Monitoring of Epstein-Barr viral load in pediatric heart and lung transplant recipients by real-time polymerase chain reaction

Screening and Management of PTLD

Posttransplant lymphoproliferative disorder (PTLD) represents a heterogeneous group of lymphoproliferative diseases occurring in the setting of immunosuppression following hematopoietic stem cells transplant and solid organ transplantation. Despite its overall low incidence, PTLD is a serious complication following transplantation, with a mortality rate as high as 50% in transplant recipients. Therefore, it is important to establish for each transplant recipient a personalized risk evaluation for the development of PTLD based on the determination of Epstein-Barr virus serostatus and viral load following the initiation of immunosuppression. Due to the dynamic progression of PTLD, reflected in the diverse pathological features, different therapeutic approaches have been used to treat this disorder. Moreover, new therapeutic strategies based on the administration of virus-specific cytotoxic T cells have been developed. In this review, we summarize the available data on screening and treatment to suggest a strategy to identify transplant recipients at a higher risk for PTLD development and to review the current therapeutic options for PTLD.

Pediatric lung transplantation as standard of care

For infants, children, and adolescents with progressive advanced lung disease, lung transplantation represents the ultimate therapy option. Fortunately, outcomes after pediatric lung transplantation have improved in recent years now producing good long-term outcomes, no less than comparable to adult lung transplantation. The field of pediatric lung transplantation has rapidly advanced; thus, this review aims to update on important issues such as transplant referral and assessment, and extra-corporal life support as "bridge to transplantation". In view of the ongoing lack of donor organs limiting the success of pediatric lung transplantation, donor acceptability criteria and surgical options of lung allograft size reduction are discussed. Post-transplant, immunosuppression is vital for prevention of allograft rejection; however, evidence-based data on immunosuppression are scarce. Drug-related side effects are frequent, close therapeutic drug monitoring is highly advised with an individually tailored patient approach. Chronic lung allograft dysfunction (CLAD) remains the Achilles' heel of pediatric lung transplant limiting its long-term success. Unfortunately, therapy options for CLAD are still restricted. The last option for progressive CLAD would be consideration for lung re-transplant; however, numbers of pediatric patients undergoing lung re-transplantation are very small and its success depends highly on the optimal selection of the most suitable candidate.

Can immune biomarkers predict infections in solid organ transplant recipients? A review of current evidence

Despite improvements in graft survival, solid organ transplantation is still associated with considerable infection induced morbidity and mortality. If we were able to show that serious infection risk was associated with excessive suppression of immune capacity, we would be justified in "personalizing" the extent of immunosuppression by carefully monitored reduction to see if we can improve immune compromize without increasing the risk of rejection. Reliable biomarkers are needed to identify this patients at an increased risk of infection. This review focuses on the currently available evidence in solid organ transplant recipients for immune non-pathogen specific biomarkers to predict severe infections with the susceptibility to particular pathogens according to the component of the immune system that is suppressed. This review is categorized into immune biomarkers representative of the humoral, cellular, phagocytic, natural killer cell and complement system. Biomarkers humoral and cellular systems of the that have demonstrated an association with infections include immunoglobulins, lymphocyte number, lymphocyte subsets, intracellular concentrations of adenosine triphosphate in stimulated CD4⁺ cells and soluble CD30. Biomarkers of the innate immune system that have demonstrated an association with infections include natural killer cell numbers, complement and mannose binding lectin. Emerging evidence shows that quantification of viral nucleic acid (such as Epstein Barr Virus) can act as a biomarker to predict all-cause infections. Studies that show the most promise are those in which several immune biomarkers are assessed in combination. Ongoing research is required to validate non-pathogen specific immune biomarkers in multi-centre studies using standardized study designs.

Risk factors and long-term outcomes of pediatric liver transplant recipients with chronic high Epstein-Barr virus loads

BACKGROUND

Serial monitoring of Epstein-Barr virus (EBV) reveals that certain pediatric liver transplant (LT) recipients exhibit high EBV loads for long periods. We investigated the incidence and risk factors of chronic high EBV (CHEBV) loads (continuous EBV DNA >10 000 IU/mL of whole blood for ≥6 months) and long-term outcomes.

METHODS

This single center, retrospective observational study investigated pediatric LT recipients who survived ≥6 months. We quantitated EBV DNA weekly during hospitalization and subsequently every 4 or 6 weeks at the outpatient clinic. Tacrolimus was maintained at a low trough level (<3 ng/mL, EBV DNA load >5000 IU/mL).

