Improved thymic index, density and output in HIV-infected patients following low-dose growth hormone therapy: a placebo controlled study

Abstract

To investigate the effect of low-dose, long-term recombinant human growth hormone (rhGH) therapy on immune reconstitution in human immunodeficiency virus (HIV)-infected patients with focus on thymic index, density and output. Randomized, placebo-controlled, double-blind, single-centre trial. Forty-six HIV-infected Caucasian men on highly active antiretroviral therapy, 21-60 years of age, were included. Twenty-eight patients were randomized to 0.7 mg/day rhGH and 18 patients to placebo, administrated as daily subcutaneous injections between 1300 and 1500 h for 40 weeks. Endpoints were changes from baseline in thymic size and thymic output measured as T-cell receptor rearrangement excision circles (TREC) frequency and total TREC content, and total and naive CD4 cells. Thymic density and thymic index increased in the GH group, compared with the placebo group (28 versus 4 Hounsfield units, P = 0.006 and 1 versus 0, P = 0.004). TREC frequency and total TREC content increased in the GH group, compared with the placebo group (37 versus -8%, P = 0.049 and 51 versus -14%, P = 0.026). Total CD4 cells and naive CD4+ cells increased insignificantly more in the GH than the placebo group [11.4%, 95% confidence interval (CI) -6.0 to 28.9; P = 0.19 and 18%, interquartile range (IQR) -4, 40 versus 13%, IQR -12, 39; P = 0.79]. Therapy was well tolerated. Daily treatment with a low dose rhGH of 0.7 mg for 40 weeks stimulated thymopoiesis expressed by thymic index, density and area, TREC frequency and total TREC content in CD4 cells in HIV-infected patients on highly active antiretroviral therapy.