Expression of costimulatory molecules on peripheral blood mononuclear cells in multiple sclerosis

Objective - To determine whether there was aberrant expression of costimulatory molecules and their receptors on peripheral blood mononuclear cells of MS patients and healthy individuals and whether expression correlated with disease status. Methods - Forty-six patients with MS and 29 healthy individuals were analyzed by direct 2-color immunofluorescence flow cytometry for expression of CD80, CD86, CD28 and CTLA-4 on T and B cells and monocytes. Results - Expression of CD80 on CD4(+) T cells was upregulated in progressing MS patients compared to stable MS patients and controls. Marked increase in the expression of CD80 and CD86 was seen on both CD4(+) and CD8(+) T cells from an MS patient with rapidly progressing disease. No difference in the expression of the costimulatory molecules or their ligands was seen between IFN-P treated and non-treated MS patients. Conclusions - Aberrant expression of costimulatory molecules occurs on T lymphocytes in MS patients with progressing disease.