Significance of CD56+ Cell Aggregation in the Graft Following Kidney Transplantation.

Abstract

Objective In the context of kidney transplantation, little is known about the involvement of natural killer (NK) cells in the immune reaction leading to either rejection or graft failure. We investigated the significance of CD56+ cell aggregation in human kidney transplant biopsies in regard of graft function and survival. Methods One hundred seventy-four clinically indicated transplant biopsies were included in this analysis. Immunohistochemical stainings for C4d and CD56 were performed and clinical correlation was assessed by serum creatinine and graft status. ResultsTen or more CD56+ cells/high power field (HPF) were associated with acute cellular rejection (P=0.001), chronic active antibody-mediated rejection (P<0.001), glomerular disease (P=0.022), and interstitial fibrosis and tubular atrophy (P=0.002). There was a significant positive correlation between the degree of C4d deposits and the number CD56+ cells (r=0.23, P=0.002). Compared with patients with 0 to 9 cells/HPF, those with 10 to 29 cells/HPF and those with greater than 30 cells/HPF had worse death-censored graft survival 1 year postbiopsy with a hazard ratio of 8.2 (95% CI 1.05-64.39, P=0.045) and 13.3 (95% CI 1.65-106.55, P=0.015), respectively in multivariate Cox regression. In addition, the postbiopsy mean levels of serum creatinine in patients with 10 or more cells/HPF were significantly higher than in those with 0 to 9 cells/HPF during the 1 year follow-up period which was confirmed by a linear mixed effect model (P<0.001). Conclusions CD56+ cell aggregation in human kidney transplant biopsies can be a predictive marker for graft function and survival.