[1654] The Diagnostic Utility of Ki-67 Staining in Acute Renal Tubular Injury

Cynthia X Zhao, Xin Gu, Stephen M Bonsib. Louisiana State University Health Science Center, Shreveport, LA; Nephropath, Little Rock, AR

Background: Acute tubular injury (ATI) is one of the most common structural changes that can lead to acute renal failure. However, renal histological abnormalities are often subtle and may not be detectable. A reliable marker is needed to support the clinical findings of ATI. Ki-67 is a nuclear non-histone protein expressed in all phases of active proliferating cells. Renal tubular cell proliferation is increased following ATI. Thus, we hypothesize to use Ki-67 proliferation index (percentage of proliferating cells) to aid the diagnosis of ATI.
Design: Twenty kidney biopsies with the diagnosis of ATI and 20 kidney biopsies with no light microscopic tubular injury or glomerular abnormalities (18 thin basement membrane disease and 2 minimal change disease) were retrospectively selected. Ki-67 stain was performed on all 40 cases and the proliferation indices were calculated to evaluate tubular epithelial cell proliferative activities. Two-proportion Z-test was utilized to test the statistical significance between the two groups.

Ki-67 proliferation index in ATI and Non-ATI groups
 Marked Increased (>10/HPF)Increased (5-10/HPF)Rare (<5/HPF)Negative

Results: The Ki-67 index was increased or markedly increased in 19 out of 20 ATI cases (95%) with one case showing rare positive nuclear staining. In 20 Non-ATI cases, the Ki-67 index revealed no increased cell proliferation. Only 4 Non-ATI biopsies showed rare positive staining and the remaining 16 Non-ATI cases had negative staining. The Ki-67 index was significantly increased in ATI group compared with Non-ATI group (p < 0.05).
Conclusions: This study indicates that the Ki-67 stain of renal tubular epithelial cells is a useful ancillary tool to diagnose ATI. It can be used as a supportive marker for kidney biopsies from patients with acute renal failure but no significant morphological changes.
Category: Kidney (does not include tumors)

Monday, March 4, 2013 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 255, Monday Morning


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