Publications by authors named "Annette M Jackson"

46 Publications

A 2020 Banff Antibody-mediatedInjury Working Group examination of international practices for diagnosing antibody-mediated rejection in kidney transplantation - a cohort study.

Transpl Int 2021 Mar;34(3):488-498

Division of Nephrology/Transplant Nephrology, Johns Hopkins University, Baltimore, MD, USA.

The Banff antibody-mediated rejection (ABMR) classification is vulnerable to misinterpretation, but the reasons are unclear. To better understand this vulnerability, we evaluated how ABMR is diagnosed in practice. To do this, the Banff Antibody-Mediated Injury Workgroup electronically surveyed an international cohort of nephrologists/surgeons (n = 133) and renal pathologists (n = 99). Most providers (97%) responded that they use the Banff ABMR classification at least sometimes, but DSA information is often not readily available. Only 41.1% (55/133) of nephrologists/surgeons and 19.2% (19/99) of pathologists reported that they always have DSA results when the biopsy is available. Additionally, only 19.6% (26/133) of nephrologists/surgeons responded that non-HLA antibody or molecular transcripts are obtained when ABMR histologic features are present but DSA is undetected. Several respondents agreed that histologic features concerning for ABMR in the absence of DSA and/or C4d are not well accounted for in the current classification [31.3% (31/99) pathologists and 37.6% (50/133) nephrologist/surgeons]. The Banff ABMR classification appears widely accepted, but efforts to improve the accessibility of DSA information for the multidisciplinary care team are needed. Further clarity is also needed in Banff ABMR nomenclature to account for the spectrum of ABMR and for histologic features suspicious for ABMR when DSA is absent.
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http://dx.doi.org/10.1111/tri.13813DOI Listing
March 2021

Understanding the impact of HLA molecular mismatch in solid organ transplantation: Are we there yet?

Am J Transplant 2021 01 18;21(1):9-10. Epub 2020 Nov 18.

Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois.

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http://dx.doi.org/10.1111/ajt.16376DOI Listing
January 2021

The role of non-HLA antibodies in solid organ transplantation: a complex deliberation.

Curr Opin Organ Transplant 2020 Dec;25(6):536-542

Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA.

Purpose Of Review: There is tremendous interest in understanding when, if, and how non-HLA antibodies contribute to allograft injury. Numerous non-HLA target antigens have been identified and sensitization to these targets have been associated with delayed allograft function, rejection, and allograft failure. This review focuses on the clinical utility of HLA antibody testing, highlighting the strengths and limitations of current clinical studies, and the need for defining characteristics to inform non-HLA antibody pathogenicity.

Recent Findings: Clinical studies continue to show associations between non-HLA antibodies and rejection and reduced allograft survival across multiple transplanted organ types. The worst clinical outcomes continue to be observed among recipients testing positive for both non-HLA and donor-specific HLA antibodies. Mechanistic insights from both animal and clinical studies support a model in which tissue injury accompanied by an inflammatory environment influence non-HLA antibody formation and pathogenicity.

Summary: Immune triggers that lead to non-HLA antibody formation and pathogenicity are complex and poorly understood. The ability of non-HLA antibodies to mediate allograft injury may depend upon their affinity and strength (titer), target specificity, density of the target antigen, and synergy with donor-specific HLA antibodies.
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http://dx.doi.org/10.1097/MOT.0000000000000811DOI Listing
December 2020

Efficacy and Safety of Immunosuppression Withdrawal in Pediatric Liver Transplant Recipients: Moving Towards Personalized Management.

Hepatology 2020 Aug 12. Epub 2020 Aug 12.

Department of Pathology, University of Pittsburgh, Pittsburgh, PA, USA.

Background And Aims: Tolerance is transplantation's holy grail as it denotes allograft health without immunosuppression and its toxicities. Our aim was to determine, among stable long-term pediatric liver transplant recipients, the efficacy and safety of immunosuppression withdrawal to identify operational tolerance.

Approach And Results: We conducted a multi-center, single-arm trial of immunosuppression withdrawal over 36-48 weeks. Liver tests were monitored biweekly (year 1), monthly (year 2) and bimonthly (years 3-4). For-cause biopsies were done at investigators' discretion but mandated when alanine aminotransferase or gamma glutamyl transferase exceeded 100U/L. All subjects underwent final liver biopsy at trial end. The primary efficacy endpoint was operational tolerance, defined by strict biochemical and histological criteria 1 year after stopping immunosuppression. Among 88 subjects (median age 11 years; 39 boys; 57 deceased donor grafts), 33 (37.5%; 95%CI 27.4%, 48.5%) were operationally tolerant, 16 were non-tolerant by histology (met biochemical but failed histological criteria) and 39 were non-tolerant by rejection. Rejection, predicted by subtle liver inflammation in trial entry biopsies, typically (n=32) occurred at ≤32% of the trial entry immunosuppression dose and was treated with corticosteroids (n=32) and/or tacrolimus (n=38) with resolution (liver tests within 1.5X baseline) for all but 1 subject. No death, graft loss, or chronic, severe, or refractory rejection occurred. Neither fibrosis stage nor the expression level of a rejection gene set increased over 4 years for either tolerant or non-tolerant subjects.

