Risk factors and clinical outcomes of pediatric liver transplant recipients with post-transplant lymphoproliferative disease in a multi-ethnic Asian cohort

Epidemiology and pathogen characteristics of infections following solid organ transplantation

Solid organ transplantation (SOT) recipients have a heightened risk for infection due to prolonged immunosuppressive drug use following transplant procedures. The occurrence of post-transplant infections is influenced not only by the transplanted organ type but also by varied factors. The kidney is the most common organ in SOT, followed by the liver, heart, and lung. This review aims to provide a comprehensive overview of the current epidemiological characteristics of infections after kidney, liver, heart, and lung transplantation, focusing on bacterial, fungal, and viral infections. The incidence and infection types demonstrated significant variability across different SOTs. Furthermore, this review attempts to elucidate the clinical characteristics of infections across patients following different SOTs and contribute to the development of individualized prevention strategies according to infection incidence, ultimately enhancing the quality of life of transplant recipients.

The IPTA Nashville Consensus Conference on Post-Transplant lymphoproliferative disorders after solid organ transplantation in children: III - Consensus guidelines for Epstein-Barr virus load and other biomarker monitoring

The International Pediatric Transplant Association convened an expert consensus conference to assess current evidence and develop recommendations for various aspects of care relating to post-transplant lymphoproliferative disorders after solid organ transplantation in children. In this report from the Viral Load and Biomarker Monitoring Working Group, we reviewed the existing literature regarding the role of Epstein-Barr viral load and other biomarkers in peripheral blood for predicting the development of PTLD, for PTLD diagnosis, and for monitoring of response to treatment. Key recommendations from the group highlighted the strong recommendation for use of the term EBV DNAemia instead of "viremia" to describe EBV DNA levels in peripheral blood as well as concerns with comparison of EBV DNAemia measurement results performed at different institutions even when tests are calibrated using the WHO international standard. The working group concluded that either whole blood or plasma could be used as matrices for EBV DNA measurement; optimal specimen type may be clinical context dependent. Whole blood testing has some advantages for surveillance to inform pre-emptive interventions while plasma testing may be preferred in the setting of clinical symptoms and treatment monitoring. However, EBV DNAemia testing alone was not recommended for PTLD diagnosis. Quantitative EBV DNAemia surveillance to identify patients at risk for PTLD and to inform pre-emptive interventions in patients who are EBV seronegative pre-transplant was recommended. In contrast, with the exception of intestinal transplant recipients or those with recent primary EBV infection prior to SOT, surveillance was not recommended in pediatric SOT recipients EBV seropositive pre-transplant. Implications of viral load kinetic parameters including peak load and viral set point on pre-emptive PTLD prevention monitoring algorithms were discussed. Use of additional markers, including measurements of EBV specific cell mediated immunity was discussed but not recommended though the importance of obtaining additional data from prospective multicenter studies was highlighted as a key research priority.

Probable posttransplant lymphoproliferative disorder after pediatric living donor liver transplantation: Is a biopsy still needed?

Posttransplant lymphoproliferative disorder (PTLD) is a complication of solid organ transplantation and is associated with Epstein-Barr virus (EBV). Recently, EBV-related PTLD was defined as probable PTLD or proven PTLD. Probable PTLD involves significant lymphadenopathy, hepatosplenomegaly, or other end-organ manifestations, without a histological diagnosis, together with significant EBV DNAemia. Proven PTLD is the detection of EBV-encoded proteins in a tissue specimen, together with symptoms and/or signs originating from the affected organ. Probable PTLD after pediatric liver transplantation has not been well documented. Therefore, here, we aimed to describe cases of five pediatric patients with probable PTLD after liver transplantation, who were successfully treated with preemptive immunosuppression reduction with or without rituximab. All five patients (age range, 1-4 years; two girls and three boys) had EBV DNAemia. Three patients developed probable PTLD within 12 months of transplantation. Further, three patients had a significantly high EBV viral load, but the other two patients with lymphadenopathy and end-organ manifestation had a relatively low EBV viral load. Early onset pediatric PTLD with significant EBV DNAemia is almost universally EBV-related. Biopsy was not performed in any patient due to the relative inaccessibility of the lesion and young age of the patients. If the patient's symptoms are too mild, if excisional biopsy is too difficult to perform, or if the patient is too sick to undergo an invasive procedure, initiating preemptive treatment without a histological diagnosis could be the treatment option.

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.

Post-transplant Lymphoproliferative Disorder in Pediatric Liver Transplantation: A Population-based Study from Shiraz, Iran

