T-lymphocyte subsets defined by double immunofluorescence in multiple sclerosis.

T-lymphocyte subpopulations were studied in the blood of 25 multiple sclerosis patients and 25 healthy age and sex-matched controls. Monoclonal antibodies labelled with different fluorochromes were used to define the percentages of CD4 (helper/inducer) and CD8 (suppressor/cytotoxic) positive cells and to dissect them into phenotypic subgroups. The results confirm the decrease in CD8 positive cells in the blood associated with multiple sclerosis. The subset showing the most marked decrease was the CD11 marker negative population, which has been reported to be associated with cytotoxicity rather than suppression. There was no significant decrease in the percentage of cells positive for both CD4 and CD45R markers reported to contain suppressor-inducer or naive T-helper cells in the MS patients. The results suggest that further dissection of T-cell subpopulations may clarify our understanding of this disease process.