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.
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.