HIV-1 viral load in plasma ([•] 10⁴ copies/mL), absolute CD4⁺ T-cell counts ([▵] cells per microliter), and CD95L-mRNA levels in freshly isolated T cells ([○] femtograms per 250 ng total RNA) during antiretroviral combination therapy with zidovudine and didanosine in an HIV-1⁺ infant. Initial reduction of HIV-1 viral load and CD95L-mRNA levels were paralleled by an increase in CD4⁺ T-cell counts. However, as early as 12 weeks after the introduction of antiretroviral treatment, HIV-1 viral load and CD95L-mRNA levels increased and CD4⁺ T-cell counts decreased.