Significance of tumor necrosis factor microsatellite polymorphism in renal transplantation

Plasma levels of tumor necrosis factor (TNF) alpha are raised during acute rejection following organ transplantation. Variations in TNF alpha production have been found to be associated with the polymorphism of TNF microsatellite. Therefore, there is a possibility that a transplant recipient with some type of TNF microsatellite can be a high-risk patient of graft rejection. The purpose of this study was to examine whether TNF microsatellite polymorphism is related to acute allograft rejection. We investigated the relation of two microsatellites, TNFa and TNFd, to acute rejection after renal transplantation. Among 189 primary living-related renal transplantations from one haplotype-mismatched and one DRB1-mismatched donor, we analyzed TNF microsatellites of 163 patients whose DNA were available to this study. The frequency of the TNFa9 microsatellite allele was significantly higher in the rejection group compared to the rejection-free group. In contrast, the frequency of TNFd4 was significantly lower in the rejection group compared to the rejection-free group. TNFa9 and TNFd4 showed strong associations with HLA-B35 and B44, respectively. However, the TNF microsatellite locus was more closely related to acute rejection than HLA-B. It was suggested that the analysis of TNF microsatellite polymorphism can provide useful information in predicting prognosis after transplantation.