Sequencing of PCR amplified genomic DNA including most of the coding region was used to identify killer cell immunoglobulin-like receptor 2DL1 alleles from three families and 77 bone marrow transplant patients and donors. Alleles 2DL1*00302 and *002 were frequently observed in addition to two other known alleles and four new alleles, 2DL1*00402, 2DL1*007, 2DL1*008, and 2DL1*009.

Exons 2-9 of KIR3DL3 alleles were characterized by genomic DNA sequencing in two families and in 78 bone marrow transplant samples. Several strategies were used to isolate single alleles for characterization and to resolve alternative allele combinations. We describe 17 novel 3DL3 alleles carried by 30 individuals. Compared with the most closely matched alleles, the new alleles differ by from one to three nucleotides and from zero to three amino acids. The majority of the substitutions were shared with other 3DL3 alleles although three novel polymorphic codons, 151 (exon 4), 327 (exon 7) and 352 (exon 9), are described. Of the 36 different 3DL3 alleles detected in the transplant population, the three most common alleles accounting for 47% of the total were KIR3DL3*00101 (13.5%), KIR3DL3*003 (21.2%) and KIR3DL3*00901 (12.2%).

The KIR2DS4 variants differ in exon 5 and play a role in hematopoietic stem cells transplantation (HSCT). A sequence-based testing (SBT) and TOPO TA cloning system identifying and distinguishing alleles of the KIR2DS4 gene was established and applied to a total of 150 Chinese-Han individuals: 75 patients received T-cell-depleted HSCT and their unrelated donors. The majority (139) of the 150 samples (92.7%) were positive for KIR2DS4. Four of the nine known KIR2DS4 alleles, KIR2DS4 *00101, *003,*004, and *007, were identified. In the haplotype A/A group, a higher risk of acute graft-versus-host disease (aGVHD) was seen when the donor carried two full-length KIR2DS4 alleles (RR 9.0 [95% CI 1.2-66.9], P = 0.010). Our findings suggested that the expression of full-length 2DS4 (*001) in A/A group may contribute to a worse clinical outcome after URD-HSCT. These data would be beneficial for the selection of suitable donors.