title: Selective deficiency of immunoglobulin A2.
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.
mesh_terms: D000293:Adolescent; D000328:Adult; D000888:Antibodies, Anti-Idiotypic / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology; D002648:Child; D002846:Chromatography, Affinity; D004406:Dysgammaglobulinemia / Q000235:genetics / Q000276:immunology*; D005260:Female; D006801:Humans; D017098:IgA Deficiency; D007126:Immunoglobulin Allotypes / Q000235:genetics / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology; D010375:Pedigree
chemical_list: D000888:Antibodies, Anti-Idiotypic; D007126:Immunoglobulin Allotypes; D007074:Immunoglobulin G