[Alpha-2-macroglobulin in children with glomerular diseases (author's transl)].

The serum and urine levels of alpha-2-macroglobulin (alpha2-MG) was determined in 33 children with glomerular diseases and in 26 healthy control children. Healthy children showed a minimum level of 275 mg% and maximum level of 337 mg%, with a mean concentration of 301 mg% and a standard deviation of 13 mg%. No alpha2-MG was detected in the urine. Steroid-treated patients with idiopathic nephrotic syndrome displayed elevated inhibitor levels of up to 490 mg%. This might be a direct result of steroid therapy or a consequence of reactively-increased protein synthesis in response to the renal protein loss. In all these patients the urine was found to be alpha2-MG-negative, irrespective of the presence or absence of proteinuria. In the miscellaneous group of glomerulopathies without the nephrotic syndrome, serum levels of alpha2-MG were shown to be normal. The urinary concentrations of alpha2-MG were related to the activity of the disease. alpha2-MG determination in serum and urine seems to be a tool for differential diagnosis and prognosis in some cases of glomerular disease.