Blood center of zhejiang province, Zhejiang, China (People's Republic)
Background/Case Studies: Polymorphism of Killer-cell Immunoglobulin-like Receptor (KIR) genes influences the effector activity of cytotoxic NK cells and T cells. It is therefore important to understand the extent and consequences of KIR genetic polymorphism across human populations worldwide. In this study, we have investigated KIR diversity at high-resolution in three distinct Chinese ethnic minority populations - She, Yugur, and Tajik - and compared them to the Zhejiang Han, representing the majority Southern Han population.
Study
Design/Methods: A total of 333 whole blood specimens were collected from unrelated healthy adult individuals representing three ethnic minorities in China: Yugur (n=100), She (n=136), and Tajik (n=97). Specimen collection was approved by the regional ethics committee in the Blood Center of Zhejiang Province. All participants gave informed consent. An exome capture based high-throughput sequencing method was used to capture and sequence KIR genes. The distributions of KIR genes, alleles, and haplotypes in these three populations were calculated and compared to that of Zhe population described previously.
Results/Findings: We discovered that the Tajik have the most diverse gene copy number, allele distribution, and haplotype diversity of the four populations. Reflecting their proposed ancestral origin, the distribution of KIR genes in the Tajik population is close to that of the Iranian population, with a relatively higher presence of KIR-B genes, alleles and haplotypes than the other populations. The Yugur population was found to have a KIR distribution close to that of Tibet and southeast Asians, whereas the She population's distribution is similar to that of the Zhejiang and other East Asians, as confirmed by genetic distance analysis. Additionally, 12.9% of individuals were identified with haplotypes characterized by insertions or deletions of specific gene blocks. Conclusions: In summery, our finding showed that the observed diversity is likely shaped by population demographic, as well as evolutionary mechanisms specific to the local environment. Together, our findings provide valuable insight into the distribution of KIR diversity among distinct populations and ethnicities, informing future clinical and population studies. This work was supported by National Natural Science Foundation of China (82200258), the Science Research Foundation of Zhejiang Province (LGF22H080004), and Science Research Foundation of Zhejiang Healthy Bureau (2022KY139).
Importance of research: KIR genes, alleles, and haplotypes correlate directly with NK cell function through affecting receptor specificity, binding strength, signal transduction and NK cell development, a thorough understanding of worldwide KIR diversity is critical.This study will help towards a deeper understanding of the diversity and function of KIR and NK cells across populations.
