Primary thymic endocrine failure in HIV-1-infected children

Thymulin, an essential hormone for the T lymphocyte differentiation process and function, was evaluated to asses thymic endocrine function in a cohort of 17 HIV-1-infected children aged between 2 months and 14 years, 18 seror everted subjects and 47 normal controls. The rosette inhibition assay by Da rdenne and Bach (1975) is the only method available to evaluate the biologi cally active form of this hormone (thymulin or Zn-facteur thymique serique, Zn-FTS), as immunoassays cannot discriminate between thymulin and the inac tive form of the hormone not containing Zn (FTS). HIV-1 patients presented undetectable or significantly lowered plasma levels of thymulin. Plasma zin c levels were significantly reduced in patients although inactive, zinc-unb ound thymulin molecules were not demonstrated. The investigation of inhibit ory anti-thymulin molecules performed in all patients was negative. Thymuli n titers did not correlate with CD4+ lymphocyte count at the different dise ase stages. This study suggests that a primary thymic endocrine deficiency is present in HIV children. The critical importance of these results in ass essing disease progression and a potential therapeutic approach are discuss ed. Copyright (C) 2001 S. Karger AG, Basel.