Abstract
Rheumatoid pleural effusion (RPE) is a rare complication of rheumatoid arthritis (RA) with no sufficiently established treatment. Sarilumab, a monoclonal antibody targeting the interleukin-6 receptors, is widely used to treat RA. Here, we present the case of a 68-year-old man with refractory RA and RPE, who was successfully treated with sarilumab. The patient presented with polyarthritis and pleural effusion. Based on serum and pleural fluid test results, he was diagnosed with RA and RPE but did not respond to prednisolone (PSL) therapy. Notably, arthritis and pleural effusion resolved after initiation of sarilumab treatment, with sustained remission even after PSL discontinuation. Previous reports suggest that the inflammatory mechanisms underlying pleural effusion and synovitis in RA are similar. To date, only a few studies have investigated the use of biological disease-modifying antirheumatic drugs for RPE. This case highlights the efficiency of sarilumab for RPE treatment via interleukin-6 inhibition.