Chimerism in children with primary immunodeficiencies is influenced by number of activating killer cell immunoglobulin-like receptor genes in the donor and/or killer cell immunoglobulin-like receptor ligand mismatch

Background: Stem cell transplantation (SCT) is a curative treatment for children with primary immunodeficiencies.

Methods: The present retrospective analysis describes the long-term outcomes at a median follow-up of 9 years of 29 patients with immunodeficiency after SCT; 5 sibling and 24 alternative donor transplantations. T-cell engraftment emphazed on thymic dependent signal-joint T-cell receptor excision circles (sjTREC) generation and donor chimerism in relation to killer cell immunoglobulin-like receptor genes and their ligands.

Results: All children except two were reconstituted successfully from grafted material, including 9 and 18 cases of mixed chimerism (MC) and complete chimerism (CC), respectively. Univariate analyses showed that the number of activating KIR genes or HLA-C1/C2 ligand mismatches (P = .048) and possibly transplantation from an alternative donor (P = .054) facilitated CC development. Multivariate analysis showed that the presence of donor KIR haplotype B or incompatibility within C1/C2 ligands (relative risk, 6.1; 95% confidence interval, 1.08-34.69; P = .025) were significantly associated with the development of CC.

Conclusions: These results suggested that the donor-activating KIR gene repertoire affected successful engraftment.