The expression of CD8 on B lymphocytes in HIV-infected individuals

In HIV-1 infected individuals the CD8 + T lymphocyte population is markedly activated as reflected by increased expression of the CD38 and CD45RO activation markers and elevated serum levels of soluble CD8 antigen. We have previously shown that in vitro activation of peripheral blood lymphocytes results in the appearance of T cell markers on B cells. In the present study B lymphocytes from HIV-1-infected individuals were tested for the expression of the CD8 T cell antigen, using F(ab')2 fragments of antibodies against the CD8 and CD19 antigens. The proportion of CD19 + B cells which co-expressed CD8 was significantly elevated among 55 HIV-infected individuals (7.20 +/- 1.24%, mean +/- S.E.) as compared with among 22 normal controls (3.32 +/- 0.70%). The proportion of CD4 + cells decreased significantly in HIV-infected individuals in accordance with the progression of the infection, but no significant change in the level of CD8 + CD19 + B cells was seen in different stages of the disease. In contrast, the proportion of CD8 + B cells showed a significant correlation with the proportion of CD8 + cells.