From the Guidelines
Patients with a serum IgA level of less than 7 mg/dL and normal serum IgG and IgM levels, in whom other causes of hypogammaglobulinemia have been excluded, should be given a diagnosis of Selective Immunoglobulin A (IgA) deficiency. This diagnosis is based on the criteria outlined in the practice parameter for the diagnosis and management of primary immunodeficiency 1. The management of IgA deficiency focuses on treating infections promptly when they occur, typically with appropriate antibiotics based on culture results. For those with frequent infections, preventive strategies include good hygiene practices, avoiding known triggers, and in some cases, prophylactic antibiotics.
Key Considerations
- Most people with IgA deficiency remain asymptomatic throughout their lives and require no specific treatment 1.
- Some individuals may experience recurrent infections, particularly of the respiratory, gastrointestinal, and urinary tracts.
- Patients with IgA deficiency should be monitored over time for the occurrence of complications, including respiratory and gastrointestinal tract infections, atopy, autoimmune diseases, celiac disease, and malignancy 1.
- Individuals with IgA deficiency should inform healthcare providers before receiving blood products, as they may develop anti-IgA antibodies that could cause anaphylactic reactions to IgA-containing blood products 1.
Diagnostic Criteria
- A serum IgA level of less than 7 mg/dL is required for a diagnosis of IgA deficiency, with normal serum IgG and IgM levels 1.
- Other causes of hypogammaglobulinemia must be excluded before making a diagnosis of IgA deficiency 1.
- Only methods capable of detecting IgA concentrations of less than 7 mg/dL can determine whether IgA is truly absent or present at very low concentrations 1.
Management Strategies
- Treat infections promptly when they occur, typically with appropriate antibiotics based on culture results.
- Preventive strategies include good hygiene practices, avoiding known triggers, and in some cases, prophylactic antibiotics.
- IgA replacement therapy is not typically used because IgA has a very short half-life in the bloodstream and would require frequent administration.
From the Research
Diagnosis of Selective Immunoglobulin A (IgA) Deficiency
- Selective IgA deficiency is the most common primary immunodeficiency, with a prevalence of approximately 1/600 in whites 2
- It is characterized by low or undetectable levels of IgA in the blood, while other immunoglobulin levels are normal 3
- Most individuals with IgA deficiency are asymptomatic, but some may experience recurrent sinopulmonary or gastrointestinal infections, particularly those with associated IgG2 or IgG4 deficiency or specific antibody deficiency 3, 4
- Diagnosis is typically made by measuring IgA levels in the blood, and may involve additional tests to rule out other immunodeficiencies or underlying conditions 5
Management of Selective Immunoglobulin A (IgA) Deficiency
- There is no specific treatment for patients with symptomatic IgA deficiency, but antibiotics may be prescribed to manage acute infections 3
- Prophylactic antibiotics may be indicated in some cases, particularly those with recurrent infections or associated immune defects 4, 5
- Immunoglobulin replacement therapy may be considered for patients with severe or frequent infections, particularly those with associated IgG2 deficiency or impaired antibody response 6, 2
- However, immunoglobulin preparations containing low amounts of IgA are required to avoid adverse effects related to anti-IgA alloantibodies 2
- Patients with IgA deficiency should be monitored regularly and educated to recognize potential complications, such as anaphylaxis due to anti-IgA IgE antibodies 4
- Subclassification of IgA deficiency regarding associated immune defects can help guide medical care and monitoring, as patients with concomitant immune defects may be at higher risk for recurrent infections and complications 5