Immune functions in homosexual men with antibodies to HTLV-III in Finland.

The occurrence of HTLV-III antibodies in a voluntary group of 175 homosexual men in a low risk AIDS area was studied, and the findings were correlated to clinical, virological, immunological and lifestyle parameters. Fifteen of 175 men had HTLV-III antibodies; two of these had AIDS, five had LAS and two had enlarged lymph nodes. In the HTLV-III antibody negative group, no signs of AIDS or pre-AIDS were seen during a 10 month follow-up. In HTLV-III antibody positive individuals, low TH/TS ratio was mainly due to decreased number of TH cells. Most HTLV-III antibody positive cases had low responses to a specific antigen, PPD, while responses to the mitogens PHA and PWM were only slightly affected. In HTLV-III antibody negative cases, 13% had a low TH/TS ratio, mostly due to elevation of TS cells. In this group, mitogen and antigen responses were normal or only slightly affected. The results reinforce the causal relationship between HTLV-III and AIDS and suggest that the cells primarily affected by the virus infection are TH cells, responsible for antigen specific responses. Longitudinal studies are required to find out, what is the relationship of immune response to the development of clinical AIDS in HTLV-III infected individuals.