Studies on human low serum IgD phenotype and Gm markers

Abstract
The human low serum IgD phenotype was studied by simultaneous Gm typing and IgD immunoassay of several populations. An association between Gm (f+b+) haplotype and low human IgD was confirmed and extended to the low serum IgD phenotype as defined from population distribution and genetic studies by Dunnette et al. 1978. Black American sera determined by Gm haplotype had a similar percentage of low serum IgD phenotype samples (16%) although they lacked the associated Gm(f+b+) haplotype of White American samples. Sardinian [Italy] sera showed a low incidence of the low serum IgD phenotype which was not correlated with Gm haplotype distribution. Familial aggregation of the low serum IgD phenotype was observed. No association was found between low serum IgD phenotype and serum IgE values. Age related abiotrophy of IgD could not be attributed to selective survival of low serum IgD phenotype persons.