Incidence and effects on growth of antibodies to human growth hormone.

Antibodies to human growth hormone (HGH) have been measured by radioimmunoassay on one or more occasions in 98 children with short stature treated with HGH, and in 51 other children. Positive antibody binding reactions occurred in nearly a third of these 149 children, but the great majority of these showed an assay curve significantly non-parallel to the standard, denoting the presence of only non-specific antibodies. However reactions above 0·1% antibody binding capacity in relation to the M.R.C. standard anti-serum are mostly specific to HGH. Specific reaction over 0·1% occurred in 19 sera taken from 10 children, all of whom were under treatment with HGH. Only 4 of these children showed a slowing down of growth associated with the development of antibodies, 2 children permanently and 2 only for a period of three months with spontaneous recovery of growth rate and drop of antibodies. The level of antibodies which appears to cause growth inhibition is between 0·5% and 1% binding capacity of the M.R.C. standard. In all, 4 out of 42 children with isolated growth hormone deficiency have developed `permanent' growth-retarding antibodies on HGH treatment. No children with other diagnoses have done so. Specific antibodies were not present in any of our patients before treatment.