RESULTS

Thirty-one of 77 LT recipients developed CHEBV. Univariate analysis revealed that age <2 years and body weight <10 kg upon LT, operation time <700 minutes, warm ischemia time (WIT) >35 minutes, graft-to-recipient weight ratio (GRWR) >2.7%, and preoperative EBV seronegativity were significantly associated with the development of CHEBV loads. Multivariate analysis identified significant associations of CHEBV with WIT >35 minutes, GRWR >2.7%, and preoperative seronegative. None of the recipients developed post-transplantation lymphoproliferative disorder. Survival rates of patients with and without CHEBV loads were not significantly different.

CONCLUSIONS

A significant number of pediatric LT recipients developed CHEBV loads. Long WIT, high GRWR, and preoperative EBV seronegativity were significantly associated with the development of CHEBV loads. Although the long-term outcomes of patients with or without CHEBV loads were not significantly different, further studies of more subjects are warranted.

Post-transplant lymphoproliferative disease is associated with early sternotomy and left ventricular hypoplasia during infancy: a population-based retrospective review

BACKGROUND

Heart transplantation has been an option for children in Sweden since 1989. As our unit faced an increased rate of post-transplant lymphoproliferative disorder, the objective of the study was to identify possible risk factors.

METHODS

This is a retrospective study of all children aged 0-18 years who underwent heart transplantation in Gothenburg from 1989 to 2014.

RESULTS

A total of 71 children underwent heart transplantation. The overall incidence of post-transplant lymphoproliferative disorder was 14% (10/71); however, 17% (6/36) of those undergoing transplantation after 2007 developed lymphoma, compared with only 10% (4/35) of transplantation cases before 2007 (p=0.85). The mean age at transplantation was 9 years (0-17). The mean post-transplant follow-up time was 5.5 years (0.5-21.9) in the group that developed post-transplant lymphoproliferative disorder, compared with 10.2 years (0.02-25.2) in those who did not. In our study group, risk factors for post-transplant lymphoproliferative disorder were surgically palliated CHD (p=0.0005), sternotomy during infancy (p⩽0.0001), hypoplastic left ventricle (p=0.0001), number of surgical events (p=0.0022), mismatch concerning Epstein-Barr virus infection - that is, a positive donor-negative recipient (p⩽0.0001) - and immunosuppressive treatment with tacrolimus compared with ciclosporine (p=0.028). Discussion This study has three major findings. First, post-transplant lymphoproliferative disorder only developed in subjects born with CHD. Second, the vast majority (9/10) of the subjects developing the disorder had undergone sternotomy as infants. Third, the number of surgical events correlated with a higher risk for developing post-transplant lymphoproliferative disorder.

Persistent Epstein-Barr viral load in Epstein-Barr viral naïve pediatric heart transplant recipients: Risk of late-onset post-transplant lymphoproliferative disease

AIM

To examine the risk of late-onset post-transplant lymphoproliferative disorder (PTLD) in the presence of persisting high Epstein-Barr virus (EBV) in EBV naïve pediatric heart transplant (HT) recipients.

METHODS

A retrospective review of the medical records of the 145 pediatric HT recipients who had serial EBV viral load monitoring at our center was performed. We defined EBV naive patients whose EBV serology either IgM or IgG in the blood were negative at the time of HT and excluded passive transmission from mother to child in subjects less than 6 mo of age.

RESULTS

PTLD was diagnosed in 8 out of 145 patients (5.5%); 6/91 (6.5%) in those who were EBV seropositive and 2/54 (3.7%) in the EBV naïve group at the time of HT (P = 0.71). We found 32/145 (22%) patients with persistently high EBV load during continuing follow-up; 20/91 (22%) in EBV seropositive group vs 12/54 (22%) in EBV naïve group (P = 0.97). There was no significant association between pre-HT serostatus and EBV load after transplant (P > 0.05). In the EBV seropositive group, PTLD was diagnosed in 15% (3/20) of patients with high EBV vs 4.2% (3/71) of patients with low or undetectable EBV load (P = 0.14) whereas in EBV naïve patients 8.3% (1/12) of those with high EBV load and 2.3% (1/42) with low or undetectable EBV load (P = 0.41). There was a highly significant association between occurrence of PTLD in those with high EBV load and duration of follow up (4.3 ± 3.9 years) after HT by Cochran-Armitage test for the entire cohort (P = 0.005). At least one episode of acute rejection occurred in 72% (23/32) of patients with high EBV vs 36% (41/113) patients with low or undetectable EBV after HT (P < 0.05).

