Changes in T-helper cell function in human immunodeficiency virus-infected children during didanosine therapy as a measure of antiretroviral activity.

Didanosine has shown activity against the human immunodeficiency virus (HIV) in both children and adults. We prospectively assessed T-helper cell (Th) function as determined by in vitro interleukin-2 (IL-2) production in response to a panel of T-cell stimuli in 22 HIV-infected children before and during didanosine therapy and we correlated the incidence of opportunistic and recurrent bacterial infections with changes in p24 antigen and CD4 counts. Didanosine (270, 360, or 540 mg/m2/d) was administered orally for periods ranging from 8 to 40 weeks (mean, 24 weeks). Five of six asymptomatic patients (Centers for Disease Control P-1) compared with 6 of 16 symptomatic (P-2) patients exhibited improved Th function (greater than threefold increase in IL-2 production to at least 2 of the 4 stimuli) during therapy. Of 12 patients without infections during therapy, 9 (75%) showed improvement in Th function, compared with only 2 of 10 patients with infections (P = .03). Notably, the incidence of infections was not correlated with improvements in CD4 count or decreases in p24 antigen. Improvement in Th function during didanosine therapy is correlated with decreased incidence of infections. Assessment of Th function may provide an additional measurement of immunologic response to antiretroviral therapy.