The association of two single-nucleotide polymorphisms of the FOXP3 gene (rs3761548 and rs3761547) with renal allograft function and survival in kidney transplant recipients

Abstract

Introduction: The FOXP3 protein is an immune regulatory protein that specifically maintains the function and differentiation of regulatory T cells (Tregs) and prevents autoimmunity. Variations in FOXP3 gene may alter its function and also the immune response. Objectives: The present study was conducted to investigate the association of the FOXP3 gene polymorphisms -3499 A/G and -3279 A/C with renal allograft function and survival in kidney transplant recipients. Patients and Methods: In this cross-sectional study, 150 eligible kidney transplant recipients were evaluated. Kidney function was evaluated at three- and five-year post-transplant using serum creatinine level and glomerular filtration rate as indicators. Genotyping of the study participants was performed using the PCR– restriction fragment length polymorphism method. Results: The frequencies of AA, AG, and GG genotypes of the -3499 A/G polymorphism were 62.42%, 29.53%, and 8.05%, respectively. For the -3279 A/C polymorphism, the frequencies of the AA, AC, and CC genotypes were 21.33%, 32%, and 46.67%, respectively. The mean ± SD of serum creatinine level, three and five years after transplantation were 1.70 ± 1.58 and 1.87 ± 1.94, respectively. Serum creatinine level and kidney function did not show any significant association with these polymorphisms. Conclusion: In the present study, only 10% of participants experienced episodes of severe kidney dysfunction and we did not find any significant association between kidney function and the subjects’ genotypes. Further epidemiologic studies with greater sample sizes may be needed to clarify this association.