Background Sarcoidosis is a chronic granulomatous disease characterized by non-caseating granuloma formation. It can mimic many rheumatic diseases and/or may be coexist with them. There are limited data in the literature about the association of sarcoidosis with autoimmune diseases.

Objectives The purpose of this study is to determine the frequency and characteristics of autoimmune diseases associated with patients with sarcoidosis.

Methods One hundred and thirty-one sarcoidosis patients folowed-up in single rheumatology center were included in the study. Demographic, clinical, laboratory and radiological data of these cases were evaluated retrospectively. The characteristics of autoimmune diseases associated with sarcoidosis (sarcoidosis-overlap group) patients and isolated sarcoidosis (isolated sarcoidosis group) were analyzed and compared.

Results Autoimmune disease was detected in 15 (11.5%) of 131 patients with sarcoidosis (1Sjögren syndrome, 3rheumatoid arthritis, 1Still disease, 1scleroderma, 4ankylosing spondylitis, 1familial Mediterranean fever, 1gut arthritis, 1immune trombocytopenic purpura, 1Hashimoto thyroiditis and 1Graves disease). Most of these diseases occurred before (such as RA, AS, Still, FMF) and others after sarcoidosis diagnosis. Among 15 sarcoidosis patients with autoimmune disease 10 were female and 5 were male, the mean age was 50.8 years and mean disease duration was 3 months (1–30 months). When compared with isolated sarcoidosis patients, more hand finger joint involvement, RF positivity, higher ESR and less NSAIDs usage were found in patients with sarcoidosis-overlap group (p=0.035, p=0.049, p=0.015, p=0.018 respectively). There was no statistically significant differences between the two groups when evaluated for demographic, clinical parameters and other treatment modalities.

Conclusions Concomitant autoimmune diseases in patients with sarcoidosis may be often seen. This patients are characterized with more hand finger joint involvement, RF positivity, higher ESR and less NSAIDs usage. Therefore, in patients with a diagnosis of sarcoidosis, it is necessary for the physician to be careful and to make a wider differential diagnosis in terms of the presence of another underlying autoimmune disease. Multicenter, prospective studies involving large numbers of patients are needed to understand whether the association of sarcoidosis-autoimmune diseases is based only on coincidence or on a common etiopathogenesis.

Disclosure of Interest None declared