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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. [ABSTRACT FROM AUTHOR]

Unlabelled: Objective：To calculate the prevalence of IgAD in a replicate cohort of the Chinese Han population in Shanghai area by screening blood donors and to study the genetic difference of IgAD individuals in the Mongoloid population., Methods: The prevalence of IgAD in a large number of Chinese blood donors (n=61624) in Shanghai area was investigated. The immunoglobulin class, IgG subclass and anti-IgA serum levels were measured among the IgAD donors. These donors were subsequently tissue typed and the allele frequency was compared with the Shanghai bone marrow donor HLA registry., Results: Thirty-one IgAD blood donors were identified, giving a prevalence of 1:2000(31/61624). Most IgAD donors had serum IgG levels above the normal range with no major IgG subclass deficiency and 3 donors was positive for anti-IgA. Two-thirds of the IgAD donors carried Caucasian IgAD associated risk haplotypes, including DRB1*0301-DQB1*0201, DRB1*0701-DQB1*020 and DRB1*0102-DQB1*0501, giving a significantly higher frequency of these haplotypes as compared to the Shanghai bone marrow donor HLA registry., Conclusion: The prevalence of IgAD in Chinese Han population is markedly lower than that in Caucasians. The low prevalence of IgAD can potentially be due to the low frequency of the disease associated risk haplotypes in China. However, potential risks exist in performing blood transfusion to IgAD persons, and measures should be taken to reduce IgA anaphylaxis. Meanwhile, it is necessary to set up a Shanghai rare blood bank of IgAD donor for patients to meet the needs of IgA-poor transfusion.