Post-transplant lymphoproliferative disease in children

Seropositivity for cytomegalovirus and PCR-EBV monitoring: Protective factors for posttransplant lymphoproliferative disorder in pediatric liver transplant

BACKGROUND

PTLD is a clinical condition with high mortality. Monitoring EBV replication can be a useful tool to avoid the development of PTLD.

MATERIALS AND METHODS

This was a retrospective analysis of 428 pediatric patients who underwent liver transplantation between 1989 and 2016. The patients were divided into 2 groups (transplanted before 2006, when PCR-EBV was not monitored, and after 2006, when PCR-EBV monitoring was started). Patients with continuous PCR measurements for EBV were evaluated for the impact of a reduction in immunosuppression or a change in immunosuppressants on the number of viral copies. A logistic regression model was applied to evaluate factors related to PTLD.

RESULTS

The prevalence of PTLD was 4.2%. After monitoring patients with PCR for EBV levels, a predominance of the most severe, monomorphic form of lymphoproliferative disorder was observed (p = .009). The PTLD mortality was 5%. There was a change in the PCR level after tacrolimus reduction (p = .002) and after tacrolimus exchange for mTOR (p = .008). The number of EBV copies was significantly higher (p = .029) in patients who developed PTLD. In the multiple regression model, seropositivity for CMV was an independent protective factor for lymphoproliferative disorder (OR=0.09; 95% CI 0.02-0.42), reducing the chance of having PTLD adjusted by serology for EBV by 91%.

CONCLUSIONS

Monitoring the EBV viral load by PCR seems to prevent the emergence of milder forms of lymphoproliferative disorder. Pretransplant seropositivity for CMV is a protective factor for PTLD.

Posttransplant Lymphoproliferative Disorder Presenting as Testicular Lymphoma in a Kidney Transplant Recipient: A Case Report and Review of the Literature

Posttransplant lymphoproliferative disorder (PTLD) is a malignancy caused by the immunosuppression that occurs after transplantation. It is primarily a nodal lesion but frequently it involves extranodal masses. Treatment is usually by reducing immunosuppressive therapy. Testicular lymphoma as PTLD is notably rare in documented literature and there is limited evidence of definitive treatment guidelines. This manuscript describes a patient who developed diffuse large B-cell lymphoma of his right testis one year following kidney transplantation. A diagnosis of PTLD was made and treatment with rituximab, locoregional radiotherapy, and intrathecal methotrexate in addition to the standard reduction of immunosuppression resulted in complete remission until now. We submit this case along with literature review of similar cases in the past and a review of specific peculiarities of our case with emphasis on our treatment plan to further the understanding of this diversiform disease.

Pharmacoepidemiology of tacrolimus in pediatric liver transplantation

AEs during immunosuppressive treatment with tacrolimus are very common. We retrospectively evaluated FK safety and efficacy in a large pediatric liver transplant cohort in Latin America. During 2-year follow-up, we analyzed data from patients who underwent liver transplantation over the period 2010-2012 and recorded FK exposure, AEs, and AR episodes. AEs were classified according causality and severity. Tacrolimus exposure before and during AE was compared using Wilcoxon matched-pairs test. Kaplan-Meier curves were used for survival analysis. In total, 46 patients (out of 72 patients) experienced 69 AEs, such as hypomagnesemia (49%), PTLD (6%), hypertension (6%), and/or nephrotoxicity (22%). 43% of AEs were classified as moderate or serious, and 89% were assigned as probable or definitive. Patients who had one or more AR episodes accounted for 65%. The 12-month acute rejection-free survival was 41% (95% CI, 30.1%-53.1%). A significant difference was observed in FK trough concentrations before and during hypomagnesemia and nephrotoxicity (P<.05). This study is the first report of FK safety in a large group of pediatric liver transplant patients in Latin America. Children experience AEs, even in protocols with low FK doses. Therapeutic monitoring is an important tool to manage immunosuppressive schemes containing tacrolimus in vulnerable populations.

Diagnostic Approach to Life-Threatening Pulmonary Infiltrates

Diagnosis of pulmonary disease is typically based upon consideration of presenting symptoms, physical examination, and pulmonary function testing in combination with classification of radiographic features, to guide diagnostic tests and initiate empiric treatment. When diagnostic efforts and/or empiric treatment fails, thoracic surgeons have traditionally been called upon to perform surgical biopsy of the lung to aid in the diagnosis of indeterminate, life-threatening pulmonary disease. Such biopsy has been requested specifically in the case of diffuse lung disease among patients receiving treatment for solid-organ or hematologic cancers, particularly when symptoms of respiratory failure progress and when noninvasive diagnostic tests and empiric treatments fail to halt progression. In such circumstances, radiologists, pulmonologists, and thoracic surgeons may be consulted and asked to provide tissue specimens that will allow rapid, accurate diagnosis leading to specific treatment. It is imperative that biopsy take place before respiratory failure supervenes [1], and that the specimens provided to clinical laboratories, pathologists, and microbiologists are comprehensive and properly preserved.

