To the Editor.
— Hersh et al1 reported a clinical benefit in HIV-infected patients with ditiocarb therapy. To date, four other studies have shown similar results, but the mechanism responsible for this improvement remains unclear. Ditiocarb is a compound with antioxidant and chelating activities and is associated with immunorestorative properties, presumably through modulation of T-cell differentiation. Whether besides the aforementioned properties it may eventually exhibit an antiretroviral activity remains controversial. As it is a potent stimulator of the immune response, there was a need for virological observations in treated patients to clarify whether ditiocarb could have an impact on HIV replication in vivo.We have studied this by HIV isolation and cultures in 14 HIV-infected patients enrolled in a randomized trial.2 Patients with stage II or III of the disease (Centers for Disease Control scale) received 10 mg of ditiocarb per kilogram of body weight orally once a