IgA deficiency and transfusion

• Anti-IgA antibodies have been identified in severely IgA deficient patients who experienced infusion reactions to blood products containing small amounts of IgA, typically in plasma, including the following: whole blood, RBCs, plts, FFP, cryoprecipitate, granulocytes, IVIG
• It is suggested that screening for anti-IgA antibodies in all patients with severe IgA deficiency and for patients with partial IgA deficiency who have received blood products in the past and experienced an infusion reaction.
• In patients who have anti-IgA antibodies, it is suggested that repeat testing be done before each administration of plasma-containing blood products (except immune globulin).
• All blood products should be used with caution in IgA deficient patients, and appropriate staff and medication should be available to treat anaphylaxis
• Patients can receive cells that have been washed to remove as much of the contaminating IgA as possible
• Desensitization to blood products is another management approach that may be appropriate in specific circumstances

Updated definition 2020:

IgA deficiency is the most common primary immune deficiency with about 1 in every 600 individuals. While this deficiency is largely asymptomatic, it does have its clinical implications. Individuals with IgA deficiency may have increased numbers of acute and chronic respiratory infections that may lead to bronchiectasis. Additionally, these patients may also have an increased susceptibility to drug allergies, atopic disorders, and autoimmune diseases.

Patients with severe IgA deficiency (undetectable serum IgA) can experience anaphylaxis to blood products containing small amounts of IgA. These products include:

– Whole blood

– RBCs

– Platelets

– FFP

– Cryoprecipitate

– Granulocytes

The mechanism behind these infusion reactions is believed to come from the anti-IgA antibodies that have been identified in severely IgA-deficient patients. These anti-IgA antibodies can be IgG or IgE which allow the sudden systemic release of mediators such as histamine and tryptase by mast cells and basophils which we see in anaphylactic reactions. Management of these reactions include:

– Immediate cessation of the transfusion

– Epinephrine: 0.3mL of a 1:1000 solution intramuscularly

– Resuscitation of hypotensive patients with IV fluids

– Preparation for IV epinephrine drip

– Airway maintenance, oxygenation

– Vasopressors, if necessary

Current recommendations for screening for anti-IgA antibodies state that all patients with severe IgA deficiency and patients with partial IgA deficiency who have experience an infusion reaction in the past should be screened prior to any potential blood transfusion. The screening test is a commercial assay for the detection of IgG against IgA.

Even with the screening test, all blood products should be used with caution in IgA deficient patients, and staff should be ready to treat anaphylaxis.

Patients with positive screen should have a strategy in place for blood administration, which may include a transfusion medicine specialist consult. If RBCs are required, these cells can be washed to remove as much of the contaminating IgA as possible. Desensitization to blood products may be another option for blood product administration.