HLA-DQ mismatches stimulate de novo donor specific antibodies in heart transplant recipients

HLA Mismatches Identified by a Novel Algorithm Predict Risk of Antibody-mediated Rejection From De Novo Donor-specific Antibodies

BACKGROUND

The development of de novo donor-specific antibodies (dnDSA) and antibody-mediated rejection (AMR) remains a barrier to long-term graft and patient survival. Most dnDSA are directed against mismatched donor HLA-DQ antigens. Here, we describe a novel algorithm, which we have termed categorical amino acid mismatched epitope, to evaluate HLA-DQ mismatches.

METHODS

In this algorithm, amino acid residues of HLA-DQ protein were categorized into 4 groups based on their chemical characteristics. The likelihood of categorically mismatched peptides presented by the recipient's HLA-DRB1 was expressed as a normalized value, %Rank score. Categorical HLA-DQ mismatches were analyzed in 386 heart transplant recipients who were mismatched with their donors at the HLA-DQB1 locus.

RESULTS

We found that the presence of DQB1 mismatches with %Rank score ≤1 was associated with the development of dnDSA (P = 0.002). Furthermore, dnDSA increased the risk of AMR only in recipients who had DQ mismatches with %Rank score ≤1 (hazard ratio = 5.8), but the freedom from AMR was comparable between recipients with dnDSA and those without dnDSA if %Rank scores of DQ mismatching were >1.

CONCLUSIONS

These results suggest that HLA-DQ mismatches evaluated by the categorical amino acid mismatched epitope algorithm can stratify the risk of development of dnDSA and AMR in heart transplant recipients.

Pseudomonas aeruginosa infection correlates with high MFI donor-specific antibody development following lung transplantation with consequential graft loss and shortened CLAD-free survival

BACKGROUND

Donor-specific antibodies (DSAs) are common following lung transplantation (LuTx), yet their role in graft damage is inconclusive. Mean fluorescent intensity (MFI) is the main read-out of DSA diagnostics; however its value is often disregarded when analyzing unwanted post-transplant outcomes such as graft loss or chronic lung allograft dysfunction (CLAD). Here we aim to evaluate an MFI stratification method in these outcomes.

METHODS

A cohort of 87 LuTx recipients has been analyzed, in which a cutoff of 8000 MFI has been determined for high MFI based on clinically relevant data. Accordingly, recipients were divided into DSA-negative, DSA-low and DSA-high subgroups. Both graft survival and CLAD-free survival were evaluated. Among factors that may contribute to DSA development we analyzed Pseudomonas aeruginosa (P. aeruginosa) infection in bronchoalveolar lavage (BAL) specimens.

RESULTS

High MFI DSAs contributed to clinical antibody-mediated rejection (AMR) and were associated with significantly worse graft (HR: 5.77, p < 0.0001) and CLAD-free survival (HR: 6.47, p = 0.019) compared to low or negative MFI DSA levels. Analysis of BAL specimens revealed a strong correlation between DSA status, P. aeruginosa infection and BAL neutrophilia. DSA-high status and clinical AMR were both independent prognosticators for decreased graft and CLAD-free survival in our multivariate Cox-regression models, whereas BAL neutrophilia was associated with worse graft survival.

CONCLUSIONS

P. aeruginosa infection rates are elevated in recipients with a strong DSA response. Our results indicate that the simultaneous interpretation of MFI values and BAL neutrophilia is a feasible approach for risk evaluation and may help clinicians when to initiate DSA desensitization therapy, as early intervention could improve prognosis.

DQB1 antigen matching improves rejection-free survival in pediatric heart transplant recipients

BACKGROUND

Presence of donor-specific antibodies (DSAs), particularly to class II antigens, remains a major challenge in pediatric heart transplantation. Donor-recipient human leukocyte antigen (HLA) matching is a potential strategy to mitigate poor outcomes associated with DSAs. We evaluated the hypothesis that antigen mismatching at the DQB1 locus is associated with worse rejection-free survival.

METHODS

Data were collected from Scientific Registry of Transplant Recipients for all pediatric heart transplant recipients 2010-2021. Only transplants with complete HLA typing at the DQB1 locus for recipient and donor were included. Primary outcome was rejection-free graft survival through 5 years.