CONCLUSION

There is an association between persistently high EBV load during post-HT follow up and the occurrence of late-onset PTLD in pediatric HT recipients irrespective of serostatus at the time of transplant. The occurrence of allograft rejection increased in patients with high EBV load presumably due to reduction in immunosuppression.

[Post-transplantation lymphoproliferative disorder in childhood]

INTRODUCTION

Among possible complications of transplantation the post-transplant lymphoproliferative disease due to immunosuppressive therapy is of paramount importance. In most cases the direct modulating effect of Epstein-Barr virus on immune cells can be documented.

AIM

The aim of the authors was to evaluate the incidence os post-transplant lymphoproliferative diseases in pediatric transplant patients in Hungary.

METHOD

The study group included kidney, liver and lung transplant children followed up at the 1st Department of Pediatrics, Semmelweis University, Budapest and stem cell transplant children at Szent László Hospital, Budapest. Data were collected from 78 kidney, 109 liver and 17 lung transplant children as well as from 243 children who underwent allogenic stem cell transplantation.

RESULTS

Between 1998 and 2012, 13 children developed post-transplant lymphoproliferative disorder (8 solid organ transplanted and 5 stem cell transplanted children). The diagnosis was based on histological findings in all cases. Mortality was 3 out of the 8 solid organ transplant children and 4 out of the 5 stem cell transplant children. The highest incidence was observed among lung transplant children (17.6%).

CONCLUSIONS

These data indicate that post-transplant lymphoproliferative disease is a rare but devastating complication of transplantation in children. The most important therapeutic approaches are reduction of immunosuppressive therapy, chemotherapy and rituximab. Early diagnosis may improve clinical outcome and, therefore, routine polymerase chain reaction screening for Epstein-Barr virus of high risk patients is recommended.

Posttransplant Lymphoproliferative Disorder after Cardiac Transplantation in Children: Life Threatening Complications Associated with Chemotherapy Combined with Rituximab

Despite the excellent long-term survival currently achieved in pediatric heart transplant recipients, posttransplant lymphoproliferative disorders (PTLDs) are one of the most important causes of morbidity and mortality after heart transplantation (HTx), especially in children. Timely and accurate diagnosis based on histological examination of biopsy tissue is essential for early intervention for PTLD. Chemotherapy is indicated for patients with poor response to reduction of immunosuppressive medication and for highly aggressive monomorphic PTLD. The use of rituximab in combination with chemotherapy is effective to suppress B cell type PTLD (B-PTLD). However, PTLD relapses frequently and the outcome is still poor. Although everolimus (EVL) has been reported to inhibit growth of human Epstein-Barr-virus- (EBV-) transformed B lymphocytes in vitro and in vivo, EVL has several side effects, such as delayed wound healing and an increase in bacterial infection. During combined treatment of chemotherapy and rituximab, B-PTLDs are sometimes associated with life-threatening complications, such as intestinal perforation and cardiogenic shock due to cytokine release syndrome. In HTx children especially treated with EVL, stoma should be made to avoid reoperation or sepsis in case of intestinal perforation. In cases with cardiac graft dysfunction possibly due to cytokine release syndrome by chemotherapy with rituximab for PTLD, plasma exchange is effective to restore cardiac function and to rescue the patients.

A 16-year multi-institutional study of the role of age and EBV status on PTLD incidence among pediatric heart transplant recipients

The objective was to determine the incidence and hazard for posttransplant lymphoproliferative disease (PTLD) in a study of 3170 pediatric primary heart transplants between 1993 and 2009 at 35 institutions in the Pediatric Heart Transplant Study. 147 of 151 reported malignancy events were classified as PTLD. Overall freedom from PTLD was 98.5% at 1 year, 94% at 5 years and 90% at 10 years. Freedom from PTLD was lowest in children (ages 1 to < 10 years) versus infants (<1 year) and adolescents (10 to < 18 years) with children at highest risk for PTLD with a relative risk of 2.4 compared to infants and 1.7 compared to adolescents. Positive donor EBV status was a strong risk factor for PTLD in the seronegative recipient, but risk magnitude was dependent on recipient age at the time of transplantation. Nearly 25% of EBV seronegative recipients of EBV+ donors at ages 4-7 at transplantation developed some form of PTLD. The overall risk for PTLD declined in the most recent transplant era (2001-2009, p = 0.003). These findings indicate that EBV status and the age of the recipient at the time of transplantation are important variables in the development of PTLD in the pediatric heart transplant recipient.

