Mast cell synovitis: potential target in RA?

MAUI, HAWAII – Could mast cell-rich synovitis become a novel target in patients with early rheumatoid arthritis?

Investigators at the University of London believe so. In a small but provocative study presented at the 2017 annual meeting of the American College of Rheumatology, they demonstrated that these mast cells are not an innocent bystander in joint inflammation; rather, they play an active albeit still incompletely understood role in the synovial inflammatory infiltrate and in disease progression, Orrin M. Troum, MD, said at the 2018 Rheumatology Winter Clinical Symposium.

^{Bruce Jancin/Frontline Medical News}

Dr. Orrin M. Troum

Treatment with synthetic DMARDs was partially effective, both clinically and at the cellular level. Mean mast cell density fell from 14.2/mm² at baseline to 8.2/mm² at 6 months. But synovial mast cells were still present at 6 months in 9 of 20 patients. Those nine patients had significantly higher DAS28 scores – a mean of 4.08 versus 2.41 in the synovial mast cell–negative group – as well as higher synovitis scores. Disease remission as defined by a DAS28 score below 2.6 was achieved in only 2 of 9 patients with persistent mast cell-rich synovitis, as compared with 8 of 11 mast cell-negative patients.