The pattern of activation antigen expression on T-lymphocyte subpopulation in infectious mononucleosis

The peripheral blood mononuclear cells of patients with infectious mononucleosis (IM) have been characterized by the determination of activation antigens using a panel of 11 monoclonal antibodies (MoAbs) belonging to 9 clusters. The activation of CD8+ peripheral blood mononuclear cells of IM patients was found to be determined by HLA-DR and CD45RO MoAbs. The antibodies of the CD30, CD40 and CD70 termed antigens also showed an increased expression as compared to the controls. In contrast, the CD25, CD69, CD71, and CD45 antigens were expressed at a low rate on the surface of the CD8+ cells. We found, on the other hand, a very low percentage of B lymphocytes in the peripheral blood, which reflects on the virus caused antigen modulation and on the effectivity of activated CD8 cells with the characteristic expression of the above outlined markers in IM. In six asymptomatic patients, the percentage of CD8+HLA-DR+, as well as of CD8+CD45RO+ cells proved to be lower than that in the active phase of the disease. The number of B cells showed normal value in the clinically asymptomatic cases.