Immunoglobulin subclass distribution of human anti-carbohydrate antibodies: aberrant pattern in IgA-deficient donors.

The IgG and IgA subclass distribution of anti-carbohydrate antibodies in normal and immunodeficient donors was investigated. In normal donors, the specific anti-dextran antibodies were mainly of the IgG2 and IgA2 subclass, although substantial amounts of antibodies could also be of the IgG1 subclass. In children, IgG1 was the predominant subclass expressed. An aberrant IgG subclass distribution pattern of specific antibodies occurred in some IgA-deficient donors, with preferential expression of IgG1 and IgG3 anti-dextran antibodies.