Conclusions: Immunosuppression withdrawal showed that 37.5% of selected pediatric liver transplant recipients were operationally tolerant. Allograft histology did not deteriorate for either tolerant or non-tolerant subjects. The timing and reversibility of failed withdrawal justifies future trials exploring the efficacy, safety, and potential benefits of immunosuppression minimization.
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http://dx.doi.org/10.1002/hep.31520DOI Listing
August 2020

Physical Crossmatching vs Virtual Crossmatching: The end of an era? or Why give up a good thing?

Hum Immunol 2020 08 16;81(8):401-406. Epub 2020 Jul 16.

Duke University, Department of Surgery, Durham, NC, USA. Electronic address:

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http://dx.doi.org/10.1016/j.humimm.2020.06.009DOI Listing
August 2020

Rejection in the setting of non-HLA antibody: New tools for navigating bench to bedside.

Am J Transplant 2020 10 25;20(10):2639-2641. Epub 2020 May 25.

Department of Pathology, Duke University, Durham, North Carolina, USA.

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http://dx.doi.org/10.1111/ajt.15975DOI Listing
October 2020

B cells in transplant tolerance and rejection: friends or foes?

Transpl Int 2020 01;33(1):30-40

Department of Surgery, Duke Transplant Center, Duke University Medical Center, Durham, NC, USA.

Our understanding of the role of B cells in organ transplantation remains incomplete and continues to grow. The majority of research has focused on the detrimental role of antibodies that drive the development of pathogenesis of the transplanted organ. However, it has been shown that not all donor-specific antibodies are harmful and in some circumstances can even promote tolerance through the mechanism of accommodation. Furthermore, B cells can have effects on transplanted organs through their interaction with T cells, namely antigen presentation, cytokine production, and costimulation. More recently, the role and importance of Bregs was introduced to the field of transplantation. Due to this functional and ontogenetic heterogeneity, targeting B cells in transplantation may bring undesired immunologic side effects including increased rejection. Therefore, the selective control of B cells that contribute to the humoral response against donor antigens will continue to be an important and challenging area of research and potentially lead to improved long-term transplant outcomes.
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http://dx.doi.org/10.1111/tri.13549DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7184555PMC
January 2020

Tracking HLA Antibody Changes among Kidney Waitlist Candidates: One Protocol May Not Fit All.

J Am Soc Nephrol 2019 11 25;30(11):2042-2044. Epub 2019 Oct 25.

Department of Surgery, Duke University, Durham, North Carolina; and.

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http://dx.doi.org/10.1681/ASN.2019090946DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6830794PMC
November 2019

IgG4 donor-specific HLA antibody profile is associated with subclinical rejection in stable pediatric liver recipients.

Am J Transplant 2020 02 1;20(2):513-524. Epub 2019 Nov 1.

Department of Surgery, University of California San Francisco, San Francisco, California, USA.

The impact of donor-specific HLA antibody (DSA) following liver transplantation remains controversial. We hypothesized DSA IgG subclass characteristics, compared to total DSA IgG, might correlate with specific histopathological phenotype(s) of subclinical graft injury. We therefore studied 129 stable, arguably "clinically ideal," pediatric liver recipients at the time of a screening biopsy to enter an immunosuppression withdrawal trial. Sixty-five (50%) subjects tested positive for class II DSA. IgG subclass profile was characterized by mean fluorescence intensity (MFI) and normalized subclass composition (>5%). A prominent IgG4 DSA profile was strongly correlated with greater HLA mismatch, a histopathological phenotype characterized by the presence of interface activity (with variable degrees of fibrosis), and a transcriptional profile of attenuated T cell-mediated rejection. Specifically, compared to those without class II DSA, those with IgG4 class II DSA MFI sum >2000 exhibited an odds ratio (OR) of 20.79 (95% confidence interval [CI] 4.38-98.69) and IgG4 subclass composition >5% exhibited an OR of 8.99 (95% CI 2.70-29.9). Our data suggest that IgG4 DSA may serve as a useful biomarker to identify, among clinically and biochemically stable liver transplant recipients, a subset with histological and transcriptional features indicative of an active, suboptimally controlled alloimmune response.
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http://dx.doi.org/10.1111/ajt.15621DOI Listing
February 2020

Prediction system for risk of allograft loss in patients receiving kidney transplants: international derivation and validation study.

BMJ 2019 09 17;366:l4923. Epub 2019 Sep 17.

Université de Paris, INSERM, Paris Translational Research Centre for Organ Transplantation, Paris, France.

Objective: To develop and validate an integrative system to predict long term kidney allograft failure.

Design: International cohort study.

Setting: Three cohorts including kidney transplant recipients from 10 academic medical centres from Europe and the United States.

Participants: Derivation cohort: 4000 consecutive kidney recipients prospectively recruited in four French centres between 2005 and 2014. Validation cohorts: 2129 kidney recipients from three centres in Europe and 1428 from three centres in North America, recruited between 2002 and 2014. Additional validation in three randomised controlled trials (NCT01079143, EudraCT 2007-003213-13, and NCT01873157).

Main Outcome Measure: Allograft failure (return to dialysis or pre-emptive retransplantation). 32 candidate prognostic factors for kidney allograft survival were assessed.

