Concomitant administration of recombinant human growth hormone (rhGH) may boost the expansion of immune reconstitution and broaden specific T cell responses not achievable by vaccination alone. The main objective of that study is to test the validity of this hypothesis with vaccines which are routinely administered to HIV-1 patients(tetanus toxoid and hepatitis A virus vaccines) in order to, if proven of value, use this strategy of HIV vaccination in the near future. This is a pilot, randomized, clinical open label study aimed to investigate thymic functionality and the HIV-specific responses after administration of rhGH in HIV-1 infected patients in highly active antiretroviral therapy (HAART) regimen.

The purpose of a therapeutic vaccine is to control, induce and expand humoral and cellular immune responses capable to control HIV infection. The administration of a conventional vaccine results in the expansion of peripheral clones. Concomitant administration of rhGH may boost this expansion and reconstitute specific T cell responses not achievable by vaccination alone. In this study we want to investigate whether the administration of rhGH expand T cell repertoire and whether there is an increase in the specific cellular responses to HIV-1 and recall antigens and, lately, whether this responses can be further amplified after immunization with tetanus toxoid and hepatitis A vaccines. This Hypothesis will be evaluated by the measurement of thymic volume, the expansion of naïve, memory and effector cell subsets, analysis of thymic emigrants (TRECs) before, during and after rhGH administration and vaccination. Moreover, T cell receptor rearrangement, specific antibodies and cellular responses to antigenic peptides will be determined.

Inclusion Criteria:

1. HIV-1 asymptomatic patients in HAART regimen (> 6 months)
2. Viral load < 50 copies/ml
3. Number CD4 cells > 250 cells/mm3
4. Non responders to vaccination (tetanus toxoid and/or Hepatitis A virus)
5. Well-disposition to rhGh daily administration (6 months of treatment)

Exclusion Criteria:

1. AIDS outbreak
2. Allergy or hyperreactivity to rhGH or vaccines
3. Diabetes Mellitus
4. Renal, hepatic, pancreatic disorders
5. Chronic diseases
6. Dementia
7. Pregnancy