Production of Interleukin-1α and Interleukin-2 by Mononuclear Cells from Children with Growth Delay in Relation to the Degree of Growth Hormone Deficiency: Effects of Substitutive Treatment

Interleukin-1α (IL-1α) and interleukin-2 (IL-2) levels were measured by radioimmunoassay in samples of conditioned medium from mononuclear cells taken from 20 normal subjects (14 adults ranging in age from 20 to 45 years and 6 children ranging in age from 3 to 11 years) and from 49 children with growth delay. Cultures were performed with 106 cells/ml in medium containing 1 % normal human serum and 4.8 g/l phytohemagglutinin M. The incubation was performed for 48 h in an atmosphere containing 5 % CO2. In normal subjects, the production of IL-lα was 38.5 ± 9.8 fmol/ml of conditioned medium (mean ± SEM) in 14 adults and 41.6 ± 3.0 fmol/ml in 6 children. The production of IL-2 was 46.9 ± 6.5 and 57.3 ± 10.5 fmol/ml, respectively. In the 16 patients with growth hormone (GH) deficiency studied before treatment, the production of ILs was significantly decreased in relation to the degree of deficiency. We observed a positive correlation between the produciton of IL-lα and the values of insulin-like growth factor I but not with serum GH values. IL-lα production was normalized after 15 days of substitutive GH therapy and IL-2 was normalized after 3 months of therapy. In 10 other patients with GH deficiency (4 with total and 6 with partial isolated GH deficiency) studied after long-term GH treatment (5 months or more), the mean of IL production was not significantly different from that of GH-deficient children treated for 3 months. In the 23 patients with constitutional delay of growth, we observed also a significant decrease in ILs compared to the control. No correlation was found between IL production and bone age ranging from 3 to 10 years. We conclude that GH is required for IL production.