T cell immunosuppression is a central defect in patients with HIV infection. There is evidence from autopsy studies that AIDS patients have substantial thymic damage. Also, there is evidence that HIV can infect cells in the thymus. It is thus possible that thymic damage is a limiting factor in the therapy of AIDS. There is some evidence that thymic involution in aged rats can be partially reversed by certain pituitary hormones (including growth hormone). Drs. Murphy, Durum, and Longo in the NCI have reported that recombinant human growth hormone (rhGH) could increase the number of CD4 T cells in the thymus and peripheral nodes in mice with severe combined immunodeficiency disease given human peripheral blood lymphocytes. Additional studies performed by investigators at Genentech, Inc. have indicated that recombinant human insulin-like growth hormone type 1 (rhIGF- 1) can induce immunologic improvement in rodents, and that the two hormones were synergistic when given together. These results suggested that rhGH or rhIGF-1 might be useful in restoring immune function in patients with HIV infection if given with anti-retroviral therapy. Based on the above observations, we are exploring whether either or both of these hormones can induce immunologic improvements in patients with HIV infection. We have initiated a phase I trial in which rhGH, rhIGF-1, or both, will be administered to patients with symptomatic HIV infection in conjunction with antiretroviral therapy. We will closely monitor a variety of immunologic parameters.
