Targeting IL-1 in SLE-Associated Recurrent Pericarditis: A Case Series and Review of Mechanistic Rationale

Pericarditis is the most common cardiac manifestation of systemic lupus erythematosus (SLE), yet optimal management remains poorly defined. Glucocorticoids are frequently used but are associated with toxicity and increased recurrence risk. Interleukin-1 (IL-1) inhibition has demonstrated efficacy in recurrent pericarditis, though data in SLE-associated pericarditis is limited. In order to evaluate the clinical impact of IL-1 blockade on the treatment of SLE-associated recurrent pericarditis, we performed a retrospective case series of six patients with SLE-associated recurrent pericarditis treated with the IL-1 inhibitor rilonacept at a tertiary care cardio-rheumatology center. Clinical response, inflammatory markers, imaging findings, and use of concomitant therapies were assessed before and after IL-1 inhibition. Following initiation of rilonacept, all six patients achieved clinical improvement: three (50%) attained complete symptom resolution and three (50%) demonstrated partial symptomatic improvement. C-reactive protein normalized in all four patients with elevated baseline levels. Any post-treatment imaging, available in five of six patients (83.3%), demonstrated objective reduction in pericardial inflammation or effusion in all five. Use of concomitant therapies decreased substantially. IL-1 blockade with rilonacept was associated with clinical and imaging improvement and substantially reduced reliance on glucocorticoids and other anti-inflammatory agents in SLE-associated recurrent pericarditis. These findings support IL-1 inhibition as a targeted, steroid-sparing strategy in refractory disease and further prospective investigation.