Presentation, anagement, and outcomes of norovirus in adult and pediatric solid organ and hematopoietic stem cell transplant recipients: A multicenter, retrospective study

BACKGROUND

Norovirus (NoV) can cause chronic relapsing and remitting diarrhea in immunocompromised patients.  Few multicenter studies have described the clinical course, outcomes, and complications of chronic NoV in transplant recipients.

METHODS

A multicenter retrospective study of adult and pediatric SOT and HSCT recipients diagnosed with NoV between November 1, 2017, and February 28, 2021. Data were obtained from electronic medical records (EMR) and entered into a central REDCap database. Descriptive statistics were calculated.

RESULTS

A total of 280 NoV+ patients were identified across eight sites. The majority were adults (74.1%) and SOT recipients (91.4%). Initial diagnosis of NoV occurred a median of 36 months post-Tx (IQR [15.0, 90.0]). Most NoV cases had >3 diarrheal episodes daily (66.0%), nausea and vomiting (60.1%). Duration of diarrhea varied greatly (median = 10 days, mean = 85.9 days, range (1, 2100)). 71.3% were hospitalized. Adjustment of immunosuppression, including reduction and discontinuation of mToR inhibitor, CNI, and/or MMF, was the most common management intervention for NoV. Other therapies resulted only in temporary improvement. Four patients died within 30 days and three others died by 180 days postdiagnosis. Clinically significant renal dysfunction was observed in 12.5% by 30 days and 21.4% by 180 days post-NoV diagnosis.

CONCLUSION

In HSCT and SOT patients, NoV frequently resulted in severe symptoms, prolonged diarrhea (30% persistent with diarrhea for >30 days), and clinically significant renal dysfunction (up to 21% of patients). Utilized therapies did not reliably result in the resolution of infection demonstrating the need for more effective treatment.

Current and Emerging Antiviral Agents in the Prevention and Treatment of Cytomegalovirus in Pediatric Transplant Recipients

Despite current prophylaxis regimens, cytomegalovirus (CMV) is common in hematopoietic cell transplantation (HCT) and solid organ transplantation (SOT) and remains a significant cause of morbidity and mortality. Newer antiviral medications are reshaping the landscape for prevention and treatment of CMV DNAemia, infection, and disease. Letermovir is approved for CMV prevention in adult HCT patients and is attractive due to the absence of marrow suppression seen with ganciclovir/valganciclovir. Letermovir should not be routinely used for CMV treatment due to its low threshold for resistance. Maribavir is approved for the treatment of refractory or resistant CMV disease in HCT and SOT recipients ≥12 years of age, though it has no current role in CMV prevention. More research is needed to fully elucidate the roles, efficacy, and safety of these newer agents in prevention and treatment of CMV in pediatric transplant recipients.

Omicron Infections in Vaccinated Pediatric Solid Organ Transplant Recipients

SARS-CoV-2 infection during the Omicron period was frequent amongst a cohort of vaccinated pediatric solid organ transplant recipients (pSOTRs) despite robust anti-receptor-binding domain (anti-RBD) antibody response, suggesting poor neutralizing capacity against Omicron subvariants. Breakthrough infections among pSOTRs were overall limited in severity.

Anti-spike antibody durability after SARS-CoV-2 vaccination in adolescent solid organ transplant recipients

BACKGROUND

Adolescent solid organ transplant recipients (aSOTRs) who received three doses of the COVID-19 mRNA vaccine experience high seroconversion rates and antibody persistence for up to 3 months. Long-term antibody durability beyond this timeframe following three doses of the SARS-CoV-2 mRNA vaccine remains unknown. We describe antibody responses 6 months following the third vaccine dose (D3) of the BNT162b2 mRNA vaccination among aSOTRs.

METHODS

Participants in a multi-center, observational cohort who received the third dose of the vaccine were analyzed for antibodies to the SARS-CoV-2 spike protein receptor-binding domain (Roche Elecsys anti-SARS-CoV-2-S positive: ≥0.8, maximum: >2500 U/mL). Samples were collected at 1-, 3-, and 6-months post-D3. Participants were surveyed at each timepoint and at 12-months post-D3.

RESULTS

All 34 participants had positive anti-RBD antibody titers 6 months post-D3. Variations in titers occurred between 3 and 6 months post-D3, with 8/28 (29%) having decreased antibody levels at 6 months compared to 3 months and 2/28 (7%) reporting increased titers at 6 months. The remaining 18/28 (64%) had unchanged antibody titers compared to 3-month post-D3 levels. A total of 4/34 (12%) reported breakthrough infection within 6 months and 3/32 (9%) reported infection after 6-12 months following the third dose of the SARS-CoV-2 mRNA vaccine.

CONCLUSIONS

The results suggest that antibody durability persists up to 6 months following three doses of the SARS-CoV-2 mRNA in aSOTRs. Demography and transplant characteristics did not differ for those who experienced antibody weaning. Breakthrough infections did occur, reflecting immune-evasive nature of novel variants such as Omicron.

