Soluble Low Affinity Fc Receptors for IgE in the Serum of Allergic and Nonallergic Children

Abstract

IgE-binding factors are thought to have regulatory activity in in vitro IgE synthesis. To obtain evidence of the participation of IgE-binding factors in in vivo IgE synthesis, the serum level of low affinity Fc receptors for IgE (sFceRII) (IgE-BFs) was examined in 41 nonallergic children and in 37 allergic children whose serum IgE levels were significantly higher than those of nonallergic children. The serum level of sFceRII showed a marked age-dependent variation. It was highest in infants and then decreased gradually with age. The serum level of sFceRII in allergic children was significantly higher than that of nonallergic children in early childhood (1128.0 ± 323.8 vs 777.3 ± 227.0 pg/ml, pppp<0.001 in 27 allergic and Spearman's rank correlation coefficient = 0.72, p<0.001 in 19 nonallergic children). In conclusion, serum sFceRII may be derived mainly from FceRII(+) lymphocytes, and may have relationship to the increased production of IgE in early childhood (0-2 y).