RESULTS

Of 5,115 children, 4,135 had complete DQB1 typing and were included. Of those, 503 (12%) had 0 DQB1 donor-recipient mismatches, 2,203 (53%) had 1, and 1,429 (35%) had 2. Rejection-free survival through 5 years trended higher for children with 0 DQB1 mismatches (68%), compared to those with 1 (62%) or 2 (63%) mismatches (pairwise p = 0.08 for both). In multivariable analysis, 0 DQB1 mismatches remained significantly associated with improved rejection-free graft survival compared to 2 mismatches, while 1 DQB1 mismatch was not. Subgroup analysis showed the strongest effect in non-Hispanic Black children and those undergoing retransplant.

CONCLUSIONS

Matching at the DQB1 locus is associated with improved rejection-free survival after pediatric heart transplant, particularly in Black children, and those undergoing retransplant. Assessing high-resolution donor typing at the time of allocation may further corroborate and refine this association. DQB1 matching may improve long-term outcomes in children stabilized either with optimal pharmacotherapy or supported with durable devices able to await ideal donors.

Role of HLA matching and donor specific antibody development in long-term survival, acute rejection and cardiac allograft vasculopathy

Although there are different data supporting benefits of HLA matching in kidney transplantation, its role in heart transplantation is still unclear. HLA mismatch (MM) between donor and recipient can lead to the development of donor-specific antibodies (DSA) which produces negative events on the outcome of heart transplantation. Moreover, DSAs are involved in the development of antibody-mediated rejection (AMR) and are associated with an increase in cardiac allograft vasculopathy (CAV). In this study it is analyzed retrospectively the influence of HLA matching and anti-HLA antibodies on overall survival, AMR and CAV in heart transplantation. For this retrospective study are recruited heart transplanted patients at the Cardiac Transplantation Centre of Naples between 2000 and 2019. Among the 155 heart transplant patients, the mean number of HLA-A, B, -DR MM (0 to 6) between donor and recipient was 4.5 ± 1.1. The results show a negative association between MM HLA-DR and survival (p = 0.01). Comparison of patients with 0-1 MM at each locus to all others with 2 MM, for both HLA class I and class II, has not showed significant differences in the development of CAV. Our analysis detected DSA in 38.1% of patients. The production of de novo DSA reveals that there is not an influence on survival (p = 0.72) and/or AMR (p = 0.39). Instead, there is an association between the production of DSA class II and the probability of CAV development (p = 0.03). Mean fluorescence intensity (MFI) values were significantly higher in CAV-positive patients that CAV-negative patients (p = 0.02). Prospective studies are needed to evaluate HLA class II matching as an additional parameter for heart allocation, especially considering the increment of waiting list time.

Assessment of IgM DSAs in Transplant Recipients: Relationship to De Novo IgG DSAs and Risk for Antibody Rejection

Background

The presence of anti-HLA donor-specific antibodies (DSAs) is associated with antibody-mediated rejection (AMR) and inferior graft survival. However, recent data suggest that ~50% of AMR episodes are IgG DSA negative and possibly related to non-HLA DSAs. After the initial activation of B cells to alloantigen, IgM is the first immunoglobulin produced. In addition, both IgM and IgG isotopes can activate the classic complement pathway and induce complement-dependent cytotoxicity to allograft targets. Current practices focus on the assessment of IgG DSAs with little concern for the assessment of IgM DSAs.

Methods

Here, we examined anti-HLA IgM in a cohort of 22 patients who developed de novo IgG DSAs by a modified single-antigen bead-based test.

Results

We found IgM HLA DSAs developed before IgG DSAs. The median time from the detection of IgM DSAs to the appearance of de novo IgG DSAs was 461 d. Most patients had IgM DSAs against the same HLA-DQ antigens, for which IgG de novo DSAs were also later detected. IgM DSAs were detected in patients with biopsies suspected of AMR.

Conclusions

The detection of IgM DSAs could be an early indicator of alloimmune responses to allografts before IgG de novo DSAs appear.

Role of HLA in cardiothoracic transplantation

In current clinical practice, transplant clinicians create collaborative working relationships with histocompatibility laboratory scientists to identify the risk of long-term graft failure, which may assist in establishing strategies for treatment and surveillance. Transplant immunology research also focuses on optimizing human leukocyte antibody tissue typing and defines the most effective test for detecting the presence of donor-specific antibodies. Although several studies have been conducted, data on pediatric heart transplant recipients are limited. Epitope load information may be utilized to identify donors with permissible human leukocyte antibody mismatches to increase transplant success. Although current guidelines do not consider human leukocyte antibody epitope-based matching tools, these guidelines could be useful for identifying recipients at a high risk of donor-specific antibody production, which would be appropriate for routine donor-specific antibody screening to initiate early interventions to prevent antibody-mediated rejection. Human leukocyte antibody matching at the epitope level offers an effective approach for identifying acceptable mismatches in sensitized patients and provides information about epitope loads. In the future, eplet matching may be used to define the best immunosuppressive therapy protocol for cardiothoracic organ transplantation. This report provides an overview of the role of human leukocyte antibodies in heart and lung transplantation.

