Detection of immunoglobulin genes in individuals with immunoglobulin class or subclass deficiency. Evidence for a pretranslational defect.

Individuals with IgA class or IgG or IgA subclass deficiencies, as well as patients with the phenotypic expression of common variable hypogammaglobulinemia with undetectable IgA, were investigated for immunoglobulin structural gene defects. In total, more than 100 donors were studied using Southern blots. In none of these individuals did we find evidence for structural C alpha- or C gamma-gene deletions. Digestion with BamHI, PstI and PvuII, did not reveal any polymorphism in the samples analyzed with the alpha gene probe. We were unable to detect alpha-chain mRNA in lymphocytes from 8 individuals with undetectable serum and salivary IgA.