Percentile ranges for serum IgG subclass concentrations in healthy Chinese children

Abstract

SUMMARY In order to establish normal reference ranges of serum immunoglobulin G subclasses for different age groups in Chinese, we measured the four IgG subclasses by radial immunodiffusion using poiyclonal antisera in 350 normal healthy subjects (148 males and 202 females) recruited Irom ihe community. There was no signifieant sex difference for all the four IgG subclasses. Using Box-Cox transformation, we constructed smooth age-dependent percentile curves lor the four IgG subclasses. For the 50th percentile values, the plateaus Tor IgGl lo lgG4 are respectively 970 mg/dl at 13 years old. 481 mg/dl al 18. 48 mg/dl at 17 and 80 mg/dl at 13. Methodology, reagents, environmental and genetic factors might be responsible for the observed difference among the various reports. The IgG2 level in our Chinese population seemed to be higher than that in Caucasians, which might account for the very low incidence of invasive Haemophilus influenzae type b disease among the Chinese. Our IgG l level also plateaued later and at a higher level than that in other studies.