Active MRI lesion appearance in MS patients is preceded by fluctuations incirculating T-helper 1 and 2 cells

Background: The role of T cell subpopulations and their ability to produce immunoregulatory cytokines has been extensively studied in multiple scleros is (MS). However, the exact mechanisms by which T cells and cytokines contr ibute to disease activity remain to be clarified. Objectives: To analyze th e longitudinal relation between markers of T cell activation and differenti ation and disease activity in MS patients. Methods: During a period of 9 mo nths. clinical disease activity was scored, monthly MRI scans were performe d, and blood was taken for immune measurements in a group of 13 untreated c linically definite MS patients. Results: Disease activity, as measured by t he occurrence of active MRI lesions, is associated with a significant trans ient decrease in both T cells producing interferon-gamma (IFN-gamma) and T cells producing interleukin (IL)-4. Conclusions: Our results suggest that M RI-documented disease activity is associated with a transient decrease in c irculating cytokine producing T cells, possibly due to the migration of act ivated T cells into the CNS. (C) 2001 Elsevier Science B.V. All rights rese rved.