- In patients with rheumatoid arthritis (RA) in remission, high levels of an atypical CD4+ T cell subset related to inflammation exposure -- dubbed inflammation-related cells or IRC -- predict relapse, UK researchers report in the June issue of the Annals of the Rheumatic Diseases.
Dr. Frederick Ponchel of St. James's University Hospital, Leeds and colleagues examined blood samples from 41 patients with active RA, 42 patients with RA in remission, 12 patients with osteoarthritis, 13 with Crohn's disease and controls.
High IRC levels were identified in patients with RA and Crohn's disease but not in those with osteoarthritis or in healthy controls.
Moreover, IRC levels were high in both patients with active RA and, unexpectedly, those in remission. Furthermore, levels of the proapoptotic mediator Bax were reduced and were inversely correlated with IRC. This, say the investigators, suggests that a mechanism lowering Bax expression may be involved in IRC persistence.
Nearly half of the patients in remission (20/41) experienced a disease flare within 18 months, and the frequency of IRC was significantly higher in this group (odds ratio, 6.4).
These results, say the investigators, "suggest a model in which, despite the lack of systemic inflammation, IRC persist in remission, indicating that IRC are an acquired feature of RA."
"I think the main use of IRC," Dr. Ponchel told Reuters Health, "would be in monitoring disease and remission to establish whether patients are indeed at risk of relapsing."
"If we could find a way to eliminate these cells specifically," he added, "this may prove beneficial for these particular patients at risk."
Ann Rheum Dis 2008;67:750-757.
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