Results: Among the 7557 kidney transplant recipients included, 1067 (14.1%) allografts failed after a median post-transplant follow-up time of 7.12 (interquartile range 3.51-8.77) years. In the derivation cohort, eight functional, histological, and immunological prognostic factors were independently associated with allograft failure and were then combined into a risk prediction score (iBox). This score showed accurate calibration and discrimination (C index 0.81, 95% confidence interval 0.79 to 0.83). The performance of the iBox was also confirmed in the validation cohorts from Europe (C index 0.81, 0.78 to 0.84) and the US (0.80, 0.76 to 0.84). The iBox system showed accuracy when assessed at different times of evaluation post-transplant, was validated in different clinical scenarios including type of immunosuppressive regimen used and response to rejection therapy, and outperformed previous risk prediction scores as well as a risk score based solely on functional parameters including estimated glomerular filtration rate and proteinuria. Finally, the accuracy of the iBox risk score in predicting long term allograft loss was confirmed in the three randomised controlled trials.

Conclusion: An integrative, accurate, and readily implementable risk prediction score for kidney allograft failure has been developed, which shows generalisability across centres worldwide and common clinical scenarios. The iBox risk prediction score may help to guide monitoring of patients and further improve the design and development of a valid and early surrogate endpoint for clinical trials.

Trial Registration: Clinicaltrials.gov NCT03474003.
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http://dx.doi.org/10.1136/bmj.l4923DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6746192PMC
September 2019

The impact of belatacept on third-party HLA alloantibodies in highly sensitized kidney transplant recipients.

Am J Transplant 2020 02 8;20(2):573-581. Epub 2019 Oct 8.

Department of Pathology, Emory University School of Medicine, Atlanta, Georgia.

Recent evidence suggests that belatacept reduces the durability of preexisting antibodies to class I and class II human leukocyte antigens (HLAs). In this case series of 163 highly sensitized kidney transplant candidates whose calculated panel-reactive antibody (cPRA) activity was ≥98% to 100%, the impact of belatacept on preexisting HLA antibodies was assessed. Of the 163 candidates, 72 underwent transplantation between December 4, 2014 and April 15, 2017; 60 of these transplanted patients remained on belatacept consecutively for at least 6 months. We observed a decrease in the breadth and/or strength of HLA class I antibodies as assessed by FlowPRA in belatacept-treated patients compared to controls who did not receive belatacept. Specifically, significant HLA antibody reduction was evident for class I (P < .0009). Posttransplant belatacept-treated patients also had a clinically significant reduction in their cPRA compared to controls (P < .01). Collectively, these findings suggest belatacept can reduce HLA class I antibodies in a significant proportion of highly sensitized recipients and could be an option to improve pretransplant compatibility with organ donors.
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http://dx.doi.org/10.1111/ajt.15585DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6984982PMC
February 2020

Sensitization to endothelial cell antigens: Unraveling the cause or effect paradox.

Hum Immunol 2019 Aug 1;80(8):614-620. Epub 2019 May 1.

Imagine Institute, French National Institute of Health and Medical Research (Inserm) U1163, Department of Biotherapy, Necker Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France; Necker-Enfants Malades Institute, Inserm U1151, Paris Descartes, Sorbonne Paris Cité University, RTRS Centaure, LabEx Transplantex, Department of Nephrology and Kidney Transplantation, Necker Hospital, AP-HP, Paris, France.

Anti-endothelial cell antibodies (AECAs) have been correlated with increased acute and chronic rejection across all organ types and early graft dysfunction in kidney and heart transplantation. Nevertheless, the lack of appropriate tools and clear criteria for defining injurious versus non-injurious AECAs prohibits their routine inclusion in clinical risk assessments and diagnostic algorithms for antibody mediated injury. Clinical characterization of AECAs is complicated due to the wide range of polymorphic and non-polymorphic antigens expressed across different vascular tissues and the diverse array of specificities observed between individuals. This complexity is also reflected in the broad spectrum of reported injury phenotypes. AECAs detected at time of allograft dysfunction may represent biomarkers of past vascular injury or active contributors to a current rejection process. New tools within the fields of proteomics, genomics, bioinformatics, and imaging are currently being validated and hold great promise for unraveling the AECA paradox.
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http://dx.doi.org/10.1016/j.humimm.2019.04.014DOI Listing
August 2019

Microvascular inflammation in renal allograft biopsies assessed by endothelial and leukocyte co-immunostain: a retrospective study on reproducibility and clinical/prognostic correlates.

Transpl Int 2019 03 11;32(3):300-312. Epub 2018 Dec 11.

Renal Pathology Service, Johns Hopkins University, Baltimore, MD, USA.