Safety and Immunogenicity of Live Viral Vaccines in a Multicenter Cohort of Pediatric Transplant Recipients

Importance

Live vaccines (measles-mumps-rubella [MMR] and varicella-zoster virus [VZV]) have not been recommended after solid organ transplant due to concern for inciting vaccine strain infection in an immunocompromised host. However, the rates of measles, mumps, and varicella are rising nationally and internationally, leaving susceptible immunocompromised children at risk for life-threating conditions.

Objective

To determine the safety and immunogenicity of live vaccines in pediatric liver and kidney transplant recipients.

Design, Setting, and Participants

This cohort study included select pediatric liver and kidney transplant recipients who had not completed their primary MMR and VZV vaccine series and/or who displayed nonprotective serum antibody levels at enrollment between January 1, 2002, and February 28, 2023. Eligibility for live vaccine was determined by individual US pediatric solid organ transplant center protocols.

Exposures

Exposure was defined as receipt of a posttransplant live vaccine. Transplant recipients received 1 to 3 doses of MMR vaccine and/or 1 to 3 doses of VZV vaccine.

Main Outcome and Measure

Safety data were collected following each vaccination, and antibody levels were obtained at 0 to 3 months and 1 year following vaccination. Comparisons were performed using Mann-Whitney U test, and factors associated with development of postvaccination protective antibodies were explored using univariate analysis.

Results

The cohort included 281 children (270 [96%] liver, 9 [3%] kidney, 2 [1%] liver-kidney recipients) from 18 centers. The median time from transplant to enrollment was 6.3 years (IQR, 3.4-11.1 years). The median age at first posttransplant vaccine was 8.9 years (IQR, 4.7-13.8 years). A total of 202 of 275 (73%) children were receiving low-level monotherapy immunosuppression at the time of vaccination. The majority of children developed protective antibodies following vaccination (107 of 149 [72%] varicella, 130 of 152 [86%] measles, 100 of 120 [83%] mumps, and 124 of 125 [99%] rubella). One year post vaccination, the majority of children who initially mounted protective antibodies maintained this protection (34 of 44 [77%] varicella, 45 of 49 [92%] measles, 35 of 42 [83%] mumps, 51 of 54 [94%] rubella). Five children developed clinical varicella, all of which resolved within 1 week. There were no cases of measles or rubella and no episodes of graft rejection within 1 month of vaccination. There was no association between antibody response and immunosuppression level at the time of vaccination.

Conclusions and Relevance

The findings suggest that live vaccinations may be safe and immunogenic after solid organ transplant in select pediatric recipients and can offer protection against circulating measles, mumps, and varicella.

Survey of pediatric transplant center practices regarding COVID-19 vaccine mandates for transplant candidates and living donors and use of COVID-19-positive deceased organs

BACKGROUND

COVID-19 vaccine is recommended for individuals ages ≥6 months; however, whether vaccination should be mandated for transplant candidates and living donors remains controversial. This study assessed COVID-19 policies at US pediatric solid organ transplant centers.

METHODS

A 79-item survey was emailed between March and April 2022 to 200 UNOS Medical Directors detailing center COVID-19 vaccine policies for transplant candidates and living donors and use of grafts from COVID-19-positive deceased donors.

RESULTS

The response rate was 77% (154/200). For children aged 5-15 years, 23% (35/154 centers) have a COVID-19 vaccine mandate, 27% (42/154) anticipate implementing a future mandate, and 47% (72/154) have not considered or do not anticipate implementing a mandate. For children ≥16 years, 32% (50/154 centers) have a COVID-19 vaccine mandate, 25% (39/154) anticipate implementing a future mandate, and 40% (62/154) have not considered or do not anticipate implementing a mandate. The top two reasons for not implementing a COVID-19 vaccine mandate were concerns about penalizing a child for their parent's decision and worsening inequities in transplant. Of 85 kidney and liver living donor centers, 32% (27/85) require vaccination of donors. Twenty percent (31/154) of centers accept organs from COVID-19-positive deceased donors.

CONCLUSIONS

There is great variation among pediatric SOT centers in both the implementation and details of COVID-19 vaccine mandates for candidates and living donors. To guide more uniform policies, further data are needed on COVID-19 disease, vaccine efficacy, and use of grafts from donors positive for COVID-19 in the pediatric transplant population.

Absolute Monocyte Count as Early and Safe Marker for Antibiotic Cessation in Febrile Neutropenia Without Etiology in Pediatric Oncology Patients

BACKGROUND

There is no practice standard regarding antibiotic duration in children with cancer and unexplained febrile neutropenia (FN). We hypothesized that absolute monocyte count (AMC) and absolute phagocyte count (APC= ANC + AMC + bands) are more sensitive, earlier, and safe markers of antibiotic cessation compared with absolute neutrophil count (ANC).

METHODS

A retrospective review of FN episodes (FNEs) in pediatric oncology patients was conducted between 2009 and 2016. Included patients were afebrile for 24 hours and without an identified infectious source at antibiotic cessation. Primary endpoints, including recurrent fever, readmission, bloodstream infection, microbiologically documented infection, and adverse outcomes, were assessed 10 days after antibiotic cessation and compared among different bone marrow recovery parameters (ANC, AMC, APC). Secondary endpoints included length of FN stay, antibiotic-free days, and cost.

