Significance of the Pathologic Findings in Implantation Biopsies for Kidney Allografts Survival

Abstract

Background: There is no consistent association between individual histological lesions and composite scores in donor kidney biopsy and transplant outcomes.

Objective: To evaluate which acute or chronic individual histological lesions and composite scores in donor kidney were associated with graft survival in the recipient.

Methods: We investigated the association of individual histological lesions and 8 composite scoring systems in implantation biopsies of cadaveric (n=101) and living (n=29) kidneys with 5-year death-censored graft survival.

Results: We found a high frequency of chronic lesions in donor kidneys, mostly associated with arteriosclerosis, and less dependent from donor age. Acute, chronic, and total Banff scores for post-transplant biopsies, chronic and total Banff scores for pre-implant biopsies, donor damage score and chronic damage score predicted death-censored graft loss. However, only chronic and total Banff-scores had significant effects in multivariate model. Chronic pre-implant and total post-transplant Banff scores demonstrated the highest area under the curve (AUC) of 0.722 and 0.717, respectively. Among individual lesions, glomerulosclerosis ≥20%, interstitial inflammation >0, arteriosclerosis =3, arteriolar hyalinosis >0, and interstitial fibrosis >0, assessed with Banff-grading criteria, were associated with lower allograft survival. We created the Donor Kidney Damage Index (DKDI), by summing regression coefficients for these lesions, which yielded the AUC of 0.747. When combined with retransplantation, cold ischemia time and acute rejection, DKDI, chronic pre-implant and total post-transplant Banff scores further improved their predictive accuracy, yielding AUCs of 0.842, 0.807, and 0.802, respectively.

Conclusion: DKDI, chronic pre-implant and total post-transplant Banff scores alone and combined with clinical variables may facilitate decision making in post-transplant period.

Keywords: Implantation biopsy histology; Individual and composite histological scores; Kidney allograft survival.

Figure 1

Histopathological findings in implantation kidney biopsies. A) Focal acute tubular necrosis, H&E staining (original magnification ×400); B) Glomerular thrombi, H&E (original magnification ×400); C) Arteriolar hyalinosis, PAS staining (original magnification ×400); D) Arteriosclerosis, focal interstitial fibrosis, and acute tubular injury, PAS staining (original magnification ×200).

Figure 2

Association of death-censored kidney graft survival and selected composite histological scores in intra-operative zero-hour biopsies (Kaplan-Meier estimates). A) Chronic pre-implant Banff score; B) Chronic post-transplant Banff score; C) Donor damage score; D) Chronic damage score; E) Acute post-transplant Banff score; and F) Donor Kidney Damage Index. P values are calculated with the log-rank test

Figure 3

Association of death-censored kidney graft survival and selected individual histological lesions in intra-operative zero-hour biopsies (Kaplan-Meier estimates). A) Glomerulosclerosis; B) Arteriolar hyalinosis; C) Arteriosclerosis; D) Interstitial fibrosis; and E) Interstitial inflammation. P values are calculated with the log-rank test