Natural Killer Cell Subsets and IL-2, IL-15, and IL-18 Genes Expressions in Chronic Kidney Allograft Dysfunction and Graft Function in Kidney Allograft Recipients

BACKGROUND: While acute rejection and early graft loss rates have decreased substantially over the past four decades, progressive chronic allograft dysfunction (CAD) still remains a common cause of late graft loss in kidney transplant recipients. OBJECTIVE: This study was conducted to investigate the percentage of natural killer (NK) cell subsets and IL-2, 15 and 18 genes expression in two groups of CAD and well-function graft (WFG) recipients. METHODS: 30 renal allograft recipients with biopsy-proven interstitial fibrosis/tubular atrophy (IF/TA) and impaired renal function, and 30 sex- and age-matched WFG patients were enrolled in this study. The percentage of NK cell subsets including NK CD56(bright) and NK CD56(dim) cells were determined by flowcytometry; IL-2, IL-15, and IL-18 genes expressions were assessed by real-time PCR. RESULTS: Compared to WFG patients, there was a significant (p<0.05) increase in the percentage of NK CD56(bright) cells in CAD patients. However, the difference in percentage of NK CD56(dim) cells or CD56(dim)/CD56(bright) ratio between the studied groups was not significant. In addition, IL-2, 15 and 18 genes expressions were almost similar in CAD and WFG patients. CONCLUSION: We found higher percentages of NK CD56(bright) subset in kidney transplant recipients with CAD without considerable changes in related cytokines’ gene expression, suggesting a possible defect of NK cells maturation in these patients.