Severe post-transplant lymphoproliferative disorder after living donor liver transplantation

Post-transplant lymphoproliferative disorder (PTLD) is a well-known complication after transplantation. A living donor liver transplantation was performed on a 31-year-old man for fulminant hepatitis. He again developed liver dysfunction after 7 months. He was diagnosed as having acute cellular rejection and the steroid pulse therapy introduced resulted in little improvement. He gradually developed a high fever and right axillary lymphadenopathy appeared. Chest computed tomography (CT) was performed revealing small lung nodules and axillary lymphadenopathy. Because his serological status for Epstein-Barr virus was positive, PTLD was highly suspected and immunosuppression treatment was withdrawn with little improvement. One week later, he developed tachycardia. Chest CT was re-performed revealing an infiltration to the left cardiac chamber. For diagnosis, axillary lymph node biopsy was performed and during the procedure, he developed ventricular tachycardia (VT). Immunohistological staining revealed PTLD of T lymphocytes, and chemotherapy was introduced on the same day he developed VT. After two cycles of tetrahydropyranyl, adriamycin, cyclophosphamide, vincristine, prednisolone and etoposide treatment, he completely recovered. This is a first case report of severe PTLD with VT, and our case implies the feasibility of chemotherapy after the appearance of dissemination symptoms.

More benign lymphoproliferative disease after liver transplant in infants

CONTEXT-Despite the high frequency of liver transplants in infants, few data are available on the characteristics of posttransplant lymphoproliferative disorders in liver transplant patients (PTLD). OBJECTIVE-To analyze special features and behavior of PTLD arising after liver transplant in infants. METHODS-A comprehensive search of the literature was conducted for the available data on PTLD in infant liver transplant recipients through PubMed and Google scholar. An infant was defined as a liver recipient who was less than 2 years old at the time of transplant. Overall, 205 cases of PTLD were found in 24 reports, and the 100 infants with PTLD were compared with children and adults with PTLD. RESULTS-PTLD lesions in infants were more likely to be polymorphic whereas monomorphic lesions were more prevalent among older patients (P= .05). Remission rates, metastasis frequency, and organ involvement did not differ significantly between the groups. Survival analysis showed that the infants had a significantly better outcome than did older patients (P= .05). CONCLUSION-PTLD is more benign and may have a better outcome in infant liver transplant recipients than in older recipients. A prospective multicenter approach is needed for future research studies.

Clinicopathological characteristics of posttransplant lymphoproliferative disorders of T-cell origin: single-center series of nine cases and meta-analysis of 147 reported cases

T-cell or natural killer (NK)-cell posttransplant lymphoproliferative disorder (T-PTLD) is a rare but severe complication after transplant. Here we present the clinicopathological features of a single-center series of nine cases. Additionally, we summarize the clinicopathological findings of 147 cases of T/NK-cell PTLD reported in the literature in an attempt to define subtype-specific characteristics. T/NK-cell PTLD occurs in patients of all ages, usually extranodally, and most frequently after kidney transplant. Organ specific incidence, however, is highest following heart transplant. Approximately one-third of T-cell PTLDs are Epstein-Barr virus (EBV)-related, with peripheral T-cell lymphoma, not otherwise specified (PTCL, NOS) being the most prevalent EBV-associated T-cell PTLD. A male predominance is observed, which is most striking in the EBV(+) group, particularly in PTCL, NOS. With a median posttransplant interval of 72 months, T-cell PTLDs are among the late-occurring PTLDs. Of the most common T-cell PTLDs, anaplastic large cell lymphoma (ALCL) has the best prognosis, whereas PTCL, NOS and hepatosplenic T-cell lymphoma (HSTCL) have the worst prognosis. EBV(+) cases seem to have a longer survival than EBV(-) cases, suggesting a different pathogenetic mechanism.

Early onset, EBV− PTLD in pediatric liver-small bowel transplantation recipients: a spectrum of plasma cell neoplasms with favorable prognosis

Five cases of EBV− PTLD in pediatric recipients of combined liver and small bowel allografts are reported. The lesions were plasma cell neoplasms that resolved completely after minimal treatment.

Risk factors for posttransplant lymphoproliferative disorder in pediatric liver transplant recipients with cytomegalovirus antigenemia

Epstein-Barr virus (EBV) infections, associated with posttransplant lymphoproliferative disorder (PTLD) are known to develop in cytomegalovirus (CMV)-infected transplant recipients due to the indirect effects of CMV. This study evaluated risk factors for PTLD among pediatric liver transplant recipients with CMV infections. We reviewed the medical records of 119 patients<or=18 years old who underwent liver transplantation between September 1996 and April 2009. Sixty-six subjects (55.5%) displayed CMV antigenemia during the study period; 15 (12.6%) developed PTLD. Of these, 10 developed PTLD after CMV antigenemia. The other patients (n=5) were excluded due to negative CMV antigenemia. The incidence of PTLD influenced by CMV infection was not significantly different from the incidence of PTLD without underlying CMV (P=.258). There were no differences in age, gender, antiviral prophylaxis, type of liver transplantation, or acute rejection episodes in the incidence of between patients with versus without PTLD. EBV but not CMV high-risk groups were a predictor for the development of PTLD (P=.035). CMV syndrome, tissue-invasive CMV disease, and CMV peak titer were not associated with an increased risk of PTLD. The primary risk factor for PTLD was EBV high-risk patients (donor positive/recipient negative). CMV disease was not associated with PTLD in pediatric liver transplant recipients with CMV infections.

