Quilty Effect Correlates With Biopsy-proven Acute Cellular Rejection But Does Not Predict Transplanted Heart Coronary Artery Vasculopathy

Histopathological Characteristics of Percutaneous Endomyocardial Biopsy in Heart Transplant Rejection Surveillance: A Single Center Experience

BACKGROUND

Heart transplantation (HT) remains the ultimate treatment for end-stage heart failure. An endomyocardial biopsy (EMB) is "the gold standard" diagnostic procedure used in HT rejection surveillance. The aim of this study is to provide a detailed analysis of the histopathological characteristics of the EMB and to investigate if there is a correlation between some histopathological changes, such as fibrosis, vasculitis, Quilty effect (Q.E.), myocytes damage, and the presence of episodes of acute rejection.

METHODS

In this retrospective study, 200 EMBs were included, coming from 65 patients transplanted in the Emergency Institute for Cardiovascular Diseases and Transplantation (ICvDT) Targu Mures between 2012 and 2024. Fibrosis, vasculitis, Q.E., myocyte damage, etc., were microscopically evaluated to see if these parameters correlate with rejection episodes.

RESULTS

The mean age was 38.18 years (SD 15.67), 25% of biopsies being recorded in the 41-50 age group. 77.14% of total acute cellular rejection (ACR) was of mild rejection, with most registered in the 11-20 age group; the cases of severe rejection being recorded in the 41-50 age group. Antibody-mediated rejection (AMR) was recorded more frequently in women with a representation of 23.4%, compared to 8.5% of men. 86.7% (39 cases) of the total number of EMBs with fibrosis score 3 and 71.4% (15 cases) of the total EMBs with fibrosis score 2 were recorded in men, compared to the 28.6% (6 cases) of fibrosis score 2 recorded in women (p = 0.013). 50.0% of all the EMB recorded in the 61-70 age group showed fibrosis score 3, compared to 34.8% of those from the 21-30 age group. The Q.E. was identified in 13% of the biopsies and, in some patients, it was observed across 3-4 successive biopsies. Mild vasculitis was associated in 34.9% of cases with ISHLT ≥ 1R and moderate vasculitis was associated in 87.5% of cases with ISHLT ≥ 1R.

CONCLUSIONS

Fibrosis was detected much more frequently in men and in the 61-70 age group. In addition to the histopathological changes specific to acute rejection, there are other pathological changes, such as the Q.E., and vasculitis and myocytes damage and disarray, that seem to suggest a close connection with rejection, but extensive studies are needed to confirm this.

Advanced Tertiary Lymphoid Tissues in Protocol Biopsies are Associated with Progressive Graft Dysfunction in Kidney Transplant Recipients

BACKGROUND

Tertiary lymphoid tissues (TLTs) are ectopic lymphoid tissues found in chronically inflamed organs. Although studies have documented TLT formation in transplanted kidneys, the clinical relevance of these TLTs remains controversial. We examined the effects of TLTs on future graft function using our histologic TLT maturity stages and the association between TLTs and Banff pathologic scores. We also analyzed the risk factors for the development of TLTs.

METHODS

Serial protocol biopsy samples (0 hour, 1, 6, and 12 months) without rejection were retrospectively analyzed from 214 patients who underwent living donor kidney transplantation. TLTs were defined as lymphocyte aggregates with signs of proliferation and their stages were determined by the absence (stage I) or presence (stage II) of follicular dendritic cells.

RESULTS

Only 4% of patients exhibited TLTs at the 0-hour biopsy. Prevalence increased to almost 50% at the 1-month biopsy, and then slightly further for 12 months. The proportion of advanced stage II TLTs increased gradually, reaching 19% at the 12-month biopsy. Presence of stage II TLTs was associated with higher risk of renal function decline after transplantation compared with patients with no TLT or stage I TLTs. Stage II TLTs were associated with more severe tubulitis and interstitial fibrosis/tubular atrophy at 12 months and predicted poorer graft function independently from the degree of interstitial inflammation. Pretransplantation rituximab treatment dramatically attenuated the development of stage II TLTs.

CONCLUSIONS

TLTs are commonly found in clinically stable transplanted kidneys. Advanced stage II TLTs are associated with progressive graft dysfunction, independent of interstitial inflammation.

