Date: Saturday, May 30, 2020
Session Time: 3:15pm-4:00pm
Presentation Time: 3:30pm-4:00pm
*Purpose: Late acute rejections appear to exert a more negative effect on graft kidney allograft survival than earlier events. Literature lacks studies that detail the histological aspects of these episodes relatively to time after transplantation. Thus, the aim of the present study was to describe the different histological phenotypes that predominate in each 6-month period of the first year of transplantation, in order to understand the possible mechanisms of injury that may lead to the worse prognosis of late rejections compared to the early ones.
*Methods: This retrospective, single-center study compares histological characteristics (Banff 2017) of treated acute renal allograft rejection episodes in adult kidney transplant recipients without donor specific antibodies receiving a single 3mg/kg dose of rabbit antithymocyte globulin, followed by tacrolimus-based immunosuppressive therapy.
*Results: Among 99 biopsies, 62% occurred up to 6 months (early, E) and 38% occurred between 7 and 12 months after transplantation (late, L). There were no differences in the incidence of borderline changes (37% vs. 33%) and T cell mediate rejection (63% vs. 64%), respectively. There was only one case of mixed acute rejection in L (3%). There were no differences in the proportion of biopsies with glomerulitis ≥ 2 (14% vs. 11%), peritubular capillaritis ≥ 2 (18% vs. 19%), interstitial inflammation ≥ 2 (49% vs. 51%), tubulitis ≥ 2 (59% vs. 84%) and intimal arteritis ≥ 2 (8% vs. 10%), respectively. The proportion of biopsies with inflammation (i-IFTA ≥ 2) in scarred areas (33% vs. 57%), presence of plasmocytes (7% vs. 14%) and interstitial edema (20% vs. 32%) were higher in L. Interstitial fibrosis (19% vs. 56%) and tubular atrophy (19% and 55%) were more frequent in L, with no difference in arteriolar hyalinosis (10% vs. 14%) and vascular fibrous intimal thickening (30% vs. 34%), respectively.
*Conclusions: In this cohort of patients, TCMR and borderline changes were the predominant phenotypes, with chronic changes already present in late biopsies.
To cite this abstract in AMA style:Campos RS, Cristelli M, Proença H, Foresto RD, Viana L, Martins SStopa, Nakamura M, Takara L, Taddeo J, Felipe C, Jr HTTedesco, Pestana J. Characterization of Histological Phenotypes of Acute Rejection Episodes in Kidney Transplant Recipient Receiving a Single 3mg/kg Dose of Rabbit Antithymocyte Globulin [abstract]. Am J Transplant. 2020; 20 (suppl 3). https://atcmeetingabstracts.com/abstract/characterization-of-histological-phenotypes-of-acute-rejection-episodes-in-kidney-transplant-recipient-receiving-a-single-3mg-kg-dose-of-rabbit-antithymocyte-globulin/. Accessed March 7, 2021.
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