Distribution of alpha-chain subclasses in normal and pathological IgA-globulins

Abstract

Of 332 monoclonal IgA-components, 6·6 per cent belonged to the He subclass, and the remainder to the Le subclass of α-chains. The light-chain type distribution (κ or λ) was not statistically different in these two subclasses, being 54·5 and 57·7 per cent, respectively. Proteins of subclass He tended to occur at higher average concentrations in the pathological sera, and were of a higher electrophoretic mobility, than were components of the Le type.

From a comparison of the concentrations of Le-type IgA and total IgA (Le+He) in a large number of individual sera without monoclonal components, it was concluded that the proportions of Le-type and He-type molecules were approximately the same (i.e. 93·4:6·6) in most individuals. The data suggest that Le- and He-type IgA molecules are produced by separate gene loci.