Selective deficiency of immunoglobulin A2.

E van Loghem; B J Zegers; E J Bast; L Kater

doi:10.1172/JCI111155

Published December 1, 1983 - More info

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Abstract

A case of familial selective IgA2 deficiency is described. The mother had no detectable IgA2, but a low level of IgA1. She had anti-alpha 2 antibodies of the IgG class. One of her daughters also lacked IgA2 with a normal level of IgA1. The analysis of the immunoglobulin haplotypes of the family suggested the deletion of the alpha 2-gene. In addition, the analysis of B lymphocytes of mother and daughter showed the absence of IgA2-bearing cells. Upon stimulation with pokeweed mitogen, the B cells differentiated into IgA1-containing plasma cells, but IgA2-containing cells were not found. The results suggest a defect in the generation of intraclonal B cell isotype diversity. The molecular basis of this phenomenon is unknown.