J.‐X. Zhen

Genetic profile of KIR and HLA in southern Chinese Han population

KIR and their HLA ligands are encoded by two of the most diverse gene families in the human genome. The function of KIR on the NK cell is highly dependent on the normal expression of class I HLA on the target cell. Previous population studies in southern Chinese have been focused on the KIR framework genes and genotypes but little is known about the compound profiles of KIR/HLA. The present study examined 503 unrelated individuals from southern Chinese Han population for the polymorphism of KIR and class I HLA genes. All 16 KIR genes were detected in the study population and the four framework genes KIR3DL2, 3DL3, 3DP1, and 2DL4 were present in all individuals. Thirty unique KIR gene profiles were found reflecting a rather limited number of KIR haplotypes in this population. KIRAA1 was the most common profile observed in 54.7% of the samples. Among the AA1 individuals, 15.6% were homozygous for the deleted KIR2DS4. Haplotype A (74.8%) was more common than haplotype B (25.2%). HLA-C1 was a much more common ligand for 2D KIRs than C2. Bw4-80I, Bw4-80T, and the Bw4-bearing HLA-A alleles were detected at similar frequencies. The matched KIR+HLA pairs 2DL2/3+C1 (98.1%), 3DL1+Bw4 (73.3%), 3DL2+A3/11 (60.0%) were the most common ones whereas 3DS1+Bw4-80I was the least common (9.4%). A total of 193 unique compound profiles of KIR-HLA were identified in 480 informative individuals, 130 of the profiles being detected only once. The study provided a comprehensive analysis of the KIR/HLA profiles in southern Chinese in regards of the presence/absence of KIR genes, HLA ligands, matched KIR+HLA pairs, and KIR/HLA compound profiles. The results could help to better understand the role played by KIR/HLA interaction in associated diseases and clinical transplantation in southern Chinese.

Description of the novel HLA-DPB1*166:01 allele identified by sequence-based typing.

The novel HLA-DPB1*166:01 allele differs from the closest allele DPB1*152:01 by a single missense mutation at CDS nt 315G>A in exon 2.

Identification of the novel HLA-C*03:240 allele

HLA-C*03:240 differs from HLA-C*03:42 by a single nucleotide substitution that results in a missense mutation Tyr 99 Cys (TAT to TGT).

[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.

A novel KIR2DL3 variant allele, KIR2DL3*032, which has arisen by a missense mutation in codon 231

The novel 2DL3*032 allele differs from the closest allele KIR2DL3*0010101 by a non-synonymous mutation in exon 7.

Allelic polymorphism of KIR2DL2/2DL3 in a southern Chinese population

KIR2DL2 and KIR2DL3 segregate as alleles of the same killer cell immunoglobulin-like receptor (KIR) gene locus. They have been associated with viral infectious diseases and certain cancers and their allelic information may help to better comprehend mechanisms. The allelic polymorphism of KIR2DL2/2DL3 has been shown to influence their binding specificity and affinity to the HLA-C1 ligands. The present study aims to investigate the distribution of the allelic polymorphism of KIR2DL2/2DL3 in a southern Chinese population using sequence-specific primer polymerase chain reaction (PCR-SSP) and PCR-sequence-based typing (SBT) at the entire coding sequence. Of the 306 tested individuals, 1.96% were positive for KIR2DL2 only, 78.10% for KIR2DL3 only, and 19.93% for both KIR2DL2 and 2DL3. KIR2DL3 showed a high degree of diversity in the study population with 15 alleles detected including 8 novel ones. The predominant 2DL3 allele in the study population is 2DL3*00101 (92.81%) followed by 2DL3*00201 (24.18%), 2DL3*023 (4.25%), and 2DL3*00109 (1.31%). The remaining 11 2DL3 alleles all had a frequency below 1%. Three detected 2DL2 alleles were 2DL2*00301 (18.95%), 2DL2*00101 (3.59%), and the novel 2DL2*013 (0.33%). These results provide further insight into the KIR gene diversity in Southern Chinese and may help to better understand the role played by KIR genes in associated diseases.

Identification of the novel KIR3DL1*01505 allele from southern Chinese Han individual

The novel KIR3DL1*01505 allele differs from the closest allele KIR3DL1*0150201 by a single silent mutation.

A novel KIR2DL3 variant allele, KIR2DL3*031, identified from a southern Chinese Han individual.

The novel KIR2DL3*031 allele differs from KIR2DL3*00101 by a synonymous mutation and a non-synonymous mutation.

The novel KIR2DL3*025 allele identified in an individual from a southern Chinese Han population.

The novel KIR2DL3*025 allele differs from the closest allele KIR2DL3*0010101 by a non-synonymous mutation at CDS nt280 C>A in exon 4.

Characterization of the novel KIR2DL3*00109 allele identified in a southern Chinese Han individual

Killer cell immunoglobulin-like receptors (KIRs) are expressed mainly in natural killer (NK) cells. KIR molecules interact in a complex fusion with their ligands and play an important role in innate immunity against viral infection and tumor transformation. The KIR gene cluster includes 14 functional framework genes and 2 pseudogenes located on chromosome 19q13.4. The KIR repertoire can vary not only in allelic polymorphism, but also its gene content. Up to now, 678 KIR alleles have been identified from different world population according to the IPD-KIR database released in October 2013 (1). KIR2DL2 and KIR2DL3 share the same locus, they have HLA-C group 1 as their ligand, but appear on different haplotypes. KIR2DL2 is usually associated with haplotype B, whereas KIR2DL3 is usually associated with haplotype A. Currently, the allelic diversity of KIR2DL2/L3 in Caucasian and African population has been reported and many novel KIR alleles have been identified (2, 3). In our study regarding investigation of the allelic polymorphisms of KIR2DL3 in non-related southern Chinese Han population by sequence-based typing (SBT), DNA samples isolated from non-related bone marrow volunteer donors of Chinese Han population were subjected to SBT at the entire coding sequence of KIR2DL3 allotype using our in-house method. Nucleotide sequencing was performed using the ABI 3730 DNA Sequencer (Applied Biosystems, Foster City, CA).