Essentials in the diagnosis of postoperative myocardial lesions similar to or unrelated to rejection in heart transplant

Background, objectives: Histological diagnosis of control biopsies in patients with heart transplant represents a significant step of monitoring, with a great influence on adjusting immunosuppressive treatment. Histological lesions are usually related to ischemia and reperfusion, with varying degrees of intensity. This study aimed to highlight the most important aspects of the histological diagnosis and differential diagnosis of postoperative myocardial lesions associated or unrelated to rejection in heart transplant.

Materials and Methods: This retrospective study involved 53 patients who received cardiac transplant between 2000 and 2017. Patients were monitored by lesion quantification of endomyocardial biopsies, with diagnoses established based on biopsy material in the early, medium and late post-transplant periods. Hematoxylin eosin, Masson’s trichrome, and Van Gieson stains were used; immunohistochemical determinations used CD4, CD20, CD45, CD68, HLA-DR, VEGF and CD31.

Results: Ischemia and reperfusion lesions were diagnosed on all biopsies in the first 6 weeks post-transplant. Nine cases of the Quilty effect were identified, and in 12 cases, the biopsies were performed on the same spot as previous biopsies. A significant number of transplanted patients presented cytomegalovirus that was difficult to diagnose on endomyocardial biopsies.

Conclusions: The detailed study of ischemia and reperfusion lesions, as well as of changes un-related to rejection becomes a major objective in the short, medium and late post-transplant period. Overdiagnosis of rejection induces changes of the immunosuppressive therapeutic protocol, with alarming repercussions on cytomegalovirus reactivation, and risks of potentiating inflammation, myocyte destruction and the recurrence of disorders related to both inducing and aggravating heart failure.

Usefulness of speckle tracking echocardiography and biomarkers for detecting acute cellular rejection after heart transplantation

BACKGROUND

Acute cellular rejection (ACR) is a major complication after heart transplantation. Endomyocardial biopsy (EMB) remains the gold standard for its diagnosis, but it has concerning complications. We evaluated the usefulness of speckle tracking echocardiography (STE) and biomarkers for detecting ACR after heart transplantation.

METHODS

We prospectively studied 60 transplant patients with normal left and right ventricular systolic function who underwent EMB for surveillance 6 months after transplantation. Sixty age- and sex-matched healthy individuals constituted the control group. Conventional echocardiographic parameters, left ventricular global longitudinal, radial and circumferential strain (LV-GLS, LV-GRS and LV-GCS, respectively), left ventricular systolic twist (LV-twist) and right ventricular free wall longitudinal strain (RV-FWLS) were analyzed just before the procedure. We also measured biomarkers at the same moment.

RESULTS

Among the 60 studied patients, 17 (28%) had severe ACR (grade ≥ 2R), and 43 (72%) had no significant ACR (grade 0 - 1R). The absolute values of LV-GLS, LV-twist and RV-FWLS were lower in transplant patients with ACR degree ≥ 2 R than in those without ACR (12.5% ± 2.9% vs 14.8% ± 2.3%, p=0.002; 13.9° ± 4.8° vs 17.1° ± 3.2°, p=0.048; 16.6% ± 2.9% vs 21.4%± 3.2%, p < 0.001; respectively), while no differences were observed between the LV-GRS or LV-GCS. All of these parameters were lower in the transplant group without ACR than in the nontransplant control group, except for the LV-twist. Cardiac troponin I levels were significantly higher in patients with significant ACR than in patients without significant ACR [0.19 ng/mL (0.09-1.31) vs 0.05 ng/mL (0.01-0.18), p=0.007]. The combination of troponin with LV-GLS, RV-FWLS and LV-Twist had an area under curve for the detection of ACR of 0.80 (0.68-0.92), 0.89 (0.81-0.93) and 0.79 (0.66-0.92), respectively.

CONCLUSION

Heart transplant patients have altered left ventricular dynamics compared with control individuals. The combination of troponin with strain parameters had higher accuracy for the detection of ACR than the isolated variables and this association might select patients with a higher risk for ACR who will benefit from an EMB procedure in the first year after heart transplantation.

