The determinants, biomarkers, and consequences of microvascular injury in kidney transplant recipients

Independent of the initial cause of kidney disease, microvascular injury to the peritubular capillary network appears to play a central role in the development of interstitial fibrosis in both native and transplanted kidney disease. This association is explained by mechanisms such as the upregulation of profibrotic genes and epigenetic changes induced by hypoxia, capillary leakage, endothelial and pericyte transition to interstitial fibroblasts, as well as modifications in the secretome of endothelial cells. Alloimmune injury due to antibody-mediated rejection and ischemia-reperfusion injury are the two main etiologies of microvascular damage in kidney transplant recipients. The presence of circulating donor-specific anti-human leukocyte antigen (HLA) antibodies, histological findings, such as diffuse C4d staining in peritubular capillaries, and the extent and severity of peritubular capillaritis, are commonly used clinically to provide both diagnostic and prognostic information. Complement-dependent assays, circulating non-HLA antibodies, or evaluation of the microvasculature with novel imaging techniques are the subject of ongoing studies.

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Association of non-HLA antibodies against endothelial targets and donor-specific HLA antibodies with antibody-mediated rejection and graft function in pediatric kidney transplant recipients

Pediatric Nephrology ◽

10.1007/s00467-021-04969-1 ◽

2021 ◽

Author(s):

Alexander Fichtner ◽

Caner Süsal ◽

Britta Höcker ◽

Susanne Rieger ◽

Rüdiger Waldherr ◽

...

Keyword(s):

Kidney Transplant ◽

Graft Function ◽

Transplant Recipients ◽

Kidney Transplant Recipients ◽

Hla Antibodies ◽

Antibody Mediated Rejection ◽

Peritubular Capillaries ◽

Increased Risk ◽

Antibody Positivity ◽

Hla Antibody

Abstract Background Non-HLA antibodies against endothelial targets have been implicated in the pathogenesis of antibody-mediated rejection (ABMR), but data in pediatric patients are scarce. Methods We retrospectively analyzed a carefully phenotyped single-center (University Children’s Hospital Heidelberg, Germany) cohort of 62 pediatric kidney transplant recipients (mean age at transplantation, 8.6 ± 5.0 years) at increased risk of graft function deterioration. Patients had received their transplant between January 1, 1999, and January 31, 2010. We examined at time of late index biopsies (more than 1-year post-transplant, occurring after January 2004) the association of antibodies against the angiotensin II type 1 receptor (AT1R), the endothelin type A receptor (ETAR), the MHC class I chain-like gene A (MICA), and vimentin in conjunction with overall and complement-binding donor-specific HLA antibodies (HLA-DSA) with graft histology and function. Results We observed a high prevalence (62.9%) of non-HLA antibody positivity. Seventy-two percent of HLA-DSA positive patients showed additional positivity for at least one non-HLA antibody. Antibodies against AT1R, ETAR, and MICA were associated with the histological phenotype of ABMR. The cumulative load of HLA-DSA and non-HLA antibodies in circulation was related to the degree of microinflammation in peritubular capillaries. Non-HLA antibody positivity was an independent non-invasive risk factor for graft function deterioration (adjusted hazard ratio 6.38, 95% CI, 2.11–19.3). Conclusions Our data indicate that the combined detection of antibodies to HLA and non-HLA targets may allow a more comprehensive assessment of the patients’ immune responses against the kidney allograft and facilitates immunological risk stratification.

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Non-HLA Antibodies and Epitope Mismatches in Kidney Transplant Recipients With Histological Antibody-Mediated Rejection

Frontiers in Immunology ◽

10.3389/fimmu.2021.703457 ◽

2021 ◽

Vol 12 ◽

Author(s):

Marta Crespo ◽

Laura Llinàs-Mallol ◽

Dolores Redondo-Pachón ◽

Carrie Butler ◽

Javier Gimeno ◽

...

