A Hybrid Strategy for the Prevention of Cytomegalovirus-Related Complications in Pediatric Liver Transplantation Recipients

Multicenter Analysis of Valganciclovir Prophylaxis in Pediatric Solid Organ Transplant Recipients

Background

Valganciclovir is the only approved antiviral for cytomegalovirus (CMV) prevention in pediatric solid organ transplantation (SOT). Additional approaches may be needed to improve outcomes.

Methods

A multicenter retrospective study from 2016 to 2019 was conducted of pediatric SOT recipients in whom at least 3 months of valganciclovir prophylaxis was planned. Episodes of CMV DNA in blood (DNAemia), CMV disease, drug-related toxicities, as well as other infections in the first year posttransplant and demographic and clinical data were collected. CMV DNAemia in the first year after prophylaxis or during prophylaxis (breakthrough) was analyzed by multivariate hazard models.

Results

Among the 749 patients enrolled, 131 (17.5%) had CMV DNAemia at any time in the first year; 85 (11.4%) had breakthrough DNAemia, and 46 (6.1%) had DNAemia after prophylaxis. CMV disease occurred in 30 (4%). In a multivariate model, liver transplantation compared to kidney or heart, intermediate or high risk based on donor/recipient serologies, neutropenia, and valganciclovir dose modifications attributed to toxicity were associated with increased risk of total and/or breakthrough DNAemia. Bacteremia was also associated with increased hazard ratio for CMV DNAemia. In a separate multivariate analysis, rejection occurred more often in those with breakthrough CMV DNAemia (P = .002); liver transplants, specifically, had increased rejection if CMV DNAemia occurred in the first year (P = .004). These associations may be bidirectional as rejection may contribute to infection risk.

Conclusions

CMV DNAemia in the first year posttransplantation occurs despite valganciclovir prophylaxis and is associated with medication toxicity, bacteremia, and rejection. Pediatric studies of newer antivirals, especially in higher-risk subpopulations, appear to be warranted.

Prevention of Cytomegalovirus Infection in Solid Organ Transplant Recipients: Guidelines by the Korean Society of Infectious Diseases and the Korean Society for Transplantation

Cytomegalovirus (CMV) is the most important opportunistic viral pathogen in solid organ transplant (SOT) recipients. The Korean guideline for the prevention of CMV infection in SOT recipients was developed jointly by the Korean Society for Infectious Diseases and the Korean Society of Transplantation. CMV serostatus of both donors and recipients should be screened before transplantation to best assess the risk of CMV infection after SOT. Seronegative recipients receiving organs from seropositive donors face the highest risk, followed by seropositive recipients. Either antiviral prophylaxis or preemptive therapy can be used to prevent CMV infection. While both strategies have been demonstrated to prevent CMV infection post-transplant, each has its own advantages and disadvantages. CMV serostatus, transplant organ, other risk factors, and practical issues should be considered for the selection of preventive measures. There is no universal viral load threshold to guide treatment in preemptive therapy. Each institution should define and validate its own threshold. Valganciclovir is the favored agent for both prophylaxis and preemptive therapy. The evaluation of CMV-specific cell-mediated immunity and the monitoring of viral load kinetics are gaining interest, but there was insufficient evidence to issue recommendations. Specific considerations on pediatric transplant recipients are included.

Body surface area compared to body weight dosing of valganciclovir is associated with increased toxicity in pediatric solid organ transplantation recipients

Optimal dosing of valganciclovir (VGCV) for cytomegalovirus (CMV) prevention in pediatric solid organ transplantation recipients (SOTR) is controversial. Dosing calculated based on body surface area (BSA) and creatinine clearance is recommended but simplified body weight (BW) dosing is often prescribed. We conducted a retrospective 6-center study to compare safety and efficacy of these strategies in the first-year posttransplant There were 100 (24.2%) pediatric SOTR treated with BSA and 312 (75.7%) with BW dosing. CMV DNAemia was documented in 31.0% vs 23.4% (P = .1) at any time during the first year and breakthrough DNAemia in 16% vs 12.2% (P = .3) of pediatric SOTR receiving BSA vs BW dosing, respectively. However, neutropenia (50% vs 29.3%, P <.001), lymphopenia (51% vs 15.0%, P <.001), and acute kidney injury causing treatment modification (8.0% vs 1.8%, P <.001) were documented more frequently during prophylaxis in pediatric SOTR receiving BSA vs BW dosing. The adjusted odds ratio of VGCV-attributed toxicities comparing BSA and BW dosing was 2.3 (95% confidence interval [CI], 1.4-3.7] for neutropenia, 7.0 (95% CI, 3.9-12.4) for lymphopenia, and 4.6 (95% CI, 2.2-9.3) for premature discontinuation or dose reduction of VGCV, respectively. Results demonstrate that BW dosing is associated with significantly less toxicity without any increase in CMV DNAemia.

A quick algorithmic review on management of viral infectious diseases in pediatric solid organ transplant recipients

Pediatric solid organ transplant is a life-saving procedure for children with end-stage organ failure. Viral infections are a common complication following pediatric solid organ transplantation (SOT), which can lead to increased morbidity and mortality. Pediatric solid organ transplant recipients are at an increased risk of viral infections due to their immunosuppressed state. The most commonly encountered viruses include cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus (HSV), varicella-zoster virus (VZV), adenoviruses, and BK polyomavirus. Prevention strategies include vaccination prior to transplantation, post-transplant prophylaxis with antiviral agents, and preemptive therapy. Treatment options vary depending on the virus and may include antiviral therapy and sometimes immunosuppression modification. This review provides a Quick Algorithmic overview of prevention and treatment strategies for viral infectious diseases in pediatric solid organ transplant recipient.

