Refractory Systemic Lupus Erythematosus-associated Pericarditis Treated with Anifrolumab.

A 30-year-old woman with cutaneous lupus erythematosus, Kikuchi disease, and anti-ribonucleoprotein (RNP)/SS-A antibodies presented with fever and anterior chest pain. Initial echocardiography showed no pericardial effusion; however, follow-up revealed pericardial effusion, thus leading to a diagnosis of systemic lupus erythematosus (SLE)-associated acute pericarditis. Anti-RNP/SS-A antibodies are associated with serositis and elevated type I interferon (IFN) activity. Despite treatment with prednisolone, her condition persisted, thus prompting the administration of anifrolumab (300 mg), a monoclonal antibody that targets the type I IFN receptor. Following treatment, both pericardial effusion and the C-reactive protein levels promptly improved. This case highlights the fact that anifrolumab is a promising therapy for steroid-resistant SLE-associated pericarditis.