Difference in Severity of Acute Rejection Grading between Superfical Cortex and Deep Cortex in Renal Allograft Biopsies

ABSTRACT

Twenty-six renal allograft biopsies which showed acute rejection and had renal capsule and medulla in the same specimen were selected in order to compare the severity of acute rejection between superficial cortex, deep cortex and medulla. Disregarding the mid cortical region, the superficial cortex was considered as being one-third of the distance from the renal capsule to the medulla and the deep cortex as being that one-third of the cortex which was adjacent to the medulla. Using semiquantitative histologic analysis the following parameters were compared in superficial cortex, deep cortex, and medulla interstitial inflammation, edema, tubulitis, and acute tubulointerstitial rejection grade. Also, the presence of lymphocyte activation and polymorphonuclear leukocytes was evaluated. Significantly greater histologic changes of acute rejection were found in the deep cortex vs. superficial cortex for the following parameters interstitial inflammation(P=0.013), edema (P= 0.023) and tubulointerstitial rejection grade(P=0.016). These findings support the view that biopsies in which deep cortex is not included may result in underestimation of the severity of renal allograft rejection.