RESUMO
BACKGROUND: Acute and chronic rejections remain an important cause of graft loss after renal transplantation. Currently, activation of innate immune responses through Toll-like receptors (TLRs) is suspected to be implied in the loss of the transplant tolerance. OBJECTIVES: We investigated functional single nucleotide polymorphisms (SNPs) of TLR4 and its coreceptor CD14 in kidney transplantation and looked for any potential role in acute rejection (AR) and chronic allograft nephropathy (CAN) and impact on graft survival. PATIENTS AND METHODS: TLR4 (Asp299Gly) and CD14 (C/T -159) SNPs were detected using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 209 kidney transplant recipients (KTRs) including 132 treated with mycophenolate mofetil (MMF+). AR occurred in 59 patients and 24 were identified as having CAN by biopsy and scored according to the Banff criteria. RESULTS: There were no significant associations between TLR4 and CD14 genotypes and alleles and the occurrence of both AR episodes and CAN. Moreover, TLR4 and CD14 SNPs did not seem to influence kidney graft survival. Analysis according to human leukocyte antigen (HLA) compatibility status, positivity of anti-HLA antibodies, and immunosuppression by MMF confirmed the absence of correlation of the investigated SNPs with the graft outcome. In addition, incidence of post-transplantation infections, including cytomegalovirus (CMV) infections, was not influenced by both TLR4 and CD14 SNPs. CONCLUSION: These results suggest that TLR4 (Asp299Gly) and CD14 (C/T -159) functional SNPs do not play a major role in AR, CAN, and kidney graft survival. Therefore, intragraft monitoring of TLR4/CD14 genes expression by messenger RNA (mRNA) would provide clarity on the exact role of these receptors in graft injuries.