Clinical phenotype and cytokine profile of adult IgA vasculitis with joint involvement

Abstract

Objective: Joint involvement can be observed during the course of adult IgA vasculitis (IgAV). However, clinical picture, prognosis, or pathophysiological data associated with this condition have been overlooked. We aimed to describe the clinical characteristics and outcome of IgAV patients with joint involvement and look to a specific cytokine profile.

Methods: We analyzed clinical and biological data from a nationwide study that included adult IgAV patients. Presentation and outcomes of patients with or without joint involvement were compared at baseline and during follow-up. Plasma cytokine measurements of IgAV patients included in a prospective study were also analyzed using multiplex assays.

Results: Among 260 patients, 62% had joint involvement. Among them, rheumatological manifestations included arthralgia (100%) or arthritis (16%), mostly involving the knees and ankles. In multivariate analysis, patients with joint involvement, compared to those without, were younger (p = 0.002; OR 0.87; 95% CI 0.80-0.95) and showed more frequent gastrointestinal tract involvement (p = 0.012; OR = 2.08; 95% CI 1.18-3.67). However, no difference in terms of clinical response, relapse, end-stage renal disease, or death was observed between groups. Among 13 cytokines measured, plasma interleukin (IL)-1β level was higher in patients with joint involvement compared to those without (mean ± SEM IL-1β, 3.5 ± 1.2 vs. 0.47 ± 0.1 pg/ml; p = 0.024) or healthy controls (vs. 1.2 ± 0.5 pg/ml; p = 0.076).

Conclusion: Joint involvement is frequent in adult IgAV and is associated with more frequent gastrointestinal involvement. Increased plasma IL-1β levels raise the question of targeting this cytokine in patients with chronic and/or refractory joint involvement. Key Points • Joint involvement in adult IgAV is a frequent manifestation. • Joint involvement is associated with more frequent gastrointestinal manifestations. • Interleukin-1β (IL-1β) might orchestrate joint inflammation in adult IgAV. • IL-1β might be a therapeutic target in patients with chronic and/or refractory joint involvement.

Keywords: Gastrointestinal tract involvement; Henoch-Schönlein purpura; IL-1β; IgA vasculitis; Joint involvement.