Frequency of Wra antigen and anti-Wra in Brazilian blood donors

BACKGROUND: Wra is a low-incidence antigen, which is antithetical to the high prevalence red blood cell antigen, Wrb. Anti-Wra is a naturally occurring antibody that is found in approximately 1-2% of blood donors. The aim of this study was to determine the frequency of Wra and anti-Wra in Brazilian blood donors.METHODS: A total of 1662 Brazilian blood donors were molecularly analyzed using the SNaPshot methodology to determine the WR*A/B alleles and to predict the frequency of the Wra antigen. To detect the anti-Wra, samples from 1049 blood donors were analyzed using a gel test with Wr(a+) red...