Immunological findings associated with HTLV-III antibody positivity.

In order to evaluate the immunological findings associated with HTLV-III virus infection, T-lymphocyte subpopulations and lymphocyte stimulation responses were studied in a voluntary group of 174 homosexual men living in Finland. Antibodies against HTLV-III were found in 17 individuals. Decreased T-helper/T-suppressor ratio and low responses to mitogens (phytohaemagglutinin, pokeweed mitogen) and a specific antigen (purified protein derivative of tuberculin) were typical for HTLV-III antibody positive individuals. The reason for this decreased Th/Ts ratio was the low level of T-helper cells. In the HTLV-III antibody negative group, where a low Th/Ts ratio was occasionally seen, it was due to elevated T-suppressor cells. The low T-helper cell values were in good correlation with the poor clinical status of these persons and with low stimulation responses.