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Selective deficiency of immunoglobulin A2
The Journal of Clinical Investigation
|December 1, 1983
Summary
This study describes familial selective immunoglobulin A2 (IgA2) deficiency, where affected family members lack IgA2 due to a potential alpha 2-gene deletion. This suggests a defect in B cell isotype diversity generation.
Area of Science:
- Immunology
- Genetics
Background:
- Immunoglobulin A (IgA) is crucial for mucosal immunity.
- Selective IgA deficiency is the most common primary immunodeficiency.
- IgA exists in two subclasses: IgA1 and IgA2.
Observation:
- A family presented with selective immunoglobulin A2 (IgA2) deficiency.
- The mother had undetectable IgA2 and low IgA1, with anti-alpha 2 IgG antibodies.
- One daughter also lacked IgA2 but had normal IgA1 levels.
Findings:
- Immunoglobulin haplotype analysis suggested a deletion of the alpha 2-gene.
- B lymphocyte analysis revealed an absence of IgA2-expressing cells in affected individuals.
- Stimulated B cells differentiated into IgA1-producing plasma cells, but not IgA2-producing cells.
Implications:
- The findings suggest a defect in intraclonal B cell isotype diversification.
- This genetic defect may impair the generation of IgA2-producing B cells.
- The molecular basis for this familial IgA2 deficiency remains to be elucidated.
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