The polymorphisms of human leukocyte antigen loci may contribute to the susceptibility and severity of severe aplastic anemia in Chinese patients

The human leukocyte antigen (HLA) system has been reported to be involved in the development of aplastic anemia (AA). We compared and analyzed HLA-A, B, C, DRB1 and DQB1 alleles in 96 Chinese severe AA (SAA) patients to those in 600 healthy people chosen randomly from the China Marrow Donor Program to investigate the association of HLA class I and II allele polymorphisms with disposition of SAA and its severity degree in Chinese population. The DNA of patients was extracted and HLA high-resolution genotyping was conducted using polymerase chain reaction-sequence based typing technique. The gene frequencies of A∗02:01, A∗02:06, B∗13:01, DRB1∗07:01, DRB1∗09:01, DRB1∗15:01 and DQB1∗06:02 in SAA patients were significantly higher than in controls (all P < 0.05), while the allelic frequencies of A∗02:07, A∗11:01 and B∗40:01 were notably lower in SAA patients than those in the controls (P = 0.001, 0.002, 0.005, respectively). Comparison among different severity of SAA groups exhibited significant increases of DRB1∗15:01 (P = 0.027) and DQB1∗06:02 (P = 0.013), but obviously lower frequencies of B∗46:01 (P = 0.023) and DRB1∗09:01 (P = 0.020) in non-VSAA patients than in VSAA patients. Thus, our results identified several risk and protective HLA alleles for Chinese SAA patients. Moreover, DRB1∗15:01, DQB1∗06:02, B∗46:01 and DRB1∗09:01 may be associated with severity of SAA.