A molecular reappraisal of quilty lesions: Insights from tissue and circulating biomarkers in heart transplantation.

Prevalence of Clinical Events Following High Donor Derived Cell Free DNA in the Absence of Rejection in Heart Transplant Recipients

Solid Gold, or Liquid Gold?: Towards a New Diagnostic Standard for Heart Transplant Rejection.

Microvascular Inflammation: An Incremental Path to Refining the Diagnosis of Antibody-mediated Rejection in Heart Transplantation

Correlations of lymphocyte subset infiltrates with donor-specific antibodies and acute antibody-mediated rejection in endomyocardial biopsies.

BackgroundThe aim of this study was to investigate the clinical significance of Quilty lesions in endomyocardial biopsies (EMBs) of cardiac transplantation patients.MethodsA total of 1190 EMBs from 117 cardiac transplantation patients were evaluated histologically for Quilty lesions, acute cellular rejection, and antibody-mediated rejection. Cardiac allograft vasculopathy was diagnosed by computed tomography coronary angiography. Clinical information, including the patients’ survival was retrieved by a review of medical records.ResultsEighty-eight patients (75.2%) were diagnosed with Quilty lesions, which were significantly associated with acute cellular rejection, but not with acute cellular rejection ≥ 2R or antibody-mediated rejection. In patient sdiagnosed with both Quilty lesions and acute cellular rejection, the time-to-onset of Quilty lesions from transplantation was longer than that of acute cellular rejections. We found a significant association between Quilty lesions and cardiac allograft vasculopathy. No significant relationship was found between Quilty lesions and the patients’ survival.ConclusionsQuilty lesion may be an indicator of previous acute cellular rejection rather than a predictor for future acute cellular rejection.

Use of Donor Derived Cell Free DNA for Long Term Rejection Surveillance in OHT Recipients

The Impact of Grade 1R Endomyocardial Biopsies on Donor-Derived Cell-Free DNA, Higher-Grade Rejection and Development of Donor Specific Antibodies

Prognostic Implications and Characteristics of Low dd-cfDNA Results in Heart Transplant Patients with Biopsy Proven Rejection

Donor-Derived Cell-Free DNA Predicts De Novo DSA after Heart Transplantation

Quadritherapy vs standard tritherapy immunosuppressant regimen after heart transplantation: A propensity score-matched cohort analysis.

Acute cellular (ACR) and antibody-mediated (AMR) rejection are risk factors for allograft loss in heart transplant (HT) recipients. Endomyocardial biopsy (EMB), although considered the gold standard for rejection surveillance, is invasive and has high interobserver variability. Noninvasive donor-derived cell-free DNA (dd-cfDNA) sampling has a high negative predictive value (NPV) for rejection in adults and is increasingly used in pediatrics. This single center study aimed to test the performance of dd-cfDNA in screening for acute rejection (AR) and donor-specific antibodies (DSAs) in pediatric HT recipients. Blood samples for dd-cfDNA were obtained per clinical protocol for all eligible HT recipients in our center from July 1, 2022 to December 31, 2023. Primary endpoints were episodes of AR, pathology grading of EMBs temporally related to ddcfDNA sampling (0-150 days), and presence of DSAs. There were 471 interpretable samples, in 192 unique patients. Of those, 199 dd-cfDNA tests were paired with EMB ± DSA in 152 patients. Abnormal dd-cfDNA (> 0.2%) was found in 77 samples (median 0.48%, range 0.21%-11%) and led to EMB, where one sample was positive for ACR (grade 2R), 13 for AMR, yielding an NPV of 97% for AMR. After excluding abnormal ddcfDNA testing associated with AR, 65 abnormal dd-cfDNA tests were paired with DSA testing. The NPV of the test for detection of DSAs was 93%. Implementation of noninvasive rejection surveillance with dd-cfDNA in a pediatric cohort demonstrates high NPV for AR and high DSAs, making it an ideal screening tool for long-term monitoring of allograft health in pediatrics.

