ANALYSIS OF CD27 SURFACE EXPRESSION ON T-CELL SUBSETS IN MS PATIENTS AND CONTROL INDIVIDUALS

Within the peripheral blood, CD4(+)CD27(-) T cells only reside within the CD45RA(-) (memory or primed)T cell subset. Cells with this phenotype have characteristics of specialized effector T cells according to their cytokine secretion profiles and the expression of tissue-specific adhesion molecules. This subset was previously found to be increased in certain diseases that are associated with immune activation. Therefore we analyzed CD27 expression of peripheral blood and CSF T cells in MS patients. Within the CD4(+) T cell subset no differences were seen between MS patients and controls in proportions of CD45RA(-)CD27(-) cells. However, when the CD3(+) T cell compartment was analyzed, CD27(-) cells were also found within the CD45RA(+) subset. These cells, most likely CD8(+), are significantly reduced in PBL and CSF of MS patients as compared with OND patients. In MS and OND groups the level of CD27(-) cells in peripheral blood correlated significantly with that in CSF, indicating a balanced migration of CD27(-) cells between the two compartments. In OIND patients, however, this equilibrium was lost. The correlation of the level of CD27(+) cells with the amount of intrathecally produced IgG in MS patients may suggest that CD27(+) cells are responsible for B cell help in this disease.