RESULTS

Three hundred ninety-one FNEs in 235 patients were included. Three groups were compared based on ANC (cells/μL) at the time of antibiotic cessation: < 200 in 102 (26%), 200 to 500 in 111 (28%), and >500 in 178 (46%). No statistically significant differences in primary endpoints were identified among the 3 ANC groups; however, a trend toward unfavorable outcomes in the ANC ≤200 cells/μL group compared with the ANC >200 cells/μL was observed. Primary endpoints based on AMC >100 cells/μL at the time of antibiotic cessation showed statistically significant favorable outcomes compared AMC ≤100 cells/μL (80%, 88%, 90%, 89%, and 93% risk reduction in recurrent fever, readmission, new bloodstream infection, new microbiologically documented infection, and adverse events, respectively). Similar favorable results were seen when APC >300 cells/μL was used as a threshold for antibiotic cessation. The median length of stay for FN if discharged when AMC >100 cells/μL was 3 days shorter and associated with fewer unfavorable outcomes, thus resulting in fewer hospital days, fewer antibiotic days, and decreased cost.

CONCLUSION

Our results suggest that AMC >100 cells/μL (regardless of ANC) or APC >300 cells/μL may be safe thresholds for empiric antibiotic cessation and result in reduced unfavorable clinical outcomes within 10 days postdischarge, reduced antibiotic days of therapy and reduced health care costs. Further prospective studies are needed to validate AMC as an accurate surrogate marker for antibiotic cessation in FNEs in children with cancer.

2162. Risk Factors Associated with Hospitalization among 0 to 21 Years Old Patients with Active Asthma/Active Airway Disease: Preliminary Findings from Multi-Center Study Across United States

Background

More data are needed to understand the risk for COVID-19 severity among pediatric asthma patients. We present findings from a national registry characterizing COVID-19 hospitalizations among pediatric asthma patients.

Methods

Data were obtained from the Pediatric COVID-19 US Registry, which included medical records of COVID-19 cases &lt; 21 years old between March 2020 and May 2021. Those with asthma were eligible while immunocompromised and transplant cases were excluded. Descriptive statistics and chi-square tests were performed.

Results

Of the 1089 eligible asthma cases, half were 12 to 17 years old [Figure 1], the majority were male [Figure 2], a third Black African American [Figure 3], and most were Non-Hispanic/Latino 825 (76%). 242 (22%) reported a history of smoking.

A fourth of cases (257 (23.6%) were hospitalized for COVID-19. More than half (54%) reported asthma as their only pre-existing condition. The majority (n=71, 28%) were taking regular inhaled corticosteroids. Almost half (n=120, 47%) had abnormal chest radiographic findings, 20 (7.8%) had abnormal CT findings, and 24 (9%) progressed to lower respiratory infection. About 10% (n=25) needed mechanical ventilation. A third (n=88, 34%) required ICU care with 33% of those receiving inhaled corticosteroids. A quarter needed mechanical ventilation [Figure 5].

Compared to asthma patients not hospitalized for COVID-19, those hospitalized were significantly (P&lt; 0.05) more likely to be non-Hispanic, havemultiple pre-existing conditions, and be obese [Figure 6]. Compared to those not admitted to ICU, ICU cases were significantly more likely to be obeseand be diagnosed with MIS-C [Figure 7].

Demographics

The majority of cases (N=479, 44%) were between 12 and 17 years old, Male (N=610,56%) and Black or African American (N=410, 38%).

Clinical Characteristics

Risk factors assessment

Conclusion

This is one of the first national studies examining COVID-19 among pediatric cases with asthma. Our data suggest that children with asthma who have multiple pre-existing conditions and/or are obese have a higher risk for hospitalization. These early data may aid clinicians in developing future prospective studies to understand COVID-19 risk among this vulnerable population.

Disclosures

Lara A. Danziger-Isakov, MD, Ansun BioPharma: Contracted clinical research|Astellas: Contracted clinical research|GSK: Advisor/Consultant|Merck: Advisor/Consultant|Merck: Contracted clinical research|Pfizer: Contracted clinical research|Takeda: Grant/Research Support|Takeda: Contracted clinical research|Viracor: Grant/Research Support.

1119. Covid-19 Mab Use in High-Risk Pediatric Patients

Background

Effective therapeutic agents for the treatment of COVID-19 have been investigated since the onset of the pandemic. Monoclonal antibodies targeting the spike protein of SARS-CoV-2 have been developed for treatment of mild or moderate COVID disease in high-risk populations. Despite widespread use in the adult population, data are limited on the safety and efficacy of monoclonal antibody infusions in the adolescent and young adult population.

Methods

Patients who received bamlanivimab, bamlanivimab-etesevimab, casirivimab-imdevimab, or sotrovimab for treatment of mild COVID disease at Cincinnati Children’s Hospital Medical Center from 5/1/2020 through 3/1/2022 were identified retrospectively. In accordance with the FDA EUA, patients were eligible for monoclonal antibody administration if they were ≥12 years of age, weighed ≥40kg, and were at high risk of progressing to severe disease or hospitalization.