Most commonly asked questions from parents of pediatric transplant recipients

Pediatric solid-organ transplant (SOT) recipients and their parents are often challenged to cope with new transplant regimens as well as common situations in the context of organ transplantation. Health care professionals will receive questions from parents and children regarding clinical transplant care as well as general pediatric concerns that seem unfamiliar to families now that their child has a transplant. The literature is limited in some areas of pediatric care after SOT, and there is little guidance for the health care practitioner. To help address gaps in the literature and provide guidance for health care professionals, this article reviews some of the most commonly asked questions regarding general care after SOT, parenting the child with a chronic illness, and growth and development. The answers provided stem from the literature in part but also the combined clinical experiences of transplant centers that over time have moved toward decreased limitations and full social integration.

Post-transplant lymphoproliferative disorder after pediatric liver transplantation: characteristics and outcome

Post-Transplant Lymphoproliferative Disorder (PTLD) is a life threatening complication in organ transplant recipients. Risk factors include primary Epstein-Barr virus infection, intensity of immunosupression and cytomegalovirus infection.

OBJECTIVES

To evaluate the incidence, clinical presentation, risk factors, histopathologic appearance and outcome of pediatric liver recipients with PTLD at our institution.

METHOD

Retrospective, descriptive and observational analysis. Between November 1992 and December 2005, 383 liver transplants were performed. The diagnosis of PTLD was based on clinical history and physical examination and confirmed by histologic appearance and immunohistologic staining. Knowles' classification was used for histopathologic diagnosis.

RESULTS

The incidence of PTLD was 5.7% (n: 22p). The average onset after tansplantation (OLT) was 24.9 months. Clinical manifestations were malaise, anorexia, fever of more than 3 days, peripheral adenopathy, tonsillar hypertrophy, abdominal mass, hepatosplenomegaly, snoring, interstitial pulmonary infiltrate, G.T.-tract bleeding, rash, submaxilar mass. Histopathologic diagnosis were Plasmocytic Hyperplasia (n: 10), Polymorphic Lymphoproliferative Disorder (n: 8), Non-Hodgkin Lymphoma (n: 4). Mortality was 18%.

CONCLUSION

The clinical presentations were protean and not specific. A high index of suspicion is important for early diagnosis as it correlates with more benign lesions and more favorable outcume. The lower mortality rate in our series is concordant with that reported in more recent articles.

Lung transplantation in infants and toddlers from 1990 to 2004 at St. Louis Children's Hospital

In a retrospective, single-center cohort study, outcomes of infants and toddlers undergoing lung transplant at St. Louis Children's Hospital between 1990 and 2004 were compared to older children. Patients with cystic fibrosis (exclusively older children) and those who underwent heart-lung, liver-lung, single lung or a second transplantation were excluded from comparisons. One hundred nine lung transplants were compared. Thirty-six were in infants <1 year old, 26 in toddlers 1-3 years old and 47 in children >3 years old. Graft survival was similar for infants and toddlers (p = 0.35 and p = 0.3, respectively) compared to children over 3 years old at 1 and 3 years after transplant. Significantly more infants (p < 0.0001 and p = 0.003) and toddlers (p = 0.002 and p = 0.03) were free from acute rejection and bronchiolitis obliterans compared to older patients. While most infants and toddlers had only minimal lung function impairment, and achieved normal to mildly delayed developmental scores, somatic growth remained depressed 5 years after transplant. Lung transplantation in infants and young children carries similar survival rates to older children and adults. Further insights into the unique immunologic aspects of this group of patients may elucidate strategies to prevent acute and chronic rejection in all age groups.

BCL6 expression correlates with monomorphic histology in children with posttransplantation lymphoproliferative disease

Posttransplantation lymphoproliferative disease (PTLD) is a complication of organ transplantation with high mortality. Predicting response to first-line therapy, reduction of immune suppression, is difficult because of the heterogeneity of lesions and disease behavior. We sought to determine if BCL6 protein expression in PTLD cells is associated with poor outcome. In a cohort of 25 children with PTLD, 9 of the patients' tumor specimens were positive for BCL6 protein expression. Eight of 13 monomorphic lesions were BCL6 positive, compared with 1 of 11 evaluable polymorphic lesions (P=0.01). Only 1 of the patients with BCL6 expression responded to reduced immune suppression (P=0.19). Recipients of heart transplants who developed PTLD had reduced overall survival rates compared with recipients of other organ transplants who developed PTLD (P=0.04).

Pediatric T-cell post-transplant lymphoproliferative disorder after solid organ transplantation

Post-transplant lymphoproliferative disorder (PTLD) is the most common treatment related malignancy that occurs after solid organ transplantation (SOT). PTLD has extended from its initial description as an Epstein-Barr virus (EBV)-driven B-cell proliferation to include EBV-negative and non B-lineage cases. T-cell PTLD (T-PTLD) is rare in both adults and children. We report two cases of pediatric T-PTLD after SOT (liver and lungs) and review cases reported in the literature. Both patients had a bimodal response to therapy with initial eradication of bulky nodal disease with regimens typically used to treat leukemia, but persistence of low-level clonal T-cells in marrow, CSF and lung in one case.

