SO030HISTOLOGICAL CHARACTERIZATION OF RENAL BIOPSIES FROM HCV-INFECTED DONORS: A VALUABLE SOURCE OF KIDNEY ALLOGRAFTS
Authors: L'Imperio Vincenzo , Rossi Mattia , Naik Ruchi , Concepcion Beatrice , Kapp Meghan 
Published: June 2020

Abstract

Background and Aims
The introduction of effective direct-acting antiviral agents (DAAs) has allowed safe transplantation of kidneys from HCV positive (HCV+) donors into HCV negative (HCV-) recipients. Some studies demonstrated an increased risk for rejection as well as polyomavirus infection in these situations (Molnar et al, Am J Transplant. 2019 Nov;19(11):3046-3057), possibly due to the development of an inflammatory milieu in the setting of HCV seroconversion and persistent viremia (Durand et al, Am J Transplant. 2019 Nov;19(11):2969-2970). With this concern for HCV-associated renal injury and increased risk for rejection, this retrospective study explores the histologic findings of allograft biopsies from HCV+ donors.

Method
Fifty renal allograft biopsies from 28 recipients of HCV+ donors evaluated at Vanderbilt University Medical Center between September 2018 and December 2019 were retrospectively reviewed with recording of clinical and histological features, and final diagnoses. All recipients were transplanted under a clinical protocol and were treated with DAA therapy. In the same period of time, 30 renal allograft biopsies from 24 recipients of HCV- donors were selected having the same post-transplant interval as the study cohort. Categorical variables are expressed in percentage and compared using Pearson’s chi-squared test. Continuous variables are expressed as mean±SD and compared used Student t-test. A p-value of &lt;0.05 was considered as statistically significant.

Results
The complete results of the comparison between the two groups (HCV+ and HCV- donors) are demonstrated in Figure. The differences reaching statistical significance include higher frequency of males and tubulointerstitial fibrosis (IFTA) in the HCV+ group (p = 0.038 and 0.044, respectively) and the higher incidence of DSA positivity and acute tubular injury in the control group (p = 0.001 and 0.029). Notably, no significant differences were noted in terms of antibody-mediated events (microcirculation inflammation, transplant glomerulopathy, C4d positivity, or diagnostic ABMR), or T-cell mediated events including borderline or diagnostic T-cell mediated rejection (Banff 2013). The two groups also demonstrated the same incidence of polyomavirus nephropathy and de novo/recurrent glomerulonephritis. Interestingly, two of the HCV+ cases showed mesangial IgA deposits on immunofluorescence and electron microscopy on the first biopsy, of which one showed persistence of deposits, 18 and 44 days after transplant respectively. Once case demonstrated a de novo focal proliferative IgM-dominant glomerulonephritis on the 7th biopsy, 266 days after transplantation.

Conclusion
Kidneys from HCV+ donors represent a valuable resource in the era of DAA therapy. This reported experience demonstrates similar frequency of rejection and viral infection affecting allografts from HCV positive and negative donors. The presence of immune complex deposits and glomerulonephritis in some of these cases could represent either a donor-derived injury or an acquired post-seroconversion feature. In conclusion, HCV+ donors appear to be a safe resource for transplantation. Further studies with post-transplant intervals will provide additional characterization of their impact.