Incidence of cytomegalovirus DNAemia in pediatric kidney, liver, and heart transplant recipients: Efficacy and risk factors associated with failure of weight-based dosed valganciclovir prophylaxis

BACKGROUND

Cytomegalovirus (CMV) is associated with morbidity and mortality in solid organ transplant recipients (SOTR). Valganciclovir (VGC) is extensively used for prophylaxis. Optimal dosing in children, risk factors for failure, and the impact of dose adjustments on CMV DNAemia is not well established.

METHODS

This retrospective cohort study of pediatric SOTR transplanted between 2010-2018 evaluated the epidemiology of CMV DNAemia and used Cox-regression to assess the risk factors for CMV DNAemia within one-year following SOTR.

RESULTS

In 393 pediatric SOTR (heart [96, 24.4%], kidney [180, 45.6%], liver [117, 29.8%]; median age 9.5 ± 0.3 years), overall CMV DNAemia incidence was 6.6/10 000 days (95%CI 5.1/10 000-7.9/10 000) and varied by organ groups: heart 8.2/10 000 days (95%CI 4.9/10 000-11.4/10 000), kidney 5.8/10 000 days (95%CI 3.9/10 000-7.8/10 000), liver 6.2/10 000 days (95%CI 3.7/10 000-8.7/10 000). CMV DNAemia was detected in 75 of 275 (27.2%) patients who received prophylaxis (40 cases occurred during prophylaxis and 35 occurred after completion of prophylaxis). The median VGC dose given according to institutional weight-based algorithm was approximately 1.5-fold lower than the manufacturer-recommended dose. This discordance was more prominent at younger age groups (3.2-fold lower in <2-year-old [100 mg versus 325 mg], 2.5-fold lower in <6-year-old [200 mg versus 447 mg]). Dose reduction due to adverse events was an independent risk factor for breakthrough CMV DNAemia (hazard ratio 2.2, 95%CI 1.2-3.8) among patients with similar age, CMV risk stratification, starting VGC dose, immunosuppressive therapy, and organ group.

CONCLUSION

CMV events occurred while on VGC prophylaxis. Weight-based VGC may prevent supratherapeutic VGC exposure especially in younger children. Dose reduction of VGC prophylaxis for adverse event management places patients at an increased risk for CMV DNAemia suggesting other agents with fewer adverse effects should be considered and need to be studied in children.

Antiviral toxicities in pediatric solid organ transplant recipients

Prophylaxis with valganciclovir (VGCV) is used routinely to prevent cytomegalovirus (CMV) infections in at-risk pediatric solid organ transplant (SOT) recipients. However, the rate and factors associated with toxicities in this population are not well-described. We conducted a retrospective cohort study of children undergoing SOT at our hospital from January 2012-June 2018. We evaluated the frequency of hematologic and renal toxicities from day 15 through 1-year post-SOT in relation to antiviral exposures, focused on VGCV prophylaxis. Marginal rate models were used to determine the risk of kidney injury and neutropenia in relation to VGCV prophylaxis. Among 281 SOTs, VGCV prophylaxis was administered on 20.1% of all follow-up days. The incidence rates of kidney injury, leukopenia, and neutropenia were significantly higher during VGCV prophylaxis compared to when no antiviral agents were given. Using multivariable marginal rate models, receipt of VGCV prophylaxis was associated with development of kidney injury (rate ratio [RR] 1.79, 95% confidence interval [CI]: 1.22-2.65) and neutropenia (RR 4.82, 95% CI: 3.08-7.55). VGCV dosing did not impact the development of kidney injury or neutropenia. Toxicities are common with VGCV prophylaxis in pediatric SOT recipients.

Antiviral prophylaxis or preemptive therapy for cytomegalovirus after liver transplantation?: A systematic review and meta-analysis

BACKGROUND

To conduct a meta-analysis with the aim of comparing the outcomes of antiviral prophylaxis and preemptive therapy for the prevention of cytomegalovirus (CMV) infection in liver transplant (LT) recipients.

METHODS

We searched databases for qualified studies up until March 2022. Finally, a meta-analysis was carried out using a fixed-effect or random-effect model based on the heterogeneity.

RESULTS

With a total of 1834 LT patients, the pooled incidence of CMV infection and CMV disease in the overall LT recipients using antiviral prophylaxis and preemptive therapy were 24.7% vs. 40.4% and 6.4% vs. 9.4%, respectively. Our meta-analysis exhibited a significant reduction in the incidence of CMV infection due to antiviral prophylaxis when compared to preemptive therapy in the high-risk group (OR: 6.67, 95% CI: 1.73, 25.66; p = 0.006). In contrast, there was a significant reduction in the incidence of late-onset of CMV disease in preemptive therapy compared to antiviral prophylaxis in the high-risk group (OR: 0.29, 95% CI: 0.12, 0.74; p = 0.009). However, the incidence of CMV disease, allograft rejection, graft loss, drug related adverse effects, opportunistic infections and mortality did not differ significantly between both the interventions (all p> 0.05).

CONCLUSIONS

We found the use of antiviral prophylaxis, compared with preemptive therapy, is superior in controlling CMV infection and prolonging the time to CMV disease in LT recipients without an increased risk of opportunistic infections, allograft rejection, graft loss, drug related adverse effects, development of drug resistance, and mortality.

CMV infection and management among pediatric solid organ transplant recipients

BACKGROUND

Cytomegalovirus (CMV) is an important cause of morbidity and mortality in pediatric solid organ transplant (SOT) recipients. However, the impact of asymptomatic CMV infections (ie, DNAemia) on clinical outcomes is not well established.