Results

Ninety-four patients received monoclonal antibody therapy, of which 14 (13.5%) received either bamlanivimab or bamlanivimab-etesevimab, 54 (51.9%) received casirivimab-imdevimab, and 26 (25%) received sotrovimab. Ten patients (10.6%) experienced one or more adverse events. Of those, 2 (14.3%) received either bamlanivimab or bamlanivimab-etesivimab, 7 (12.9%) received casirivimab-imdevimab, and 1 (3.8%) received sotrovimab. Most common symptoms include rash, nausea, and throat irritation (table R1), the majority (90%) of which were mild, either self-resolving with infusion cessation (60%) or persistent but requiring no medical intervention (30%) (table R2). Of the patients who experienced adverse events, only 1 (10%) received medical intervention - epinephrine. No life-threatening events or deaths occurred. Within 90 days of receiving a monoclonal antibody, 15 patients (15.9%) required additional medical care for ongoing COVID symptoms (table R3). Eight (53.3%) of these were either hospitalized or received escalation of care while already in the hospital. Table R1.

Infusion-related adverse events. Of note, several patients had more than one symptom. Table R2.

Classification of adverse events by grade and monoclonal antibody. Grade I events are defined as mild and generally not bothersome. Grade II events are defined as moderate: bothersome, but not dangerous. Grade III events are defined as medically significant, but not immediately life-threatening, and often require medical intervention. Table R3.

Patients who required additional medical care for ongoing COVID-19 symptoms within 90 days of receiving a monoclonal antibody.

Conclusion

Overall, monoclonal antibodies are safe, largely well-tolerated COVID-19 therapies in high-risk adolescent and young adult populations.

Disclosures

Grant Schulert, MD, PhD, Novartis: Advisor/Consultant Paul Spearman, MD, CyanVac: Grant/Research Support|Meissa Vaccines: Grant/Research Support Grant C. Paulsen, MD, AstraZeneca: Grant/Research Support|Moderna: Grant/Research Support|Pfizer: Grant/Research Support Lara A. Danziger-Isakov, MD, Ansun BioPharma: Contracted clinical research|Astellas: Contracted clinical research|GSK: Advisor/Consultant|Merck: Advisor/Consultant|Merck: Contracted clinical research|Pfizer: Contracted clinical research|Takeda: Grant/Research Support|Takeda: Contracted clinical research|Viracor: Grant/Research Support.

The impact of COVID-19 on the pediatric solid organ transplant population

The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has significantly impacted all aspects of healthcare including solid organ transplantation. In this review, we discuss the specific impact of COVID-19 on the pediatric solid organ transplant population including access to grafts for pediatric transplant candidates as well as COVID-19 disease manifestations in pediatric transplant recipients. We address the current knowledge of prevention and management of COVID-19 in pediatric transplant recipients and provide additional information regarding social distancing, infection prevention and return to school.

Return to School and COVID-19 Vaccination for Pediatric Solid Organ Transplant Recipients in the United States: Expert Opinion for 2021-2022

The COVID-19 pandemic continues to generate challenges for pediatric solid organ transplant (SOT) recipients and their families. As rates of COVID-19 fluctuate, new SARS-CoV-2 variants emerge, and adherence to and implementation of mitigation strategies vary from community to community, questions remain about the best and safest practices to prevent COVID-19 in vulnerable patients. Notably, decisions about returning to school remain difficult. We assembled a team of specialists in pediatric infectious diseases, transplant infectious diseases, public health, transplant psychology, and infection prevention and control to re-address concerns about school re-entry, as well as COVID-19 vaccines, for pediatric SOT recipients in the United States in 2021. Based on available literature and guidance from national organizations, we generated expert statements specific to pediatric SOT recipients focused on school attendance in 2021.

Early stool microbiome and metabolome signatures in pediatric patients undergoing allogeneic hematopoietic cell transplantation

BACKGROUND

The contribution of the gastrointestinal tract microbiome to outcomes after allogeneic hematopoietic cell transplantation (HCT) is increasingly recognized. Investigations of larger pediatric cohorts aimed at defining the microbiome state and associated metabolic patterns pretransplant are needed.

METHODS

We sought to describe the pretransplant stool microbiome in pediatric allogenic HCT patients at four centers. We performed shotgun metagenomic sequencing and untargeted metabolic profiling on pretransplant stool samples. Samples were compared with normal age-matched controls and by clinical characteristics. We then explored associations between stool microbiome measurements and metabolite concentrations.

RESULTS

We profiled stool samples from 88 pediatric allogeneic HCT patients, a median of 4 days before transplant. Pretransplant stool samples differed from healthy controls based on indices of alpha diversity and in the proportional abundance of specific taxa and bacterial genes. Relative to stool from healthy patients, samples from HCT patients had decreased proportion of Bacteroides, Ruminococcaeae, and genes involved in butyrate production, but were enriched for gammaproteobacterial species. No systematic differences in stool microbiome or metabolomic profiles by age, transplant indication, or hospital were noted. Stool metabolites demonstrated strong correlations with microbiome composition.

