ObjectiveTo test the hypothesis that serum levels of soluble markers in children change after initiation of zidovudine therapy and that the extent and pattern of these longitudinal changes correlates with clinical outcome.Patients and methodsWe measured serum levels of soluble CD8, neopterin, β2-microglobulin (βM), and p24 antigen, and CD4 cell counts, before the initiation of zidovudine therapy and at 12, 24 and 48 weeks of treatment in 24 HIV-1-infected children (Centers for Disease Control classification P2) and 15 controls.ResultsSoluble CD8 levels were elevated before therapy in 70% of the infected children; subsequent decreases were associated with lower risk of disease progression. The mean serum neopterin level before treatment was elevated in infected children; decreases in neopterin levels marginally reflected improved or stable clinical status. Serum β2M levels and CD4+ cell counts were not associated with clinical outcome. Only 10 out of the 24 patients had detectable levels of serum p24 antigen before treatment; again, the amount of decline after initiation of therapy did not predict clinical outcome.ConclusionDecreasing levels of soluble CD8 and neopterin in HIV-1-infected children receiving zidovudine therapy might reflect a good response to treatment and a slowing of disease progression.