To investigate the safety of thymic humoral factor (THF gamma 2), its effect on HIV load based on at least a 75 percent decrease in HIV quantitative PCR RNA copies/ml, and its persistence when administered in combination with an antiretroviral nucleoside derivative (zidovudine; AZT). To assess the effects of THF gamma 2 on T-cells, quality of life, and progression of disease.

All patients receive 12 weeks of AZT before being randomized to self-administer one of two doses of THF gamma 2 or placebo for 15 consecutive days and then twice weekly for an additional 50 weeks.