A subset of γδ lymphocytes is increased during HIV-1 infection

Abstract

SUMMARY The γδ T cell receptor (TcR) lymphocytes constitute 3–10% of human peripheral blood lymphocytes. Only a very small fraction of these cells is recognized by the δTCS1 monoclonal antibody, directed against the Vγδ1 chain of the receptor. We describe the immunological, virological and clinical data of a small group of seropositive subjects having high levels of γδ TcR T cells in the peripheral blood. Our flow cytometric studies show that most of these cells belong to the δTCS1+ (Vδ1+), CD8± (dim staining) subset. Patients with high γδ TcR T cell numbers were not characterized by the presence of an acute (IgM positive) or reactivated (as defined by high IgG litres against early antigen or IgA titres against viral capsidic antigen) Epstein-Barr virus infection. Cytomegalovirus infection was excluded by serological assays, and other herpesviral infections were not found after clinical examination. HIV p24 antigenaemia was present in two out of 11 subjects. AIDS patients had very high percentages of γδ TcR T cells. Altogether these data show that the selective expansion of δTCS1+ cells in HIV1 seropositive subjects is not related to some exogenous antigen stimulation, but may be related to peculiar pathologic processes involving the immune system.