DISCUSSION

Stool samples from pediatric allogeneic HCT patients demonstrate substantial dysbiosis early in the transplant course. As microbiome disruptions associate with adverse transplant outcomes, pediatric-specific analyses examining longitudinal microbiome and metabolome changes are imperative to identify causal associations and to inform rational design of interventions.

Risk and reward: Balancing safety and maximizing lung donors during the COVID-19 pandemic

In response to Kaul et al.’s article (page 2885), the editorialists recommend testing lower respiratory tract samples from potential deceased lung donors for SARS-CoV-2 to mitigate the risk of donor derived disease.

Immunity to varicella, measles, and mumps in patients evaluated for lung transplantation

Vaccine-preventable viral infections are associated with increased risk of morbidity and mortality in post-transplant patients on immunosuppression regimens. Therefore, we studied rates of immunity against vaccine-preventable viruses in lung transplantation (LTx) candidates and their associations with underlying lung disease and clinical characteristics. We retrospectively studied 1025 consecutive adult patients who underwent first-time evaluation for LTx at a single center between January 2016 and October 2018. Viruses studied included varicella zoster (VZV), measles, and mumps. Young age (17-48 years old) was negatively associated with immunity for VZV (OR 4.54, p < .001), measles (OR 15.45, p < .001) and mumps (OR 3.1, p < .001), as compared to those 65+. Many LTx candidates with cystic fibrosis (CF) had undetectable virus-specific antibody titers including: 13.5% for VZV, 19.1% for measles, and 15.7% for mumps with significant odds of undetectable titers for VZV (OR 4.54, p < .001) and measles (OR 2.32, p = .010) as compared to those without CF. Therefore, a substantial number of patients undergoing LTx evaluation had undetectable virus-specific antibody titers. Our results emphasize the importance of screening for immunity to vaccine-preventable infections in this population and the need for revaccination in selected patients to boost their humoral immunity prior to transplantation.

Return to School for Pediatric Solid Organ Transplant Recipients in the United States During the Coronavirus Disease 2019 Pandemic: Expert Opinion on Key Considerations and Best Practices

The coronavirus disease 2019 (COVID-19) pandemic has created many challenges for pediatric solid organ transplant (SOT) recipients and their families. As the pandemic persists, patients and their families struggle to identify the best and safest practices for resuming activities as areas reopen. Notably, decisions about returning to school remain difficult. We assembled a team of pediatric infectious diseases (ID), transplant ID, public health, transplant psychology, and infection prevention and control specialists to address the primary concerns about school reentry for pediatric SOT recipients in the United States. Based on available literature and guidance from national organizations, we generated consensus statements pertaining to school reentry specific to pediatric SOT recipients. Although data are limited and the COVID-19 pandemic is highly dynamic, our goal was to create a framework from which providers and caregivers can identify the most important considerations for each pediatric SOT recipient to promote a safe return to school.

Sterility Cultures Following Pancreatectomy with Islet Autotransplantation in the Pediatric Population: Do They Matter?

BACKGROUND

Pancreatectomy with islet autotransplantation (IAT) is a treatment option for children with debilitating chronic pancreatitis. Sterility cultures from preservation solutions are often positive, yet their impact has not been well studied in children.

METHODS

A retrospective review of all patients who underwent IAT from 2015 to 2018 at a single institution was performed. Sterility culture data were obtained from both the pancreas transport and islet transplant media. All patients received prophylactic perioperative meropenem and vancomycin for 72 h per our protocol. If cultures resulted positive, antibiotics were extended for a total of 7 days. Primary outcomes were postoperative fever and 30-day infectious complications.

RESULTS

Forty-one patients underwent IAT during the study period. Seventeen (41.5 %) patients had negative cultures of both the transport and transplant media, while 24 (58.5 %) patients had a positive culture from either sample. Of these patients, 13 (31.7 %) were positive in both, 10 (24.4 %) were positive in only the transport media, and 1 (2.4 %) was positive in only the transplant media. Patients with positive transplant media were similar with regard to age, gender, etiology, and disease duration compared to those with negative transplant media (all p > 0.05), but the positive group was more likely to have a pancreatic stent in place at the time of surgery (38.5 % vs. 4.2 %, p = 0.01). The overall postoperative infectious complication rate was 31.2 % (n = 13). No difference was detected between the transplant positive and negative culture groups in postoperative fever or 30-day infectious complications (p > 0.05 for each).

CONCLUSION

An existing pancreatic stent at the time of pancreatectomy with IAT is a risk factor for positive sterility cultures. However, positive islet transplant media culture was not associated with increased risk of post-IAT infection or morbidity in the setting of an empiric antibiotic protocol. Future work is necessary to study the optimal perioperative antibiotic regimen in pediatric IAT.

Maintaining Hepatitis B Protection in Immunocompromised Pediatric Rheumatology and Inflammatory Bowel Disease Patients

OBJECTIVE

Hepatitis B virus (HBV) infection remains a significant public health challenge, particularly for immunocompromised patients. Our aim was to evaluate the serologic immunity in immunocompromised rheumatology and inflammatory bowel disease (IBD) patients, assess factors for serologic nonimmunity, and evaluate their response to 1 HBV booster dose.