The most prominent histologic lesion in antibody-mediated rejection is microvascular inflammation (MVI); however, its recognition and scoring can be challenging and poorly reproducible between pathologists. We developed a dual immunohistochemical (IHC)-stain (anti-CD34/anti-CD45 for endothelium/leukocytes) as ancillary tool to improve on the semi-quantitative Banff scores and allow quantification of MVI. We examined the relationship between CD34-CD45 IHC-based quantitative MVI score (the inflamed peritubular capillary ratio, iptcr) and renal-graft failure or donor-specific antibodies (DSA) strength at the time of biopsy. Quantitative iptcr score was significantly associated with renal graft failure (hazard ratio 1.81, per 1 SD-unit [0.13 points] of iptcr-increase; P = 0.026) and predicted the presence and strength of DSA (ordinal odds ratio: 2.42; P = 0.005; 75 biopsies/60 kidney transplant recipients; 30 HLA- and/or ABO-incompatible). Next, we assessed inter-pathologist agreement for ptc score and ptc extent (focal/diffuse) using CD34-CD45 IHC as compared to conventional stain. Compared to conventional stain, CD34-CD45 IHC significantly increased inter-pathologist agreement on ptc score severity and extent (κ-coefficient from 0.52-0.80 and 0.46-0.68, respectively, P < 0.001). Our findings show that CD34-CD45 IHC improves reproducibility of MVI scoring and facilitates MVI quantification and introduction of a dual anti-CD34/CD45 has the potential to improve recognition of MVI ahead of DSA results.
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http://dx.doi.org/10.1111/tri.13371DOI Listing
March 2019

Evidence of Chronic Allograft Injury in Liver Biopsies From Long-term Pediatric Recipients of Liver Transplants.

Gastroenterology 2018 12 23;155(6):1838-1851.e7. Epub 2018 Aug 23.

Institute of Liver Studies, King's College, London, London, United Kingdom.

Background & Aims: A substantial proportion of pediatric liver transplant recipients develop subclinical chronic allograft injury. We studied whether there are distinct patterns of injury based on histopathologic features and identified associated immunologic profiles.

Methods: We conducted a cross-sectional study of 157 stable, long-term pediatric recipients of transplanted livers (70 boys; > 6 years old at time of transplantation; mean, 8.9 ± 3.46 years after liver transplantation) who underwent liver biopsy analysis from August 13, 2012, through May 1, 2014. Participants had received livers from a living or deceased donor and had consistently normal results from liver tests. Liver biopsy specimens were scored by a central pathologist; an unsupervised hierarchical cluster analysis of histologic features was used to sort biopsy samples into 3 clusters. We conducted transcriptional and cytometric analyses of liver tissue samples and performed a systems biology analysis that incorporated clinical, serologic, histologic, and transcriptional data.

Results: The mean level of alanine aminotransferase in participants was 27.6 ± 14.57 U/L, and the mean level of γ-glutamyl transferase was 17.4 ± 7.93 U/L. Cluster 1 was characterized by interface activity (n = 34), cluster 2 was characterized by periportal or perivenular fibrosis without interface activity (n = 45), and cluster 3 had neither feature (n = 78). We identified a module of genes whose expression correlated with levels of alanine aminotransferase, class II donor-specific antibody, portal inflammation, interface activity, perivenular inflammation, portal and perivenular fibrosis, and cluster assignment. The module was enriched in genes that regulate T-cell-mediated rejection (TCMR) of liver and other transplanted organs. Functional pathway analysis showed overrepresentation of TCMR gene sets for cluster 1 but not clusters 2 or 3.

Conclusion: In an analysis of biopsies from an apparently homogeneous group of stable, long-term pediatric liver transplant recipients with consistently normal liver test results, we found evidence of chronic graft injury (inflammation and/or fibrosis). Biopsy samples with interface activity had a gene expression pattern associated with TCMR.
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http://dx.doi.org/10.1053/j.gastro.2018.08.023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6279538PMC
December 2018

Temporal Changes in the Impact of HLA Mismatching Among Pediatric Kidney Transplant Recipients.

Transplantation 2019 06;103(6):1267-1271

Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD.

Background: Allocation for pediatric deceased-donor kidney transplantation (pDDKT) in the United States now de-emphasizes HLA matching to improve equality in access to transplantation, but other national systems still consider HLA matching due to concerns about graft survival. We hypothesized that the impact of HLA mismatching has decreased over time due to advances including improved immunosuppression.

Methods: Using Scientific Registry of Transplant Recipient data, we analyzed whether the association between the number of HLA mismatches and outcomes of first-time pDDKTs changed between 2 eras: 1995 to 2004 (N = 2854) and 2005 to 2014 (N = 4643).

Results: Between eras, the median number of mismatches increased from 4 to 5 (P < 0.001). Overall graft failure risk was higher among HLA-mismatched versus HLA-matched transplants (adjusted hazard ratio 1.211.431.69 for 3-6 versus 0-2 mismatches; P < 0.001), and this association was similar pre-2005 and post-2005 (Pinteraction = 0.5). Median panel-reactive antibody change at relisting increased from 79 to 85 (P = 0.01), but the association between number of HLA mismatches and panel-reactive antibody change was similar between eras (Pinteraction = 0.6).

Conclusions: Our finding that increased HLA mismatching continues to impact graft survival, with 43% higher risk of graft failure, highlights the tradeoff between transplant access equity and outcomes and calls into question the deemphasis on HLA matching in pDDKT allocation in the United States.
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http://dx.doi.org/10.1097/TP.0000000000002426DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6382603PMC
June 2019

Meeting report of the STAR-Sensitization in Transplantation Assessment of Risk: Naïve Abdominal Transplant Organ subgroup focus on kidney transplantation.

Am J Transplant 2018 09 3;18(9):2120-2134. Epub 2018 Aug 3.

Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada.

The development of de novo donor-specific HLA antibody (dnDSA) is a critical feature contributing to late allograft failure. The complexity of the issue is further complicated by organ-specific differences, detection techniques, reliance of tissue histopathology and changing diagnostic criteria, ineffective therapies, and lack of consensus. To tackle these issues, the Sensitization in Transplantation Assessment of Risk (STAR) 2017 was initiated as a collaboration of the American Society of Transplantation and American Society of Histocompatibility and Immunogenetics consisting of 8 working groups with the goal to provide guidelines on how to assess risk and risk stratify patients based on their potential alloimmune and DSA status. Herein is a summary of discussions by the Naïve Abdominal Working Group, highlighting currently available data and identifying gaps in our knowledge on the development and impact of dnDSA following kidney transplantation.
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http://dx.doi.org/10.1111/ajt.14977DOI Listing
September 2018

Complement-activating donor-specific anti-HLA antibodies and solid organ transplant survival: A systematic review and meta-analysis.

PLoS Med 2018 05 25;15(5):e1002572. Epub 2018 May 25.

Paris Translational Research Center for Organ Transplantation INSERM Unit 970, Paris, France.

Background: Anti-human leukocyte antigen donor-specific antibodies (anti-HLA DSAs) are recognized as a major barrier to patients' access to organ transplantation and the major cause of graft failure. The capacity of circulating anti-HLA DSAs to activate complement has been suggested as a potential biomarker for optimizing graft allocation and improving the rate of successful transplantations.

Methods And Findings: To address the clinical relevance of complement-activating anti-HLA DSAs across all solid organ transplant patients, we performed a meta-analysis of their association with transplant outcome through a systematic review, from inception to January 31, 2018. The primary outcome was allograft loss, and the secondary outcome was allograft rejection. A comprehensive search strategy was conducted through several databases (Medline, Embase, Cochrane, and Scopus). A total of 5,861 eligible citations were identified. A total of 37 studies were included in the meta-analysis. Studies reported on 7,936 patients, including kidney (n = 5,991), liver (n = 1,459), heart (n = 370), and lung recipients (n = 116). Solid organ transplant recipients with circulating complement-activating anti-HLA DSAs experienced an increased risk of allograft loss (pooled HR 3.09; 95% CI 2.55-3.74, P = 0.001; I2 = 29.3%), and allograft rejection (pooled HR 3.75; 95% CI: 2.05-6.87, P = 0.001; I2 = 69.8%) compared to patients without complement-activating anti-HLA DSAs. The association between circulating complement-activating anti-HLA DSAs and allograft failure was consistent across all subgroups and sensitivity analyses. Limitations of the study are the observational and retrospective design of almost all included studies, the higher proportion of kidney recipients compared to other solid organ transplant recipients, and the inclusion of fewer studies investigating allograft rejection.

Conclusions: In this study, we found that circulating complement-activating anti-HLA DSAs had a significant deleterious impact on solid organ transplant survival and risk of rejection. The detection of complement-activating anti-HLA DSAs may add value at an individual patient level for noninvasive biomarker-guided risk stratification.

Trial Registration: National Clinical Trial protocol ID: NCT03438058.
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http://dx.doi.org/10.1371/journal.pmed.1002572DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5969739PMC
May 2018

Sensitization in Transplantation: Assessment of Risk (STAR) 2017 Working Group Meeting Report.

Am J Transplant 2018 07 22;18(7):1604-1614. Epub 2018 May 22.

University of Manitoba, Winnipeg, MB, Canada.

The presence of preexisting (memory) or de novo donor-specific HLA antibodies (DSAs) is a known barrier to successful long-term organ transplantation. Yet, despite the fact that laboratory tools and our understanding of histocompatibility have advanced significantly in recent years, the criteria to define presence of a DSA and assign a level of risk for a given DSA vary markedly between centers. A collaborative effort between the American Society for Histocompatibility and Immunogenetics and the American Society of Transplantation provided the logistical support for generating a dedicated multidisciplinary working group, which included experts in histocompatibility as well as kidney, liver, heart, and lung transplantation. The goals were to perform a critical review of biologically driven, state-of-the-art, clinical diagnostics literature and to provide clinical practice recommendations based on expert assessment of quality and strength of evidence. The results of the Sensitization in Transplantation: Assessment of Risk (STAR) meeting are summarized here, providing recommendations on the definition and utilization of HLA diagnostic testing, and a framework for clinical assessment of risk for a memory or a primary alloimmune response. The definitions, recommendations, risk framework, and highlighted gaps in knowledge are intended to spur research that will inform the next STAR Working Group meeting in 2019.
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http://dx.doi.org/10.1111/ajt.14752DOI Listing
July 2018

Late manifestation of alloantibody-associated injury and clinical pulmonary antibody-mediated rejection: Evidence from cell-free DNA analysis.

J Heart Lung Transplant 2018 07 31;37(7):925-932. Epub 2018 Jan 31.

