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Aim To investigate the impact of patients with anti-HLA antibodies or with donors mismatched at HLA-DP locus on outcomes after unrelated-donor hematopoietic stem cell transplantation (HSCT). Method We explored the data from 123 patients that received allo-HSCT matched for HLA-A, B, C, DRB1, DQB1, and DQA1 (12/12) from unrelated donors from the CMDP with a 2-year follow up. The examination of anti-HLA antibodies was scheduled at 3 time points: before the start of conditioning treatment and 1 month, 3 months after transplantation. Results The presence of anti-HLA antibodies detected before and 1 month, 3 months after transplantation was 37.4% (46/123), 40.2% (47/117), 22.6% (24/106), respectively. 16.4% (18/110) recipients with donors matched in HLA-DPA1 and HLA -DPB1 loci, and the mismatched rate was 83.6% (92/110). Patients with preformed anti-HLA antibodies had delayed platelet recovery. Anti-HLA antibodies detected before and after transplantation were responsible for increased occurrence of grade 2–4 acute graft-versus host disease (aGVHD) and reduced overall survival (OS), especially in acute myeloid leukemia and myelodysplastic syndrome patients. Pre-existing HLA-Ab was an independent risk factor for the GVHD and OS. Unfortunately, we found that HLA-DP mismatches have nothing to do with outcomes after transplantation. For HLA-Ab negative group, HLA-DP matched subgroup had a modest trend towards a lower rate of aGVHD, and a higher occurrence of OS and DFS compared with HLA-DP mismatched subgroup. Conclusions Our results suggest that anti-HLA antibodies detected before and after transplantation had a negative effect of outcomes, but HLA-DP loci mismatches have no significance after HLA- 12/12 matched unrelated donor of allo-HSCT. Anti-HLA antibodies should be the primary consideration in the setting of HLA 12/12-matched unrelated-donor HSCT, followed by the status of HLA-DP matching. [ABSTRACT FROM AUTHOR]

Abstract: Killer cell immunoglobulinlike receptors (KIRs) are a diverse family of receptors on natural killer cells. The KIR2DS4-deleted variant differs from the normal KIR2DS4 sequence by a 22-bp deletion in exon 5, which causes a frame shift, yielding a truncated KIR2DS4 protein with loss of the transmembrane and cytoplasmic domains of the full-length KIR2DS4 protein. A sequence-based testing and TOPO TA cloning system identifying and distinguishing alleles of the KIR2DS4 gene was established. The method was applied to 150 Chinese Han individuals: 75 patients who received T-depleted hematopoietic stem cells transplantation and their unrelated donors, establishing frequencies of 2DS4 allele and KIR gene within the local population. A majority (139) of the 150 samples (92.7%) were positive for KIR2DS4. The ratio of deleted to nondeleted versions of KIR2DS4 was approximately 1:2. Three KIR2DS4 novel alleles were identified. Forty-four percent individuals carried two group A haplotypes. The 17 KIR gene loci were found in 21.3%–100% in the population. Our findings suggest that the Chinese Han population is distinct in KIR gene frequencies and 2DS4 allele frequencies in comparison with some other populations. [Copyright &y& Elsevier]

Aim To investigate the impact of donor Killer Immunoglobulin-like Receptors (KIR) genotypes and centromeric motif B (Cen-B) on clinical outcomes after unrelated donor (URD) hematopoietic stem cell transplantation (HSCT) for Chinese population. Method A total of 210 Chinese patients underwent URD-HSCT were investigated in this 4-year retrospective study. KIR genotyping and HLA typing were performed for the population. Results The risk of transplant from Bx1 donors and the benefit of the presence of Cen-B (ignoring the number) were observed for standard risk AML/MDS patients Donor KIR genotype Bx was associated with significant improved OS (P = .026) and RFS (P = .021), and reduced NRM (P = .017) for AML/MDS patients. A much worse survival was observed for transplants from Bx1donors compared to Bx2, Bx3, and Bx4 donors for patients in CR1, ( n = 82; OS: P = .024; RFS: P = .021). Transplant form donors with Cen-B improved OS (HR = .256; 95% CI = .084 to .774; P = .016) and RFS (HR = .252; 95% CI = .084 to .758; P = .014) for AML/MDS patients in CR1. However, the effect did not increase with the number of Cen-B motifs (cB/B vs. cA/B; OS: P = .755; RFS: P = .768). No effect was observed for high risk AML/MDS and ALL/NHL, CML patients. Conclusions Avoiding the selection of HSCT donors with KIR genotype Bx1 is strongly advisable for AML/MDS patients of standard risk. The presence of cen-B motif rather than the number was more important in donor selection for Chinese population. [ABSTRACT FROM AUTHOR]

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]