KIR2DS4 and Its Variant KIR1D Are Associated with Acute Graft-versus-Host Disease, Cytomegalovirus, and Overall Survival after Sibling-Related HLA-Matched Transplantation in Patients with Donors with KIR Gene Haplotype A.

Outcomes for hematopoietic stem cell transplantation (HSCT) in various donor and recipient killer immunoglobulin-like receptor (KIR) genotypes have been studied extensively. The associations between KIR2DS4 and its variant KIR1D with outcomes of HSCT from a sibling-related HLA-matched donor with KIR haplotype A have not been explored, however. To study this, we genotyped donor-recipient pairs and divided 165 recipients of HSCT from a KIR gene haplotype A donor into 3 groups: 2DS4+/2DS4+ (2 intact KIR2DS4 alleles), 2DS4+/1D+ (heterozygous), and 1D+/1D+ (homozygous for the deletion variant KIR1D). No difference in the recovery of neutrophils and platelets among the 3 groups was observed. The cumulative incidence of grade III-IV acute graft-versus-host disease (aGVHD) within day +100 was 28.94% in the 2DS4+/2DS4+ group, 14.11% in the 2DS4+/1D+ group, and 44.44% in the 1D+/1D+ group (P = .0159). Multivariate analysis identified 1D+/1D+ as an independent risk factor for aGVHD (hazard ratio [HR], 4.221; 95% confidence interval [CI], 1.470 to 12.124; P = .007). In contrast, the cumulative incidences of chronic GVHD, 3-year cumulative relapse, and treatment-related mortality did not differ significantly among the 3 groups. The rate of cytomegalovirus (CMV) reactivation was 46.96% in the 2DS4+/2DS4+ group, 20.16% in the 2DS4+/1D+ group, and 53.25% in the 1D+/1D+ group (P = .0017). Multivariate analysis identified 2DS4+/1D+ as an independent protective factor for CMV reactivation (HR, 0.268; 95% CI, 0.125 to 0.574; P = .001). Although overall survival (OS) did not differ among the groups in the first year, the 2DS4(+)/2DS4(+) group had significantly better OS than the other groups after 1 year (P = .0361). In patients with advanced-stage disease, the 3-year probability of disease-free survival was 51.06% in the 2DS4+/2DS4+ group, 34.01% in the 2DS4+/1D+ group, and 0% in the 1D+/1D+ group (P = .0314). Collectively, our data suggest that the KIR 2DS4/1D allelic variance is associated with the outcome of sibling-related HLA-matched HSCT, and that donor subclassification of KIR 2DS4/1D alleles should be considered in this setting.