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[IgA deficiency].
1Unité d'immunologie-hématologie pédiatrique, hôpital Necker-Enfants malades, 149, rue de Sèvres, 75743 Paris, France. quartier@necker.fr
Summary
Selective Immunoglobulin A (IgA) deficiency, the most common primary immunodeficiency, often presents asymptomatically but can lead to infections. Treatment considerations include avoiding immunoglobulin administration and careful use of immunoglobulin substitution for specific patient groups.
Area of Science:
- Immunology
- Genetics
Context:
- Selective IgA deficiency is the most common primary immunodeficiency, affecting approximately 1/600 individuals in white populations.
- While often asymptomatic, it can manifest as recurrent respiratory and gastrointestinal infections.
Purpose:
- To outline the clinical presentation, genetic associations, and management strategies for Selective IgA deficiency.
- To differentiate it from other immunodeficiencies and highlight contraindications for treatment.
Summary:
- Patients with frequent infections often exhibit impaired antibody responses to polysaccharides, frequently linked to IgG2 deficiency.
- Genetic predisposition is associated with loci on chromosome 6p21.
- Selective IgA deficiency can be associated with more severe conditions like common variable immunodeficiency or ataxia-telangiectasia.
Impact:
- Contraindicates general immunoglobulin administration due to potential adverse effects from anti-IgA alloantibodies.
- Prophylactic intravenous immunoglobulin substitution is reserved for a minority with severe infections and IgG2 deficiency or impaired antibody response.
- Requires specialized immunoglobulin preparations with minimal IgA content for eligible patients.