METHODS

We performed a retrospective cohort study of children undergoing first SOT at our institution from January 2012 to June 2018. We evaluated the epidemiology of CMV infections and performed multivariable Cox regression to assess the association between CMV DNAemia without disease or CMV disease (syndrome or end-organ disease) on negative outcomes (death, re-transplantation, or moderate/severe rejection) within the first year after SOT.

RESULTS

Among 271 individuals, 43 (15.9%) developed ≥1 CMV infection during the first year after SOT. There were 56 unique CMV infections including 14 episodes of CMV disease. In 167 patients offered CMV prophylaxis, only 8 (4.8%) developed their first CMV DNAemia episode while on prophylaxis 32 developed CMV DNAemia after prophylaxis completion; only 1 episode of CMV disease occurred while on antiviral prophylaxis. When accounting for receipt of ATG, oral steroids, and number of immunosuppressives on a given day, CMV disease was more strongly associated with negative outcomes (Hazard Ratio (HR): 3.28, 95% CI: 0.73-14.64; p = .12) than CMV DNAemia without disease (HR 1.42, 95% CI: 0.19- 10.79; p = .74), although not to a statistically significant degree.

CONCLUSIONS

Most CMV infections occurred after completion of antiviral prophylaxis. CMV disease was more strongly associated with negative outcomes than asymptomatic CMV DNAemia and should be the focus of CMV prevention practices.

Cytomegalovirus infection in liver-transplanted children

Cytomegalovirus (CMV) infection is a common complication of liver trans-plantation in children. The CMV serostatus of recipients and donors is the primary risk factor, and prophylaxis or pre-emptive strategies are recommended for high-risk patients. Graft rejection, coinfection and Epstein-Bar virus reactivation, which can lead to post-transplant lymphoproliferative disease, are indirect effects of CMV infection. Assessment of CMV infection viral load should be routinely performed upon clinical suspicion. However, tissue-invasive CMV disease is not associated with CMV viraemia and requires confirmation by tissue pathology. Oral valganciclovir and intravenous ganciclovir are equivalent treatments, and the duration of treatment depends on factors including CMV viral load, tissue pathology, and clinical response. Risk stratification by donor and recipient status prior to transplantation and post-transplantation antiviral prophylaxis or pre-emptive therapy are recommended. Adult guidelines have been established but additional study of the effectiveness of the preventive guidelines in children is needed. This review summarizes the burden, risk factors, clinical manifestations, laboratory evaluation, treatment, and prevention of CMV infection in children after liver transplantation.

National survey of prevention and management of CMV infection in pediatric kidney transplantation in comparison to clinical practice guidelines

BACKGROUND

Cytomegalovirus (CMV) is one of the most frequent opportunistic infections in kidney transplant (KT) recipients and is a risk factor for patient and graft survival after KT. Center-to-center variation, optimal prevention and treatment strategies in pediatric KT are currently unknown. This survey aimed to assess current CMV prevention and treatment strategies used among French pediatric KT centers.

METHODS

A web-based survey was sent to all 13 French pediatric kidney transplantation centers.

RESULTS

Twelve (92%) centers responded to the survey. All centers used prophylaxis for the donor-positive/recipient-negative (D+/R-) group. For R + patients, 54% used prophylaxis, 37% used a pre-emptive strategy. In the low-risk group, D-/R-, 50% used a pre-emptive approach and 50% had no specific prevention strategy. The antiviral used by all centers for prophylaxis was valganciclovir (VGCV). The duration of prophylaxis varied from 3 to 7 months and the duration of viral load monitoring varied from 6 months to indefinitely. No center used a hybrid/sequential approach. For the treatment of CMV DNAemia, VGCV or intravenous GCV were used. Therapeutic drug monitoring of VGCV was performed in 5 centers (42%). Five centers reported drug resistance. Eight centers (67%) administered VGCV during the treatment of acute graft rejection.

CONCLUSIONS

There is uniformity in CMV management in some areas among pediatric KT centers in France but not in others which remain diverse and are not up to date with current guidelines, suggesting unnecessary variation which could be reduced with better evidence to inform practice.

Epidemiology and long-term outcomes of cytomegalovirus DNAemia and disease in pediatric solid organ transplant recipients

Despite prevention strategies, cytomegalovirus (CMV) remains a common infection in pediatric solid organ transplant recipients (SOTR). We sought to determine the frequency, associations with, and long-term outcomes of CMV DNAemia in pediatric SOTR. We performed a single-center retrospective cohort study, including 687 first time SOTR ≤21 years receiving universal prophylaxis from 2011 to 2018. Overall, 159 (23%) developed CMV DNAemia, the majority occurring after completing primary prophylaxis. CMV disease occurred in 33 (5%) SOTR, 25 (4%) with CMV syndrome and 10 (1%) with proven/probable tissue-invasive disease. CMV contributed to the death of three (0.4%) patients (all lung). High-risk (OR 6.86 [95% CI, 3.6-12.9]) and intermediate-risk (4.36 [2.3-8.2]) CMV status and lung transplantation (4.63 [2.33-9.2]) were associated with DNAemia on multivariable analysis. DNAemia was associated with rejection in liver transplant recipients (p < .01). DNAemia was not associated with an increase in graft failure, all-cause mortality, or other organ-specific poor outcomes. We report one of the lowest rates of CMV disease after SOTR, showing that universal prophylaxis is effective and should be continued. However, we observed CMV morbidity and mortality in a subset of patients, highlighting the need for research on optimal prevention strategies. This study was IRB approved.

Persistent hypogammaglobulinemia in pediatric solid organ transplant recipients

INTRODUCTION

Hypogammaglobulinemia has not been well studied in pediatric solid organ transplant (SOT) recipients. We evaluated plasma immunoglobulin (Ig) and lymphocyte phenotypes among 31 pediatric heart and kidney recipients for two years post-transplant and from 10 non-transplanted children.

