Induction of α1 and α2 gene expression in selective immunoglobulin A deficiency.

[]

Immunoglobulin A deficiency (IgAD ) is the most common immunodeficiency , but the pathogenesis of most cases of IgAD is poorly understood . The gene and protein expression levels of members of the IgA subclasses in IgAD patients were analyzed by a reverse transcriptase (RT )-PCR method that could differentiate between α 1 and α 2 gene expression . Three selective , 5 partial and 2 secondary IgAD patients were examined . Peripheral blood mononuclear cells which were unstimulated or stimulated with TGF-β 1 and PMA for 24 h were cultured . The IgA 1 /IgA 2 expression ratios were measured by zone densitometry . Three bands appeared (the α 1 and α 2 genes and a hetero-duplex formation ), owing to the difference of 39 bases between α 1 and α 2 mRNAs . In the controls , there were no significant differences in the IgA 1 /IgA 2 ratios between unstimulated and stimulated cells . In selective IgAD patients , both α 1 and α 2 gene expression was induced following stimulation , and α 1 gene expression was induced more dominantly than in the other IgAD patients following stimulation . Based on our results , suppression of α 1 gene expression may be related to the pathogenesis of IgAD .