Keyword(s):

Kidney Transplant ◽

De Novo ◽

Transplant Recipients ◽

Kidney Transplant Recipients ◽

Serum Samples ◽

Hla Antibodies ◽

Aortic Endothelial Cells ◽

Antibody Mediated Rejection ◽

Donor Specific Antibodies

BackgroundCorrelation between antibody-mediated rejection (ABMR) and circulating HLA donor-specific antibodies (HLA-DSA) is strong but imperfect in kidney transplant (KT) recipients, raising the possibility of undetected HLA-DSA or non-HLA antibodies contributing to ABMR. Detailed evaluation of the degree of HLA matching together with the identification of non-HLA antibodies in KT may help to decipher the antibody involved.MethodsWe retrospectively assessed patients with transplant biopsies scored following Banff’15 classification. Pre- and post-transplant serum samples were checked for HLA and non-HLA antibodies [MICA-Ab, angiotensin-II type-1-receptor (AT1R)-Ab, endothelin-1 type-A-receptor (ETAR)-Ab and crossmatches with primary aortic endothelial cells (EC-XM)]. We also analyzed HLA epitope mismatches (HLA-EM) between donors and recipients to explore their role in ABMR histology (ABMRh) with and without HLA-DSA.ResultsOne-hundred eighteen patients with normal histology (n = 19), ABMRh (n = 52) or IFTA (n = 47) were studied. ABMRh patients were HLA-DSApos (n = 38, 73%) or HLA-DSAneg (n = 14, 27%). Pre-transplant HLA-DSA and AT1R-Ab were more frequent in ABMRh compared with IFTA and normal histology cases (p = 0.006 and 0.003), without differences in other non-HLA antibodies. Only three ABMRhDSAneg cases showed non-HLA antibodies. ABMRhDSAneg and ABMRhDSApos cases showed similar biopsy changes and graft-survival. Both total class II and DRB1 HLA-EM were associated with ABMRhDSApos but not with ABMRhDSAneg. Multivariate analysis showed that pre-transplant HLA-DSA (OR: 3.69 [1.31–10.37], p = 0.013) and AT1R-Ab (OR: 5.47 [1.78–16.76], p = 0.003) were independent predictors of ABMRhDSApos.ConclusionsIn conclusion, pre-transplant AT1R-Ab is frequently found in ABMRhDSApos patients. However, AT1R-Ab, MICA-Ab, ETAR-Ab or EC-XM+ are rarely found among ABMRhDSAneg patients. Pre-transplant AT1R-Ab may act synergistically with preformed or de novo HLA-DSA to produce ABMRhDSApos but not ABMRhDSAneg. HLA epitope mismatch associates with ABMRhDSApos compared with ABMRhDSAneg, suggesting factors other than HLA are responsible for the damage.

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CRISPR/Cas9-Engineered HLA-Deleted Glomerular Endothelial Cells as a Tool to Predict Pathogenic Non-HLA Antibodies in Kidney Transplant Recipients

Journal of the American Society of Nephrology ◽

10.1681/asn.2021050689 ◽

2021 ◽

Vol 32 (12) ◽

pp. 3231-3251

Author(s):

Baptiste Lamarthée ◽

Carole Burger ◽

Charlotte Leclaire ◽

Emilie Lebraud ◽

Aniela Zablocki ◽

...

Keyword(s):

Endothelial Cells ◽

Kidney Transplant ◽

Transplant Recipients ◽

Kidney Transplant Recipients ◽

Hla Antibodies ◽

Specific Antibodies ◽

Antibody Mediated Rejection ◽

Biopsy Specimens ◽

Glomerular Endothelial Cells ◽

Donor Specific Antibodies

BackgroundAfter kidney transplantation, donor-specific antibodies against human leukocyte antigen donor-specific antibodies (HLA-DSAs) drive antibody-mediated rejection (ABMR) and are associated with poor transplant outcomes. However, ABMR histology (ABMRh) is increasingly reported in kidney transplant recipients (KTRs) without HLA-DSAs, highlighting the emerging role of non-HLA antibodies (Abs).MethodsW e designed a non-HLA Ab detection immunoassay (NHADIA) using HLA class I and II–deficient glomerular endothelial cells (CiGEnCΔHLA) that had been previously generated through CRISPR/Cas9-induced B2M and CIITA gene disruption. Flow cytometry assessed the reactivity to non-HLA antigens of pretransplantation serum samples from 389 consecutive KTRs. The intensity of the signal observed with the NHADIA was associated with post-transplant graft histology assessed in 951 adequate biopsy specimens.ResultsW e sequentially applied CRISPR/Cas9 to delete the B2M and CIITA genes to obtain a CiGEnCΔHLA clone. CiGEnCΔHLA cells remained indistinguishable from the parental cell line, CiGEnC, in terms of morphology and phenotype. Previous transplantation was the main determinant of the pretransplantation NHADIA result (P<0.001). Stratification of 3-month allograft biopsy specimens (n=298) according to pretransplantation NHADIA tertiles demonstrated that higher levels of non-HLA Abs positively correlated with increased glomerulitis (P=0.002), microvascular inflammation (P=0.003), and ABMRh (P=0.03). A pretransplantation NHADIA threshold of 1.87 strongly discriminated the KTRs with the highest risk of ABMRh (P=0.005, log-rank test). A multivariate Cox model confirmed that NHADIA status and HLA-DSAs were independent, yet synergistic, predictors of ABMRh.ConclusionThe NHADIA identifies non-HLA Abs and strongly predicts graft endothelial injury independent of HLA-DSAs.

