No Direct Effect of NOD2/CARD15 Variants On Clinical Outcome After Non-Myeloablative Allogeneic Stem Cell Transplantation.

Single nucleotide polymorphisms (SNPs) in the innate immunity receptor NOD2/CARD15 have been demonstrated to modulate the outcome of allogeneic haematopoietic stem cell transplantation. The effect of the NOD2/CARD15 polymorphism seems to be associated with donor source as well as type of conditioning regimen.

We reviewed NOD2/CARD15 mutations in all donor/recipient pairs of 192 consecutive patients who received non-myeloablative allogeneic stem cell transplantation(SCT) at our institution between 2002 and 2006. All patients were treated uniformly with fludarabine 30 mg/m²/day for 3 days followed by 200 cGy TBI (n=154) or TBI alone (n=38) and received grafts from HLA-matched related (n=132) or unrelated (n=60) donors.

Mutated alleles were observed in 36 of 192 (19%) patients and in 35 of 192 (18%) donors. These SNPs, however, did not have a significant impact on clinical outcome data (P > 0.05, Kaplan Meier and Fine & Gray's test).

Acute graft-versus-host disease (GVHD) occurred in 24 of 61 (39%) patients with the polymorphism and in 66 of 131 (50%) patients without the polymorphism. Chronic GVHD developed in 28 of 55 (51%) patients with SNP pairs and in 79 of 121 (65%) patients with the wild type. The incidence of transplant-related mortality was 21% in both groups, 13 of 61 patients in the group with the polymorphism and 27 of 131 without the polymorphism. Relapse was seen in 23 of 61 (38%) patients with the SNP pairs and in 48 of 131 (37%) wild type patients. Finally, overall survival was 43% (26/61) in patients with the polymorphism and 39% (51/131) in patients without the polymorphism.

These data indicate that mutations in the NOD2/CARD15 genes do not influence the clinical outcome of non-myeloablative allogeneic SCT directly. Since NOD2/CARD15 variants are not recognized as a single significant prognostic factor, screening for NOD2/CARD15 when selecting a donor does not seem to have additional value in patients undergoing non-myeloablative SCT.

No relevant conflicts of interest to declare.