Changes in activated T cells in the blood correlate with disease activity in multiple sclerosis

Objective: To determine whether changes in activation markers on peripheral blood T cells correlate with disease activity in patients with multiple sclerosis. Design: In a prospective longitudinal study during 1 year, we analyzed the change in percentage of activated T lymphocytes in the peripheral blood of 40 patients with multiple sclerosis in relation to clinical findings and changes on brain magnetic resonance imaging (MRI) scans. The patients underwent repeated imaging of the brain (mean number of MRIs for each patient, 22) at the time blood samples were obtained as well as at monthly neurological examinations, and at the time of scoring on the Kurtzke Expanded Disability Status Scale (EDSS) and ambulation index scale. Results: A change in the percentage of cells expressing the activation markers interleukin 2 receptor (CD25), class II major histocompatibility complex (MHC) (13) or surface dipeptidyl peptidase (CD26) correlated significantly with a change in lesion volume or a change in number of gadolinium-enhancing lesions as detected on MRI. Changes in CD25(+) cells and in CD4(+) cells expressing class II MHC also correlated with changes in disability as measured by EDSS in patients with relapsing-remitting disease, and changes in CD4(+)CD25(+) cells correlated with the occurrence of attacks in patients with relapsing-remitting disease. These correlations are dependent on measurement of changes between time points sampled at 1- or 2-week intervals. Conclusion: There is a linkage between peripheral T-lymphocyte activation as measured by cell surface markers and disease activity in patients with multiple sclerosis.