BACKGROUNDRh blood group system is the most complex and immunogenetic blood group system. Prevalent RHD alleles varied in different populations. The purpose of this study is to determine the molecular basis of weak D and DEL phenotype in Anhui Chinese Han population.

METHODSThe D antigen was determined with IgM monoclonal anti-D conformed to the guidelines for donor testing in China. Weak D samples were identified by an indirect antiglobulin test. DEL phenotype was determined by adsorption and elution test. All the RHD 10 exons were screened by PCR with sequence-specific priming or sequenced for the first-time donors who typed weak D, DEL or D negative by serologic test.

RESULTSOf all the 30 799 blood donors, 155 blood samples were found D negative with IgM anti-D; 34 blood samples were found D positive by indirect antiglobulin test or absorption elution test. RHD alleles were identified by nucleotide sequencing. Total 4 RHD alleles were found including two new. One hundred and twenty of 155 (77.4%) of the serologically D negative samples lacked the RHD gene. One D negative was RHD(615del2). Thirty-two of 155 (20.6%) carried RHD(K409K) among them one carrying 1227G > A and 845G > A. Two of 155 (1.3%) was weak D type 15.

CONCLUSIONSIn this study at the molecular level, all DEL phenotype is RHD(K409K); weak D type 15 is the prevalent weak D allele in Anhui Chinese Han population. Additionally, an improved more efficient method was adopted to amplify all the RHD exons in one PCR program. Our study added to the understanding of molecular mechanisms underlying D antigen expression in Anhui Han population and provided useful information for adopting suitable genotyping strategies in routine use.