Lymphocyte adherence in multiple sclerosis: effect of aspirin.

Peripheral blood lymphocytes from multiple sclerosis (MS) patients form substantially greater numbers of rosettes with measles virus-infected human epithelial cells than do lymphocytes from healthy controls or from patients with other diseases. We have previously shown that prostaglandin E(1)-treated normal lymphocytes exhibit increased lymphocyte adherence, and thus behave like MS lymphocytes in this in vitro system. In this study we describe the effect of prostaglandin synthesis inhibition on lymphocyte adherence in both MS and control patients. Direct addition of aspirin or indomethacin to peripheral blood mononuclear cells from MS patients in vitro reduced lymphocyte adherence to control levels. Ingestion of therapeutic (anti-inflammatory) doses of aspirin (1 g, 4 times daily for 2 d) by MS patients resulted in reduction of lymphocyte adherence to levels seen in healthy controls. A single 325-mg dose of aspirin did not reduce lymphocyte adherence. A dose-dependent reduction in lymphocyte adherence was observed after single doses ranging from 650 mg to 1.3 g; duration of the effect was directly related to the aspirin dose. These observations indicate that treatment of MS patients with aspirin profoundly influences adherence of their lymphocytes to measles virus-infected cells and suggest that the altered cellular response, which results in increased lymphocyte adherence in MS patients, may be mediated by a prostaglandin-sensitive mechanism.