Objective: To investigate the genotypes of natural killer cell immunoglobulin-like receptor (KIR) genes and their frequencies in Chinese subjects and explore the mechanism of the actions of nature killer cells.
Methods: The DNA samples were obtained from 67 randomly selected unrelated Chinese Han individuals for genotyping of the KIR genes using PCR with sequence-specific primers (PCR-SSP), and the frequencies of the KIR genes in these Chinese subjects were compared with the reported frequencies in populations of other nationalities.
Results: Sixteen KIR genes were identified in these Chinese subjects, and 87.5% of these genes were expressed at frequencies above 0.35. Fourteen functional KIR genes combined into 25 KIR genotypes, among which the most frequent genotype KIR-2DL1-2DL3-2DL4-3DL1-3DL2-3DL3-2DS4 showed a frequency of 0.373, while the frequencies of all the other genotypes were no greater than 0.09. Comparison of the KIR combinations in Chinese Han population with those of Japanese, Korean, and Caucasians populations identified 8.93% of the KIR combinations shared by all these populations; the Chinese, Koreans and Caucasians shared 5.36% common KIR combinations, whereas only 1.79% common combinations were found in Chinese and Caucasians. In this study, 16 new gene combinations were identified (25.28%).
Conclusion: This study shows the high-frequency distribution of a single KIR gene polymorphism. The KIR combination KIR-2DL1-2DL3-2DL4-3DL1-3DL2-3DL3-2DS4 has the highest frequency in Chinese, Japanese, Korean and Caucasian populations, indicating that inhibitory signal transduction pathway plays an important role in the function of the natural killer cells. This study provide clues for new approaches for improving the prognosis of kidney transplantation by enhancing or inhibiting the function of the natural killer cells instead of life-time usage of immunosuppressive agents.