Autoinflammation leading to autoimmunity in adult-onset Still’s disease: more than simple coincidence?

BACKGROUND: Adult-onset Still’s disease (AOSD) should be considered in the differential diagnosis of patients with endocarditis, with or without a cardiac decompensation. CASE PRESENTATION: We report the case of a 68-year-old Caucasian male diagnosed with AOSD after an initial acute manifestation of endocarditis with severe aortic acute manifestation of endocarditis with severe aortic insufficiency. The histological findings revealed Libman–Sacks endocarditis. He was treated with the IL-1 receptor inhibitor anakinra. Two years later the patient developed a symptomatic dilated cardiomyopathy with reduced ejection fraction (23.5%) and functional anti-beta-1-adrenergic receptor antibodies, which was initially treated with plasmapheresis; anakinra was maintained. While his AOSD symptoms responded well, our patient presented with recurrent arthritis in multiple joints, dual-energy CT showed urate deposition compatible with a gouty arthropathy. Over 7 years, he presented with recurrent episodes of arthritis and the adjustment of dosages of colchicine and febuxostat was needed. In 2018, our patient died due to a deterioration of his underlying cardiac disease. CONCLUSIONS: Only two cases with initial endocarditis prior to AOSD diagnosis have been published, and we are not aware of any other cases reporting -β1AR-Ab development with DCM and gout in the setting of AOSD treated with anakinra.