Initiation of Noninvasive Surveillance for Allograft Rejection in a Cohort of Heart Transplant Patients >1 Year after Transplant: An Exploratory Analysis

Introduction: Heart transplant recipients with donor-specific antibodies (DSA) have increased risk for antibody-mediated rejection (AMR). However, many patients with graft dysfunction and DSA do not show AMR by endomyocardial biopsy (EMB). Hypothesis: We hypothesized that, similar to EMB-defined AMR, AMR defined as DSA presence + graft dysfunction on echocardiography is associated with 1) graft injury via elevated donor-derived cell-free DNA (dd-cfDNA) and 2) risk for long-term adverse outcomes. Methods: Adult heart transplant recipients from the Genomic Research Alliance for Transplantation (GRAfT, a prospective, multicenter study from 2015 to 2020) had DSA, echocardiogram, and dd-cfDNA evaluated at time of EMB. AMR was defined by EMB (pAMR ≥ 1), DSA/EF (DSA presence + LVEF drop by ≥ 10% to an LVEF ≤50%), or a composite of EMB or DSA/EF criteria. The composite long-term endpoint was death or long-term EF reduction ≤ 50% for >90 days. Results: 216 patients (29% Female, 39% Black race, mean age 52 ± 12 years) had 1489 EMB, 1959 DSA, 1821 echocardiogram, and 1190 dd-cfDNA evaluations. DSA were present in 71 patients (34%), predominantly class II (69%). AMR was detected by EMB in 16 subjects and by DSA/EF in 10 subjects. Median %dd-cfDNA for subjects with AMR by EMB was 0.63% (IQR 0.23-2.0), by DSA/EF was 0.40% (IQR 0.36-1.24), and for controls was 0.01% (IQR 0.001-0.10). There were 18 deaths and 10 subjects with long term EF reduction. As compared to controls, development of each AMR definition was associated with the composite long-term endpoint: AMR by EMB, HR=3.6, P =0.010; AMR by DSA/EF, HR=23.4, P <0.0001; composite AMR, HR=7.6, P <0.0001, Figure. Conclusions: Heart transplant recipients with EMB and EF/DSA AMR have similar evidence of graft injury via dd-cfDNA as well as risk of long-term adverse outcomes, as compared to those without AMR. Therefore, a composite definition of AMR, including EMB or DSA/EF may better allow for identification of patients at risk for graft failure.

Correlation of circulating donor-specific anti-HLA antibodies and presence of C4d in endomyocardial biopsy with heart allograft outcomes: A single-center, retrospective study

Introduction: Acute rejection (AR) is a risk factor for mortality following heart transplant. Prior studies relied on endomyocardial biopsy (EMB), an invasive gold standard with poor sensitivity, and excluded EMB-negative antibody mediated rejection. They also did not evaluate risk in relation to sustained LV dysfunction, a reversible precursor to death. Plasma donor-derived cell-free DNA (%dd-cfDNA) is sensitive and can detect AR earlier than EMB. Its prognostic utility is unknown. This study assesses the association of AR and %ddcfDNA at diagnosis of AR with risk of adverse outcomes. Methods: In the prospective multicenter GRAfT study (NCT02423070), heart transplant recipients were enrolled and serial plasma samples were collected to quantify %dd-cfDNA via shotgun sequencing. Acute cellular rejection (ACR) was defined as grade ≥2 and AMR as grade ≥1 on EMB. EMB-negative AMR was defined as donor specifici antibody (DSA) positivity with LV dysfunction. AR was classified as mild (ACR 2 or AMR 1) or severe (ACR ≥3, AMR ≥2, or DSA+/LV dysfunction). The primary outcome was a composite of sustained LVEF <50% for ≥3 months and/or death. Cox regression models assessed the association between AR, %dd-cfDNA at diagnosis, and clinical outcomes. Patients were further stratified by a validated %dd-cfDNA threshold of 0.25%. Results: Among 277 patients, AR occurred in 26.9%: 16.2% with ACR, 9.4% with pathologic AMR, and 6.6% with DSA+LV dysfunction. Severe AR occurred in 4.4%, and mild AR in 18.8%. At 5 years post-transplant, the primary outcome occurred in 25.2%, and overall survival was 80.4%. In multivariable analysis, severe—but not mild—AR was associated with increased risk. Among those with severe AR, %dd-cfDNA > 0.25% at diagnosis was associated with higher risk of the primary outcome (adjusted HR 6.06 [95% CI,1.78–20.6]; p < 0.005) and death (HR 10.3 [95% CI, 2.85–37.3]). %dd-cfDNA levels remained persistently elevated after AR treatment in patients who experienced adverse outcomes. Conclusion: We demonstrate the severe AR is associated with risk of poor outcomes, using contemporary definitions. The %dd-cfDNA levels at diagnosis of severe AR offers novel prognostic utility, identifying patients at high risk for death or graft dysfunction. The persistently elevated %dd-cfDNA levels following treatment could indicate poor response to therapy and need for intensified or prolonged therapy.