressed in several different malignancies, including melanoma, hepatocellular carcinoma, glioblastoma, retinoblastoma, bladder cancer, T-cell large granular lymphocyte leukemia, and acute myelogenous leukemia independent of the t(6;9) translocation (7,10,19,20,29,30,32,39,64). Although DEK has previously been described as a strictly nuclear protein, DEK autoreactivity has been identified as a major component of the autoantibody profile in patients with juvenile idiopathic arthritis (JIA) and is also seen in patients with other autoimmune diseases (8,21,38,49,54,55). In the studies presented in this paper, we show that the nuclear protein DEK can be actively secreted by inflammatory cells, is found in synovial fluid samples from JIA patients, and can function as a chemoattractant for inflammatory cells, suggesting a potential role for DEK in immunity and/or autoimmunity. MATERIALS AND METHODSCell preparation. Monocyte-derived macrophages (MDM) were prepared as previously described (31). Briefly, heparinized venous blood samples were collected from healthy volunteers following a protocol approved by the institutional review board, and peripheral blood mononuclear cells were separated by FicollHypaque (Amersham Pharmacia Biotech AB, Uppsala, Sweden) density gradient centrifugation. MDM were purified by adherence to plastic for 2 h at 37°C at a concentration of 5 ϫ 10 5 /ml. Adherent cells were consistently Ͼ90% monocytes (31). Adherence-purified human mon...