Brief Report: Dialister as a Microbial Marker of Disease Activity in Spondyloarthritis.

OBJECTIVE: Dysbiosis of the intestinal microbiota has been widely established in inflammatory bowel disease (IBD). There is significant clinical and genetic overlap between spondyloarthritis (SpA) and IBD, and up to 50% of all patients with SpA exhibit microscopic signs of bowel inflammation, often bearing particular resemblance to early Crohn's disease, a subtype of IBD. This study was undertaken to assess the relationship between intestinal microbial composition, gut histology, and disease activity markers in SpA. METHODS: Gene analysis by 16S ribosomal RNA amplicon sequencing was used to compare the microbial composition in ileal and colonic biopsy specimens from 27 patients with SpA (14 with microscopic bowel inflammation, 13 without) and 15 healthy control subjects (ileal samples from all 15 subjects and colonic samples from 6). Spearman's rank correlation tests were used to assess correlations of the microbial composition with disease activity measures. RESULTS: The intestinal inflammation status (histologically normal versus acute or chronic inflammation) was strongly associated with the mucosal microbiota profile of patients with SpA. In inflamed biopsy tissue, the detected bacterial community composition clustered separately from that in noninflamed biopsy tissue (P < 0.05 by permutational multivariate analysis of variance, using hierarchical clustering on Bray-Curtis distances). Interestingly, abundance of the genus Dialister was found to be positively correlated with the Ankylosing Spondylitis Disease Activity Score (Spearman's rho = 0.62, false discovery rate-corrected q < 0.01). This finding was further supported by the low frequency of Dialister observed in noninflamed ileal and colonic biopsy tissue from patients with SpA and healthy controls. CONCLUSION: These findings demonstrate a significant difference in the intestinal microbial composition in patients with SpA who have microscopic gut inflammation compared to those without microscopic gut inflammation. Moreover, Dialister may represent a potential microbial marker of disease activity in SpA.

Degree of bone marrow oedema in sacroiliac joints of patients with axial spondyloarthritis is linked to gut inflammation and male sex: results from the GIANT cohort.

INTRODUCTION: Bone marrow oedema (BMO) of the sacroiliac joints (SIJs) is a hallmark of axial spondyloarthritis (SpA). However, the relationship between the extent of BMO and disease phenotype is poorly understood. OBJECTIVE: To assess the link between BMO of the SIJs and gut inflammation. We have also evaluated the correlation between BMO and established disease activity parameters. METHODS: Sixty-eight patients with axial SpA from the Gent Inflammatory Arthritis and spoNdylitis cohorT underwent ileocolonoscopy and MRI of the SIJs. Histopathological analysis and SPondyloArthritis Research Consortium of Canada (SPARCC) scores were performed. RESULTS: A significant higher SPARCC score (median (range)) was observed in axial SpA patients showing chronic gut inflammation (16.9 (3.8-68.3)) compared with axial SpA patients showing normal gut histology (9.8 (0.0-45.0); p<0.05). In a multiple linear regression model, we identified, besides chronic gut inflammation (effect size of 11.3, 95% CI (2.1 to 20.4)), male sex (effect size of 10.5, 95% CI (3.3 to 17.8)) to be independently associated to the extent of BMO. There was a low to moderate correlation between the degree of BMO and C-reactive protein(r=0.39, p=0.002) and Ankylosing Spondylitis Disease Activity Score (r=0.35, p=0.007). CONCLUSIONS: Higher degrees of BMO were observed in patients showing chronic gut inflammation. These data solidify a link between mucosal inflammation and progressive disease in axial SpA.

Adalimumab dose escalation and dose de-escalation success rate and predictors in a large national cohort of Crohn's patients.

BACKGROUND AND AIMS: Adalimumab is efficacious in inducing and maintaining remission in Crohn's disease but dose escalation is needed in 30-40% after 1 year. Attempts for dose de-escalation have not been studied. This study aimed to assess the need for, predictors, and outcome of dose escalation and de-escalation in a large cohort of adalimumab treated Crohn's patients. METHODS: All consecutive patients treated with open label adalimumab for active Crohn's disease from the participating centres were included in this cohort study. A detailed retrospective chart review was performed to look for possible factors predicting outcome. RESULTS: Eighty four percent of 720 patients had a primary response and were followed up for a median of 14 months. Thirty four percent needed escalation after a median of 7 months (0-55 months). Multivariate predictors for dose escalation were the following: prior anti-TNF use (p<0.0001), no concomitant azathioprine or <3 m (p<0.02) and abnormal CRP at start (p<0.05). Dose escalation re-induced response for at least 6 months in 67%. Only abnormal CRP at start correlated with failure of dose escalation (p=0.02). Dose de-escalation was attempted in 54% and was successful in 63%. After a median follow-up of 14 m adalimumab was discontinued in 29% of patients. CONCLUSION: In this study real life nationwide cohort of Crohn's patients treated with adalimumab dose escalation was needed in 34% and was successful in 67%. Dose de-escalation was attempted in 54% and was successful in 63%. Overall 71% of patients maintained long term response on adalimumab.

Microscopic gut inflammation in axial spondyloarthritis: a multiparametric predictive model.

OBJECTIVE: To assess the rates and explore predictors of microscopic gut inflammation in a cohort of patients with axial and peripheral spondyloarthritis (SpA). METHODS: Ileocolonoscopy was performed in 65 patients with axial and peripheral SpA from the Gent Inflammatory Arthritis and spoNdylitis cohorT. Histopathological analysis and scoring were performed by an experienced pathologist. RESULTS: Overall, 46.2% of the patients with SpA showed microscopic gut inflammation. In axial SpA, the following parameters were independently associated with gut involvement: male sex (OR=8.9, p=0.035); high disease activity measured by the Bath Ankylosing Spondylitis Disease Activity Index (OR=2.05, p=0.032); restricted spinal mobility measured by the Bath Ankylosing Spondylitis Metrology Index (OR=1.94, p=0.009); and younger age (OR=0.85, p=0.013). No clear association was found for human leucocyte antigen-B27 status, presence of peripheral arthritis, enthesitis, uveitis, psoriasis, intake of non-steroidal anti-inflammatory drugs and family history of SpA. The prevalence of gut inflammation in non-radiographic axial SpA and ankylosing spondylitis was comparable. CONCLUSIONS: The prevalence of microscopic gut inflammation in SpA remains unaltered over time. Younger age (shorter symptom duration), progressive disease, male sex and higher disease activity are independently associated with microscopic gut inflammation in axial SpA.