Graft-versus-host disease (GVHD) is the major complication of allogeneic hematopoietic stem cell transplantation
(HSCT); cytokines are recognized as important mediators in its pathogenesis. In this study we investigated
the role of cytokine gene polymorphisms on HSCT outcome. A total of 106 patient and 98 donors were genotyped
by polymerase chain reaction sequence specific primers (PCR-SSP) based assay for tumor necrosis factorα−308
(TNFα -308), interleukin (IL)-6-174, IL-10-1082, −819, −592, Interferon-γ+874 (IFN-γ+874), and
transforming growth factor-β1 (TGF-β1) codon10 and 25 polymorphisms. Except one in each category, all patients
and donors were TNFα -308 high producers and the majority were IL-6-174 high producers (93.3% and 90.8%
respectively); a pattern that would alleviate any potential biological impact. Patient's IFN-γ+874 showed significant
association with the development of chronic GVHD. Patients with IFN-γ +874 high producer showed an
8 folds likelihood to develop chronic GVHD as compared to those with IFN-γ+874 low producer predicted
phenotype (95% CI: 1.59-40.2, p = 0.01). Patient's TGFβ1-codon 10 and 25 high/intermediate producers
showed a lower incidence of acute GVHD though it did not achieve statistical significance (p = 0.065) on account
of the low frequency of this genotype in our patients and donors (11.4 and 8.2% respectively). Other
factors contributing to risk of GVHD included older age for both acute and chronic (p = 0.01 and 0.02 respectively)
with age 24 as the best discriminating cutoff; CD34+ cell dose for chronic GVHD (p = 0.045) with a
dose of 8 × 106
/kg as the best discriminating cutoff; and conditioning regimen with Flu/Bu associated with the
lowest incidence of acute GVHD (p = 0.003) and no impact on chronic GVHD. In conclusion the current study
further indicates a potential role of some cytokine gene polymorphisms in the development of GVHD. The
relative distribution of high and low producer genotypes in different ethnic groups contributes to their biological
impact in different populations.