CD5+ B lymphocytes in HIV infection: relationship to immunological progression of disease.

We analyzed CD5+ B cells in HIV-seropositive individuals because there is accumulating evidence of the involvement of this subset in natural immunity against virus and bacteria. There are also arguments maintaining that CD5+ B cells play a role in autoimmunity and lymphoid malignancies, both phenomena which are strongly associated with HIV infection. Seventy-two HIV-positive subjects (58 drug abusers, 7 homosexual men, 4 heterosexuals, and 3 hemophiliacs) were included in a phenotypic study of mononuclear cells. A direct immunofluorescence with doubly conjugated monoclonal antibodies was performed, and analysis was carried out in a FACScan cytometer. HIV-infected patients showed a striking increase in the percentage of CD5+ B lymphocytes (54.7 +/- 19% of circulating B cells) compared with HIV-negative drug users (35.5 + 14%) and with healthy controls (17 +/- 5%), P < 0.01 and P < 0.0001, respectively. In addition, levels of CD5+ B cells were correlated with CD4+ cell counts (r = -0.50373), WR staging (r = 0.5295), lymphocytopenia (r = 0.57356), and T4/T8 ratio (r = -0.3151) and showed a close association with the progression of immune system damage by HIV. Patients who developed hypergammaglobulinemia, thrombocytopenia, or other autoimmune manifestations associated with HIV infection showed levels of CD5+ B cells increased over those of the remaining HIV-seropositive individuals (P < 0.001, P < 0.001, and P < 0.05).