Prevalence of immunoglobulin A deficiency in Chinese blood donors and evaluation of anaphylactic transfusion reaction risk

Objectives/Aims: We investigated the incidence of immunoglobulin A (IgA) deficiency in Chinese population. Background: The frequency of IgA deficiency, defined as a serum IgA level of <0.05 mg dL(-1), has been broadly studied in different ethnic groups. Individuals with IgA deficiency may form specific antibodies against IgA, which can cause an anaphylactic response when the patient receives an IgA-containing blood transfusion. Methods: A sandwich enzyme-linked immunosorbent assay was performed to screen for IgA deficiency and particle gel immunoassay used for confirmation. IgA antibodies were further detected by the DiaMed anti-IgA test in IgA-deficient blood donors. Results: Of the total 22 609 healthy blood donors screened, only seven cases were confirmed as having IgA deficiency (<0.05 mg dL(-1)). Another seven cases displayed relative IgA deficiencies, with mean IgA concentrations ranging from 0.39 to 3.70 mg dL(-1). Anti-IgA was identified in 2 of the 14 IgA-deficient blood donors whose IgA levels were <5 mg dL(-1). Estimation of the theoretical risk for IgA anaphylactic transfusion reaction was 0.009%. Conclusion: The prevalence of IgA deficiency in Chinese is low. However, potential risks exist in performing blood transfusion to IgA-deficient persons, and measures should be taken to reduce IgA anaphylaxis.