Coexistence of systemic lupus erythematosus and familial Mediterranean fever.

Abstract

Sir, We read the article by Devrimsel et al. reporting a patient with systemic lupus erythematosus (SLE) and familial Mediterranean fever (FMF). We believe some statements made in this article need clarification. The authors stated that FMF and SLE were autoimmune diseases and that they had similar clinical signs and symptoms. However, FMF, which is the most common autoinflammatory disease around the world, is not an autoimmune disease. TheMEFV gene encoding pyrin is mutated in FMF patients. Pyrin forms a part of the NLRP3 inflammasome complex, and dysfunctional pyrin causes increased interleukin 1b production through hyperactivated inflammasome. This is not an autoimmune process. The phenotypes of SLE and FMF are also not alike. FMF is an autoinflammatory disease characterized by attacks of polyserositis and fever lasting for 0.5 to 3 days, while SLE is an autoimmune disease with severe morbidity and mortality characterized by the presence of autoantibodies and involvement of multiple systems. Mutations in the MEFV gene may cause a tendency to certain rheumatic diseases, such as acute rheumatic fever, rheumatoid arthritis and systemic juvenile idiopathic arthritis, whereas SLE is not one of them. We have previously suggested that the rarity of SLE in FMF patients might be because of the high levels of C-reactive protein (CRP) which mediates the removal of apoptotic cells. This process eliminates a potential contributor to the pathogenesis of SLE. Funding