Combined analysis of cytokine gene polymorphism and the level of expression with allograft function in kidney transplant recipients.

Cytokines are important factors determining the outcome of transplantation since host ability in cytokine production may be affected by cytokine gene polymorphisms. The aim of the present study was to investigate the effect of IL-17, IL-23R and IL-21 gene polymorphisms in the outcome of kidney transplantation. A total of 250 kidney transplant recipients were included in this study. Overall 70 recipients (28%) experienced an acute rejection. IL-17 197 A/G, IL-21+1472 G/T, IL-21 5250 C/T, and IL-23R C/T gene polymorphisms were evaluated by PCR-RFLP or ARMS-PCR methods. The serum levels of IL-17 and IL-21 were also checked by ELISA. IL-17 GG carriers and G allele were significantly more frequent in patients with acute rejection as compared to patients without any sign of rejection (P=0.045 and P=0.032, respectively). In addition after gender classification, IL-23R AA carriers and A allele were significantly more frequent in male patients who experienced an acute rejection as compared to non-rejected patients (P=0.03, P=0.011, respectively). The IL-17 serum levels have also shown significant differences between rejected and non-rejected groups (24.37±32.94 for AR and 8.6±9.9 for non-AR groups, respectively; P=0.035). The mentioned results indicate that IL-17GG genotype, G allele and its serum level have predictive values for acute rejection. GG genotype and G allele of IL-17 is a genetic risk factor for development of acute rejection. Also, AA genotype and A allele of IL-23R is a sex dependent genetic risk factor for the development of acute rejection, but this subject needs to be studied in a different population.