De Novo Donor-Specific Antibodies after Heart Transplantation: A Comprehensive Guide for Clinicians

Antibodies directed against donor-specific human leukocyte antigens (HLAs) can be detected de novo after heart transplantation and play a key role in long-term survival. De novo donor-specific antibodies (dnDSAs) have been associated with cardiac allograft vasculopathy, antibody-mediated rejection, and mortality. Advances in detection methods and international guideline recommendations have encouraged the adoption of screening protocols among heart transplant units. However, there is still a lack of consensus about the correct course of action after dnDSA detection. Treatment is usually started when antibody-mediated rejection is present; however, some dnDSAs appear years before graft failure is detected, and at this point, damage may be irreversible. In particular, class II, anti-HLA-DQ, complement binding, and persistent dnDSAs have been associated with worse outcomes. Growing evidence points towards a more aggressive management of dnDSA. For that purpose, better diagnostic tools are needed in order to identify subclinical graft injury. Cardiac magnetic resonance, strain techniques, or coronary physiology parameters could provide valuable information to identify patients at risk. Treatment of dnDSA usually involves plasmapheresis, intravenous immunoglobulin, immunoadsorption, and ritxumab, but the benefit of these therapies is still controversial. Future efforts should focus on establishing effective treatment protocols in order to improve long-term survival of heart transplant recipients.

Selection and Interpretation of Molecular Diagnostics in Heart Transplantation

The number of heart transplants performed annually in the United States and worldwide continues to increase, but there has been little change in graft longevity and patient survival over the past 2 decades. The reference standard for diagnosis of acute cellular and antibody-mediated rejection includes histologic and immunofluorescence evaluation of endomyocardial biopsy samples, despite invasiveness and high interrater variability for grading histologic rejection. Circulating biomarkers and molecular diagnostics have shown substantial predictive value in rejection monitoring, and emerging data support their use in diagnosing other posttransplant complications. The use of genomic (cell-free DNA), transcriptomic (mRNA and microRNA profiling), and proteomic (protein expression quantitation) methodologies in diagnosis of these posttransplant outcomes has been evaluated with varying levels of evidence. In parallel, growing knowledge about the genetically mediated immune response leading to rejection (immunogenetics) has enhanced understanding of antibody-mediated rejection, associated graft dysfunction, and death. Antibodies to donor human leukocyte antigens and the technology available to evaluate these antibodies continues to evolve. This review aims to provide an overview of biomarker and immunologic tests used to diagnose posttransplant complications. This includes a discussion of pediatric heart transplantation and the disparate rates of rejection and death experienced by Black patients receiving a heart transplant. This review describes diagnostic modalities that are available and used after transplant and the landscape of future investigations needed to enhance patient outcomes after heart transplantation.

New insights into maladaptive vascular responses to donor specific HLA antibodies in organ transplantation

Transplant vasculopathy (TV) causes thickening of donor blood vessels in transplanted organs, and is a significant cause of graft loss and mortality in allograft recipients. It is known that patients with repeated acute rejection and/or donor specific antibodies are predisposed to TV. Nevertheless, the exact molecular mechanisms by which alloimmune injury culminates in this disease have not been fully delineated. As a result of this incomplete knowledge, there is currently a lack of effective therapies for this disease. The immediate intracellular signaling and the acute effects elicited by anti-donor HLA antibodies are well-described and continuing to be revealed in deeper detail. Further, advances in rejection diagnostics, including intragraft gene expression, provide clues to the inflammatory changes within allografts. However, mechanisms linking these events with long-term outcomes, particularly the maladaptive vascular remodeling seen in transplant vasculopathy, are still being delineated. New evidence demonstrates alterations in non-coding RNA profiles and the occurrence of endothelial to mesenchymal transition (EndMT) during acute antibody-mediated graft injury. EndMT is also readily apparent in numerous settings of non-transplant intimal hyperplasia, and lessons can be learned from advances in those fields. This review will provide an update on these recent developments and remaining questions in our understanding of HLA antibody-induced vascular damage, framed within a broader consideration of manifestations and implications across transplanted organ types.

