Cytokine gene polymorphisms associating with severe acute graft-versus-host disease in HLA-identical sibling transplants.

It is now well known that the initial phase of graft-versus-host disease (GVHD) involves cytokine release during preconditioning of the recipient of an allogeneic bone marrow transplant (BMT). Tumor necrosis factor (TNF), in particular, has been implicated in pathological damage and is released pretransplant due to irradiation and cytotoxic preconditioning regimens. Interleukin-10 (IL-10), a natural immunosuppressant of TNF, may be involved in downregulation of these responses, which may be an individual patient-specific effect. In this study, we determined the genotype for polymorphisms associated with TNF and IL-10 in 80 potential allo-BMT recipients and correlated the genotype with the severity of GVHD in 49 patients for whom clinical data relating to GVHD was available. The widely studied TNF -308 polymorphism does not show any significant associations, but the d3 homozygous allele of the TNFd microsatellite is preferentially associated with grade III/IV GVHD (7 of 11 patients) compared with its occurrence in 8 of 38 patients with grade 0/II GVHD (P =.006). Alleles of the IL-10 (-)1064 promoter region microsatellite polymorphism that possess greater numbers of dinucleotide (CA) repeats also significantly associate with more severe GVHD. This region has been demonstrated to be important in the regulation of the IL-10 promoter. Eighteen of 38 patients with grade 0-II GVHD possessed alleles with greater numbers (12 or more) of dinucleotide repeats, compared with 9 of 11 cases with grade III-IV GVHD (P <.02). Of the 38 patients with grade 0-II GVHD, 3 of 38 had a both TNFd3/d3 and IL-10 (12-15) genotype, compared with 6 of 11 patients with grade III-IV GVHD (P <.001). There was no association of either the TNFd or IL-10 microsatellite polymorphisms with mortality (P =.43 and.51, respectively). Our results suggest that patient cytokine gene polymorphism genotypes may influence GVHD outcome by affecting cytokine activation during the pretransplant conditioning regimens, and these results are the first to suggest a genetic predisposition to this important transplant-related complication.