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ObjectivesDiverse evidence including clinical, genetic and microbiome studies support a major role of the gut microbiome in the common immune-mediated arthropathy, ankylosing spondylitis (AS). We set out to (1) further define the key microbial characteristics driving disease, and (2) examine the effects of tumour necrosis factor-inhibitor (TNFi) therapy upon the microbiome.MethodsThe stools from a case–control cohort of 250 Han-Chinese subjects underwent shotgun metagenomic sequencing. All subjects were genotyped using the Illumina CoreExome SNP microarray.ResultsPrevious reports of gut dysbiosis in AS were reconfirmed and several notable bacterial species and functional categories were differentially abundant. TNFi therapy was correlated with a restoration the perturbed microbiome observed in untreated AS cases to that of healthy controls, including several important bacterial species that have been previously associated with AS and other related diseases. Enrichment of bacterial peptides homologous to HLA-B27-presented epitopes was observed in the stools of patients with AS, suggesting that either HLA-B27 fails to clear these or that they are involved in driving HLA-B27-associated immune reactions. TNFi therapy largely restored the perturbed microbiome observed in untreated AS cases to that of healthy controls, including several important bacterial species that have been previously associated with AS and other related diseases. TNFi therapy of patients with AS was also associated with a reduction of potentially arthritogenic bacterial peptides, relative to untreated patients.ConclusionThese findings emphasise the key role that the gut microbiome plays in driving the pathogenesis of AS and highlight potential therapeutic and/or preventative targets.

ObjectiveThe COVID-19 pandemic is not only a traumatic event, but a collective stressor unfolding over time, causing devastating implications for the mental health. This study aimed to shed light on the mental health status of patients with rheumatic disease (RD) during the massive outbreak of COVID-19 in China, especially the prevalence and severity of post-traumatic stress disorder (PTSD) compared with healthy individuals.MethodsA total of 486 patients with RD and 486 age-matched and sex-matched healthy individuals were recruited into the study. For each participant, we collected demographic and clinical characteristics data. The PTSD Checklist for DSM-5 (PCL-5) and four items from the Pittsburgh Sleep Quality Index (PSQI) were used to investigate the prevalence and severity of PTSD and sleep quality, respectively.ResultsCompared with healthy control subjects (n=486), patients with RD (n=486) had a higher prevalence of PTSD (12.1% vs 4.1%; pConclusionDuring the COVID-19 outbreak, patients with RD presented a higher prevalence and severity of PTSD and showed more sleep disturbances. Our findings confirm the importance of psychological assessment and mental healthcare out of regular clinical care for patients with RD during the pandemic.

Background and objectivesEfficacy of adalimumab for ankylosing spondylitis (AS) has been established for Western populations but not in the Chinese population. This study is the first to evaluate the efficacy and safety of adalimumab in Chinese patients with AS.MethodsChinese adults with active AS who had an inadequate response or were intolerant to ≥1 non-steroidal anti-inflammatory drugs were randomised to adalimumab 40 mg (N=229) or matching placebo (N=115) subcutaneously every other week (EOW) for 12 weeks, followed by a 12-week open-label adalimumab 40 mg EOW phase. The primary efficacy endpoint was the percentage of patients meeting the Assessment in Spondyloarthritis International Society (ASAS20) response criteria at week 12. The recently developed AS Disease Activity Score (ASDAS), as well as efficacy measures of spinal mobility, disease activity, physical function and quality of life were evaluated.ResultsAt week 12, adalimumab treatment resulted in a significantly greater percentage of ASAS20 responders than placebo (67.2% versus 30.4%, respectively; pConclusionsAdalimumab significantly reduced the signs and symptoms, improved physical function and quality of life of Chinese patients with active AS, and was generally safe and well tolerated in this population.

BackgroundThe genome-wide association study era has made great progress in identifying susceptibility genes and genetic loci for rheumatoid arthritis (RA) in populations of White European ancestry. However, few studies have tried to dissect disease aetiopathogenesis in other ethnic populations.ObjectiveTo investigate these associations in the Han Chinese population.MethodsHaplotypes from the HapMap database Chinese population were used to select tag-single-nucleotide polymorphisms (SNPs) (r2=0.8) across 19 distinct RA genomic regions. A two phase case–control association study was performed, with 169 SNPs genotyped in phase I (n=571 cases, n=880 controls), and 64 SNPs achieving pResultsRobust association was detected for MMEL1 and CTLA4, and modest association was identified for another six loci: PADI4, STAT4, PRDM1, CDK6, TRAF1-C5 and KIF5A-PIP4K2C. All three markers genotyped in MMEL1 demonstrated association, with peak signal for rs3890745 (p=2.6×10−5 unadjusted, p=0.003 adjusted, OR=0.79). For CTLA4, significance was detected for three of five variants showing association, with peak association for marker rs12992492 (p=4.3×10−5 unadjusted, p=0.0021 adjusted, OR=0.77). Lack of association of common variants in PTPN22 with RA in Han Chinese was confirmed.ConclusionThis study identifies MMEL1 and CTLA4 as RA susceptibility genes, provides suggestive evidence of association for a further six loci in the Han Chinese population and confirms lack of PTPN22 association in Asian populations. It also confirms the value of multiethnic population studies to help dissect disease aetiopathogenesis.

Recent data are presented which indicate a critical role for interleukin (IL)‐18 in rheumatoid arthritis (RA). The T cells and macrophages invading the synovium or in the synovial fluid are the chief cellular targets of IL‐18 in RA. Neutrophils, dendritic cells and endothelial cells may also be cellular mediators of IL‐18. The direct effect of IL‐18 on fibroblast‐like synoviocytes or chondrocytes may not be essential or important. In RA, IL‐18, which is mainly produced by macrophages, activates T cells and macrophages to produce proinflammatory cytokines, chemokines, adhesion molecules and RANKL which, in turn, perpetuate chronic inflammation and induce bone and cartilage destruction.

OBJECTIVES--To evaluate the role of low molecular weight (LMW) IgM and CD5 B cells in rheumatoid arthritis (RA) and to explore the possibility that LMW IgM is derived selectively from this subset of B cells. METHODS--LMW IgM in sera and culture supernatants was detected by a sensitive immunoblot technique with an enhanced chemiluminescence detection system. CD5 B cells were determined by FACScan cytometry. In vitro studies were established in culture plates containing pokeweed mitogen with or without 2-mercaptoethanol (2-ME). Supernatants were obtained from CD5 positive hybridomas and CD5 negative hybridomas. Other immunological indices were measured by laser nephelometry. RESULTS--Circulating LMW IgM was detected in all rheumatoid patients with significantly higher levels being observed in sero-positive patients. LMW IgM correlated significantly with total IgM and RF. Peripheral blood mononuclear cells (PBMC) from the majority of the patients with RA secreted LMW IgM in vitro as did mononuclear cells from a synovial fluid sample. The addition of low concentrations of 2-ME to the culture medium enhanced the proportions of secreted monomeric IgM. In contrast, PBMC from healthy subjects secreted only trace quantities of LMW IgM. In RA no significant correlations were observed between CD5 B cells and LMW IgM and RF. LMW IgM could be detected in the supernatants from both CD5+ and CD5- B cell lines. Finally, CD5 B cells were not significantly elevated in RA and levels remained constant over time. CONCLUSION--LMW IgM exists in high concentrations in RA sera and synovial fluid. Serum level correlates with RF and IgM. In vitro studies have suggested that the occurrence of LMW IgM may be due to an intrinsic defect(s) in the assembly of the IgM pentameric molecule. LMW IgM is unlikely to be derived solely from CD5 B cells.