IgA anaphylactic transfusion reactions

Area of Science:

• Transfusion Medicine
• Immunology
• Allergy

Background:

• Anaphylactic transfusion reactions due to IgA antibodies are infrequent but serious.
• Clinical presentation of IgA anaphylaxis is indistinguishable from other anaphylactic causes.
• Diagnosis relies on detecting IgA antibodies in patient serum, often using the PHA method.

Purpose of the Study:

• To evaluate the diagnostic utility of the PHA method for detecting anti-IgA antibodies in suspected anaphylactic transfusion reactions.
• To determine the prevalence of IgA deficiency and anti-IgA antibodies in blood donors.
• To assess the reliability of anti-IgA detection for predicting transfusion reaction risk.

Main Methods:

• Sera from patients with suspected IgA anaphylactic reactions were tested for IgA antibodies using the PHA method.
• Serum IgA levels and anti-IgA antibodies were measured in blood donors using PHIA and PHA.
• Prevalence of IgA deficiency and anti-IgA antibodies was calculated.

Main Results:

• An IgA antibody was found in 76.3% of IgA-deficient patients but only 17.5% of all referred samples, suggesting other causes for suspected reactions.
• The frequency of IgA deficiency and anti-IgA in blood donors was approximately 1 in 1,200.
• Anti-IgA titers did not differentiate blood donors from patients with a history of anaphylactic transfusion reactions.

Conclusions:

• The PHA method for anti-IgA detection is not a reliable predictor of anaphylactic transfusion reaction risk.
• The high prevalence of anti-IgA in blood donors compared to reaction frequency indicates a low predictive value.
• More specific markers are required to identify individuals at risk for IgA-related transfusion reactions.