Frequency of autoinflammatory features in rheumatoid arthritis and its effect on treatment response

Aim: Rheumatoid arthritis (RA) is an autoimmune disease however, may show autoinflammatory clinical features such as fever, serositis and intermittent arthritis. The aim of this study is to determine the frequency, clinical features, and response to standard treatments in RA patients with autoinflammatory features. Methods: The study included 311 patients who were diagnosed as RA and were receiving medical treatment for at least six months in Koc University Hospital Rheumatology outpatient clinics between July 2018 and July 2021. The patients were divided into two groups according to autoinflammatory features. Demographic, clinical and laboratory findings, response to treatments were compared. Results: There were 246 (79%) female and 65 (21%) male patients. Median age was 60 (IQR: 49-70) and disease duration was 3 (IQR: 3-12) years. Twenty-four (8%) patients had at least one autoinflammatory feature. Leukocytosis and thrombocytosis rates were higher in the autoinflammatory group (p=0.013 and p=0.002). There was no difference in terms of seropositivity and uric acid levels. Anakinra was used only in the autoinflammatory group in four patients and was effective in all. Colchicine usage was higher in the autoinflammatory group (p<0.001). Inadequate response rates to methotrexate and TNF (tumor necrosis factor) inhibitors were similar for two groups (p=0.572 and p=1). Conclusion: Autoinflammatory clinical features can be seen in a small group of patients diagnosed with RA. The cause of this may be mutations in MEFV or other genes related to periodic fever disorders, and colchicine and IL-1 targeted drugs are effective treatment options in these patients when standard treatments are inadequate. Keywords: rheumatoid arthritis, autoinflammation, autoimmunity, colchicine, anakinra