Lymphocyte subsets in renal transplant recipients during growth hormone therapy.

OBJECTIVE To evaluate the effect of growth hormone treatment on growth, levels of insulin-like growth factor I (IGF-I) and lymphocyte subsets in immunosuppressed renal allograft recipients. METHODS 18 children (aged 8.0-16.6 years) received growth hormone 1 IU/Kg/week daily for two years. Height, IGF-I levels and in 11/18 patients, lymphocyte subsets were evaluated serially. RESULTS Standardized growth velocity increased from -1.0+1.5 to +1.2+2.2 and standardized IGF-I levels from +0.8+1.5 to +3.1+1.1 (1 year) and to +1.4+1.7 (2 years). The total lymphocyte count and the number of T lymphocytes (CD3+) decreased. The decrease was more marked in CD8+ (from 1.5+0.3 x10(9)/L to 0.9+0.3 x10(9)/L, 1 year and to 0.8+0.1 x10(9)/L, 2 years) compared to CD4+ (from 1.5+0.3 x10(9)/L to 1.0+0.2 x10(9)/L, 1 year and to 1.3+0.2 x10(9)/L, 2 years), resulting in an increment of the CD4+/CD8+ index. CONCLUSIONS The differential effect of growth hormone treatment on CD4+ and CD8+ lymphocytes might be explained by different expression of the IGF-I receptor in these distinct subsets.