METHODS

Immunocompromised rheumatology and IBD patients with completed HBV screening were identified. A chart review was performed to collect demographics, clinical information, baseline HBV serology results, and serologic response to booster vaccination. Serologic nonimmunity was defined as a negative/indeterminate hepatitis B surface antibody (anti-HBs) level.

RESULTS

Among 580 patients, 71% were nonimmune. The highest portion of nonimmune patients were 11-18 years old (P = 0.004). There was no significant difference between immune and nonimmune patients with regards to diagnosis (P = 0.34), age at diagnosis (P = 0.64), duration of treatment (P = 0.07), or type of medications (P = 0.08). Sixty-two percent of those who received a booster vaccine were rescreened, and most (68%) seroconverted. In those 18 years or older, only half seroconverted.

CONCLUSION

Results of this study support the benefit of HBV screening in immunosuppressed patients. Beginning at age 11 years, most patients lacked serologic immunity to HBV. Seroconversion for most patients 11-18 years occurred after 1 booster vaccine. Thus, for immunocompromised patients without recent HBV serologic data, obtaining the HBV serology beginning at age 11 years might be considered. Those 18 years and older were least likely to seroconvert after 1 booster, indicating that they may benefit from receiving the 3-dose HBV vaccine series.

Usefulness of gene expression profiling of bronchoalveolar lavage cells in acute lung allograft rejection

BACKGROUND

Chronic lung allograft dysfunction (CLAD) is the main limitation to long-term survival after lung transplantation. Because effective therapies are lacking, early identification and mitigation of risk factors is a pragmatic approach to improve outcomes. Acute cellular rejection (ACR) is the most pervasive risk factor for CLAD, but diagnosis requires transbronchial biopsy, which carries risks. We hypothesized that gene expression in the bronchoalveolar lavage (BAL) cell pellet (CP) could replace biopsy and inform on mechanisms of CLAD.

METHODS

We performed RNA sequencing on BAL CPs from 219 lung transplant recipients with A-grade ACR (n = 61), lymphocytic bronchiolitis (n = 58), infection (n = 41), or no rejection/infection (n = 59). Differential gene expression was based on absolute fold difference >2.0 and Benjamini-adjusted p-value ≤0.05. We used the Database for Annotation, Visualization and Integrated Discovery Bioinformatics Resource for pathway analyses. For classifier modeling, samples were randomly split into training (n = 154) and testing sets (n = 65). A logistic regression model using recursive feature elimination and 5-fold cross-validation was trained to optimize area under the curve (AUC).

RESULTS

Differential gene expression identified 72 genes. Enriched pathways included T-cell receptor signaling, natural killer cell–mediated cytotoxicity, and cytokine–cytokine receptor interaction. A 4-gene model (AUC = 0.72) and classification threshold defined in the training set exhibited fair performance in the testing set; accuracy was 76%, specificity 82%, and sensitivity 60%. In addition, classification as ACR was associated with worse CLAD-free survival (hazard ratio = 2.42; 95% confidence interval = 1.29–4.53).

CONCLUSIONS

BAL CP gene expression during ACR is enriched for immune response pathways and shows promise as a diagnostic tool for ACR, especially ACR that is a precursor of CLAD.

Training in transplant infectious diseases: A survey of infectious diseases and transplant infectious diseases fellows in the United States and Canada

BACKGROUND

Infectious diseases (ID) specialists with experience in managing infections in transplant recipients and other immunocompromised hosts are increasingly needed as these fields expand.

METHODS

To evaluate experiences and identify trainee-described needs in transplant infectious diseases (TID) training, the American Society of Transplantation, Infectious Diseases Community of Practice (AST IDCOP) surveyed ID fellows across the United States and TID fellows in the United States and Canada and received responses from 203 ID fellows and 13 TID fellows.

RESULTS

Among ID fellows, the amount of TID training during ID fellowship was rated between less than ideal and adequate. Reasons cited included limited frequency of didactic activities and limited exposure to transplant patients during training. In particular, ID fellows at low-volume transplantation centers expressed interest in more TID training time, away training opportunities, and specific TID didactics. Educational resources of high interest among trainees were case-based interactive websites, mobile phone applications with TID guidelines, and a centralized collection of relevant articles. Pediatric ID fellows reported lower satisfaction scores with TID training, while TID fellows were overall satisfied or more than satisfied with their training experience.

CONCLUSION

Findings from this survey will inform local and national TID educational initiatives.

