UNLABELLEDObjective：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.

METHODSThe 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.

RESULTSThirty-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.

CONCLUSIONThe 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.