T-cell large granular lymphocyte leukemia of donor origin after cord blood transplantation

We report the first case of T-cell large granular lymphocyte leukemia of donor origin after a second cord blood transplantation for acute myeloid leukemia, and review the literature regarding rare cases of T-cell-origin posttransplantation lymphoproliferative disorders.

Epstein-Barr virus DNA load and seroconversion in pediatric renal transplantation with tacrolimus immunosuppression

EBV infection is one of major complications arising in pediatric patients who have undergone renal transplantation. A strong correlation between the grade of immunosuppression and the development of PTLD, one of the most severe EBV-associated diseases, has been recognized. In this study, we monitored the serologic profile in conjunction with peripheral blood EBV-DNA load of 32 children who underwent renal transplantation with tacrolimus as an immunosuppressant. Six patients were EBV-seronegative (EBV-) before the transplantation, and the mean DNA load in the EBV- group was significantly higher than that in the EBV-seropositive (EBV+) group. Seroconversion occurred in five of these patients in a mean period of 22 weeks after the transplantation. The EBV-DNA load in the EBV+ group was maintained at a low level for a year, whereas it increased rapidly to over 1 x 10(5) copies/mL in two patients in the EBV- group three to seven months after the transplantation, which corresponds to the timing of seroconversion, and one of them developed PTLD. These observations suggest that the close monitoring of the EBV-DNA load, along with longitudinal observation of seroconversion, is essential in pediatric renal transplantation, particularly for younger children who are more likely to be EVB-.

Pulmonary dysfunction in pediatric hematopoietic stem cell transplant patients: non-infectious and long-term complications

Pulmonary complications are among the most frequently encountered sequelae of pediatric hematopoietic stem cell transplantation (HSCT). Non-infectious complications are becoming increasingly more common in this unique population. This review addresses the diagnosis and management of non-infectious manifestations of lung disease in pediatric HSCT patients and briefly discusses the long-term pulmonary function of childhood HSCT survivors.

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.

Epstein-Barr viremia levels after pediatric liver transplantation as measured by real-time polymerase chain reaction

Effective immunosuppression has improved the results following liver transplantation, but also increased the risk for opportunistic infections. Epstein-Barr virus (EBV) infection in transplant patients can cause various symptoms including the life-threatening premalignant condition, post-transplantation lymphoproliferative disorder (PTLD). Serum specimens from 24 consecutive children (mean 7.6 specimens/patient), who had undergone liver transplantation in Göteborg from January 1995 to May 2002, were analyzed retrospectively for EBV DNA by real-time TaqMan polymerase chain reaction (PCR). The results were related to clinical picture, immunosuppression, graft rejection and infections with other agents. Eleven patients (46%) developed primary EBV infection at a mean time of 4.8 months after transplantation, and six (25%) reactivated EBV infection at a mean of 4.0 months after transplantation. Four of the 11 patients with primary infection had symptomatic EBV infection: two had PTLD and two hepatitis. One patient in the group with reactivated infection developed PTLD. EBV DNA levels were significantly higher in the group with primary symptomatic infection compared with the patients with primary asymptomatic infection (mean 65 500 copies/mL; range 14 200-194 300 vs. 3700 copies/mL; range 100-9780). In patients with symptomatic infection EBV DNA levels did not differ between PTLD and hepatitis patients. The data suggest that quantitative analysis of EBV DNA in serum by real-time PCR is useful for identification of EBV-related disease.

Special issues in pediatric kidney transplantation

Pediatric and adult kidney transplantation differ in many ways, but one of the most significant differences is the impact of kidney disease and kidney transplantation on growth and development in pediatric patients. Multiple facets of transplantation may have an impact on growth and development, including the timing of transplantation, choice of immunosuppressive agents, and the presence of hypertension. In addition, graft function has a significant impact on linear growth, and so preservation of function becomes important not only for general health and quality of life but also for optimizing growth. Other concerns in pediatric kidney transplantation include a heightened risk for posttransplantation infectious complications, including lymphoproliferative disease. In addition, the impact of immunosuppressive drugs on adherence to therapy is important. Although adherence is a complex and multifactorial process, immunosuppressive drugs that cause physical side effects may contribute to drug nonadherence because children, and particularly adolescents, may be inclined to stop taking medications associated with physical changes that differentiate them from their peers. Studies that further delineate factors that affect growth and development, risk for infectious complications, and nonadherence will be important to maximize outcomes in pediatric kidney transplantation.

Low-Dose Chemotherapy for Epstein-Barr Virus–Positive Post-Transplantation Lymphoproliferative Disease in Children After Solid Organ Transplantation

Purpose

To evaluate the efficacy of a low-dose chemotherapy regimen in children with Epstein-Barr virus (EBV) –positive, post-transplantation lymphoproliferative disease (PTLD) after organ transplantation who have experienced failure with front-line therapy for PTLD.