Viremia after lung transplant: a cohort study on risk factors and symptoms associated with detection of Epstein-Barr virus

Background-The frequency and impact of detection of Epstein-Barr virus in the blood of lung and heart-lung transplant recipients in the postoperative period is poorly characterized.Objective-To investigate the frequency of virus detection, associated clinical symptoms and risk factors, and influence of virus detection on outcome.Methods-A cohort of 98 lung transplant recipients were monitored for Epstein-Barr virus in blood before transplant and during their posttransplant hospital stay (median 4 weeks, range 1-21 weeks). Patients were followed up for retransplant or death for a median of 17 months.Results-Epstein-Barr virus DNA was detected in 15 recipients (18.1%) before and in 39 recipients (41.5%) after transplant. Median viral load after transplant was 2300 copies per milliliter of blood (range, 900-45 000 copies/mL). Detection of Epstein-Barr virus DNA before transplant and mechanical ventilation before transplant were associated with detection of Epstein-Barr virus DNA after transplant. Shortness of breath, fatigue, and hoarseness were associated with detection of viral DNA after transplant. The incidence of retransplant or death was not increased in recipients who had viral DNA detected in their blood.Conclusions-Epstein-Barr virus DNA in the blood before transplant and mechanical ventilation before transplant were associated with detection of viral DNA after transplant. Detection of viral DNA after transplant was frequent and clinically relevant.

Post-transplant lymphoproliferative disorders and Epstein-Barr virus DNAemia in a cohort of lung transplant recipients

BACKGROUND

Post-transplant lymphoproliferative disorders (PTLD) are serious complications in lung transplant recipients. No consensus on EBV DNAemia levels predictive of PTLD has been reached. In addition, in many instances EBV DNAemia is determined in patients with suggestive symptoms only.

METHODS

The characteristics of five patients with PTLD as well as the prevalence of EBV DNAmia in a cohort of 137 consecutive patients receiving lung transplantation are described.

RESULTS

Twenty-six out of 137 patients (18.9%) were excluded from the analysis because lost at follow-up or dead from PTLD-independent reasons within three months of transplantation. EBV DNA in peripheral blood mononuclear cells (PBMC) was determined in 83/111 patients (74.8%) because of potential PTLD-related symptoms, while 28 patients (25.2%) showed no symptoms and were not examined. EBV DNAemia was positive in 53/83 patients (63.8%), and negative in 30/83 patients (36.2%). PTLD was diagnosed in five (4.5%) patients at a median time of 270 (range 120-870) days following transplantation. All five PTLD (three large B-cell lymphomas, one Hodgkin lymphoma and one possible pre-neoplastic lesion) were potentially associated with EBV infection. However, only 3/5 patients with PTLD had detectable EBV DNAemia: < 1,000 copies EBV DNA/1 × 10⁵ PBMC in one patient and > 1,000 copies EBV DNA/1 × 10⁵ PBMC in two patients.

CONCLUSION

A systematic multidisciplinary (clinical, radiologic, virologic and histologic) approach is mandatory for the diagnosis and management of PTLD in lung transplant recipients, while monitoring of symptomatic patients only may provide an incomplete or late picture of the clinical problem. In addition, staining for EBV antigens and quantification of EBV DNA in biopsy specimens should always be performed to understand the role of EBV infection in the pathogenesis of PTLD.

Malignancies following lung transplantation

Malignancy is an important complication of thoracic organ transplantation and is associated with significant morbidity and mortality. Lung transplant recipients are at greater risk for cancer than immunocompetent persons, with cancer-specific incidence rates up to 60-fold higher than the general population. The increased risk for cancer is attributed to neoplastic properties of immunosuppressive medications, oncogenic viruses, and cancer-specific risk factors. This article addresses the epidemiology, presentation, and treatment of the most common malignancies after lung transplantation, including skin cancer, posttransplant lymphoproliferative disorder, and bronchogenic carcinoma.