Department of Medicine, Stanford University School of Medicine, Palo Alto, California, USA. Electronic address:

Background: Antibody-mediated rejection (AMR) often progresses to poor health outcomes in lung transplant recipients (LTRs). This, combined with the relatively insensitive clinical tools used for its diagnosis (spirometry, histopathology) led us to determine whether clinical AMR is diagnosed significantly later than its pathologic onset. In this study, we leveraged the high sensitivity of donor-derived cell-free DNA (ddcfDNA), a novel genomic tool, to detect early graft injury after lung transplantation.

Methods: We adjudicated AMR and acute cellular rejection (ACR) in 157 LTRs using the consensus criteria of the International Society for Heart and Lung Transplantation (ISHLT). We assessed the kinetics of allograft injury in relation to ACR or AMR using both clinical criteria (decline in spirometry from baseline) and molecular criteria (ddcfDNA); percent ddcfDNA was quantitated via shotgun sequencing. We used a mixed-linear model to assess the relationship between and ddcfDNA levels and donor-specific antibodies (DSA) in AMR LTRs.

Results: Compared with ACR, AMR episodes (n = 42) were associated with significantly greater allograft injury when assessed by both spirometric (0.1 liter vs -0.6 liter, p < 0.01) and molecular (ddcfDNA) analysis (1.1% vs 5.4%, p < 0.001). Allograft injury detected by ddcfDNA preceded clinical AMR diagnosis by a median of 2.8 months. Within the same interval, spirometry or histopathology did not reveal findings of allograft injury or dysfunction. Elevated levels of ddcfDNA before clinical diagnosis of AMR were associated with a concurrent rise in DSA levels.

Conclusion: Diagnosis of clinical AMR in LTRs lags behind DSA-associated molecular allograft injury as assessed by ddcfDNA.
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http://dx.doi.org/10.1016/j.healun.2018.01.1305DOI Listing
July 2018

Pre-transplant Screening for Non-HLA Antibodies: Who should be Tested?

Hum Immunol 2018 Apr 8;79(4):195-202. Epub 2018 Feb 8.

Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States.

Retrospective studies of angiotensin II type 1 receptor antibodies (AT1R-Ab) and anti-endothelial cell antibodies (AECA) have linked these antibodies to allograft injury. Because rising healthcare costs dictate judicious use of laboratory testing, we sought to define characteristics of kidney transplant recipients who may benefit from screening for non-HLA antibodies. Kidney recipients transplanted between 2011 and 2016 at Johns Hopkins, were evaluated for AT1R-Ab and AECA. Pre-transplant antibody levels were compared to clinical and biopsy indications of graft dysfunction. Biopsies were graded using the Banff' 2009-2013 criteria. AT1R-Ab and AECA were detected using ELISA and endothelial cell crossmatches, respectively. AT1R-Ab levels were higher in patients who were positive for AECAs. Re-transplanted patients (p < 0.0001), males (p = 0.008) and those with FSGS (p = 0.04) and younger (p = 0.04) at time of transplantation were more likely to be positive for AT1R-Ab prior to transplantation. Recipients who were positive for AT1R-Ab prior to transplantation had increases in serum creatinine within 3 months post-transplantation (p < 0.0001) and developed abnormal biopsies earlier than did AT1R-Ab negative patients (126 days versus 368 days respectively; p = 0.02). Defining a clinical protocol to identify and preemptively treat patients at risk for acute rejection with detectable non-HLA antibodies is an important objective for the transplant community.
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http://dx.doi.org/10.1016/j.humimm.2018.02.001DOI Listing
April 2018

Corrigendum: Novel Non-Histocompatibility Antigen Mismatched Variants Improve the Ability to Predict Antibody-Mediated Rejection Risk in Kidney Transplant.

Front Immunol 2018 31;9:107. Epub 2018 Jan 31.

Division of Transplant Surgery, Department of Surgery, University of California, San Francisco (UCSF), San Francisco, CA, United States.

[This corrects the article on p. 1687 in vol. 8, PMID: 29259604.].
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http://dx.doi.org/10.3389/fimmu.2018.00107DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5797733PMC
January 2018

Novel Non-Histocompatibility Antigen Mismatched Variants Improve the Ability to Predict Antibody-Mediated Rejection Risk in Kidney Transplant.

Front Immunol 2017 5;8:1687. Epub 2017 Dec 5.

Division of Transplant Surgery, Department of Surgery, University of California, San Francisco (UCSF), San Francisco, CA, United States.

Transplant rejection is the critical clinical end-point limiting indefinite survival after histocompatibility antigen (HLA) mismatched organ transplantation. The predominant cause of late graft loss is antibody-mediated rejection (AMR), a process whereby injury to the organ is caused by donor-specific antibodies, which bind to HLA and non-HLA (nHLA) antigens. AMR is incompletely diagnosed as donor/recipient (D/R) matching is only limited to the HLA locus and critical nHLA immunogenic antigens remain to be identified. We have developed an integrative computational approach leveraging D/R exome sequencing and gene expression to predict clinical post-transplant outcome. We performed a rigorous statistical analysis of 28 highly annotated D/R kidney transplant pairs with biopsy-confirmed clinical outcomes of rejection [either AMR or T-cell-mediated rejection (CMR)] and no-rejection (NoRej), identifying a significantly higher number of mismatched nHLA variants in AMR (ANOVA--value = 0.02). Using Fisher's exact test, we identified 123 variants associated mainly with risk of AMR (-value < 0.001). In addition, we applied a machine-learning technique to circumvent the issue of statistical power and we found a subset of 65 variants using random forest, that are predictive of post-tx AMR showing a very low error rate. These variants are functionally relevant to the rejection process in the kidney and AMR as they relate to genes and/or expression quantitative trait loci (eQTLs) that are enriched in genes expressed in kidney and vascular endothelium and underlie the immunobiology of graft rejection. In addition to current D/R HLA mismatch evaluation, additional mismatch nHLA D/R variants will enhance the stratification of post-tx AMR risk even before engraftment of the organ. This innovative study design is applicable in all solid organ transplants, where the impact of mitigating AMR on graft survival may be greater, with considerable benefits on improving human morbidity and mortality and opens the door to precision immunosuppression and extended tx survival.
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http://dx.doi.org/10.3389/fimmu.2017.01687DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5723302PMC
December 2017

