CD4+CD25+FoxP3+ T lymphocytes fail to suppress myelin basic protein-induced proliferation in patients with multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disorder directed against self antigens of the central nervous system. CD4(+)CD25(+)FoxP3(+) regulatory T cell (T-reg) mediated suppression is an essential mechanism of self-tolerance. We studied whether changes in the suppressive function of a mixture of CD25(high) and CD25(intermediate) expressing T-reg cells in myelin basic protein (MBP)-induced proliferation occurred in untreated MS patients. Suppression of MBP-induced proliferation was observed in 13 out of 29 (45%) MS patients; this was significantly (p < 0.05) less compared with 17 out of 19 (89%) healthy individuals. Relative T-reg counts was significantly increased in MS patients (mean +/- S.D.; 20 +/- 8%) compared with healthy individuals (15 +/- 5%). These findings suggest that impaired T-reg function may be involved in pathogenesis of MS. (c) 2006 Elsevier B.V. All rights reserved.