Background: This study aimed to determine the prevalence of post-transplant lymphoproliferative disorder (PTLD) based on the clinical and epidemiological characteristics of donors and pediatric transplant recipients. Methods: This cross-sectional study was conducted on the patients who had experienced liver transplantation at Shiraz Transplant Center, Shiraz, Iran, from April 2007 to March 2017. Data on the epidemiological characteristics, underlying diseases, dosage of immunosuppressive drugs, and duration of drug consumption from the time of liver transplantation until the onset of PTLD for transplant recipients, and donors’ age, sex, and family relationship with recipients were collected using a data-gathering form. Log rank test was employed to determine the variations in the distribution of survival in different sex and age groups. Results: The study findings indicated that 49 out of the 1207 children who had undergone liver transplantation developed PTLD, revealing a prevalence of 4%. The results showed no significant relationship between gender and the incidence of PTLD (P = 0.13). However, the mean age of the cases with PTLD was 4.93 ± 1.07 years at the time of transplantation, while non-PTLD patients showed a higher mean age at that time (7.80 ± 5.54). The mean dose of the immunosuppressive drugs (dose/kg) consumed by the recipients was as follows: tacrolimus = 0.2753 ± 0.23435, prednisolone = 0.6761 ± 0.62218, cellcept = 0.0724 ± 0.12963, and sirolimus = 0.1078 ± 0.08813. The average consumption period of the above-mentioned drugs from the time of transplantation until the onset of PTLD was 14.7 ± 14.409 months. Based on the results, the five-year survival rate was much lower in the patients with PTLD compared to the non-PTLD patients (31% Vs. 72.7%). The survival distribution was significantly different based on sex and age groups (P = 0.59 and P = 0.06, respectively). Conclusions: The prevalence of the clinical and epidemiological features of the PTLD in the patients under the present investigation was similar to those of the patients in other hospitals. Recognizing the clinical and epidemiological characteristics of transplant recipients with and without PTLD and donors can provide a basis for managing these patients.

Recurrent Intestinal Perforation After Cessation of Immunosuppression in Posttransplant Lymphoproliferative Disease in Pediatric Liver Transplant Recipient

Posttransplant lymphoproliferative disease (PTLD) is the most common malignant complication after solid organ transplantation. Gastrointestinal involvement as the presentation in early PTLD can occur in 25-30% of pediatric liver transplant recipients and can be the only system involved in 20%. Recurrent gastrointestinal perforation due to resolution of PTLD is an extremely rare complication. We report a 13-month-old male child diagnosed with PTLD, treatment of which lead to recurrent intestinal perforations. The child presented with gastrointestinal bleed 5 months after living donor liver transplantation for biliary atresia. Evaluation was suggestive of PTLD and biopsy confirmed diffuse large B-cell lymphoma. Positron emission tomography scan showed diffuse involvement of small intestine and ileum. Tacrolimus was withdrawn abruptly following diagnosis of PTLD as there was associated renal impairment. Child developed six episodes of small intestinal perforations over 3 weeks which required multiple laparotomies with closure of perforation and/or small bowel resection. Complete remission was achieved six months after diagnosis with cessation of immunosuppression alone and child is alive at 48 months follow-up without any recurrence. To avoid bowel perforation and complications related to tumor necrosis, immunosuppression reduction in PTLD should be gradual while carefully monitoring Epstein-Barr virus levels, tumor response, graft function, and general health status of the patient.

Post Transplant Lymphoproliferative Disorder risk factors in children: Analysis of a 23-year single-institutional experience

INTRODUCTION

PTLD is the most frequent malignancy following SOT in children and the second most common SOT complication in adults. However, factors determining outcomes in children are poorly understood due to its relative rarity.

METHODS

This study was performed at the University of Florida. Univariate and multivariate analyses were used to identify prognostic factors in pediatric patients diagnosed with PTLD.

RESULTS

We reviewed records of 54 pediatric (younger than 18 years old at diagnosis) patients diagnosed with PTLD from 1994 to 2017. The median follow-up was 28.8 months. The estimated 5-year survival rate was 87.6% (95% CI 74.3-94.2%). Univariate analysis showed that organ transplanted (specifically heart transplant), poor response to initial treatment, allograft rejection, and low Karnofsky score were statistically significant for negative prognostic factors in determining survival. Multivariate analysis determined progression in response to initial treatment and presence of allograft rejection as statistically significant prognostic factors affecting overall survival. We found no statistically significant impact of EBV serological status on PTLD prognosis.

CONCLUSIONS

Disease progression and allograft rejection were strong negative prognostic indicators in our study cohort. Close attention to graft status and development of therapies that protect the graft from rejection while bolstering anti-EBV immunity will be essential to further improving PTLD outcomes in children.

Epstein-Barr viral load monitoring for diagnosing post-transplant lymphoproliferative disorder in pediatric liver transplant recipients

This study aimed to investigate the incidence of PTLD in pediatric liver transplant recipients and the risk factors for the development of PTLD. We also determined clinically useful quantitative EBV PCR parameters for aiding in the diagnosis of EBV-associated PTLD in the pediatric liver transplant recipients at our institute. We reviewed children < 18 years old who had undergone liver transplantations and quantitative analysis of whole blood EBV load at our institute from January 2006 to March 2015. A total of 142 liver transplant recipients were included, and their median age was 1.5 years. Clinically significant high-level EBV DNAemia ≥ 10 000 copies/mL at least twice was observed in 53.5% and PTLD occurred in 9.9%. Among PTLD group, graft failure and mortality rate were as high as 21.4% and 14.3%, respectively. Deceased donor, presence of high-level EBV DNAemia, and primary CMV infection following transplant were associated with an increased risk for PTLD in the multivariate analysis. The peak titer at 10 875 copies/mL could be used as a cutoff value with a sensitivity of 92.9% and a specificity of 37.9%; the rate of increase in EBV load suggested a sensitivity of 64.3% and a specificity of 70.9% at the cutoff value of 44 000 copies/mL/week. In conclusion, the incidence of PTLD following liver transplant in children was as high as 10%. PTLD is associated with significant morbidity and mortality. Close monitoring of EBV DNAemia is crucial for the early diagnosis and proper treatment of PTLD in pediatric liver transplant recipients.