Patients and Methods

Eligible patients received cyclophosphamide (600 mg/m2 intravenous for 1 day) and prednisone (2 mg/kg orally for 5 days) every 3 weeks for six cycles.

Results

Thirty-six patients treated on study were assessable for analyses. Front-line therapies for PTLD before study entry included immune suppression reduction or withdrawal (n = 36), antiviral therapy (n = 33), surgical resection (n = 8), rituximab (n = 2), and interferon alfa (n = 1). Reasons for failure of front-line therapy included progressive disease (PD; n = 33) and persistent disease with concurrent allograft rejection (n = 3). Thirty patients (83%) had stage III to IV disease, 92% had extranodal disease, and 75% had ≥ three sites of disease. The overall response rate was 83% (75% complete response + 8% partial response). The relapse rate was 19%, with only one of five relapsed patients alive and disease-free. Four patients presented with fulminant, disseminated PTLD; only one of these four patients achieved a response, and all four died of PD. Two patients died of treatment-related toxicity. Three patients (8%) experienced allograft loss, but two of the three patients are alive and disease-free after a second transplantation. The 2-year overall, relapse-free, and failure-free (without PTLD and with functioning original allograft) survival rates were 73%, 69%, and 67%, respectively.

Conclusion

This low-dose chemotherapy regimen is effective for children with EBV-positive, nonfulminant PTLD who have experienced treatment failure with front-line therapy, and this study represents the largest series of PTLD patients treated prospectively with a uniform chemotherapy regimen.

Incidence of Reactive Antibodies Against Epstein-Barr in a Group of Renal Transplant Patients

Epstein-Barr virus (EBV) infection which is common among immunocompromised patients, may lead to life threatening lymphoproliferative diseases. In this study we examined the incidence and serologic status of EBV infection in 116 renal transplant patients including 84 males and 32 females as well as 72 normal volunteers. The time interval between transplantation and sampling was 1 month to 10 years. Twenty-two patients had a history of rejection. All cases were first transplants except for 3 second transplants. Four patients and no normals showed a positive PCR by a qualitative method. VCA IgM was positive in 11/116 patients (0.09%) and 3 of 72 (0.04%) normal volunteers. 99% (115/116) and 98% (65/72) of patients and normal controls were positive for VCA IgG. EA IgG was positive in 36/116 (31%) and 13/72(18%) of patients and normals, respectively. EBNA IgG was positive in 113/116 (97%) and 100% of patients versus normal controls, respectively. In all except one case with a positive VCA IgM there was a history of infectious mononucleosis-like syndrome. According to our previous data in more than 1000 renal transplant patients during more than 10 years, only one case of PTLD has been diagnosed (0.1%) which is lower than that reported. The high incidence of EBV seropositivity may contribute to this low incidence. The rate of EBV seropositivity in renal transplant patients was greater than in the normal population (P = .05). No association was observed between PCR and seropositivity and rejection or the type of treatment. After this study we began routine PCR and antibody testing in all renal transplant patients both pre- and posttransplant to determine the exact rate of reactivation versus primary infection which we plan to evaluate after 2 to 3 years. In conclusion we believe that the best easiest method to detect EBV infection in immunocompromised patients is VCA IgM ELISA; a qualitative PCR alone is not sufficient for this evaluation.

Long-term follow-up of Epstein-Barr virus viremia in pediatric recipients of renal transplants

The common observation of Epstein-Barr virus (EBV) viremia in pediatric recipients of renal transplants and the occurrence of an EBV-related pulmonary leiomyoma prompted us to intensify the follow-up of EBV infections from 1995 to October 2000. Follow-up included serology and detection of viral DNA in blood using a semi-quantitative nested polymerase chain reaction (PCR) and later a real-time PCR with higher sensitivity. The aim of this study was the early detection of primary infections or reactivations. We obtained 250 samples from 32 patients. EBV DNA detection was consistently negative in 14 patients. There were 5 patients that were considered at risk for post-transplant lymphoproliferative disease, as they were EBV seronegative and were given a kidney from a positive donor. Of these, 4 had at least one episode of high-level EBV viremia. During these episodes, an absence of noticeable symptoms that could be related to EBV was noted for all but 1 patient. This child presented with severe neutropenia 1 month after grafting and, 28 months later, several nodules of pulmonary leiomyoma, which were found to be EBV related. Four episodes of high-level viremia were observed before the discovery of the leiomyoma. Viral DNA detection is important for the follow-up of such patients that are especially at risk of serious complications of EBV infections.

T-cell Posttransplant Lymphoproliferative Disorder Occurring in a Pediatric Solid-organ Transplant Patient

Posttransplantation lymphoproliferative disorder (PTLD) is a serious complication seen in transplant patients as a consequence of immunosuppressant therapy. Most cases are of B-cell origin and are commonly associated with Epstein-Barr virus (EBV) infection. T-cell PTLDs are rare and only 13 pediatric T-cell PTLDs with clinicopathologic correlation have been reported previously. We present the histologic, immunophenotypic, and molecular features of a monomorphic PTLD (T-cell lymphoma) identified in a pediatric patient following orthotopic liver transplantation. The lymphoma was identified in the ileum, rectum, and mesenteric lymph nodes. In situ hybridization revealed numerous EBER-1-positive tumor cells. A current review of the literature is also discussed. Of the 14 cases of pediatric T-cell PTLD reported in the literature, only 3 (21.4%) are described as being EBV positive. Most of the reported PTLDs are monoclonal, with 9 of 11 cases (82%) showing a clonal T-cell population by gene rearrangement studies. T-cell PTLD cases appear to have a poor prognosis (11 of 14 patients died of the disease), although patients with involvement of specific anatomic sites may have a better outcome.