Nontraditional sites for vascular anastomoses to enable kidney transplantation in patients with major systemic venous thromboses.

Clin Transplant 2017 Dec 28;31(12). Epub 2017 Nov 28.

Transplant Institute, Department of Surgery, NYU Langone Medical Center, New York, NY, USA.

Successful renal transplantation requires low-pressure venous drainage to permit adequate outflow from the allograft. We report here a series of three patients in whom the inferior vena cava as well as bilateral iliac veins were thrombosed, making it necessary to explore less traditional vessels for venous drainage of the renal allograft. We utilized the splanchnic vasculature in two cases and the native left renal vein in another. The resulting atypical intra-abdominal locations of these allografts also presented difficulties for arterial anastomoses and for urinary drainage. Arterial conduits were utilized in two cases to facilitate anastomosis to the common iliac artery or the aorta, and in the third case, the splenic artery was used for arterial inflow. A traditional ureterocystostomy was technically feasible for only one patient. In another, ureteroureterostomy to the native ureter was performed, and in the third case, the creation of an ileal conduit was necessary. All three patients had antibodies to human leukocyte antigens and two required desensitization. All three kidneys had immediate graft function and continued to function at 1 year post-transplant. With a combination of planning, creativity, and persistence, patients with IVC thrombosis can enjoy the benefits of renal transplantation.
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http://dx.doi.org/10.1111/ctr.13127DOI Listing
December 2017

Casting a smaller net into a bigger donor pool: A single center's experience with the new kidney allocation system.

Hum Immunol 2017 Jan 24;78(1):49-53. Epub 2016 Nov 24.

Department of Medicine, The Johns Hopkins University, Baltimore, MD, USA. Electronic address:

The new kidney allocation system (KAS) provides additional allocation points for candidates with broad HLA sensitization in an effort to increase transplant rates for this underserved population. Following the implementation of KAS, our center lowered the HLA antibody threshold for listing unacceptable antigens from a cytotoxicity crossmatch level to a flow cytometric crossmatch level increasing Calculated Panel Reactive Antibody (CPRA) values and allocation points, yet restricting acceptable donor HLA phenotypes. As a result, many sensitized candidates were transitioned from 50% to 98% CPRA categories into the 99% CPRA regional share and 100% CPRA national share categories. Exposure to these larger donor pools significantly increased transplantation with compatible donors for 100% CPRA candidates, but regional sharing was not sufficient to increase transplantation rates for our 99% CPRA candidates. Competition within the 100% CPRA cohort identified inequities for 99.99-100.0% CPRA candidates and highlighted the continued need for desensitization therapies to reduce immunological barriers and provide transplant opportunities for the most highly sensitized candidates.
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http://dx.doi.org/10.1016/j.humimm.2016.11.004DOI Listing
January 2017

Non-HLA antibodies in transplantation: when do they matter?

Curr Opin Organ Transplant 2016 08;21(4):427-32

Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.

Purpose Of Review: A growing interest in the contribution of non-human leukocyte antigens (non-HLA) antibodies to allograft rejection has led to the identification of multiple target antigens and investigation into the possible mechanisms of injury. Although several non-HLA antibody specificities have been identified, the largest cohorts studied are those detected using commercial assays. This review focuses on the phenotypes of injury associated with non-HLA antibody and defines in-vivo environmental characteristics that may be conducive to non-HLA antibody-mediated injury.

Recent Findings: Mechanistic studies in animal models and clinical data suggest that an inflammatory environment, increased antigen expression, and development of neoantigens through posttranslational modifications contribute to non-HLA antibody development and their subsequent contribution to allograft injury. Furthermore, many reports show worse outcomes when HLA and non-HLA antibodies are present, suggesting possible interactions between these antibodies that lead to increased injury. Plasmapheresis and intravenous immunoglobulin are currently used to reduce HLA and non-HLA antibodies; however, therapeutic strategies targeting B cells and plasma cells simultaneously may lead to more durable antibody elimination.

Summary: Immune triggers that lead to non-HLA antibody formation are complex and poorly understood. The ability of non-HLA antibodies to mediate allograft injury may depend upon their specificity and affinity, density of the target antigen, and synergy with HLA antibodies.
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http://dx.doi.org/10.1097/MOT.0000000000000335DOI Listing
August 2016

Anti-Angiotensin II Type 1 Receptor and Anti-Endothelial Cell Antibodies: A Cross-Sectional Analysis of Pathological Findings in Allograft Biopsies.