METHODS

Plasma IgM, IgG, and IgA were quantified by immunoturbidimetric assays, IgG subclasses were quantified by bead-based multiplex immunoassay, and lymphocyte phenotypes were assessed by flow cytometry.

RESULTS

Median age at transplant for SOT recipients was similar to that of the control cohort (15 vs. 12.5 years, respectively; P = .61). Mean plasma IgG and IgM levels for SOT recipients fell significantly below the control cohort means by 1 month post-transplant (P < .001 for both) and remained lower than control levels at 12-18 months post-transplant. Heart recipients had lower frequencies of a CD4⁺ naïve T lymphocytes relative to kidney recipients.

CONCLUSIONS

Hypogammaglobulinemia was prevalent and persistent among pediatric SOT recipients and may be secondary to immunosuppressive medications, as well as loss of thymus tissue and CD45RA⁺   CD4⁺ T cells in heart recipients. Limitations of our study include but are not limited to small sample size from a single center, lack of samples for all participants at every time point, and lack of peripheral blood mononuclear cell samples for the non-transplanted cohort.

Deceased Donor Predictors for Pediatric Liver Allograft Utilization

BACKGROUND

The number of pediatric deceased organ donors has recently declined, and the nonutilization of pediatric liver allografts has limited the development of liver transplantation. We determined the utilization rate of pediatric livers and identified risk factors for graft discard.

METHODS

We used data from the Scientific Registry of Transplant Recipients database from January 1, 2000, to December 31, 2012. The trends of pediatric liver donors and utilization rates were analyzed. Donor risk factors that impacted the graft use of pediatric livers were measured. Logistic regression modelling was performed to evaluate graft utilization and risk factors.

RESULTS

A total of 11,934 eligible pediatric liver donors were identified during this period. A total of 1191 authorized liver grafts did not recover or recovered without transplantation. Factors including pediatric donors >1 year of age (odds ratio [OR] = 2.956, 95% confidence interval [CI] 2.494-3.503, P < .001), nonhead trauma (OR = 2.243, 95% CI 1.903-2.642, P < .001), lack of heartbeat (OR = 7.534, 95% CI 5.899-9.623, P < .001), hepatitis B surface antigen positivity (OR = 4.588, 95% CI 1.021-20.625, P = .047), anti-hepatitis C virus positivity (OR = 4.691, 95% CI 1.352-16.280, P = .015), total bilirubin >1 mg/dL (OR = 1.743, 95% CI 1.469-2.068, P < .001), and blood urea nitrogen >21 mg/dL (OR = 1.941, 95% CI 1.546-2.436, P < .001) were significantly related to graft nonutilization. Steroids or diuretics administered prerecovery were significantly related to graft utilization (OR = 0.684, 95% CI 0.581-0.806, P < .001; OR = 0.744, 95% CI 0.634-0.874, P < .001; respectively).

CONCLUSIONS

The pediatric liver allograft utilization rate and risk factors for nonutilization of grafts were determined.

Burden of cytomegalovirus DNAemia among pediatric renal transplant patients on antiviral prophylaxis: A hospital-based analysis

INTRODUCTION

We examined the burden of CMV DNAemia and time to such events among renal transplant patients receiving CMV prophylaxis. We targeted the first year after transplantation, with the primary focus being on the first 3 months.

METHODS

We conducted a retrospective review of renal transplant patients (<18 years) who were transplanted and followed at our center between January 2007, and December 2017. Clinical and laboratory data were obtained from the medical records and laboratory databases.

RESULTS

Among 141 patients, the median age at transplant was 12.7 years (range 0.87-17.83 years). CMV DNAemia was detected in 33 of 77 patients eligible for prophylaxis (42.9%; 95% CI 31.6-54.6) during the first post-transplant year. Proportionately more D+R- patients were present among patients with DNAemia compared with those without DNAemia (15/38, 39.5% vs 16/103, 15.5%, P = .005). Median time to first positivity was 134 days (range 0-304 days). Eight patients had a positive PCR during the first 3 months (5.7% of all patients). Among those eligible for prophylaxis, 6.5% had DNAemia during the first 3 months while on prophylaxis. Among patients whose first positive PCR was after 3 months post-transplant, the median time to positivity was 52 days (range 13-214 days) after the end of prophylaxis.

CONCLUSIONS

Breakthrough CMV DNAemia was documented among children receiving antiviral prophylaxis. While routine monitoring while on prophylaxis might not be warranted for the majority of patients, studies are needed to determine the optimal indications for CMV PCR testing while on prophylaxis.

Evaluation of a change in cytomegalovirus prevention strategy following pediatric solid organ transplantation

BACKGROUND

An optimal cytomegalovirus (CMV) prevention strategy following solid organ transplantation (SOT) remains uncertain. This study reports on the rates of CMV events following a change in a local prevention guideline involving increased surveillance, earlier transition to oral valganciclovir, and decreased CMV-immunoglobulin use.

METHODS

A retrospective cohort study utilizing historical controls evaluated the rates of CMV invasive disease pre- and post-intervention among pediatric heart, liver, and kidney recipients. Outcomes were recorded for the 4 years pre- and post-intervention, 9/2009-10/2017. Logistic regression was used to estimate the risk of a CMV event.

RESULTS

There was no difference in the rates of CMV invasive disease between the two study groups (P = 1). An increase in the detection of CMV events occurred (P = .04), predominantly asymptomatic CMV infection. This increase was independently associated with increased surveillance testing among high-risk heart and liver recipients, aOR 1.08 (1.06-1.12). Surprisingly, 28.9% of CMV events occurred during antiviral prophylaxis.

