Systemic lupus erythematosus induced by anti-tumor necrosis factor α therapy in inflammatory rheumatic diseases: a case series.

This case series aims to characterize the development of systemic lupus erythematosus (SLE) induced by anti-tumor necrosis factor α (anti-TNFα) therapy in patients with inflammatory rheumatic diseases, namely rheumatoid arthritis (RA), spondylarthritis (SpA), and psoriatic arthritis (PsA). Patients with a diagnosis of SLE induced by anti-TNFα therapy and registered on the Rheumatic Diseases Portuguese Register (Reuma.pt) who started their first anti-TNFα between 2001 and 2020 were included. Demographic, clinical, and laboratory data were obtained by consulting Reuma.pt. The diagnosis of SLE induced by anti-TNFα was considered if there was a temporal relationship between the onset of anti-TNFα therapy and manifestations (clinical and immunological) in accordance with the American College of Rheumatology/European League Against Rheumatism criteria (2019). A total of 607 patients with inflammatory rheumatic diseases and six cases of SLE induced by anti-TNF-α therapy were reviewed: two patients were affected by RA, three patients by SpA, and one by PsA. All these patients had articular and constitutional symptoms that improved after discontinuation of the anti-TNFα agent. After switching to a second anti-TNFα agent, there was no recurrence of SLE over time. The development of SLE secondary to anti-TNFα agents in inflammatory rheumatic patients is rare. In this case series, all patients had a mild disease that improved after therapy discontinuation without recurrence of the disease. SLE induced by anti-TNFα should be considered in the follow-up of RA, SpA, and PsA patients.