REDUCED FREQUENCY OF MEMORY CD8(-LYMPHOCYTES IN CEREBROSPINAL-FLUID AND BLOOD OF PATIENTS WITH MULTIPLE-SCLEROSIS() T)

Three color now cytometry was used to analyze immunoregulatory lymphoc yte subsets in peripheral blood (PB) and cerebrospinal fluid (CSF) of 21 patients with multiple sclerosis (MS) and 15 age-matched healthy co ntrol subjects. Two cell surface antigens associated with T lymphocyte memory and activation, CD45RO and CD29, were analyzed on the CD4(+) a nd CD8(+) subpopulations, respectively. A selective decrease in the ex pression of the CD45RO isoform among CD8(+) cells was noted in both PB (p < 0.005) and CSF (p > 0.0001) of patients with MS as compared with the control group while the expression of CD29 did not differ between the groups. These changes could indicate a defective differentiation into mature memory CD8(+) T lymphocytes in patients with MS. Furthermo re, the CD3(+)CD16/56(+) T lymphocyte subset capable of mediating NK c ell-like activities was investigated. Although this cell population is quantitatively small, a significant reduction of the proportion of th is cell type was detected in both BP and CSF of the MS group compared with the controls (p < 0.01 and p > 0.001, respectively). Further stud ies are needed to establish the role of these observations in the path ogenesis of MS.