CONCLUSIONS

Modification of the local CMV prevention guideline did not result in an increase in CMV invasive disease. CMV events occurred while on prophylaxis, highlighting a potential difference from adult solid organ transplant (SOT) and emphasizing the potential need for monitoring on prophylaxis in the pediatric population.

Impact of standardized protocols for cytomegalovirus disease prevention in pediatric solid organ transplant recipients

End-organ disease caused by CMV is a significant cause of morbidity and mortality in pediatric SOT recipients. Pediatric transplant centers have adopted various approaches for CMV disease prevention in this patient population. We observed significant practice variation in CMV testing, prophylaxis, and surveillance across SOT groups in our center. To address this, we implemented evidence-based standardized protocols and measured outcomes pre- and post-implementation of these protocols. We performed retrospective chart review for SOT recipients from 2009 to 2014 at Boston Children's Hospital. Using descriptive statistics, we measured practice improvement in provision of appropriate prophylaxis, occurrence of neutropenia and associated complications, and occurrence of CMV DNAemia and CMV disease pre- and post-intervention. The pre- and post-intervention periods included 141 and 109 patients, respectively. With the exception of kidney transplant recipients, provision of appropriate valganciclovir prophylaxis improved across SOT groups post-intervention (P < .01). Occurrence of >1 episode of neutropenia was greater in the preintervention period (30% vs 10%, P < .001). In both periods, neutropenia was associated with few episodes of invasive infections. The occurrence of CMV disease did not differ and was overall low. However, due to routine surveillance a significantly greater number of asymptomatic CMV DNAemia episodes were identified and treated in the post-intervention period. Implementation of standardized prevention protocols helped to improve the provision of appropriate prophylaxis to patients at risk for CMV acquisition, increased the diagnosis and treatment of asymptomatic CMV DNAemia, and decreased episodes of recurrent neutropenia in patients receiving prophylaxis.

The Third International Consensus Guidelines on the Management of Cytomegalovirus in Solid-organ Transplantation

Despite recent advances, cytomegalovirus (CMV) infections remain one of the most common complications affecting solid organ transplant recipients, conveying higher risks of complications, graft loss, morbidity, and mortality. Research in the field and development of prior consensus guidelines supported by The Transplantation Society has allowed a more standardized approach to CMV management. An international multidisciplinary panel of experts was convened to expand and revise evidence and expert opinion-based consensus guidelines on CMV management including prevention, treatment, diagnostics, immunology, drug resistance, and pediatric issues. Highlights include advances in molecular and immunologic diagnostics, improved understanding of diagnostic thresholds, optimized methods of prevention, advances in the use of novel antiviral therapies and certain immunosuppressive agents, and more savvy approaches to treatment resistant/refractory disease. The following report summarizes the updated recommendations.

Cytomegalovirus Infection under a Hybrid Strategy in Pediatric Liver Transplantation: A Single-Center Experience

PURPOSE

To evaluate the outcomes of a hybrid prophylactic strategy to prevent cytomegalovirus (CMV) disease in pediatric liver transplantation (LT) patients.

METHODS

CMV DNAemia was regularly monitored by quantitative nucleic acid amplification test (QNAT) and was quantified in all children. CMV infection and disease were defined according to the International Consensus Guidelines. The hybrid strategy against CMV infection consisted of universal 3-week prophylaxis and preemptive treatment of intravenous ganciclovir regardless of the recipient's serostatus.

RESULTS

A total of 143 children who underwent living donor LT were managed using the hybrid strategy. The overall incidence of CMV infection by QNAT was 48.3% (n=69/143). The highest CMV DNAemia positivity was observed in 49.2% (n=60/122) of children in the D+/R+ group, followed by 46.7% (n=7/15) in the D+/R- group. CMV disease was noted in 26.1% (n=18/69) patients. Forty-three (62.3%) children had undergone preemptive therapy consisting of intravenous ganciclovir. No symptomatic patients developed tissue-invasive disease, resulting in no CMV-associated mortality.

CONCLUSION

The incidence of CMV infection was high in pediatric LT patients despite the hybrid strategy. However, tissue-invasive disease in pediatric LT did not occur.

Infections in pediatric solid-organ transplant recipients

Solid-organ transplantation in pediatrics can be a life-saving procedure, but it cannot be accomplished without risk of infection-related morbidity and mortality. Evaluation of the recipient during candidacy and donor during evaluation can assist with identification of risk. Further, risk of infection from the surgical procedure can be mitigated through careful planning and attention to infection prevention processes. Finally, early recognition of infection posttransplant can limit the impact of these events.

Effectiveness of Preemptive Therapy for Cytomegalovirus Disease in Pediatric Liver Transplantation

BACKGROUND

Most pediatric liver transplantation (LT) centers administer long courses of prophylaxis against cytomegalovirus (CMV) without evidence of benefit and with significant drug exposure and costs. We aimed at evaluating overall outcomes, direct and putative indirect effects of CMV, possible impact of viremia and risk factors for CMV infection in pediatric LT recipients managed with ganciclovir-based preemptive therapy (PET).

METHODS

The records of all the children who underwent LT between 2008 and 2014 were retrospectively analyzed.

RESULTS

One hundred children were included. Three children had CMV disease; no CMV-related death or graft loss was recorded. The only identified risk factor for CMV infection was the donor/recipient serostatus (odds ratio, 17.23; 95% confidence interval, 1.88-157.87; P = 0.012), while viremia per se did not worsen LT outcomes, such as the incidence of acute rejection, Epstein-Barr virus infection, sepsis, biliary and vascular complications, nor graft dysfunction/loss or death at 3 and 5 years after LT. When compared with a historical cohort of children receiving ganciclovir prophylaxis, PET did not differ from prophylaxis for any of the selected outcomes, but was rather associated with lower antiviral drug exposure (6.4 ± 13 days vs 38.6 ± 14 days, P < 0.0001) and cost per patient (2.2 ± 3.9 k&OV0556; vs 6.6 ± 8.2 k&OV0556;, P = 0.001).