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Renal transplant patients with preformed anti-HLA antibodies: early biopsy findings and clinical outcomes

Brazilian Journal of Nephrology ◽

10.1590/2175-8239-jbn-2018-0244 ◽

2020 ◽

Vol 42 (2) ◽

pp. 201-210

Author(s):

Marcos Vinicius de Sousa ◽

Ricardo de Lima Zollner ◽

Marilda Mazzali

Keyword(s):

Renal Function ◽

Ischemia Reperfusion Injury ◽

Interstitial Fibrosis ◽

Ischemia Reperfusion ◽

Graft Function ◽

Kidney Graft ◽

Kidney Transplant Recipients ◽

Hla Antibodies ◽

Antibody Mediated Rejection

Abstract Introduction: Renal fibrosis is the end point of a process that begins at transplant, with ischemia reperfusion and early inflammation, and progresses over time with immunological and non-immunological phenomena. Early identification of morphological markers and intervention could improve graft function and survival. Objective: to evaluate the correlation between intensity and specificity of pre-transplant anti-HLA antibodies and kidney allograft pathology in order to identify early risk factors or markers of allograft dysfunction. Methods: A retrospective cohort of kidney transplant recipients with pre-transplant anti-HLA antibodies who underwent graft biopsy within the first two years post-transplant was divided into two groups according to the specificity of anti-HLA antibodies: nonspecific (non-DSA, n = 29) and specific (DSA+, n = 16). Kidney graft pathology, renal function, and proteinuria were analyzed. Results: general characteristics were similar in both groups, except for the higher dose of thymoglobulin in DSA+ group (p < 0.05). The non-DSA group had higher scores for glomerulosclerosis, interstitial inflammation (i) and interstitial fibrosis (ci) (p < 0.05) and higher incidence of cell-mediated acute rejection. No statistical difference in incidence of antibody-mediated rejection, renal function, and proteinuria was observed during follow up. Discussion and conclusions: the difference in inflammation scores and interstitial fibrosis may be associated to the higher incidence of acute cell-mediated rejection and polyomavirus nephropathy in the Non-DSA group. We also should take into account the protective effect of higher doses of thymoglobulin, reducing ischemia reperfusion injury in the DSA+ group. The short follow-up might have been insufficient to detect long-term changes in allograft tissue, renal function, and proteinuria.

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The Spectrum of Histopathological Changes in the Renal Allograft - a 12 Months Protocol Biopsy Study

Open Access Macedonian Journal of Medical Sciences ◽

10.3889/oamjms.2018.162 ◽

2018 ◽

Vol 6 (4) ◽

pp. 606-612

Author(s):

Galina Severova-Andreevska ◽

Ladislava Grcevska ◽

Gordana Petrushevska ◽

Koco Cakalaroski ◽

Aleksandar Sikole ◽

...

Keyword(s):

