KIR B haplotype donors confer a reduced risk of relapse after haploidentical transplantation in children with acute lymphoblastic leukemia

Lena Oevermann, Sebastian U. Michaelis, Markus Mezger, Peter Lang, Jacek Toporski, Alice Bertaina, Marco Zecca, Lorenzo Moretta, Franco Locatelli and Rupert Handgretinger

Key points

  • KIR haplotype-B donors and high KIR B content score confer better protection against relapse after HLA-haploidentical transplantation in pediatric ALL.

  • Haploidentical donor selection criteria for childhood ALL should include KIR haplotype and KIR B-content score.


We analyzed the influence of donor killer-cell immunoglobulin-like receptor (KIR) gene haplotypes on the risk of relapse and probability of event-free survival (EFS) in children with acute lymphoblastic leukemia (ALL) who received HLA-haploidentical transplantation of ex vivo T-cell depleted peripheral blood stem cells. The KIR gene haplotype was evaluated in 85 donors and the KIR B-content score was determined in the 63 KIR haplotype-B donors. Patients transplanted from a KIR haplotype-B donor had a significantly better EFS than those transplanted from a KIR A-donor (50.6% versus 29.5%, respectively, p=0.033). Moreover, a high donor KIR B-content score was associated with a significantly reduced risk of relapse (Log-rank test for trend p=0.026). These data indicate that KIR genotyping should be included in the donor selection algorithm for haploidentical transplantation in children with ALL with the aim of choosing, whenever possible, a KIR haplotype-B donor with a high KIR B-content score.

  • Submitted March 28, 2014.
  • Accepted July 27, 2014.