Serum concentrations of immunoglobulins E and G and α2-macroglobulin in childhood renal disease

Serum concentrations of IgE, IgG, and α₂-macroglobulin (α₂M) were determined in 67 children with renal disease and in appropriate controls. IgE concentrations were significantly elevated in patients with renal disease and proteinuria, including those with minimal change nephrotic syndrome (MCNS). IgG concentrations were lower and α₂M concentrations higher in patients with proteinuria than in patients without proteinuria. In 16 patients with nephrotic syndrome who had a decrease in proteinuria with therapy, there was a concomitant decrease in mean serum IgE level. All nine with MCNS had a decrease in serum IgE following therapy whereas eight of the nine had a concomitant increase in serum IgG. The findings suggest the possibility that IgE may play an etiologic role in the proteinuria of childhood nephrotic syndrome, and that both elevated serum IgE and proteinuria may represent unusual responses to antigens that are seldom identified. Elevations of IgE secondary to lowered IgG or to entirely nonspecific alterations in IgE metabolism in proteinuric renal disease are other possibilities. Further studies to elucidate the role of IgE in renal disease, including the nature of the altered metabolism of this immunoglobulin, are warranted.