Increase of OKT4+ cells during treatment with thymostimulin in parenteral drug addicts with persistent generalized lymphadenopathy.

Thymostimulin (TP-1), a parenterally administered calf thymus extract, has induced a significant increase of OKT4+ peripheral cells in 9 drug addicts with persistent generalized lymphadenopathy; OKT4+ lymphocytes decreased gradually after withdrawal of treatment. In a control group, a spontaneous decrease occurred in the same period of observation. A more prolonged treatment should be undertaken to assess the effectiveness of the drug on the evolution of the disease.