Transfusion Selective IgA Deficiency

Excerpt

Selective immunoglobulin A (IgA) deficiency is the most common immunodeficiency in individuals older than 4, after excluding other causes of hypogammaglobulinemia. Patients can be asymptomatic or experience recurrent infections and autoimmune illnesses. Recurrent infections, often caused by encapsulated bacteria such as Streptococcus pneumoniae and Haemophilus influenzae, most likely affect the sinopulmonary system, presenting as otitis media, sinusitis, and pneumonia. Long-term sequelae include end-organ damage, such as bronchiectasis. Infections of the gastrointestinal system caused by Giardia lamblia occur to a lesser extent, likely due to the increased presence of secreted IgM in the gastrointestinal tract. Additional associated conditions are asthma and allergies, celiac disease, inflammatory bowel disease, nodular lymphoid hyperplasia, systemic lupus erythematosus, Graves' disease, rheumatoid arthritis, and Myasthenia gravis. False-positive pregnancy tests are possible due to heterophile antibodies.

Individuals with selective IgA deficiency may develop anti-IgA antibodies causing allergic reactions when transfused with blood products containing IgA. These reactions can range from mild symptoms such as fever, chills, hives, nausea, and flushing to severe reactions such as low blood pressure, rapid heartbeat, and life-threatening anaphylaxis. Anti-IgA antibodies are most common in patients with undetectable serum IgA levels. Although studies do not conclusively link anti-IgA antibodies to these reactions, they reveal that the antibodies are significantly more prevalent in patients experiencing anaphylaxis compared to those without. Patients with selective IgA deficiency are at a significantly higher risk of transfusion reactions compared to the general population, making careful blood product selection crucial to prevent complications.

Because most patients with selective IgA deficiency do not form anti-IgA antibodies, universal testing is unnecessary. However, clinicians should administer blood products with caution in patients with selective IgA deficiency. Experts recommend screening patients with severe selective IgA deficiency and those who have experienced a reaction to blood products in the past for anti-IgA antibodies. Clinicians must implement a plan to safely administer blood products in patients who test positive for antibodies. Techniques may include sourcing blood products from IgA-deficient donors, administering washed red blood cells and platelets, administering immunoglobulin low in IgA or subcutaneously, or desensitizing the patient to blood products.