Immunological and Endocrinological Response to Growth Hormone Therapy in Short Children

ABSTRACT. We investigated the influence of human growth hormone (hGH) on mitogen-stimulated lymphoproliferation, in vitro IgM production, serum levels of immunoglobulins, somatomedin-C (Sm-C) values and serum growth-promoting activity (Thymidine Activity, TA) in 18 short children, aged between 6.6–14.5 years, undergoing a 3-month course of hGH therapy. Blood was collected the day before treatment (Group A), on the 5th day after patients were administered hGH daily (0.1 U/kg) i.m. for 4 days (Group B), after a 3-month course of hGH injected three times weekly, and finally before (Group C) and 24 h after an extra injection (Group D). In vitro IgM production from the patients' unstimulated lymphocytes decreased from 277±41 (Group A) to 168±38 (Group B), to 119±43 (Group C) and then to 119±28 ng/ml (Group D) ( p <0.05). Using PWM-stimulated lymphocytes in vitro IgM production decreased from 2015±464 (Group A) to 1116±316 (Group B), then to 511±170 (Group C) and 968±295 ng/ml (Group D) ( p <0.02). The variation of this decrease could be correlated with the variation of growth velocity during treatment ( r =0.619, p <0.05). In contrast, no significant changes were found following therapy either in serum levels of IgA, IgE, IgG, IgM, Sm-C and TA, or in phytohemagglutinin, concanavalin A and pokeweed mitogen-stimulated lymphoproliferation. Our data suggest that there is some relationship between growth hormone, growth and immunity.