CONCLUSIONS

PET is effective in controlling CMV in children receiving LT, with lower costs and lower exposure to antivirals.

A risk-stratified approach to cytomegalovirus prevention in pediatric solid organ transplant recipients

Optimal strategies to prevent cytomegalovirus (CMV) disease following pediatric solid organ transplantation remain controversial. The purpose of this study was to review the outcomes of a risk-stratified strategy that uses a hybrid or prophylactic strategy for donor (D)+ recipient (R)- patients, a preemptive strategy for D+R+/D-R+, and clinical follow-up alone for D-R+ patients. A retrospective chart review was undertaken at the Stollery Children's Hospital in Edmonton, Alberta for pediatric solid organ transplants 2004 through 2010. Transplants were risk-stratified according to D/R CMV serostatus, organ group, and type of induction or rejection immunosuppression. The incidence of DNAemia and CMV disease and adverse effects from prophylaxis were analyzed. The study included 197 recipients. CMV DNAemia was detected in 49 of 197 recipients (24.8%), and CMV disease occurred in eight of 197 (4%) of which all but one were D+R-. All recovered. Seventeen of 142 recipients who received prophylaxis (12%) had hematologic toxicity. No other toxicities were identified. In conclusion, A risk-stratified approach resulted in very low rates of CMV disease with minimal adverse effects. Lowering the dosage rather than stopping antivirals in the face of neutropenia has the potential to further lower the rate of CMV disease.

Efficacy of Extended Valganciclovir Prophylaxis in Preventing Cytomegalovirus Infection in Pediatric Kidney Transplantation

Cytomegalovirus (CMV) is one of the most frequent opportunistic infection in renal transplant (RTx) recipients. Valganciclovir (VGC) has been showed to be safe and highly effective in prophylaxis of CMV infection in RTx recipients. Recently, an increase in delayed onset CMV disease has been noted with some arguing that longer prophylaxis may decrease the late-onset disease.

We retrospectively tested the hypothesis that extended term prophylaxis (ETP) of VGC for 12 months is more effective than short term prophylaxis (STP) of 6 months in preventing CMV infection and disease in pediatric RTx performed at the University of Florida from July 2003 to December 2010. In this period, all recipients underwent prospective CMV PCR (Polymerase Chain Reaction) monitoring and were maintained on similar immunosuppression.

Eighty six patients received RTx during that period. All eligible subjects had to have at least 12 months of graft survival and 18 months of follow up, leaving 73 eligible subjects in final study group. CMV infection or disease occurred in 6/29 (20%) in the STP group vs 6/44 (14%) in the ETP group with no statistical significant difference (P= 0.42). Donor positive/recipients negative CMV serology status (D+/R-) were associated with a higher risk of CMV infection in both univariate and multivariate analysis (P=0.01). Anemia and Leucopenia directly associated with VGC were similar in both groups (P=0.58 and P=0.2 respectively). Biopsy-proven acute rejection was also non-significant in both groups (P=0.39).

Although ETP for CMV from 6 months to 12 months is safe and has minimal adverse effect, it did not reduce CMV infection or disease. Further controlled studies in pediatrics age group are considered to compare longer versus shorter periods of prophylaxis and their impact on prevention of CMV infection, resistance, cost, and toxicity.

Clinical pharmacokinetics and pharmacodynamics of ganciclovir and valganciclovir in children with cytomegalovirus infection

INTRODUCTION

Among infants and immunocompromised children cytomegalovirus (CMV) is associated with significant morbidity and mortality.

AREAS COVERED

This review describes the clinical pharmacokinetics and pharmacodynamics of ganciclovir and valganciclovir for the treatment and prevention of CMV infection in children.

EXPERT OPINION

A 24-h ganciclovir area under the concentration versus time curve (AUC₀₋₂₄) of 40 - 60 μg h/ml decreased the risk of CMV infection for adults undergoing CMV prophylaxis. For adults undergoing treatment for active CMV disease, a target AUC₀₋₁₂ of 40 - 60 μg h/ml has been suggested. The applicability of these targets to children remains uncertain; however, with the most sophisticated dosing regimens developed to date only 21% of patients are predicted to reach these targets. Moving forward, identification of optimal pediatric ganciclovir and valganciclovir dosing regimens may involve the use of an externally validated pediatric population pharmacokinetic model for empirical dosing, an optimal sampling strategy for collecting a minimal number of blood samples for each patient and Bayesian updating of the dosing regimen based on an individual patient's pharmacokinetic profile.

Current prevention strategies against cytomegalovirus in the studies in pediatric liver transplantation (SPLIT) centers

Cytomegalovirus (CMV) continues to be a significant posttransplant infectious complication after pediatric liver transplant (PLT). The optimal prevention strategy is not currently known. To assess current CMV prevention practices, a web-based survey was conducted within the North American Studies in Pediatric Liver Transplantation (SPLIT) network. Twenty-nine of the 31 centers (94%) surveyed responded. Only seven centers reported evidence-based development of protocols. For most at-risk (donor or recipient CMV seropositive) PLT recipients, a prophylactic strategy predominates current practice. For high-risk (D+/R-), only three centers used nonprophylaxis-based protocols: one preemptive and two sequential/hybrid. Duration of prophylaxis ranged from 84 to 730 days with 14 centers using around 100 days and nine centers using around 200 days. Initial therapy with ganciclovir followed by valganciclovir was the most common strategy. For lower-risk recipients (CMV D-/R-), more centers (10/29) employed a preemptive strategy while the remainder described prophylaxis (15) and sequential/hybrid (3) strategies. Prophylaxis predominates current CMV prevention strategies for at-risk recipients within SPLIT. The variation in duration of therapy provides the opportunity to perform comparative effectiveness studies within SPLIT.

