International survey on the management of IgA deficiency: The BEST Collaborative Study

Selective immunoglobulin A (IgA) deficiency is the most common human immunodeficiency, affecting approximately 1 in 500-800 individuals of European ancestry. It is defined by a serum IgA level below 7 mg/dL, with normal immunoglobulin G (IgG) and immunoglobulin M (IgM) levels. Since 1968, severe allergic transfusion reactions have been reported in IgA-deficient patients, often linked to anti-IgA antibodies. This led to recommendations for using IgA-deficient blood components in affected individuals. However, due to the rarity of such reactions, standardized and evidence-based guidelines are lacking, while blood services face logistical challenges maintaining registries of IgA-deficient donors and inventories of compatible products.

An international survey was conducted to assess current practices in managing IgA deficiency. The survey explored the frequency of transfusion reactions involving IgA/anti-IgA, detection methods for IgA deficiency and anti-IgA antibodies, reasons for requesting IgA-deficient products, product availability and strategies to facilitate access to IgA-deficient products.

Participants from 14 countries/regions across four continents reported a wide variability in defining IgA deficiency, criteria for recommending IgA-deficient products and anti-IgA testing practices.

These findings highlight the need for international reference standards and harmonized recommendations to improve the management of IgA-deficient patients. Establishing harmonized best practices and evidence-based guidelines should enhance patient safety and support clinical decision making globally.