RESUMEN
From June 1998 to July 2004, Guangzhou umbilical cord blood bank provided unrelated umbilical cord blood for 54 patients to more than 21 transplantation centers. HLA sequencing-based typing (SBT) was used to re-analyze the results of HLA antigens and alleles so as to investigate the relationship between HLA alleles and GVHD. The information about 48 out of 54 patients was obtained after 6 months of follow up. SBT was used to identify HLA-A, B, DRB1 alleles in 48 patients received the unrelated umbilical cord blood units, and the obtained results were compared with the results of HLA-SSP Low Resolution Typing. The results showed that the difference of GVHD incidence between less than 2 mismatched HLA sites and less than 3 sites was statistically significant (P < 0.05). In the results from single factor analysis and high-resolution typing of HLA-A, B and DRB1 alleles, the mismatch between HLA-B and HLA-DRB1 alleles was found to be a significant factor for the occurence of GVHD. It is concluded that SBT plays an important role in umbilical cord blood transplantation, and the incidence of GVHD is higher in the transplantation with HLA-DRB1 alleles mismatching.