Impact of MEFV mutations on inflammatory activity and long-term relapse in pediatric IgA vasculitis.

BACKGROUND: IgA vasculitis (IgAV) is the most common childhood small-vessel vasculitis. MEFV variants may enhance innate inflammatory responses, but their effect on disease course remains unclear. OBJECTIVES: To determine the prevalence of MEFV mutations in pediatric IgAV and evaluate associations with inflammatory activity and long-term outcomes. METHODS: In this retrospective cohort study, 62 children with IgAV underwent MEFV mutation analysis. Patients were classified according to mutation status. Clinical features, laboratory findings, disease activity scores (PVAS), time to remission, and long-term outcomes including relapse were compared between groups. Independent predictors of relapse were assessed using multivariable logistic regression. RESULTS: MEFV mutations were detected in 24/62 patients (38.7%), with M694V as the most frequent variant. Systemic involvement patterns and disease activity scores were comparable between groups. Mutation-positive patients exhibited higher ESR (p = 0.003), higher CRP (p = 0.004), and lower serum albumin levels (p = 0.009). Time to clinical remission was significantly longer in mutation-positive patients (p < 0.001). Long-term follow-up data were available in 57 patients. Relapse occurred more frequently in mutation-positive than mutation-negative patients (27.3% vs. 5.7%; p = 0.028). In multivariable logistic regression analysis, MEFV mutation positivity (OR = 3.12, 95% CI 1.08–9.04, p = 0.036) and ESR (OR = 1.04, 95% CI 1.01–1.07, p = 0.020) were independently associated with relapse. Clinically significant complications were observed exclusively in mutation-positive patients. CONCLUSIONS: MEFV mutations were common in pediatric IgAV and were associated with amplified inflammation, delayed remission, and increased relapse risk despite similar initial clinical presentation. These findings suggest potential prognostic relevance of MEFV mutation status.