Anellovirus loads are associated with outcomes in pediatric lung transplantation

Anelloviruses are DNA viruses ubiquitously present in human blood. Due to their elevated levels in immunosuppressed patients, anellovirus levels have been proposed as a marker of immune status. We hypothesized that low anellovirus levels, reflecting relative immunocompetence, would be associated with adverse outcomes in pediatric lung transplantation. We assayed blood samples from 57 patients in a multicenter study for alpha- and betatorquevirus, two anellovirus genera. The primary short-term outcome of interest was acute rejection, and longer-term outcomes were analyzed individually and as "composite" (death, chronic rejection, or retransplant within 2 years). Patients with low alphatorquevirus levels at 2 weeks post-transplantation were more likely to develop acute rejection within 3 months after transplant (P = .013). Low betatorquevirus levels at 6 weeks and 6 months after transplant were associated with death (P = .047) and the composite outcome (P = .017), respectively. There was an association between low anellovirus levels and adverse outcomes in pediatric lung transplantation. Alphatorquevirus levels were associated with short-term outcomes (ie, acute rejection), while betatorquevirus levels were associated with longer-term outcomes (ie, death, or composite outcome within 2 years). These observations suggest that anelloviruses may serve as useful biomarkers of immune status and predictors of adverse outcomes.

Airway plaque presenting after alteration of immunosuppression in a pediatric patient remote from heart transplantation

Success after solid organ transplantation is dependent on the proper balance of immunosuppression to prevent rejection of the allograft while limiting the risk of developing infections and malignancy. We present a 9-year-old girl, remote from transplant, who presented with airway plaque after a change in immunosuppression to include the mTOR inhibitor sirolimus. Differential diagnosis included direct medication side effect, infection, and neoplasia.

Antifungal prophylaxis in pediatric lung transplantation: an international multicenter survey

Fungal infections create a significant risk to pediatric lung transplant recipients. However, no international consensus guidelines exist for fungal infection prevention strategies. It was the aim to describe the current strategies of antifungal prophylaxis in pediatric lung transplant centers. A self-administered, web-based survey on current practices to prevent fungal infection was circulated to centers within the IPLTC. Twenty-one (88%) IPLTC centers participated, predominantly from Europe and the US. More than 50% of respondents perform adult and pediatric lung transplant operations. Twenty-four percent use universal prophylaxis, 28% give prophylaxis to all patients but stratify the antifungal coverage based on pretransplant risk, and 48% target prophylaxis to only the children with CF or pretransplantation fungal colonization. Commonly, centers aim to target Aspergillus and Candida infection. Monotherapy with either voriconazole or inhaled amphotericin B is used in the majority of centers. Institutions utilize prophylactic therapy for variable time periods (40% 3-6 months; 30% ≥12 months). Alternative drugs were prescribed for lack of tolerance, toxicity, or positive surveillance culture. TDM (itraconazole/voriconazole) was used in 86% of centers. The survey revealed a wide range of antifungal prophylaxis strategies as current international practice in pediatric lung transplant recipients.

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.

RSV prevention and treatment in pediatric lung transplant patients: a survey of current practices among the International Pediatric Lung Transplant Collaborative

RSV infection can be severe after pediatric lung transplantation. Strategies to prevent and treat RSV in this population are underreported. To assess the current practices, we surveyed the members of the IPLTC regarding RSV prevention and treatment strategies. Twenty-eight programs were surveyed; 18 (64.3%) responded at least partially. A median of 53 transplants (range, 8-355) occurred since inception. RSV testing occurs in asymptomatic (6/17) and symptomatic (17/17) patients. Diagnostic method is polymerase chain reaction at 13 sites and DFA at 8. Transplant candidates were received prophylaxis at 10 sites, with nine following national (5) or local (4) guidelines. All use palivizumab IM and/or IV. Recipients were received prophylaxis with palivizumab at eight centers (eight IM, one IV). Fourteen were treated for RSV (seven all patients; seven age-related). Medications include inhaled (6), oral (4), or IV (4) ribavirin, plus IVIG (9), steroids (8), and IV (2) or IM (3) palivizumab. Prevention and treatment barriers include insurance/hospital concerns, such as institutional reluctance to use inhaled ribavirin. RSV prevention and treatment strategies are diverse at pediatric lung transplant programs. Many centers offer prophylaxis (9/17) and treatments (14/17), but strategies are not uniform.

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.

Minimal acute rejection in pediatric lung transplantation--does it matter?

In adult lung transplantation, a single minimal AR episode is a significant predictor of BOS independent of other factors. However, the significance of single minimal AR episodes in children is unknown. A retrospective, multi-center analysis was performed to determine whether isolated single AR episodes are associated with an increased BOS risk in children. Risk factors for BOS, death, or re-transplantation, and a combined outcome of BOS, death, or re-transplantation were assessed. Original data included 577 patients (<21 yr of age). A total of 383 subjects were eligible for the study. Fifteen percent of patients developed BOS, and 13% of patients either died or underwent re-transplant within one-yr post-transplant. In the multivariable survival model for time to BOS, there was no significant risk to developing BOS after a single minimal AR (A1) episode (HR 1.7, 95% CI 0.64-4.8; p=0.28). Even after a second minimal AR episode, no significant risk for BOS was appreciated. However, a single episode of mild AR (A2) was associated with twice the risk of BOS within one-yr post-transplant. In this select cohort, a single minimal AR episode was not associated with an increased risk for BOS within one yr following lung transplantation, in contrast to previous reports in adults.