Predictive value of molecular matching tools for the development of donor specific HLA-antibodies in patients undergoing lung transplantation

Molecular matching is a new approach for virtual histocompatibility testing in organ transplantation. The aim of our study was to analyze whether the risk for de novo donor-specific HLA antibodies (dnDSA) after lung transplantation (LTX) can be predicted by molecular matching algorithms (MMA) and their combination. In this retrospective study we included 183 patients undergoing LTX at our center from 2012-2020. We monitored dnDSA development for 1 year. Eplet mismatches (epMM) using HLAMatchmaker were calculated and highly immunogenic eplets based on their ElliPro scores were identified. PIRCHE-II scores were calculated using PIRCHE-II algorithm (5- and 11-loci). We compared epMM and PIRCHE-II scores between patients with and without dnDSA using t-test and used ROC-curves to determine optimal cut-off values to categorize patients into four groups. We used logistic regression with AIC to compare the predictive value of PIRCHE-II, epMM, and their combination. In total 28.4% of patients developed dnDSA (n = 52), 12.5% class I dnDSA (n = 23), 24.6% class II dnDSA (n = 45), and 8.7% both class II and II dnDSA (n = 16). Mean epMMs (p-value = 0.005), mean highly immunogenic epMMs (p-value = 0.003), and PIRCHE-II (11-loci) (p = 0.01) were higher in patients with compared to without class II dnDSA. Patients with highly immunogenic epMMs above 30.5 and PIRCHE-II 11-loci above 560.0 were more likely to develop dnDSA (31.1% vs. 14.8%, p-value = 0.03). The logistic regression model including the grouping variable showed the best predictive value. MMA can support clinicians to identify patients at higher or lower risk for developing class II dnDSA and might be helpful tools for immunological risk assessment in LTX patients.

Immunologic risk stratification of pediatric heart transplant patients by combining HLA-EMMA and PIRCHE-II

Human leukocyte antigen (HLA) molecular mismatch is a powerful biomarker of rejection. Few studies have explored its use in assessing rejection risk in heart transplant recipients. We tested the hypothesis that a combination of HLA Epitope Mismatch Algorithm (HLA-EMMA) and Predicted Indirectly Recognizable HLA Epitopes (PIRCHE-II) algorithms can improve risk stratification of pediatric heart transplant recipients. Class I and II HLA genotyping were performed by next-generation sequencing on 274 recipient/donor pairs enrolled in the Clinical Trials in Organ Transplantation in Children (CTOTC). Using high-resolution genotypes, we performed HLA molecular mismatch analysis with HLA-EMMA and PIRCHE-II, and correlated these findings with clinical outcomes. Patients without pre-formed donor specific antibody (DSA) (n=100) were used for correlations with post-transplant DSA and antibody mediated rejection (ABMR). Risk cut-offs were determined for DSA and ABMR using both algorithms. HLA-EMMA cut-offs alone predict the risk of DSA and ABMR; however, if used in combination with PIRCHE-II, the population could be further stratified into low-, intermediate-, and high-risk groups. The combination of HLA-EMMA and PIRCHE-II enables more granular immunological risk stratification. Intermediate-risk cases, like low-risk cases, are at a lower risk of DSA and ABMR. This new way of risk evaluation may facilitate individualized immunosuppression and surveillance.

Distributions of 11-loci HLA alleles typed by amplicon-based next-generation sequencing in South Koreans

The range of HLA typing for successful hematopoietic stem cell transplantation (HSCT) is gradually expanding with the next-generation sequencing (NGS)-based improvement in its quality. However, it is influenced by the allocation of finances and laboratory conditions. HLA-A, -B, -C, -DRB1/3/4/5, -DQA1, -DQB1, -DPA1, and -DPB1 alleles were genotyped at the 3-field level by amplicon-based NGS using MiSeqDx system and compared to our previous study employing long-range PCR and NGS using TruSight HLA v2 kit, in healthy donors from South Korea. Exon 2, exons 2/3, exons 2/3/4 or 5 of 11-loci were amplified by multiplex PCR. The sequence reads of over 53 depth counts were consistently obtained in each sample exon, depending on the target exon determined to match the reference sequence contained in the IPD-IMGT/HLA Database. HLA alleles were investigated by combinations of the determined exons. A total of 18 alleles with a frequency over 10% were found at the 11 HLA loci. Three ambiguities of HLA-A, -C, and -DRB1 were resolved. We observed a total of 26 HLA-A ~ C ~ B and 6 HLA-DRB1 ~ DQA1 ~ DQB1 ~ DPA1 ~ DPB1 haplotypes having significant linkage disequilibrium between alleles at all neighboring HLA loci. This result was compatible with the previous one, using TruSight HLA v2 kit. Advantages are simple and short progress time because one plate is used for each PCR step in one PCR machine and 11-loci HLA typing is possible even if only eight samples. These data suggested that expanded 11-loci HLA typing data by amplicon-based NGS might help perform HSCT.

