The purine nucleotide content of lymphocytes of normal subjects and asymptomatic HIV-1 seropositive patients was analyzed by HPLC. An increase in IMP and a decrease in ADP, GDP, ATP and GPT were observed in the HIV-infected patients with respect to healthy subjects. The changes may depend on different factors and indicate that the virus influences purine nucleotide metabolism of the cell. The finding sheds light on the metabolic situation of the infected cell, and could be applied to monitoring the disease.