Cyclosporin A monitoring by 2-h levels: preliminary target levels in stable pediatric kidney transplant recipients

Clinical trials in adults have shown that management of transplanted patients with cyclosporin A (CsA) 2-h levels (C2) lead to superior outcome compared with monitoring of 12-h trough levels (C0). In both adults and children, C2 levels enabled a better estimation of the area under the curve concentration than C0 levels. Therefore, it can be suspected that C2 monitoring might also lead to a better outcome in children. Until now C2 target levels for children have not been defined. We measured C2 levels in 101 stable pediatric kidney recipients with a minimum time of 1 yr after transplantation. C2 levels were compared with changes in glomerular filtration rate (GFR) 6 months later. Median C2 levels in children after renal transplantation were 714 ng/mL (95% confidence interval 654-774). Patients with C2 levels below 750 ng/mL had a significantly higher percentage of decline in GFR than patients with C2 levels above 750 ng/mL (p < 0.05). In children with C2 levels below 500 ng/mL three acute rejections occurred in comparison with no rejection in the remaining patients (p < 0.05). We conclude that the lower C2 target level should be above 750 ng/mL in stable pediatric transplant recipients. An upper target level above 1000 ng/mL should be avoided. The question, whether C2 monitoring in pediatric kidney recipients is superior to C0 monitoring, is yet to be answered.

Low-dose immunosuppression reduces the incidence of post-transplant lymphoproliferative disease in pediatric liver graft recipients

OBJECTIVES

In pediatric solid organ transplantation, the Epstein-Barr virus (EBV)-related lymphoproliferative disorders (PTLD) still play a major role in post-transplant morbidity and mortality. The aim of the study was to determine the incidence of PTLD in pediatric patients with liver transplant who receive low-dose immunosuppression protocols.

METHODS

All pediatric patients (n = 269) received a dual immunosuppression therapy consisting of cyclosporine A (initial trough levels, 170-200 microg/L; trough levels for maintenance immunosuppression after 1 year, 80-100 microg/L) and prednisolone (starting dose, 60 mg/m2). Steroids were reduced to 30 mg/m2 after 1 week, followed by a weekly tapering to 5 mg/m2. Seventy-seven of 269 patients were switched to tacrolimus therapy. The authors evaluated the significance of EBV-DNA monitoring by quantitative polymerase chain reaction in identifying patients at risk for PTLD.

RESULTS

Patient survival was 90.3%; graft survival was 85.9%. Eight patients lost their grafts because of chronic rejection. The incidence of PTLD was low (0.7%), although a significant EBV viral load was found in 42.4% of the patients. One third of the patients with a viral load of 3,000 genomes/10(5) cells or greater had clinical signs of EBV infection.

CONCLUSIONS

The authors conclude that low-dose immunosuppressive protocols significantly reduce the incidence of PTLD. In patients treated with that regimen, the monitoring of EBV viral load seems not to be helpful. It can be assumed that low-dose immunosuppression does not suppress EBV-specific cytotoxic CD8+ T cells, thus allowing the host to control EBV infection without the risk of PTLD. Our low-dose immunosuppression protocol did not increase the risk of chronic rejection.

Basiliximab monotherapy following B-cell lymphoma after pediatric liver transplantation and anti-CD20 therapy

The chimeric, monoclonal antibody basiliximab inhibits the proliferation and clonal expansion of activated T cells. To date basiliximab has been used only in combination with other immunosuppressive agents for rejection prophylaxis after solid organ transplantation. An infant underwent liver transplantion (LTx) at the age of 5 months because of biliary atresia. The primary immunosuppression consisted of cyclosporine and prednisolone. As a result of a steroid resistant rejection episode on day 26 post-LTx we had to switch the initial immunosuppressive regiment to tacrolimus and steroids. Because of severe cholestasis and assumed impaired enteral resorption we were forced to administer an unusually high dosage (2 mg/kg/day) of tacrolimus. Four months after LTx an intestinal B-cell lymphoma was diagnosed when the patient suffered from a small bowel perforation. After stopping the immunosuppressive medication we started treatment with the anti-CD20 monoclonal antibody rituximab for B-cell depletion. During the 12 wk no B cells were detectable in the peripheral blood by flow cytometry. In this setting we started a monotherapy with repetitive doses of basiliximab for immunosuppression. During the following course there was no further rejection and no recurrence of the tumor. From this experience we conclude that monotherapy with basiliximab after LTx and anti-CD20 treatment for B-cell lymphoma is efficient and safe.

