Low prevalence of autoantibodies to the insulin-like growth factor I receptor in children with short stature.
Inhibition of IGF-I action by circulating IGF-I receptor autoantibodies is a potential mechanism of IGF-I resistance in growing children. To define the prevalence of IGF-I receptor antibodies in short-statured children, we have examined serum and plasma samples from a well-characterized group of 34 short, prepubertal, growth hormone-sufficient children and three growth hormone-deficient children. IGF-I receptor purified from human placental membranes was radioiodinated by the solid phase radioiodination method. Serum from a patient with severe insulin resistance immunoprecipitated 28.9-44.7% of the 125I-labeled IGF-I receptor. The ranges (mean +/- 3 SD) of 125I-labeled IGF-I receptor immunoprecipitated by 1:10 diluted and by undiluted nonimmune human serum were 1.99 +/- 0.63% and 4.42 +/- 1.32%, respectively. Immunoprecipitation of the 125I-labeled IGF-I receptor by eight samples from six children was greater than 3 SD above the mean when assayed at a 1:10 dilution. Nevertheless, when assayed undiluted, only one of these samples immunoprecipitated slightly more 125I-labeled IGF-I receptor than nonimmune serum. We conclude from these data that immunoprecipitating autoantibodies to the IGF-I receptor are not commonly present in short-statured children.
Thompson
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Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri 63110.
Dempsher
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Bier
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Tollefsen
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D000293:Adolescent; D001323:Autoantibodies / Q000097:blood*; D015551:Autoimmunity; D002648:Child; D002675:Child, Preschool; D006130:Growth Disorders / Q000209:etiology / Q000276:immunology*; D006801:Humans; D011233:Precipitin Tests; D017526:Receptor, IGF Type 1 / Q000276:immunology* / Q000302:isolation & purification
D001323:Autoantibodies; D017526:Receptor, IGF Type 1