[Association of genetic polymorphisms of KIR-HLA system with chronic myeloid leukemia among ethnic Hans from southern China].

OBJECTIVE: To explore the association of KIR-HLA gene polymorphism with chronic myeloid leukemia (CML) among ethnic Hans from southern China.

METHODS: A total of 172 adult CML patients and 480 unrelated healthy controls were screened for the presence of KIR with sequence-specific primers-PCR (PCR-SSP) and sequence-based typing (SBT) of HLA-A, -B and -C loci. Polymorphisms of the KIR-HLA system were analyzed at 4 levels, and the frequencies of KIR framework genes and KIR profiles, classⅠHLA ligands, matched KIR+HLA pairs and KIR-HLA compound profile were compared between the two groups. P values were calculated using SPSS 13.0 software.

RESULTS: For the CML group, the frequencies of HLA-C2 ligand, 2DL1+HLA-C2 pair and HLA-B Bw4-80I were significantly lower than those of the control group, suggesting a protective effect against CML (HLA-C2: OR=0.386, 95%CI:0.240-0.620, P<0.01; 2DL1+HLA-C2: OR=0.316, 95%CI:0.191-0.525, P<0.01; HLA-B Bw4-80I: OR=0.576, 95%CI:0.384-0.862, P<0.01). The frequencies of KIR2DL1 ligand (HLA-C2) and KIR3DL1 ligand (HLA-B Bw4-80I) in the CML group were significantly lower than that of the control group, suggesting that the HLA-C2 and HLA-B Bw4-80I expression is probably decreased in the CML patient group, which led to reduced inhibitory signal and enhanced activating signal of KIR2DL1(+) and/or KIR3DL1(+) NK cells. Notably, the frequency of KIR-HLA compound profiles ID2 (KIR AA1-HLA-C1/C1-Bw6/Bw6-A3/11) in CML patients significantly increased in the CML patient group compared with the control group, suggesting that the KIR-HLA compound profiles ID2 may be a risk factor for CML (OR=2.163, 95%CI 1.198-3.906, P<0.01).

CONCLUSION: Above analysis has identified certain protective and risk factors for CML from the KIR-HLA system, which may provide a clue for the pathogenesis of leukemia and development of individualized immune therapy.