From the Guidelines
Low IgA levels should be investigated when discovered incidentally or when a patient presents with recurrent infections, and management depends on the severity of symptoms rather than the IgA level itself. Initial evaluation includes confirming the low IgA level with repeat testing and assessing for other immunoglobulin deficiencies by measuring IgG, IgM, and IgG subclasses 1. Clinical history should focus on frequency and severity of infections, particularly respiratory, gastrointestinal, and mucosal infections.
Key Considerations
- For asymptomatic patients with isolated low IgA, no specific treatment is needed beyond regular monitoring 1.
- For those with recurrent infections, prophylactic antibiotics like azithromycin 500mg three times weekly or amoxicillin 500mg daily may be used.
- Patients should receive appropriate vaccinations including pneumococcal, influenza, and Haemophilus influenzae vaccines.
- Immunoglobulin replacement therapy is generally not recommended for isolated IgA deficiency as commercial preparations contain minimal IgA and cannot effectively replace mucosal IgA 1.
- Additionally, patients with IgA deficiency may develop anti-IgA antibodies, potentially causing anaphylactic reactions to blood products containing IgA 1.
Important Recommendations
- Patient education about increased infection risk and prompt treatment of infections is essential.
- Referral to an immunologist is warranted for symptomatic patients or those with additional immunoglobulin deficiencies.
- Subjects older than 4 years with a serum IgA level of less than 7 mg/dL and normal serum IgG and IgM levels and in whom other causes of hypogammaglobulinemia have been excluded should be given a diagnosis of SIGAD 1.
- Patients with SIGAD should be monitored over time for the occurrence of complications, including respiratory and gastrointestinal tract infections, atopy, autoimmune diseases, celiac disease, and malignancy 1.
From the Research
Investigation of Low IgA
- The clinical implications of selective IgA deficiency (SIgAD) have been studied, and it is found that SIgAD is the most common primary immunodeficiency, but it does not always result in clinical disease 2.
- The definition of SIgAD is based on serum IgA, but most IgA is secreted at mucosal surfaces, which cannot be measured 2.
- Clinical complications of SIgAD include increased risk of sinopulmonary infections, gastrointestinal infections, autoimmune diseases, and malignancy 2, 3.
Management of Low IgA
- Patients with SIgAD should be monitored at regular intervals and educated to be aware of particular complications 2.
- Prophylactic antibiotics may be indicated in some cases, and supplemental IgG infusions may be necessary in rare cases 2, 3.
- The use of trimethoprim-sulfamethoxazole (TMP-SMX) has been studied as a treatment option for bacterial infections, but its safety profile has raised concerns 4, 5, 6.
- A systematic review and meta-analysis found that TMP-SMX was associated with a higher risk of adverse drug events, including rash, skin disorders, and other serious reactions, compared to other antibiotics 6.
Treatment Options
- TMP-SMX has been shown to be effective in treating acute otitis media, but it may not be the best option due to its safety profile 4.
- Amoxicillin-clavulanate has been compared to TMP-SMX in the treatment of acute otitis media, and it was found to have a lower cure rate and more gastrointestinal side effects 4.
- The choice of antibiotic should be based on the specific needs of the patient and the potential risks and benefits of each option 6.