Interferon-γ and interleukin-6 gene polymorphisms associate with graft-versus-host disease in HLA-matched sibling bone marrow transplantation

Proinflammatory cytokines including interferon-γ (IFNγ), interleukin-6 (IL-6), and tumor necrosis factor-α (TNFα) are implicated in the pathogenesis of acute graft-versus-host disease (aGVHD). Cytokine gene polymorphism is associated with functional differences in cytokine regulation and altered clinical performance in a variety of diseases. Polymorphism in the IFNγIntron1 microsatellite (CA)n repeat has been linked with in vitro IFNγ production and renal transplant rejection. The IL-6−174(G/C) single nucleotide polymorphism has been linked to in vitro and in vivo IL-6 production, juvenile chronic arthritis, and renal transplant rejection. This study examined the potential association of GVHD with IFNγ and IL-6 polymorphisms in 80 sibling bone marrow transplant (BMT) donor/recipient pairs. Patients homozygous for the IFNγIntron1 allele 3 had more severe (grade III-IV) aGVHD. Patients possessing the IL-6−174G allele had a trend toward higher grades of aGVHD, and those homozygous for the IL-6−174G allele were more likely to develop chronic GVHD (cGVHD). The associations of previously identified aGVHD severity-associated cytokine gene polymorphisms (TNFd and IL-10−1064) with severe aGVHD were reconfirmed. Logistic regression analysis confirmed the association of severe aGVHD with recipient genotype at IFNγIntron1 (odds ratio [OR] 3.92;P = .02), IL-10−1064 (OR 4.61;P = .026) and TNFd (OR 3.29; P = .039), and that of cGVHD with recipient IL-6−174 genotype (OR 4.25;P = .007), in addition to age, gender mismatch, and underlying disease. Assessment of cytokine genotype may potentially allow more accurate prediction of GVHD and appropriate adjustment of GVHD prophylaxis, as well as indicating novel areas for future studies of GVHD pathogenesis.