Posttransplant lymphoproliferative diseases

The risk of developing cancer after solid organ transplantation (SOT) is about 5- to 10-fold greater than that of the general population. The cumulative risk of cancer rises to more than 50% at 20 years after transplant and increases with age, and so children receiving transplants are at high risk of developing a malignancy. Posttransplant lymphoproliferative disease (PTLD) is the most common cancer observed in children following SOT, accounting for half of all such malignancies. PTLD is a heterogeneous group of disorders with a wide spectrum of pathologic and clinical manifestations and is a major contributor to long-term morbidity and mortality in this population. Among children, most cases are associated with Epstein-Barr virus infection. This article reviews the pathology, immunobiology, epidemiology, and clinical aspects of PTLD, underscoring the need for ongoing systematic study of complex biologic and therapeutic questions.

Changing trends in infectious disease in heart transplantation

BACKGROUND

During the past 25 years, advances in immunosuppression and the use of selective anti-microbial prophylaxis have progressively reduced the risk of infection after heart transplantation. This study presents a historical perspective of the changing trends of infectious disease after heart transplantation.

METHODS

Infectious complications in 4 representative eras of immunosuppression and anti-microbial prophylaxis were analyzed: (1) 38 in the pre-cyclosporine era (1978-1980), (2) 72 in the early cyclosporine era (1982-1984), where maintenance immunosuppression included high-dose cyclosporine and corticosteroid therapy; (3) 395 in the cyclosporine era (1988-1997), where maintenance immunosuppression included cyclosporine, azathioprine, and lower corticosteroid doses; and (4) 167 in the more recent era (2002-2005), where maintenance immunosuppression included cyclosporine and mycophenolate mofetil.

RESULTS

The overall incidence of infections decreased in the 4 cohorts from 3.35 episodes/patient to 2.03, 1.35, and 0.60 in the more recent cohorts (p < 0.001). Gram-positive bacteria are emerging as the predominant cause of bacterial infections (28.6%, 31.4%, 51.0%, 67.6%, p = 0.001). Cytomegalovirus infections have significantly decreased in incidence and occur later after transplantation (88 +/- 77 days, pre-cyclosporine era; 304 +/- 238 days, recent cohort; p < 0.001). Fungal infections also decreased, from an incidence of 0.29/patient in the pre-cyclosporine era to 0.08 in the most recent era. A major decrease in Pneumocystis jiroveci and Nocardia infections has also occurred.

CONCLUSIONS

The overall incidence and mortality associated with infections continues to decrease in heart transplantation and coincides with advances in immunosuppression, the use of selective anti-microbial prophylaxis, and more effective treatment regimens.

Tumour necrosis factor gene polymorphism: a predictive factor for the development of post-transplant lymphoproliferative disease

Background:

Epstein–Barr virus-positive post-transplant lymphoproliferative disease (PTLD) is a potentially lethal complication of iatrogenic immunosupression after transplantation. Predicting the development of PTLD allowing early and effective intervention is therefore of importance. Polymorphisms within cytokine genes are implicated in susceptibility to, and progression of, disease however the published data are often conflicting. We undertook investigation of polymorphic alleles within cytokine genes in PTLD and non-PTLD transplant cohorts to determine risk factors for disease.

Methods:

SSP-PCR was used to analyse single nucleotide polymorphism within tumour necrosis factor (TNF)-α, interleukin- 1, -6, -10 and lymphotoxin-α genes. The TNF-α levels were measured by standard enzyme-linked immuno-absorbant assay.

Results:

We show an association between variant alleles within the TNF-α promoter (−1031C (P=0.005)); −863A (P=0.0001) and TNF receptor I promoter regions (−201T (P=0.02)); −1135C (P=0.03) with the development of PTLD. We also show an association with TNF-α promoter haplotypes with haplotype-3 significantly increased (P=0.0001) and haplotype-1 decreased (P=0.02) in PTLD patients compared to transplant controls. Furthermore, we show a significant increase (P=0.02) in the level of TNF-α in PTLD patient plasma (range 0–97.97 pg ml⁻¹) compared to transplant controls (0–8.147 pg ml⁻¹), with the highest levels found in individuals carrying the variant alleles.

Conclusion:

We suggest that genetic variation within TNF-α loci and the level of plasma cytokine could be used as a predictive risk factor for the development of PTLD.