Prevention of cytomegalovirus following solid organ transplantation: a literature review

CMV is the most common opportunistic infection affecting SOT recipients. Although current strategies to prevent both CMV infection and disease have been effective, CMV related complications continue to occur, particularly late-onset CMV disease. This literature review article examines the benefits and disadvantages of different prevention modalities, and presents emerging strategies to better prevent CMV in organ transplant recipients.

Updated international consensus guidelines on the management of cytomegalovirus in solid-organ transplantation

Cytomegalovirus (CMV) continues to be one of the most common infections after solid-organ transplantation, resulting in significant morbidity, graft loss, and adverse outcomes. Management of CMV varies considerably among transplant centers but has been become more standardized by publication of consensus guidelines by the Infectious Diseases Section of The Transplantation Society. An international panel of experts was reconvened in October 2012 to revise and expand evidence and expert opinion-based consensus guidelines on CMV management, including diagnostics, immunology, prevention, treatment, drug resistance, and pediatric issues. The following report summarizes the recommendations.

Assessment of Cytomegalovirus Hybrid Preventative Strategy in Pediatric Heart Transplant Patients

BACKGROUND

Prevention strategies for cytomegalovirus (CMV) in pediatric transplant recipients are sparsely reported. A hybrid strategy that combines prophylaxis with preemptive therapy using serial CMV viral load monitoring is an emerging option. We report our clinical outcomes with a hybrid strategy in pediatric heart transplant recipients.

METHODS

A retrospective chart review was performed for pediatric heart transplant recipients who received a hybrid strategy of 2-4 weeks intravenous ganciclovir followed by serial whole blood CMV monitoring from 2002 to 2010. Subject demographics, medications, drug levels, serial CMV viral loads, intravascular ultrasound and angiography reports, and histopathology were collected. Descriptive statistics and patient groups were compared using χ(2), Fisher's exact, and Wilcoxon rank-sum tests.

RESULTS

Twelve females and 13 males, ranging from 4 months to 19 years of age, underwent 26 heart transplants. Mean follow-up was 39 months (range, 5-94 months). Fourteen (54%) subjects were CMV donor (D) + /recipient (R) - , 8 (31%) were D + /R + , and 4 (15%) were D - /R + . Six subjects (23%) died of complications unrelated to CMV. Median prophylaxis duration was 25 days (range, 7-70 days). Ten (38%) subjects developed CMV infection: 1 subject had 2 episodes of CMV syndrome, and 1 subject had 2 episodes CMV. Although 6 of 14 patients with coronary artery vasculopathy had prior CMV, no association was found (P = .81). Median time to first CMV DNAemia was 2.3 months (range, 9 days to 24.8 months). Median time to viral load clearance was 29 days (range, 4-233 days). In addition, 25 D - /R- patients were transplanted and received no prophylaxis; 2 (8%) patients developed CMV infection.

CONCLUSIONS

Pediatric heart transplant recipients who were at risk for CMV and treated with a novel preventative hybrid strategy developed CMV infection, syndrome, and disease at rates similar to those reported in literature for prophylactic strategies.

Correlation and clinical utility of pp65 antigenemia and quantitative polymerase chain reaction assays for detection of cytomegalovirus in pediatric renal transplant patients

qPCR and pp65 antigenemia assays are used to monitor CMV infection in renal transplant recipients, but correlation of assays in a pediatric population has not been evaluated. Paired CMV real-time qPCR and pp65 antigenemia tests from 882 blood samples collected from 115 pediatric renal transplant recipients were analyzed in this retrospective cohort study for the strength of association and clinical correlates. The assays correlated well in detecting infection (κ = 0.61). Higher qPCR values were demonstrated with increasing levels of antigenemia (p < 0.01). Discordant test results were associated with antiviral treatment (OR 4.33, p < 0.01) and low-level viremia, with odds of concordance increasing at higher qPCR values (OR 3.67, p < 0.01), and no discordance occurring above 8500 genomic equivalents/mL. Among discordant samples, neither test preceded the other in detecting initial infection or in returning to negative while on treatment. Only two cases of disease occurred during the two-yr study period. With strong agreement in the detection of CMV infection, either qPCR or pp65 antigenemia assays can be used effectively for monitoring pediatric renal transplant patients for both detection and resolution of infection.

Infections in Pediatric Solid Organ Transplant Recipients

Infectious complications are an important cause of morbidity and mortality in children undergoing solid organ transplantation. Knowledge gained over the last 30 years provides a growing understanding of these infections. This review identifies risk factors for and timing of infections describes the common infectious syndromes and pathogens seen in children undergoing solid organ transplantation, and reviews preventive strategies.

Risk of infection and prevention in pediatric patients with IBD: ESPGHAN IBD Porto Group commentary

Combined immunosuppression by immunomodulators and biological therapy has become standard in the medical management of moderate-to-severe inflammatory bowel disease (IBD) because of clearly demonstrated efficacy. Clinical studies, registries, and case reports warn of the increased risk of infections, particularly opportunistic infections; however, already in the steroid monotherapy era, patients are at risk because it is accepted that a patient should be considered immunosuppressed when receiving a daily dose of 20 mg of prednisone for 2 weeks. Prescriptions increasingly involve azathioprine, methotrexate, and various biological agents. The TREAT registry evaluated safety in >6000 adult patients, half of them treated with infliximab (IFX) for about 1.9 years. IFX-treated patients had an increased risk of infections and this was associated with disease severity and concomitant prednisone use. The REACH study, evaluating the efficacy of IFX in children with moderate-to-severe Crohn disease, refractory to immunomodulatory treatment, reports serious infections as the major adverse events and their frequency is higher with shorter treatment intervals. The combination of immunosuppressive medications is a risk factor for opportunistic infections. Exhaustive guidelines on prophylaxis, diagnosis, and management of opportunistic infections in adult patients with IBD have been published by a European Crohn's and Colitis Organization working group, including clear evidence-based statements. We have reviewed the literature on infections in pediatric IBD as well as the European Crohn's and Colitis Organization guidelines to present a commentary on infection prophylaxis for the pediatric age group.

