75-P: CHARACTERIZATION OF KILLER-CELL IMMUNOGLOBULIN-LIKE RECEPTOR (KIR) GENOTYPES AND GROUP B HAPLOTYPES IN SOUTHERN CHINESE HAN POPULATION.

Aim: To study the distribution of the varied KIR genotypes and haplotypes in Southern Chinese Han population. Methods: We performed KIR genotyping on 1271 individuals from the south China including 102 families with 306 members and 965 unrelated individuals. The 102 families with one child and both parents were subjected for haplotype analysis. Results: The family study revealed segregation of at least 15 unique B haplotypes. The most commonly observed haplotypes in group B were B1, B2, and B3, present at a frequency of 10.05%, 6.62%, and 4.90%, respectively. Based on the combination of KIR genes, 6 centromeric and 7 telomeric gene motifs have been identified. Motif cB01 was the most frequent haplotype B specific centromeric segment while tB01 was the most frequent haplotype B specific telomeric segment. The distinct distribution of KIR haplotypes in each population may reflect the history of directional and balancing selection of different races. 43 different genotypes with at least one group B haplotype were identified (A/B or B/B). The frequencies of the KIR genotypes found in the family panel were confirmed by those found in the unrelated panel. The gene combinations of group A and B1/B2/B3 haplotype were the most frequent genotypes named as Bx1, Bx2 and Bx3, present at a frequency of 15.47%, 9.67%, and 5.56%, respectively. Conclusions: Overall, this study revealed the diversity of KIR haplotypes and genotypes in southern Chinese Han population and developed a criterion for distinguish KIR group B haplotypes/ genotypes for the population. KIR genotyping and haplotype analysis should be useful for selection of the most optimum donor grafts with favorable KIR gene content for transplants. [Copyright &y& Elsevier]