Post-transplant lymphoproliferative disease in pediatric lung transplant recipients: recent advances in monitoring

To investigate the clinical validity of newer diagnostic tests such as monitoring of EBVqPCR and lymphocyte function assay ImmuKnow in helping to diagnose PTLD in pediatric lung transplant recipients. Single-center, retrospective case-control study. CsA trough levels, EBVqPCR and ImmuKnow (Cyclex Inc., Columbia, MD, USA) levels were measured serially as part of routine care. Re-transplant patients and patients who did not reach 12 months post-transplant at the time of analysis were excluded. Twenty-seven patients met the inclusion criteria. The study group consisted of seven patients who developed PTLD, five of which were EBV- recipients who received EBV+ lungs. The rest of the eligible patients served as controls. Median time to develop PTLD was 273 days (range: 166-343). One, two, three, six, and nine months after transplant, mean (+/-s.d.) CsA trough whole blood levels (ng/mL) were not different between the two groups: 378 +/- 38, 390 +/- 52, 402 +/- 89, 359 +/- 42, and 342 +/- 115, vs. 416 +/- 105, 347 +/- 64, 337 +/- 78, 333 +/- 86, and 281 +/- 54 [PTLD vs. no-PTLD, respectively (p > 0.05 for all time points)]. Mean (+/-s.d.) EBVqPCR levels (copies/mL) measured at three, six, and nine months post-transplant were significantly elevated in PTLD group compared to no-PTLD group: 84 +/- 99, 3384 +/- 7428 and 839 +/- 1444 vs. 9 +/- 26, 8 +/- 36 and 32 +/- 136, respectively (p < 0.05 for all time points). Mean (+/-s.d.) ImmuKnow levels (ATP ng/mL) at three, six, and nine months post-transplant were significantly lower in the PTLD group when compared with no-PTLD group: 144 +/- 67, 137 +/- 110, and 120 +/- 153 vs. 290 +/- 161, 300 +/- 162, and 293 +/- 190, respectively (p < 0.05 for all time points). Close monitoring of EBV viral load by qPCR and the degree of immunosuppression via ImmuKnow may guide physicians to reach the diagnosis of PTLD early.

Interstitial inflammatory lesions of the pulmonary allograft: a retrospective analysis of 2697 transbronchial biopsies

BACKGROUND

Parenchymal and bronchial inflammatory and fibrotic lesions other than acute cellular rejection (ACR) and lymphocytic bronchiolitis are prevalent; however, the context in which they appear is unknown, and often no specific treatment is instigated.

OBJECTIVES

To describe the prevalence, incidence and possible associations between commonly identified inflammatory and fibrotic lesions in the pulmonary allograft.

METHODS

Retrospective chart review of all transbronchial biopsies performed within the first 2 years of 299 lung-transplanted patients in the period 1996 to 2006.

RESULTS

A total of 2697 biopsies were evaluated corresponding to a mean of 6+/-2 (median 8) completed schedules per patient. Diffuse alveolar damage (DAD) was the second most common histological finding within the first 2 weeks after transplantation. The peak prevalence of bronchiolitis obliterans organizing pneumonia (BOOP) and interstitial pneumonitis occurred at 4 to 6 weeks, and 6 to 12 weeks, respectively. There was a steady increase in the cumulative proportion of patients with fibrosis and bronchiolitis obliterans, at each successive scheduled surveillance time point beyond 3 months posttransplantation. The strongest histological correlations were between ACR and lymphocytic bronchiolitis (OR 5.1, P<0.0001) or interstitial fibrosis (OR 3.2, P<0.0001). Patients with interstitial pneumonitis and pulmonary hemosiderosis were also more likely to demonstrate the finding of interstitial fibrosis (OR 3.0 and 3.7, P<0.0001, respectively). Acute cellular rejection was not associated with DAD, and patients with lymphocytic bronchiolitis were not more likely to demonstrate features of organizing pneumonia (DAD or BOOP).

CONCLUSIONS

Histologic findings of ACR, lymphocytic bronchiolitis, BOOP, and interstitial pneumonitis were directly associated with the development of interstitial fibrosis and bronchiolitis obliterans.