The XVth Banff Conference on Allograft Pathology the Banff Workshop Heart Report: Improving the diagnostic yield from endomyocardial biopsies and Quilty effect revisited

The XVth Banff Conference on Allograft Pathology meeting was held on September 23-27, 2019, in Pittsburgh, Pennsylvania, USA. During this meeting, two main topics in cardiac transplant pathology were addressed: (a) Improvement of endomyocardial biopsy (EMB) accuracy for the diagnosis of rejection and other significant injury patterns, and (b) the orphaned lesion known as Quilty effect or nodular endocardial infiltrates. Molecular technologies have evolved in recent years, deciphering pathophysiology of cardiac rejection. Diagnostically, it is time to integrate the histopathology of EMBs and molecular data. The goal is to incorporate molecular pathology, performed on the same paraffin block as a companion test for histopathology, to yield more accurate and objective EMB interpretation. Application of digital image analysis from hematoxylin and eosin (H&E) stain to multiplex labeling is another means of extracting additional information from EMBs. New concepts have emerged exploring the multifaceted significance of myocardial injury, minimal rejection patterns supported by molecular profiles, and lesions of arteriolitis/vasculitis in the setting of T cell-mediated rejection (TCMR) and antibody-mediated rejection (AMR). The orphaned lesion known as Quilty effect or nodular endocardial infiltrates. A state-of-the-art session with historical aspects and current dilemmas was reviewed, and possible pathogenesis proposed, based on advances in immunology to explain conflicting data. The Quilty effect will be the subject of a multicenter project to explore whether it functions as a tertiary lymphoid organ.

Quilty Lesions in the Endomyocardial Biopsies after Heart Transplantation

BACKGROUND

The aim of this study was to investigate the clinical significance of Quilty lesions in endomyocardial biopsies (EMBs) of cardiac transplantation patients.

METHODS

A total of 1190EMBs from 117 cardiac transplantation patients were evaluated histologically for Quilty lesions,acute cellular rejection, and antibody-mediated rejection. Cardiac allograft vasculopathy wasdiagnosed by computed tomography coronary angiography. Clinical information, including thepatients' survival was retrieved by a review of medical records.

RESULTS

Eighty-eight patients(75.2%) were diagnosed with Quilty lesions, which were significantly associated with acute cellularrejection, but not with acute cellular rejection ≥ 2R or antibody-mediated rejection. In patientsdiagnosed with both Quilty lesions and acute cellular rejection, the time-to-onset of Quilty lesionsfrom transplantation was longer than that of acute cellular rejections. We found a significant associationbetween Quilty lesions and cardiac allograft vasculopathy. No significant relationship wasfound between Quilty lesions and the patients' survival.

CONCLUSIONS

Quilty lesion may be an indicator of previous acute cellular rejection rather than a predictor for future acute cellular rejection.

Myocardial perfusion reserve and global longitudinal strain as potential markers of coronary allograft vasculopathy in late-stage orthotopic heart transplantation

Coronary allograft vasculopathy (CAV) is a major cause of mortality in late-stage orthotopic heart transplantation (OHT) patients. Recent evidence has shown that myocardial perfusion reserve (MPR) derived from vasodilator cardiovascular magnetic resonance imaging (vCMR) and global longitudinal strain (GLS) from transthoracic echocardiography (TTE) are useful to detect CAV. However, previous studies have not comprehensively addressed whether these parameters are confounded by allograft rejection, myocardial scar/fibrosis, or allograft dysfunction. Our aim was to determine whether changes in late post-OHT MPR and GLS are due to CAV or other confounding factors. Twenty OHT patients (time from transplant to vCMR was 8.1 ± 4.1 years) and 30 controls (10 healthy volunteers and 20 with prior myocardial infarction to provide perspective with regards to the severity of any abnormalities seen in post-OHT patients) underwent vasodilator vCMR from which MPR index (MPRi), left ventricular ejection fraction (LVEF), and burden of late gadolinium enhancement (LGE) were quantified. TTE was used to measure GLS. The presence of CAV was determined from invasive coronary angiograms using thrombolysis in myocardial infarction (TIMI) frame counts and grading severity per guidelines. Previous endomyocardial biopsies were reviewed to assess association with episodes of rejection. We examined the correlations between MPRi and GLS with markers of CAV, allograft function, scar/fibrosis, and rejection. MPRi was abnormal in post-OHT patients compared to both healthy volunteers and MI controls. While there was no relationship between MPRi or GLS and LVEF, episodes of rejection, or LGE burden, both MPRi and GLS were associated with TIMI frame counts and presence and severity of CAV. Additionally, MPRi correlated with GLS (R = 0.68, P = 0.0002). In conclusion, MPRi and GLS are abnormal in late-stage OHT and associated with CAV, but not related to allograft rejection, myocardial scar/fibrosis, or allograft dysfunction. Non-invasive monitoring of MPRi and GLS may be a useful strategy to detect CAV.

