Survey of national and regional rare donor programmes regarding Immunoglobulin A deficiency

Immunoglobulin A (IgA) deficiency is common and typically defined as <5-7 mg/dL. Individuals with absolute IgA deficiency (aIgA def) have extremely low levels, can produce allo-anti-IgA and may be at risk for anaphylactic transfusion reactions. There is no globally-accepted definition of aIgA def. We sought to determine how rare donor programmes define IgA deficiency (IgA def), how they test for it and how they manage requests for aIgA def blood products.

We queried rare blood donor programmes that participate in the International Society of Blood Transfusion Working Party on Rare Donors using an email survey sent to 39 members representing 35 programmes in 28 countries.

Responses were obtained from 23 programmes in 16 countries. Seventeen included IgA def as a rare phenotype, with nine classifying IgA def as levels <0.05 mg/dL. Eight of the 14 programmes indicated that fulfilment of requests for IgA-deficient products requires clinical consultation and 8 programmes require patients to have detectable anti-IgA. Programmes reported provision of a small number of IgA-deficient products in the past 5 years.

While respondents from rare donor programmes in 17 countries include aIgA def as a rare blood phenotype, programmes in 5 countries do not. The level of IgA used to define IgA def varies among programmes and, in some cases, across programmes within the same country. Further study is needed to better understand IgA-mediated anaphylactic transfusion reactions. A recommendation is provided for managing transfusion support of patients considered at risk.