Epstein-Barr virus load in whole blood is associated with immunosuppression, but not with post-transplant lymphoproliferative disease in stable adult heart transplant patients

Development of Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disease (PTLD) is a serious complication following heart transplantation (HTX). This study investigates EBV DNA load in adult heart transplant recipients, its association with immunosuppression, and its potential as a marker for development of PTLD. EBV DNA load was measured prospectively by quantitative real-time polymerase chain reaction (PCR) in 172 stable HTX patients. Sixty-seven patients (39.0% of total) had a positive EBV PCR at initial examination [median 4.9 (range 1.1-16.9) years post-HTX]. In follow-up testing of 67 positive patients 6 months later, 36 patients continued to have a positive EBV PCR. Overall incidence of EBV DNA was significantly associated with calcineurin inihibitors, azathioprine medication, and with the absence of mycophenolate mofetil (MMF) treatment. In patients with positive EBV DNA levels at initial examination and negative levels at retesting, cyclosporine A levels were found to be significantly higher at initial examination (148.4 +/- 70.2 vs. 119.6 +/- 53.5 ng/ml, P < 0.05). Three patients (1.7%, 3/172) were diagnosed with PTLD during the course of the study (mean follow up 4.0 years). EBV DNA viral load determination does not appear to be useful for risk prediction or early diagnosis of PTLD in adults after HTX, but an association of EBV DNA load with qualitative and quantitative immunosuppression is demonstrated.

Pediatric lung transplantation: perspectives for the pathologist

Lung transplantation offers life-saving and life-extending treatment for children and adolescents with congenital and acquired forms of pulmonary and pulmonary vascular disease, for whom medical therapy is ineffective or insufficient for sustained response. This review summarizes the pathology related to lung transplantation for the practicing pediatric pathologist and also highlights aspects of lung transplantation unique to the pediatric population. Clinical issues related to availability of organs, candidate eligibility, surgical technique, and postoperative monitoring are discussed. Pathologic evaluation of routine surveillance transbronchial biopsies requires attention to acute cellular rejection, opportunistic infection, and other forms of acute and resolving lung injury. These findings are correlated in some cases with endobronchial biopsies and bronchoalveolar lavage as adjunctive tools in surveillance. Open or thoracoscopic biopsies also have diagnostic utility in cases with acute or chronic graft deterioration of uncertain etiology. Future challenges in pediatric lung transplantation are similar to those in the adult population, with continued efforts focused on prolonging graft survival, prevention of bronchiolitis obliterans syndrome due to chronic cellular rejection, and evaluation of humoral rejection.

Relationship of immunosuppression to Epstein-Barr viral load and lymphoproliferative disease in pediatric heart transplant patients

BACKGROUND

Post-transplant lymphoproliferative disease (PTLD) is a severe complication in transplant recipients. Detection of increased Epstein-Barr viral (EBV) load in the peripheral blood acts as a surrogate marker for increased risk of PTLD development. We prospectively monitored EBV load, immunosuppression and PTLD in pediatric heart transplant (HTx) patients to determine risk factors for an increased EBV load and risk of PTLD.

METHODS

Forty-one pediatric heart transplant recipients were included and underwent prospective monitoring of their immunosuppression and ethylene-diamine tetraacetic acid (EDTA) blood sampling for EBV load (copies/microg DNA) measurement using quantitative real-time polymerase chain reaction (PCR; TaqMan) during January 2001 to December 2006.

RESULTS

EBV load was measurable in 70% and was significantly increased (>2,000 copies/microg DNA) in 35% of the patients, with a median EBV load of 5,100 (range 0 to 50,665 copies/microg DNA). Increased EBV load was detected in patients receiving CsA-azathioprine or more than two doses of anti-thymocyte globulin (ATG) and in those <10 years of age, without any significant differences in CsA blood levels. Lowest or negative EBV load was measured in patients receiving CsA-mycophenolate mofetil (MMF) or CsA only. CsA blood levels were not predictable for increased EBV load or PTLD. Six patients developed a EBV-associated B-cell lymphoma (PTLD), among whom 4 (67%) were receiving CsA-azathioprine.

CONCLUSIONS

Frequent EBV load monitoring identifies patients at high risk for PTLD development. Azathioprine and ATG are major risk factors for increased EBV load and PTLD and patients may benefit from a change of immunosuppression in addition to pre-emptive anti-viral or anti-tumor strategies.

Epstein–Barr Virus–associated Multifocal Leiomyosarcomas Arising in a Cardiac Transplant Recipient: Autopsy Case Report and Review of the Literature

Epstein-Barr virus (EBV) associated smooth muscle tumors (SMTs) have been described in patients with acquired immune deficiency syndrome (AIDS) and, more recently, in association with immunosuppression after solid-organ transplantation. We present the autopsy findings of multiple leiomyosarcomas (LMSs) in a 24-year old man who died 18 months after undergoing orthotopic cardiac transplantation for idiopathic cardiomyopathy. The recognition of EBV-driven LMS developing in cardiac transplant recipients in multiple unusual sites is crucial for the management of these patients and should include complete surgical removal anti-viral therapy and modulation of immunosuppression.

