Reduced Structural Damage in Early Axial Spondyloarthritis Linked to Increased IL-31 Levels

In patients with early axial spondyloarthritis (axSpA), high interleukin-31 (IL-31) levels have been associated with reduced structural damage in the spine and have also been linked with low bone mineral density (BMD), according to results from the longitudinal, prospective, multicenter French DESIR cohort study (ClinicalTrials.gov identifier: NCT01648907) published in Scientific Reports.

The investigators sought to examine the relationship between circulating cytokines and patient phenotype among individuals with SpA. Serum levels of T helper type 1 cell (Th1), Th2, and Th17 cytokines were evaluated at baseline in patients with recent-onset axSpA from the DESIR study who fulfilled Assessment of SpondyloArthritis International Society (ASAS) criteria. These levels were compared with those from age- and gender-matched healthy control participants. 

A total of 708 patients with recent-onset inflammatory back pain (>3 months but <3 years’ duration) that was indicative of axSpA were enrolled in the study. The mean age of the participants was 33.8 years, 51.5% were women, and 62.6% fulfilled the ASAS criteria. At baseline, patients who fulfilled ASAS criteria (n=443) and the healthy control patients (n=79) did not differ in levels of most of the Th1, Th2, and Th17 cytokines, except for IL-31 and sCD40L, both of which were significantly higher among patients who fulfilled ASAS criteria compared with control patients (P <.001 and P =.012, respectively).

Multivariable analysis carried out among patients who fulfilled ASAS criteria demonstrated that IL-31 level was significantly associated with sCD40L level (P <.0001) and modified Stoke AS Spine Score (mSASSS) <1 (P =.035). Based on the findings from the multivariable analysis, IL-31 was an independent factor significantly associated with mSASSS <1 (P =.001) and low BMD (P =.01).

The investigators concluded that although increased levels of IL-31 might protect patients with axSpA from structural damage, elevated levels of this cytokine are also linked with low BMD. These findings suggest that IL-31 might be involved in the bone formation/resorption balance among patients with axSpA. They recommend confirming the results of this study among patients with the most severe forms of axSpA and in those with longer disease duration. These findings could inform new therapeutic options among this population.

Please see original article for a full list of funding disclosures.

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Reference

Rosine N, Etcheto A, Hendel-Chavez H, et al. Increase in Il-31 serum levels is associated with reduced structural damage in early axial spondyloarthritis. Sci Rep. 2018;8(1):7731.