DSA in solid organ transplantation: is it a matter of specificity, amount, or functional characteristics?

PURPOSE OF REVIEW

The present review describes the clinical relevance of human leukocyte antigen (HLA) donor-specific antibodies (HLA-DSAs) as biomarkers of alloimmunity and summarizes recent improvements in their characterization that provide insights into immune risk assessment, precision diagnosis, and prognostication in transplantation.

RECENT FINDINGS

Recent studies have addressed the clinical utility of HLA-DSAs as biomarkers for immune risk assessment in pretransplant and peritransplant, diagnosis and treatment evaluation of antibody-mediated rejection, immune monitoring posttransplant, and risk stratification.

SUMMARY

HLA-DSAs have proved to be the most advanced immune biomarkers in solid organ transplantation in terms of analytical validity, clinical validity and clinical utility. Recent studies are integrating multiple HLA-DSA characteristics including antibody specificity, HLA class, quantity, immunoglobulin G subclass, and complement-binding capacity to improve risk assessment peritransplant, diagnosis and treatment evaluation of antibody-mediated rejection, immune monitoring posttransplant, and transplant prognosis evaluation. In addition, integration of HLA-DSAs to clinical, functional and histological transplant parameters has further consolidated the utility of HLA-DSAs as robust biomarkers and allows to build new tools for monitoring, precision diagnosis, and risk stratification for individual patients. However, prospective and randomized-controlled studies addressing the clinical benefit and cost-effectiveness of HLA-DSA-based monitoring and patient management strategies are required to demonstrate that the use of HLA-DSAs as biomarkers can improve current clinical practice and transplant outcomes.

Formation of donor-specific antibodies depends on the epitope load of mismatched hlas in lung transplant recipients: A retrospective single-center study

The development of donor-specific antibodies (DSA) has a significant impact on graft outcome in solid organ transplantation. Mismatched HLAs are recognized directly and indirectly by the recipient immune system. Both pathways occur in parallel and result in the generation of plasma cells, DSA, cytotoxic and T helper lymphocytes. Here, we present the results of an analysis of the epitope load of mismatched HLAs in a cohort of 220 lung transplant recipients using two in silico algorithms, HLAMatchmaker and PIRCHE-II (Predicted Indirectly ReCognizable HLA Epitopes). De novo DSA (dnDSA) were detected by single antigen bead assays. The percentage of recipients who developed dnDSA was significantly higher in the group of patients who received lung transplants with a mismatching score above the detected threshold than in the group of patients who received lung transplants with a mismatching score below the threshold. In a multivariate Cox proportional hazard analysis, the PIRCHE-II score appeared to be a superior predictor of dnDSA formation. In addition, PIRCHE-II technology was shown to be useful in predicting separate dnDSA1 and dnDSA2 formation. We conclude that both algorithms can be used for the evaluation of the epitope load of mismatched HLAs and the prediction of DSA development in lung transplant recipients. This article is protected by copyright. All rights reserved.

Peptides Derived From Mismatched Paternal Human Leukocyte Antigen Predicted to Be Presented by HLA-DRB1, -DRB3/4/5, -DQ, and -DP Induce Child-Specific Antibodies in Pregnant Women

Predicted Indirectly ReCognizable Human Leukocyte Antigen (HLA) Epitopes (PIRCHE) are known to be a significant risk factor for the development of donor HLA-specific antibodies after organ transplantation. Most previous studies on PIRCHE limited their analyses on the presentation of the HLA-DRB1 locus, although HLA-DRB3/4/5, -DQ, and -DP are also known for presenting allopeptides to CD4+ T cells. In this study, we analyzed the impact of predicted allopeptides presented by these additional loci on the incidence of HLA-specific antibodies after an immunization event. We considered pregnancy as a model system of an HLA immunization and observed child-specific HLA antibody (CSA) development of 231 mothers during pregnancy by samples being taken at delivery. Our data confirm that PIRCHE presented by HLA-DRB1 along with HLA-DRB3/4/5, -DQ, and -DP are significant predictors for the development of CSA. Although there was limited peptidome overlap observed within the mothers’ presenting HLA proteins, combining multiple presenting loci in a single predictor improved the model only marginally. Prediction performance of PIRCHE further improved when normalizing scores by the respective presenters’ binding promiscuity. Immunogenicity analysis of specific allopeptides could not identify significant drivers of an immune response in this small cohort, suggesting confirmatory studies.

