An allelic typing method for 2DS4 variant used in study of haplotypes of killer cell immunoglobulin-like receptor gene

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.