Overview of the diagnosis of cytomegalovirus infection

Cytomegalovirus (CMV) is recognized as the most common congenital viral infection in humans and an important cause of morbidity and mortality in immunocompromised hosts. This recognition of the clinical importance of invasive CMV disease in the setting of immunodeficiency and in children with congenital CMV infection has led to the development of new diagnostic procedures for the rapid identification of CMV. Diagnosis of acute maternal CMV infection by the presence of immunoglobulin (Ig)M and low-avidity IgG requires confirmation of fetal infection, which is typically performed using polymerase chain reaction (PCR) assays for CMV on amniotic fluid. Viral culture of the urine and saliva obtained within the first two weeks of life continues to be the gold standard for diagnosis of congenitally-infected infants. PCR assays of dried blood spots from newborns have been shown to lack sufficient sensitivity for the identification of most neonates with congenital CMV infection for universal screening purposes. However, saliva PCR assays are currently being assessed as a useful screening method for congenital CMV infection. In the immunocompromised host, newer rapid diagnostic assays, such as phosphoprotein 65 antigenemia and CMV real-time PCR of blood or plasma have allowed for preemptive treatment, reducing morbidity and mortality. However, lack of standardized real-time PCR protocols hinders the comparison of data from different centers and the development of uniform guidelines for the management of invasive CMV infections in immunocompromised individuals.

Dynamics of cell-mediated immune responses to cytomegalovirus in pediatric transplantation recipients

CMI responses, combined with quantification of CMV DNA (DNAemia), may identify transplantation recipients at risk for invasive disease. PBMC were collected in pediatric transplantation candidates at one, three, and six months post-transplant in 10 subjects (six renal, three cardiac, one stem cell) and at single time points in eight HC and 14 children greater than one yr post-transplant (LTTx). Cells were stimulated with anti-CD3mAb or CMV pp65 peptide pools and responses assessed by IFNG enzyme-linked immunosorbent spot assay and cytokine secretion. IFNG responses to anti-CD3mAb were significantly lower pretransplant relative to HC and were further decreased at one and three months post-transplant, but recovered to levels comparable to HC by six months. Responses to pp65 among CMV-seropositive recipients followed a similar pattern but recovered by three months. CMV-seropositive LTTx and HC showed a Th1 cytokine response to pp65 stimulation. Three LTTx subjects developed CMV DNAemia; two demonstrated decreased responses to anti-CD3mAB (and pp65 in the CMV seropositive subject) at the onset of DNAemia, which recovered as DNAemia resolved. Monitoring CMI in children is feasible and may provide an adjunct biomarker to predict CMV progression and recovery.

Clinical utility of molecular surveillance for cytomegalovirus after antiviral prophylaxis in high-risk solid organ transplant recipients

BACKGROUND

Cytomegalovirus (CMV) disease after discontinuation of prophylaxis is a significant problem for CMV-seronegative recipients of CMV-seropositive organs (donor seropositive and recipient seronegative [D+/R-]). Virologic monitoring after prophylaxis has been proposed as a way to prevent late-onset disease.

METHODS

We reviewed the efficacy of this strategy. CMV D+/R- organ transplant recipients received 3 to 6 months of antiviral prophylaxis, and then viral loads were performed weekly for 8 weeks. Preemptive antiviral therapy was initiated at a predefined threshold.

RESULTS

Seventy-one CMV D+/R- patients were assessed. Symptomatic CMV disease occurred in 29 of 71 (40.8%) patients during the first-year posttransplant. A significant portion of disease occurred only after the 8-week surveillance period (n=16). Viremia occurred in 19 of 71 (26.8%) patients during the 8-week surveillance. Preemptive therapy was successfully used in only 3 of 19 (15.8%) viremic patients with no further disease development. The remaining patients cleared low-level viremia spontaneously (n=3) or had CMV disease (n=13) either at the first detection of viremia or before preemptive therapy initiation because of rapid viral load doubling (median doubling time 1.1 days).

CONCLUSION

CMV D+/R- patients had significant incidence of late-onset disease after prophylaxis. However, the use of a preemptive after prophylaxis strategy was of limited benefit in this group because of rapid viral doubling times and disease occurring after the surveillance period.

Cytomegalovirus risk, prevention, and management in pediatric solid organ transplantation

Cytomegalovirus (CMV) is an important cause of morbidity and mortality in children who have received organ transplants. Patients have been reported to be at differential risk for CMV disease based on the serostatus of the donor and recipient with highest risk reported for CMV seronegative recipients who receive an organ from a CMV seropositive donor. Prophylaxis with ganciclovir and/or oral valganciclovir is reasonable to attempt to prevent CMV infections. A hybrid strategy bridging prophylaxis and pre-emptive therapy appears to be emerging as an additional method to prevent CMV disease. However, there is no agreement on the optimal schedule of testing, duration and dosing of antiviral medications or the role of immunoglobulin therapy. This manuscript will review the most recent literature and recommendations for the prophylaxis and treatment of CMV infections and disease in pediatric transplant recipients. Multicenter, randomized, clinical studies involving several pediatric transplant centers are needed to determine the best strategies to prevent and treat CMV infections in these patients.