Idiopathic recurrent pericarditis in children: a tertiary care cohort highlighting the emergence and effectiveness of interleukin-1 blockade.

Idiopathic recurrent pericarditis (IRP) is an increasingly recognized inflammatory condition in children, characterized by recurrent flares and therapeutic challenges, with emerging evidence supporting a role for interleukin-1 (IL-1)-mediated pathways. This study aimed to characterize the clinical features of a pediatric IRP cohort at our center, to examine clinically relevant differences between patients requiring and not requiring anakinra, and to evaluate anakinra effectiveness by assessing changes in disease activity before and after treatment. In this single-center retrospective cohort study, 26 children with IRP were evaluated in terms of demographic, clinical, laboratory, genetic, and treatment characteristics. Patients were stratified according to anakinra requirement, and these characteristics were compared between groups. In patients receiving anakinra, treatment effectiveness was assessed by comparing disease activity before and after therapy using annualized attack rate (AAR) and inflammatory markers. The cohort showed a male predominance (19/26, 73%), with a median age at diagnosis of 114 months (IQR, 48-168). Chest pain was the most common presenting symptom (16/26, 62%). Pericardial effusion was present in all patients (26/26, 100%), while pleural effusion was observed in 12/26 (46%). Despite conventional therapy with nonsteroidal anti-inflammatory drugs (NSAIDs), colchicine, and corticosteroids, steroid dependency developed in 9/22 patients (41%). Anakinra was required in 16 patients (62%) and was associated with a marked reduction in disease activity, with a median relative decrease in AAR of 89.4% (IQR, 56.7-100%); a ≥ 50% reduction in AAR was achieved in 12/16 patients (75%). Significant and concordant reductions in inflammatory markers were observed. Relapse frequently occurred during anakinra dose spacing or discontinuation, while corticosteroid withdrawal was achieved in most treated patients. Patients requiring anakinra had higher baseline disease activity.

conclusionIdiopathic recurrent pericarditis in children represents a heterogeneous and frequently relapsing inflammatory condition in which conventional therapies often fail to achieve sustained disease control. As an IL-1 blockade, anakinra emerges as a key therapeutic option, enabling corticosteroid sparing while effectively achieving disease control through targeting underlying innate immunity pathways. WHAT IS KNOWN: • Idiopathic recurrent pericarditis (IRP) in children is characterized by recurrent inflammatory flares and frequent treatment resistance, with conventional therapies (NSAIDs, colchicine, and corticosteroids) often being insufficient and associated with steroid dependency. • Increasing evidence implicates autoinflammatory pathways in disease pathogenesis, highlighting the potential role of IL-1 inhibition in refractory cases. WHAT IS NEW: • The high prevalence of MEFV-associated variants, frequent steroid dependency, and substantial use of IL-1 inhibitors collectively support an auto inflammatory-driven disease model in pediatric IRP. • Anakinra markedly reduces disease activity even in patients with high baseline inflammatory burden; however, sustained disease control requires continuous therapy, as dose spacing is associated with increased relapse rates.