Posttransplant monitoring of pediatric lung transplant recipients

PURPOSE OF REVIEW

This article reviews current trends in pediatric lung posttransplant management, reveals pitfalls that exist, and introduces additional parameters that may have an impact on long-term survival.

RECENT FINDINGS

A number of parameters are monitored after transplantation to prevent or identify early complications related to lung transplantation in hope of reducing morbidity and mortality. These include routine laboratory studies, imaging, and monitoring of drug levels and lung function. Drug monitoring allows individualization of a patient's immunosuppressive therapy; however, drug levels alone may not reflect the patient's immune status. ImmuKnow is a general immune-monitoring assay that may help guide therapy. Two major complications are rejection and infection, and bronchoscopy is used to differentiate these two entities. Silent rejection may occur and increase the chance of developing bronchiolitis obliterans; therefore, many centers perform surveillance bronchoscopies. Recently, de-novo anti-histocompatibility locus antigen antibodies and gastroesophageal reflux have been associated with poor outcomes, and many centers are monitoring these entities as part of care following lung transplant.

SUMMARY

There has been little improvement in long-term outcomes of lung transplantation. Current monitoring methods are utilized to maintain or improve outcomes and recently additional monitoring parameters have been identified which hopefully will improve long-term outcomes.

Case-control study of risk factors for the development of post-transplant lymphoproliferative disease in a pediatric heart transplant cohort

PTLD is an important complication following heart transplantation. To better define the risk factors of PTLD in children, we performed a case-control study. All pediatric cardiac transplant recipients who developed their first episode of PTLD were matched by age (+/-1 yr) and time since transplant (+/-1 yr) with those who did not. PTLD occurred in nine of 95 cardiac transplant recipients (9%), 0.3-7.8 yr following cardiac transplantation (median = 2.5 yr). Patients were 0.1-16.4 yr (median = 3.7) at transplantation. Biopsies revealed polymorphic B cell hyperplasia (three), polymorphic B cell lymphoma (one), monomorphic diffuse large cell B cell lymphoma (three) and monomorphic Burkitt's-like lymphoma (two). Patients who developed PTLD were at no greater risk of death (p = 0.31). Recipient EBV seronegativity at time of transplant (p = 0.08), EBV seroconversion (p = 0.013) and recipient CMV seronegativity (p = 0.015) were associated with the development of PTLD by conditional logistic regression; sex, race, donor age, recipient diagnosis, donor CMV seropositivity, recipient treatment for CMV infection, EBV seropositivity at the time of PTLD diagnosis, and number of rejection episodes, treated rejection episodes, and lympholytics used were not. There was no significant association between PTLD and death in our recipients. EBV seroconversion and recipient CMV seronegativity were associated with the development of PTLD.

Post-transplant lymphoproliferative disorders

Post-transplant lymphoproliferative disorder is the most common malignancy, with the exception of skin cancer, after solid organ transplantation in adults. The incidence varies according to the transplanted organ and is often associated with Epstein-Barr virus. Prognosis is variable, due in part to the heterogeneity of the disease, which ranges from reactive plasmacytic hyperplasia to aggressive monoclonal disease.

Review of Epstein–Barr virus and post-transplant lymphoproliferative disorder post-solid organ transplantation (Review Article)

Post-transplant lymphoproliferative disorder (PTLD) following solid organ transplantation is an important form of post-transplant malignancy. PTLD is typically associated with Epstein-Barr virus (EBV) and occurs in the setting of profound immunosuppression resulting in a deficiency of EBV-specific cytotoxic T lymphocytes (CTL). Predisposing factors include EBV mismatch between donor and recipient, use of immunosuppression especially T-cell depletive therapies and genetic predisposition of recipients. The standard approach has been to reduce immunosuppression but is often insufficient to induce tumour regression. Further understanding of the immunobiology of PTLD has resulted in improved monitoring techniques (including EBV viral load determined by polymerase chain reaction) and newer treatment options. Recent work has highlighted a potential role for dendritic cells in both the pathogenesis and treatment of PTLD. Current treatment modalities include adoptive immunotherapy using ex vivo generated autologous EBV-specific CTL or allogeneic CTL, cytokine therapies, antiviral agents, and more recently, rituximab and dendritic-cell based therapies. This review focuses on the developments and progress in the pathogenesis, diagnosis and treatment of PTLD.