Growth hormone improves immune function in GH-deficient young adolescents

To delineate the role of growth hormone [GH] in the development and function of the immune system, sixteen GH-deficient young adolescents were studied for evaluation of the immune status before and after treatment with recombinant human growth hormone [rhGH]. Ten apparently healthy young adolescents age and sex-matched with the study group were included in the study as control group. Blood samples were obtained for immune studies before treatment and at 2, 6 and 9 months after. Immune studies included; enumeration of total T and B lymphocyte number, CD3+, CD4+, CD8+ and CD4+/ D8+ ratio, serum immunoglobulin concentrations [IgG, IgM], assessment of Iympho-proliferative response to phytohemagglutinin and testing for intracellular killing by Nitro blue tetrazolium test [NBT]. Results showed significant impairment in mitogen stimulation and phagocytic function in GH-deficient young adolescents when compared to control group [73.18 +/- 5.2 versus 146.2 +/- 7.6, P < 0.0001 and 50.13 +/- 5.8 versus 82.2 +/- 4.49, P < 0.0001 respectively]. This impairment improved significantly after treatment with rhGH [p < 0.0001]. However, there were no significant differences in the total B-Iymphocytes numbers, CD3+, CD4+, CD8+, CD4+ / CD8+ ratio, and serum immunoglobulin levels between GH-deficient group and control group, as well as between values obtained before and after rhGH treatment. These results indicate that growth hormone administration has profound immune-enhancing effects in GH-deficient young adolescents and may be of therapeutic effect in states of compromised immune function