Limitations of EBV-PCR monitoring to detect EBV associated post-transplant lymphoproliferative disorder

Post-transplant lymphoproliferative disorder (PTLD) represents a significant threat to the survival of pediatric transplant recipients. Epstein-Barr (EBV) viral load monitoring using polymerase chain reaction (PCR) has been reported to have a variable sensitively with relatively higher specificity as in an indicator of the development of PTLD. We report two cases of pathologically confirmed PTLD in children who failed to develop sustained increases in their EBV-PCR determined viral loads. We suggest that clinicians should be aware of the potential for false-negative results of EBV-PCR in pediatric transplant recipients.

Immunotherapy for Epstein-Barr virus-associated cancers in children

Latent Epstein-Barr virus (EBV) infection is associated with several malignancies, including Burkitt's lymphoma, Hodgkin's disease, nasopharyngeal carcinoma, and post-transplant lymphoproliferative disease (LPD). The presence of EBV antigens in these tumors provides a target for immunotherapy approaches, and immunotherapy with EBV-specific cytotoxic T cells (CTLs) has proved effective in post-transplant LPDs, which are highly immunogenic tumors expressing type III latency. The malignant cells in Hodgkin's disease and nasopharyngeal carcinoma express type II latency and hence a more restricted pattern of EBV antigens. Trials with autologous EBV-specific CTL responses are under way in both of these diseases, and while some activity has been seen, no patient has yet been cured. This reduced CTL efficacy may reflect either downregulation of immunodominant EBV proteins, which are major CTL targets, or the ability of these tumors to evade the immune response by secreting inhibitory cytokines. Further improvement of EBV-specific CTL therapy for these type II latency tumors will require improved methods to activate and expand CTLs specific for the subdominant EBV genes expressed and to genetically modify the expanded CTLs to render them resistant to inhibitory cytokines. If these strategies to improve the therapeutic potential of immunotherapy for EBV-associated tumors prove successful, this type of treatment may be adapted to other tumors expressing known (viral) antigens.

Pulmonary re-occurrence of post-transplant lymphoproliferative disease with hypogammaglobulinaemia

We report the case of a 12-year-old boy, who developed Epstein-Barr virus (EBV) associated post-transplant lymphoproliferative disease (PTLD) 7 years after renal transplantation. He responded well to the reduced immunosuppressive therapy and treatment with ganciclovir. Two years later he developed severe pneumonia and hypogammaglobulinaemia related to EBV infection exacerbation. An X-ray film revealed persistent pneumonia in the right lung. Lung biopsy showed a large, diffuse EBV-associated B-cell lymphoma. This constellation suggested re-occurrence of the primary PTLD.

CONCLUSION

We present a case of recurring Epstein-Barr virus-associated post-transplant lymphoproliferative disease with a remarkably late onset in addition to hypogammaglobulinaemia.

Quantitative tissue polymerase chain reaction for Epstein-Barr virus in pediatric solid organ recipients

BACKGROUND

Infections caused by herpes virus, in particular, Epstein-Barr virus (EBV), remain a major challenge in solid organ transplantation. Little is known about the significance of tissue EBV load.

METHODS

Twenty-three tissue biopsy specimens (19 kidney, 3 gastrointestinal, and 1 tonsil specimen) and 2 bronchoalveolar lavage specimens from 14 pediatric transplant recipients (10 kidney, 3 liver, 1 combined transplant) were subject to tissue EBV polymerase chain reaction (PCR) semiquantitative analysis and enzyme-linked immunosorbent assay (ELISA) methods. Results of biopsies were correlated with clinical data.

RESULTS

Five of 14 patients had clinically diagnosed EBV disease: 2 patients presented with a septic picture with multiorgan failure and pneumonitis; 1 patient had mononucleosis; 1 patient had an increase in serum creatinine level, lymphadenopathy, and chronic fatigue; and 1 patient had EBV nephritis. These 5 patients underwent 12 biopsies at the time of clinically active infection; 8 biopsies had positive results (up to 111 copies/10 microL of extracted DNA). Conversely, 1 of the remaining 13 tissue biopsy specimens from asymptomatic patients had positive results on ELISA, but undetectable viral load, whereas 8 patients had a positive EBV immunoglobulin G titer with historic evidence of EBV replication in the blood. No patient without evidence of EBV had positive EBV tissue PCR results.

CONCLUSION

Increased EBV load was found in more than 50% of patients, pointing to a previously underrecognized importance of EBV detection in tissues from transplant recipients. The presence of EBV in tissue correlated with the presence of viremia, whereas tissue PCR had 100% specificity. EBV load should be included in biopsy evaluation.

Epstein-Barr virus and post-transplant lymphoproliferative disease

There is convincing evidence that Epstein-Barr virus (EBV) is associated with post-transplant lymphoproliferative disease (PTLD). Primary EBV infection following transplantation occurs in as many as 90% of cases of PTLD in children and pretransplant EBV seronegativity is a recognized risk factor for developing PTLD. Other risk factors include young age at the time of transplant, the type of transplant that the recipient receives and the type and intensity of immunosuppression. The clinical presentation is often nonspecific and tissue biopsy is necessary to establish the diagnosis. There appears to be a correlation between PTLD and EBV viral load measured by polymerase chain reaction (PCR) of the peripheral blood and quantitative PCR may be a useful guide in the management of PTLD. Antiviral drugs and cytomegalovirus-immunoglobulin G may have a role in preventing PTLD. Because PTLD results from functional over-immunosuppression, the initial treatment is reduction of immunosuppression. Antiviral agents, interferon, immuno-based monoclonal therapy, cell-based therapy and chemotherapy also have a potential role in treating this disorder. At the present time there is no standardized approach to the evaluation and treatment of PTLD.