Human leukocyte antigen epitope mismatch loads and the development of de novo donor-specific antibodies in cardiothoracic organ transplantation

De novo donor-specific human leucocyte antigen (HLA) antibodies (dnDSA) are associated with increased risk of rejection and mortality in solid organ transplantation. Such dnDSA is produced in some recipients upon allorecognition of mismatched HLA post-transplant. HLA matching is not currently considered in the allocation of deceased donor hearts and lungs and pre-transplant immunological risk stratification is based entirely on the mean fluorescence intensity (MFI) of circulating donor-directed HLA antibodies. HLA epitope-based matching tools predict B-cell or T-cell HLA epitopes that are present in the donor's HLA but absent in the recipient's HLA. We hypothesized that patients with higher epitope mismatch loads would be at increased risk of dnDSA development. We retrospectively analysed 73 heart and/or lung transplant recipients who were tested for DSA between 2015 and 2020. HLAMatchmaker, PIRCHE-II and HLA epitope mismatch algorithm (HLA-EMMA) were used to calculate eplet mismatch (EpMM) loads, T-cell epitope mismatch (TEpMM) loads and solvent accessible amino acid mismatch (SAMM) loads, respectively. Multivariate analyses showed that HLA-EMMA was the only tool with a significant association between the total score for all HLA loci and dnDSA production [odds ratio (OR) 1.021, 95% confidence interval (CI) 1.003-1.042, p = .0225] though this increased risk was marginal. The majority of dnDSA were directed against HLA-DQ and patients with higher HLA-DQ TEpMM loads (OR = 1.008, CI = 1.002-1.014, p = .007), and HLA-DR+DQ SAMM loads (OR = 1.035, CI = 1.010-1.064, p = .0077) were most at risk of producing dnDSA. We also showed that patients with a risk epitope within the HLA molecule encoded for by HLA-DQA1*05 + HLA-DQB1*02/03:01 were significantly more likely to produce dnDSA. The use of HLA epitope-based matching tools could be used for cardiothoracic transplant risk stratification to enable early intervention and monitoring of patients at increased risk of producing dnDSA.

Donor-specific antibodies in heart transplantation: can we afford the price or is it too steep to pay?

PURPOSE OF REVIEW

One-third of patients awaiting heart transplant are sensitized and 25-35% of heart allograft recipients develop de novo DSAs. Solid phase assays for DSA measurement have facilitated wider use of antibody monitoring and as such, our experience with DSAs is continuously evolving.

RECENT FINDINGS

DSAs continue to exhibit poor correlation with biopsy-proven rejection. Novel molecular technologies, such as cell-free DNA and the molecular microscope (MMDx, which detects rejection-associated intragraft mRNA transcripts), are emerging as more sensitive methods to capture subclinical graft injury. High-resolution typing techniques are providing insight into the differential immunogenicity of HLA classes through epitope and eplet analysis. As sensitization of the transplant population is continuing to rise, our repertoire of desensitization strategies is also expanding. However, there is an acute need of predictive algorithms to help forecast the responders and the durability of desensitization. Novel immunomodulatory therapies have allowed safely transplanting across a positive crossmatch with good short-term survival but reported greater degree of rejection and lower long-term graft survival.

SUMMARY

Our experience of outcomes as pertaining to DSAs still originates primarily from single-center studies. Our field is confronted with the challenge to establish common practice algorithms for the monitoring and treatment of DSAs.

Association of vimentin antibody and other non-HLA antibodies with treated antibody mediated rejection in heart transplant recipients

Non-human leukocyte antigen (HLA) antibodies have been implicated in heart transplantation rejection. However, targets of non-HLA antibodies remain elusive. Here, we utilized a panel of multiplex beads-based assay to determine the specificity of non-HLA antibodies following heart transplantation. We utilized a selected cohort of recipients who did not have HLA donor specific antibodies, but were diagnosed with antibody mediated rejection and treated for antibody mediated rejection. We found the presence of vimentin antibody was associated with treated antibody mediated rejection. Our results suggest that, in heart transplant recipients who are suspected of AMR but in the absence of HLA donor specific antibodies, non-HLA antibodies should be examined.