Kidney Transplant ◽

Cell Activation ◽

Interstitial Fibrosis ◽

Transplant Recipients ◽

Histopathological Changes ◽

Kidney Transplant Recipients ◽

Protocol Biopsy ◽

Antibody Mediated Rejection ◽

Precise Diagnosis

INTRODUCTION: Renal transplantation became a routine and successful medical treatment for Chronic Kidney Disease in the last 30 years all over the world. Introduction of Luminex based Single Antigen Beads (SAB) and recent BANFF consensus of histopathological phenotypes of different forms of rejection enables more precise diagnosis and changes the therapeutic approach. The graft biopsies, protocol or cause, indicated, remain a golden diagnostic tool for clinical follow up of kidney transplant recipients (KTR).AIM: The study aimed to analyse the histopathological changes in renal grafts 12 months after the surgery in KTR with satisfactory kidney function.MATERIAL AND METHODS: A 12-month protocol biopsy study was performed in a cohort of 50 Kidney transplant recipients (42 from living and 8 from deceased donors). Usual work-up for suitable donors and recipients, standard surgical procedure, basic principles of peri and postoperative care and follow up were done in all KTR. Sequential quadruple immunosuppression including induction with Anti-thymocyte globulin (ATG) or Interleukin-2R antagonist (IL-2R), and triple drug maintenance therapy with Calcineurin Inhibitors (CNI), Mycophenolate Mofetil (MMF) and Steroids were prescribed to all pts. Different forms of Glomerulonephritis (16), Hypertension (10), End Stage Renal Disease (13), Hereditary Nephropathies (6), Diabetes (3) and Vesicoureteral Reflux (2) were the underlying diseases. All biopsies were performed under ultrasound guidance. The 16 gauge needles with automated “gun” were used to take 2 cores of tissue. The samples were stained with HE, PAS, Trichrome Masson and Silver and reviewed by the same pathologist. A revised and uploaded BANFF 2013 classification in 6 categories (Cat) was used.RESULTS: Out of 48 biopsies, 15 (31%) were considered as normal, 4 (8%), Borderline (BL-Cat 3), 5 (10%) as Interstitial Fibrosis/Tubular Atrophy (IF/TA-Cat 5), 5 (10%) were classified as non-immunological (Cat 6), 2 as a pure antibody-mediated rejection (ABMR-Cat 2) and T-cell Mediated Rejection (TCMR-Cat 4). The remaining 17 samples were classified as a “mixed” rejection: 7 (41%) ABMR + IF/TA, 5 (29%) ABMR + BL + IF/TA, 2 (11%) BL + IF/TA, 1 (5%) ABMR + BL, 1 (5%) ABMR + TCMR and 1 (5%) TCMR + IF/TA. The mean serum creatinine at the time of the biopsy was 126.7 ± 23.4 µmol/L, while GFR-MDRD 63.4 ± 20.7 ml/min, which means that the majority of the findings were subclinical. Among the non-immunological histological findings (Cat 6), 3 cases belonged to CNI toxicity, 1 to BK nephropathy and 1 to recurrence of the primary disease.CONCLUSION: Our 12-month protocol biopsy study revealed the presence of different forms of mixed subclinical rejection. Use of recent BANFF classification and scoring system enables more precise diagnosis and subsequently different approach to the further treatment of the KTR. More correlative long-term studies including Anti HLA antibodies and Endothelial Cell Activation- Associated Transcripts (ENDAT) are needed.

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Antibody-Mediated Rejection in Kidney Transplant Recipients

Proceedings of the Latvian Academy of Sciences Section B Natural Exact and Applied Sciences ◽

10.2478/prolas-2013-0001 ◽

2013 ◽

Vol 67 (1) ◽

pp. 2-8

Author(s):

Rafails Rozentâls ◽

Ieva Ziediņa

Keyword(s):

Kidney Transplantation ◽

Transplant Recipients ◽

Humoral Rejection ◽

Kidney Transplant Recipients ◽

Hla Antibodies ◽

Antibody Mediated Rejection ◽

Peritubular Capillaries ◽

Before And After ◽

The One ◽

Clinical Changes

This paper provides a review of the significant problem of humoral, or antibody-mediated rejection, in kidney transplantation. The main cause of antibody-mediated rejection is donor-specific anti-HLA antibodies. Patients with anti-HLA antibodies are called sensitised patients. The outcome of humoral rejection is unfavourable: graft dysfunction and failure have been frequent from the early post-transplant period and are continuing. International laboratories and clinics offer sensitive and accurate methods to determine antibodies before and after kidney transplantation, but the methods are not always successful in recognition of sensitised patients. For diagnostics of humoral rejection the important issue is detecting complement breakdown deposition (C4d) in peritubular capillaries during immunohistological examination. On the one hand, their presence is characteristic for humoral rejection, but on the other hand, they can occur without any clinical changes or can remain undetected during severe humoral rejection. Current methods of prevention, diagnostics and treatment of humoral rejection are discussed. Difficulties of evaluation of chronic antibody-mediated injury are particularly highlighted.

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