Transplantation 2017 03;101(3):608-615

1 Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD. 2 Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD. 3 Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD. 4 Clinic of Nephrology and Intensive Care Medicine Campus Virchow-Klinikum and Center for Cardiovascular Research, Medical Faculty of the Charite, Berlin, Germany.

Background: This is a cross-sectional study designed to evaluate the histologic characteristics of graft injury in the presence of anti-angiotensin II type 1 receptor antibody (AT1R-Ab) and anti-endothelial cell antibody (AECA).

Methods: Non-HLA antibody testing was included in the posttransplant evaluation for 70 kidney recipients. Biopsies were performed for cause for 47 patients and as protocol for the remaining 23 patients. Biopsy-proven rejection was defined according to the Banff 2009-2013 criteria. AT1R-Ab was measured on an ELISA platform. Patients were divided into 3 groups based on AT1R-Ab levels (>17, 10-17, and <10 U/ml). AECA was evaluated using an endothelial cell crossmatch (ECXM) in patients whose HLA antibody level was insufficient to cause a positive flow cytometric crossmatch.

Results: AT1R-Ab levels were higher in patients diagnosed with antibody mediated rejection compared to those with no rejection (P = 0.004). Glomerulitis (g) and peritubular capillaritis (ptc) scores were independently correlated with increased AT1R-Ab concentrations in the presence or absence of HLA-DSA (P = 0.007 and 0.03 for g scores; p = 0.005 and 0.03 for ptc scores). Patients with a positive ECXM had higher AT1R-Ab levels compared to those with a negative ECXM (P = 0.005). Microcirculation inflammation (MCI = g + ptc score) was higher in patients with a positive ECXM and with AT1R-Ab >17 U/ml, although this did not reach statistical significance (P = 0.07).

Conclusions: The data show an association between non-HLA antibodies detected in the ECXM and AT1R ELISA and microvascular injury observed in antibody mediated rejection.
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http://dx.doi.org/10.1097/TP.0000000000001231DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5319389PMC
March 2017

Hepatitis E Virus Infection Among Solid Organ Transplant Recipients at a North American Transplant Center.

Open Forum Infect Dis 2016 Jan 18;3(1):ofw006. Epub 2016 Jan 18.

Department of Pediatrics, Division of Pediatric Gastroenterology, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and.

Background.  Autochthonous hepatitis E virus (HEV) infection has been reported in over 200 solid organ transplant (SOT) recipients since 2006, yet little is known about the burden of HEV among SOT recipients in North America. We performed a retrospective, cross-sectional study to investigate the prevalence and risk factors associated with HEV infection among SOT recipients at our institution. Methods.  Children and adults (n = 311) who received allografts between 1988 and 2012 at the Johns Hopkins Hospital were assessed for evidence of HEV infection by testing posttransplantation serum samples for HEV antibody by enzyme immunoassay and HEV RNA by reverse transcription quantitative polymerase chain reaction. Individuals with evidence of posttransplant HEV infection (presence of anti-HEV immunoglobulin [Ig]M antibody, anti-HEV IgG seroconversion, or HEV RNA) were compared with individuals without evidence of infection and assessed for risk factors associated with infection. Results.  Twelve individuals (4%) developed posttransplant HEV infection. Posttransplant HEV infection was associated with an increased risk for graft rejection (odds ratio, 14.2; P = .03). No individuals developed chronic infection. Conclusions.  Solid organ transplant recipients in the United States are at risk for posttransplant HEV infection. Further studies are needed to characterize environmental risk factors and the risk of HEV infection after SOT in North America.
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http://dx.doi.org/10.1093/ofid/ofw006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4804338PMC
January 2016

Variable HLA expression on deceased donor lymphocytes: Not all crossmatches are created equal.

Hum Immunol 2015 Nov 9;76(11):795-800. Epub 2015 Oct 9.

Department of Medicine, The Johns Hopkins University, Baltimore, MD 21205, USA. Electronic address:

Flow cytometric crossmatch tests are used to detect donor-specific antibody and determine eligibility for transplantation. Crossmatch sensitivity is dependent on lymphocyte quality, to include HLA expression on the cell surface. The impact of HLA expression variability on crossmatch reactivity was examined using lymphocytes isolated from different donor types: deceased donor (DD) versus living donor (LD) and tissue sources (blood, spleen, or lymph nodes). HLA class I expression was similar on B cells isolated from LD blood, DD spleen, and DD lymph nodes, but significantly lower on B cells isolated from DD blood (p = 0.0004). In contrast, class II expression on B cells and class I on T cells were significantly higher in LD blood than all DD tissues. Within DD tissues, spleen provided the highest expression of class II on B cells and class I on T cells. HLA expression on B cells, but not T cells, was impacted by memory (CD27+) versus non-memory status. Importantly, HLA expression differences on lymphocytes isolated from the same donor but different tissues impacted crossmatch outcomes. HLA expression is impacted by multiple factors and should be routinely monitored to ensure crossmatch sensitivity and to reconcile crossmatch strength with solid phase HLA antibody analyses.
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http://dx.doi.org/10.1016/j.humimm.2015.09.029DOI Listing
November 2015