Lymphoid Neogenesis and Tertiary Lymphoid Organs in Transplanted Organs

The progressive organization of immune effectors into functional ectopic lymphoid structures, named tertiary lymphoid organs (TLO), has been observed in many conditions in which target antigens fail to be eliminated by the immune system. Not surprisingly, TLO have been recurrently identified in chronically rejected allografts. Although significant progress has been made over the last decades in understanding the molecular mechanisms involved in TLO development (a process named lymphoid neogenesis), the role of intragraft TLO (if any) in chronic rejection remains elusive. The prevailing dogma is that TLO contribute to graft rejection by generating and propagating local humoral and cellular alloimmune responses. However, TLO have been recently observed in long-term accepting allografts, suggesting that they might also be able to regulate alloimmune responses. In this review, we discuss our current understanding of how TLO are induced and propose a unified model in which TLO can play deleterious or regulatory roles and therefore actively modulate the kinetics of chronic rejection.

The molecular phenotype of heart transplant biopsies: relationship to histopathological and clinical variables

Histopathology of endomyocardial biopsies (EMB) is the standard rejection surveillance for heart transplants. However, ISHLT consensus criteria for interpreting biopsies are arbitrarily defined. Gene expression offers an independent re-evaluation of existing diagnostic systems. We performed histologic and microarray analysis on 105 EMB from 45 heart allograft recipients. Histologic lesions, diagnosis and transcripts were compared to one another, time posttransplantation, indication for biopsy and left ventricular ejection fraction (LVEF). Histologic lesions presented in two groups: myocyte-interstitial and microcirculation lesions. Expression of transcript sets reflecting T cell and macrophage infiltration, and γ-interferon effects correlated strongly with each other and with transcripts indicating tissue/myocardium injury. This molecular phenotype correlated with Quilty (p < 0.005), microcirculation lesions (p < 0.05) and decreased LVEF (p < 0.007), but not with the histologic diagnosis of rejection. In multivariate analysis, LVEF was associated (p < 0.03) with γ-interferon inducible transcripts, time posttransplantation, ischemic injury and clinically indicated biopsies, but not the diagnosis of rejection. The results indicate that (a) the current ISHLT system for diagnosing rejection does not reflect the molecular phenotype in EMB and lacks clinical relevance; (b) the interpretation of Quilty lesions has to be revisited; (c) the assessment of molecules in heart biopsy can guide improvements of current diagnostics.

B cells and plasma cells in coronaries of chronically rejected cardiac transplants

BACKGROUND.: Previously, we reported that transcripts of immunoglobulins were increased in coronary arteries dissected from cardiac transplants with arteriopathy, but the prevelance and patterns of B cell and plasma cell infiltration in cardiac allografts has not been documented. METHODS.: In this study, we documented the frequency and distribution of B cells and plasma cells in 16 cardiac transplants with advanced chronic rejection that were explanted during a second transplant procedure. Coronary arteries with pathologically confirmed allograft vasculopathy and controls with native atherosclerosis were immunohistologically stained for markers of T cells, B cells, plasma cells, IgG subclasses, C4d, CD21, and CXCL13. RESULTS.: We found that B cells and plasma cells were prevalent in most of the samples analyzed (14 of 16) and were distributed in three patterns: adventitial nodules, diffuse adventitial infiltrates, and neointimal infiltrates. These cells were found most frequently in nodules, some of which had distinct compartmentalization and granular C4d deposits on follicular dendritic cells (FDCs) that typify tertiary lymphoid nodules. FDCs also stained for CD21 and CXCL13. Diffuse infiltrates of B cells and plasma cells were found in fibrotic areas of the neointima and adventitia. Only a minority of control coronaries with atherosclerosis contained B cells. CONCLUSIONS.: B cells and plasma cell infiltrates are consistent findings in and around coronary arteries with allograft vasculopathy and are significantly more frequent than in coronaries with native atherosclerosis. The presence of C4d on FDCs in tertiary lymphoid nodules suggests active antigen presentation.