Sustained low‐dose growth hormone therapy optimizes bioactive insulin‐like growth factor‐I level and may enhance CD4 T‐cell number in HIV infection

High‐dose recombinant human growth hormone (rhGH) (2–6 mg/day) regimes may facilitate T‐cell restoration in patients infected with human immunodeficiency virus (HIV) on highly active antiretroviral therapy (HAART). However, high‐dose rhGH regimens increase insulin‐like growth factor‐I (IGF‐I) to supra‐physiological levels associated with severe side effects. The present study investigated whether lower doses of rhGH may improve T‐cell restoration in patients infected with HIV following an expedient response of total and bioactive (i.e., free) IGF‐I. A previous 16‐week pilot‐study included six HIV‐infected patients on stable HAART to receive rhGH 0.7 mg/day, which increased total (+117%, P < 0.01) and free (+155%, P < 0.01) IGF‐I levels. The study was extended to examine whether continuous use of low‐dose rhGH (0.7 mg/day until week 60; 0.4 mg/day from week 60 to week 140) would maintain expedient IGF‐I levels and improve CD4 T‐cell response. Total and free IGF‐I increased at week 36 (+97%, P < 0.01 and +125%, P < 0.01, respectively) and week 60 (+77%, P = 0.01 and +125%, P < 0.01) compared to baseline levels (161 ± 15 and 0.75 ± 0.11 µg/L). CD4 T‐cell number increased at week 36 (+15%, P < 0.05) and week 60 (+31%, P = 0.01) compared to baseline levels (456 ± 55 cells/µL). Following rhGH dose reduction, total IGF‐I and CD4 T‐cell number remained increased at week 88 (+44%, P = 0.01 and +33%, P < 0.01) and week 140 (+46%, P = 0.07 and +36%, P = 0.02) compared to baseline levels. These data support the notion that low‐dose rhGH regimens may increase expediently total and bioactive IGF‐I and improve T‐cell restoration in patients infected with HIV on HAART. J. Med. Virol. 82:197–205, 2010. © 2009 Wiley‐Liss, Inc.