[Analysis of HLA-Cw, KIR2D genetic variations in 2 Chinese populations].

OBJECTIVE: To explore the genetic variations of HLA-Cw and 5 KIR2D loci in 2 Chinese Han populations residing at Southern and Northern mainland China, respectively, and to investigate the HLA-Cw polymorphism of a Mongolian Chinese population.

METHODS: HLA-Cw genotyping was performed in a total of 293 healthy individuals including 1 Southern Han population living in Hunan Province (n=112), 1 Northern Han population (n=98) and 1 Mongolian Chinese population(n=83) in the Inner Mongolia Autonomous Region, using polymerase chain reaction-sequence specific primer(PCR-SSP) technique. Dimorphism at residue 80 of domain in the HLA-Cw molecule was examined by an additional set of PCR-SSP reactions. PCR-SSP was also used to detect the presence or absence of inhibitory KIR2DL1/2DL2/2DL3 loci and activating KIR2DS1/2DS2 loci for the 2 Han populations.

RESULTS: The main findings were: (1) Very significant frequency difference in the HLA-Cw alleles and dimorphism at codon 80 was detected between Hunan Han and Northern Han population, and between Hunan Han and Mongolian population (P < 0.001),while there was no such difference between the 2 Northern Chinese populations (P> 0.05); (2) There was no significant difference in frequencies of either the 5 individual KIR2D genes or the genotype distributions between the 2 Han populations (P> 0.05); (3) Asn(80)ls/Asn(80), 2DL1+/2DL2-/2DL3+/2DS1-/2DS2- predominated in both Han populations (45/112, 29/98), followed by Asn(80)/Asn(80), 2DL1+/2DL2-/2DL3+/2DS1+/2DS2- (18/112,16/98) and Asn(80)/Lys(80), 2DL1+/2DL2-/2DL3+/2DS1-/2DS2-(11/112,17/98). Among the 12 types of HLA-Cw codon 80 and KIR2D combinations, only Lys(80)/Lys(80), 2DL1+/2DL2-/2DL3+/2DS1-/2DS2- showed marginally significant frequency difference between the 2 Han populations(1/112 vs 8/98; Fisheros P was 0.0134).

CONCLUSION: Our study provided the polymorphism data of HLA-Cw gene for 3 Chinese populations with different geographic and/or ethnic background, we further analyzed the distribution of 5 KIR2D receptor genes in 2 Han populations. Our data suggest that in spite of HLA-Cw heterogeneity, remarkable similarities may exist between the Southern and Northern Chinese Han populations at the combinational level of HLA-Cw and KIR2D, which are characterized by preponderant inhibitory signal pathways.