Epstein-Barr virus-related lymphoproliferation in children after liver transplant: role of immunity, diagnosis, and management

Tumor occurrence following immunosuppression remains a major concern in children after liver transplantation. More than 50% of these tumors belong to the post-transplant lymphoproliferative diseases (PTLD) and are diagnosed during childhood. These PTLD are mostly related to primary Epstein-Barr virus (EBV) infection and a heavy immunosuppressive regimen. Improvement in their prognosis was reached thanks to a better knowledge of their pathogenesis, risk factors and clinical presentation, linked probably to earlier management. However, their incidence remains stable (occurring in 5-15% of children after liver transplantation) despite different pre-emptive strategies based on these parameters. Moreover, acute graft rejection and subsequent risk of graft loss is a common side-effect of PTLD treatment. EBV viral load determination by quantitative polymerase chain reaction (PCR) is so far the only predictive marker proposed for PTLD prevention and PTLD treatment monitoring, although limited by a lack of specificity. New immunologic techniques have allowed the demonstration of a defect of the EBV-specific cellular immunity in the patients with PTLD. The level of immunity is correlated to the viral load and improves during recovery from PTLD. These recent findings add further knowledge to PTLD pathogenesis and management.

Post-transplantation lymphoproliferative disease in Chinese: the Queen Mary Hospital experience in Hong Kong

Post-transplantation lymphoproliferative disease (PTLD) is an unique iatrogenic complication after bone marrow transplantation (BMT) and solid organ transplantation (SOTx). The pattern of EBV related lymphoma in Chinese is different from Caucasians. We surveyed the incidence, clinical and pathological spectrum of PTLD among 541 cases of allogeneic BMT, 145 cases of renal transplant, 35 cases of heart/lung transplantation and 146 cases of orthotopic liver transplantation (OLT). From 1994 to 2001, 13 consecutive cases of PTLD were diagnosed, ranging from disseminated NK cell lymphoma to localized plasmacytoma. Both donor and recipient derived PTLD was documented. Disease was often heralded by cytomegaloviral disease and antithymocyte globulin (ATG) usage. Two cases were diagnosed post-mortem, and six patients died of PTLD at a median of 3 months. Complete and partial remission was only achieved in 3 and 2 cases, respectively, despite a range of treatment (reduced immunosuppression, explantation, radiotherapy, combination chemotherapy, donor lymphocytes, autologous marrow infusion and rituximab). Most responding patients died subsequently of rejection, infection and graft versus host disease (GVHD). The incidence of PTLD is not increased in Chinese patients. However, some patients may be at increased risk, especially mismatched allogeneic BMT, parental OLT (especially involving young infants) and heavy ATG exposure.

Non-nucleoside inhibitors of herpesviruses

While the treatment of herpes simplex virus with acyclovir and similar nucleoside analogues was one of the first success stories in antiviral chemotherapy, substantial unmet medical needs remain for herpesvirus diseases. In particular, the increasing numbers of immunosuppressed people due to AIDS, transplantation, cancer and aging has driven the need for improved antivirals to treat diseases caused by human cytomegalovirus (HCMV). Currently available drugs for the treatment of HCMV diseases are less than ideal agents due to issues of toxicity, modest efficacy and poor oral bioavailability. High throughput screening of large compound collections for inhibitors of specific viral enzymes or inhibition of viral growth in cell culture have identified a number of new HCMV inhibitors at several pharmaceutical companies. These compounds act by inhibition of novel molecular targets such as the viral protein kinase, viral protease and viral proteins involved in DNA cleavage/packaging. In addition, novel non-nucleoside inhibitors of the herpesvirus DNA polymerase have recently been described. This review will summarise some of these research efforts and will focus on non-nucleoside compounds that directly inhibit a viral process.

Long-term care of pediatric renal transplant patients: from bench to bedside

In this review, we discuss current and future issues in the management of pediatric renal transplant recipients, including the optimization of long-term graft function and the minimization of complications caused by immunosuppression. Long-term management involves not only the monitoring of graft function but also the identification of patients at risk for the development of complications. The identification of patients with immunoreactive or immunoregulatory responses can be performed molecular monitoring of the immune response. Also, the use of frequent surveillance kidney biopsies, surrogate markers of chronic rejection, and glomerular filtration rate will be a part of future management. Identifying high-risk patients enables the physician to optimize immunosuppression to limit acute rejection. Short-and long-term management of pediatric transplant patients also includes adequate monitoring of growth and the monitoring for post-transplant lymphoproliferative disease. Ongoing clinical trials are underway that focus on these novel approaches in caring for pediatric transplant recipients.