One‐year protocol biopsies from ABO‐incompatible renal allografts compared with a matched cohort of ABO‐compatible allografts

Abstract

IntroductionEarly acute antibody-mediated rejection (ABMR) occurs more frequently in ABO-incompatible (ABOi) than in ABO-compatible (ABOc) kidney transplantation. This could lead to increased inflammation/scarring in the ABOi grafts. Protocol biopsy data in ABOi kidney recipients are scarce.MethodsA single-center retrospective matched cohort study was conducted. Eighty adult living donor (LD) renal transplant recipients without HLA donor-specific antibodies (DSA) transplanted between 2009 and 2012 were included; 20 ABOi and 60 ABOc controls matched for donor age and transplantation year. Protocol biopsies at one yr were scored according to the Banff classification. Three sums of scores were constructed: tubulointerstitial inflammation (t + i = 0 vs. >0), microvascular inflammation (g + ptc = 0 vs. >0), scarring/hyalinosis (ci + ct + cv + ah ≤ 1 vs. >1. Scores and presence of subclinical rejection (SCR) at one yr were compared.ResultsProtocol biopsy findings at one yr in the ABOi vs. ABOc matched control group were not statistically different: (t + i) > 0, 30% vs. 20%; (g + ptc) > 0, 5% vs. 8%; (ci + ct + cv + ah) > 1, 85% vs. 60%, respectively. No transplant glomerulopathy occurred. SCR rate at one yr was 30% vs. 18%, subclinical ABMR 5% vs. 7% (all with de novo HLA DSA).ConclusionOne-year protocol biopsies of ABOi and ABOc LD recipients do not differ in chronic changes, inflammation, or SCRs.

Clinical Outcomes and Results of Pathological Findings of 1-year Protocol Biopsy in Recipients of ABO-Incompatible Living Donor Kidney Transplantants

“…Dörje C et al compared Banff scores between ABOi and ABOc LDKTs, and did not find any significant difference. However, the interstitial fibrosis score and IFTA score showed a significant difference [8]. This result is similar to the results of our research.…”

“…Similar results have been reported by previous studies [6,8,9]. Additionally, the incidence of CMV infection requiring medication was also not significantly different between the 2 groups.…”

“…Currently, filtration plasmapheresis and anti-CD20 monoclonal antibody therapy are the standard hyposensitization therapies before ABOi KT, and many studies have reported a reduction in the percentage of acute antibody-mediated rejection with the use of these techniques [4e7]. In addition, Dorje C et al reported that pathological findings of ABOi and ABOc living donor recipients do not differ with respect to chronic changes, inflammation, or subclinical rejections after 1 year of LDKT [8].…”

Accommodation in ABO‐incompatible organ transplants

“…55,56 However, the general experience has been that at least some recipients of ABO-incompatible kidney transplants produce substantial amounts of antibody against the donor antigen and the preponderance of ABO-incompatible transplants contain deposits of C4d, in the absence of impaired function and consistent with ongoing binding of anti-donor antibodies. [57][58][59] Even more to the point, the extent of antibody rebound after the first weeks appears to have little or no impact on the long-term outcome ( Figure 5). 60,61 One problem that confounds investigation of the levels of antibodies against donor-blood groups in ABO-incompatible transplantation is that at a given point in time the transplant can absorb a substantial amount of antibody against donor blood group antigens ( Figure 2).…”

Borderline rejection in ABO‐incompatible kidney transplantation

“…Despite the good intermediate‐ to long‐term outcome of ABOi KT, little is known about the impact of histologic changes and their influence on long‐term allograft function and survival. There are only a few studies with systematic follow‐up biopsies in ABOi KTs compared with living‐donor ABOc transplantation . Although it is well known that transplant biopsies from ABOi recipients can show C4d positivity even years after transplantation in the absence of other evidence of antibody‐mediated rejection (ABMR), there is little knowledge about borderline rejections, interstitial fibrosis and tubular atrophy (IFTA) lesions, and transplant glomerulopathy (TG) in ABOi protocol biopsies.…”