Increased serum interleukin 22 levels in patients with axial spondyloarthritis

Abstract

Objectives The role of IL-22 in radiographic axial spondyloarthritis is not fully elucidated. Thus, there is a need for new insights into this cytokine in this disease. We aimed to compare interleukin (IL)-22 level between spondyloarthritis, non-specific-low back pain patients, and pain-free controls, and to evaluate associations between this cytokine and spondyloarthritis characteristics. Methods We conducted a case-control study including 62 patients with radiographic axial spondyloarthritis(G1), 46 with non-specific low back pain(G2), and 42 healthy volunteers(G3). IL-22 was measured using Enzyme-linked immunosorbent assay. We evaluate disease activity and structural damage of spondyloarthritis. Results IL-22 level was higher in G1 than in G2 and G3 (38±40 versus14.42± 8.17 versus 14.3±18.67pg/mL,p<0.01). IL-22 discriminated patients in G1 from G2 with a cutoff of 22.28pg/mL (Sensitivity:62.9%, Specificity:97.8%, area under the curve (AUC): 0.808). IL-22 cutoff of 19.27pg/mL discriminated patients in G1 from G3 (Sensitivity: 67%, Specificity:94.3%, AUC:0.855). No associations were found between IL-22 levels and disease activity and structural damage. Conclusions : Our study showed that IL-22 level was higher in radiographic axial spondyloarthritis patients compared to controls. It was also able to differentiate G1 patients from G2 and G3. This finding suggests that the IL-22 pathway showed to play a pathological role in spondyloarthritis.