Long-term impact of respiratory viral infection after pediatric lung transplantation

To evaluate the epidemiology and to investigate the impact of RVI on chronic allograft rejection after pediatric lung transplantation, a retrospective study of pediatric lung transplant recipients from 2002 to 2007 was conducted. Association between RVI and continuous and categorical risk factors was assessed using Wilcoxon rank-sum tests and Fisher's exact tests, respectively. Association between risk factors and outcomes were assessed using Cox proportional hazards models. Fifty-five subjects were followed for a mean of 674 days (range 14-1790). Twenty-eight (51%) developed 51 RVI at a median of 144 days post-transplant (mean 246; range 1-1276); 41% of infections were diagnosed within 90 days. Twenty-five subjects developed 39 LRI, and eight subjects had 11 URI. Organisms recovered included rhinovirus (n = 14), adenovirus (n = 10), parainfluenza (n = 10), influenza (n = 5), and RSV (n = 4). Three subjects expired secondary to their RVI (two adenovirus, one RSV). Younger age and prior CMV infection were risks for RVI (HR 2.4 95% CI 1.1-5.3 and 17.0; 3.0-96.2, respectively). RVI was not associated with the development of chronic allograft rejection (p = 0.25) or death during the study period. RVI occurs in the majority of pediatric lung transplant recipients, but was not associated with mortality or chronic allograft rejection.

Respiratory viral infections within one year after pediatric lung transplant

Abstract: To characterize epidemiology and risk factors for respiratory viral infections (RVI) in pediatric lung transplant recipients within the first post‐transplant year, a retrospective multicenter study of pediatric lung transplant recipients from 1988 to 2005 was conducted at 14 centers in the United States and Europe. Data were recorded for 1 year post transplant. Associations between RVI and continuous and categorical risk factors were assessed using Wilcoxon's rank‐sum and χ² tests, respectively. Associations between time to RVI and risk factors or survival were assessed by multivariable Cox proportional hazards models. Of 576 subjects, 79 subjects (14%) had 101 RVI in the first year post transplant. Subjects with RVI were younger than those without RVI (median ages 9.7, 13; P<0.01). Viruses detected included adenovirus (n=25), influenza (n=9), respiratory syncytial virus (n=21), parainfluenza virus (n=19), enterovirus (n=4), and rhinovirus (n=22). In a multivariable model for time to first RVI, etiology other than cystic fibrosis (CF), younger age, and no induction therapy were independently associated with risk of RVI. Cytomegalovirus serostatus and acute rejection were not associated with RVI. RVI was independently associated with decreased 12‐month survival (hazard ratio 2.6, 95% confidence interval 1.6–4.4). RVI commonly occurs after pediatric lung transplantation with risk factors including younger age and non‐CF diagnosis. RVI is associated with decreased 1‐year survival.

Increased mortality after pulmonary fungal infection within the first year after pediatric lung transplantation

BACKGROUND

Risk factors, morbidity and mortality from pulmonary fungal infections (PFIs) within the first year after pediatric lung transplant have not previously been characterized.

METHODS

A retrospective, multicenter study from 1988 to 2005 was conducted with institutional approval from the 12 participating centers in North America and Europe. Data were recorded for the first post-transplant year. The log-rank test assessed for the association between PFI and survival. Associations between time to PFI and risk factors were assessed by Cox proportional hazards models.

RESULTS

Of the 555 subjects transplanted, 58 (10.5%) had 62 proven (Candida, Aspergillus or other) or probable (Aspergillus or other) PFIs within the first year post-transplant. The mean age for PFI subjects was 14.0 years vs 11.4 years for non-PFI subjects (p < 0.01). Candida and Aspergillus species were recovered equally for proven disease. Comparing subjects with PFI (n = 58) vs those without (n = 404), pre-transplant colonization was associated with PFI (hazard ratio [HR] 2.0; 95% CI 0.95 to 4.3, p = 0.067). Cytomegalovirus (CMV) mismatch, tacrolimus-based regimen and age >15 years were associated with PFI (p < 0.05). PFI was associated with any prior rejection higher than Grade A2 (HR 2.1; 95% CI 1.2 to 3.6). Cystic fibrosis, induction therapy, transplant era and type of transplant were not associated with PFI. PFI was independently associated with decreased 12-month survival (HR 3.9, 95% CI 2.2 to 6.8).

CONCLUSIONS

Risk factors for PFI include Grade A2 rejection, repeated acute rejection, CMV-positive donor, tacrolimus-based regimen and pre-transplant colonization.

Variability in immunization guidelines in children before and after lung transplantation

Lung transplant candidates and recipients are at high risk of infections from vaccine-preventable diseases. However, well-established guidelines neither exist for pre- and post-transplant vaccination nor do monitoring guidelines for pediatric lung transplant recipients. To ascertain the current vaccination and monitoring practices of pediatric lung transplant centers, a self-administered questionnaire was distributed to the 18 pediatric lung transplant centers within the International Pediatric Lung Transplant Collaborative in April 2006. Sixteen of 18 centers (89%) surveyed responded. Pretransplant, national vaccination guidelines are followed. Eleven centers reported following standardized vaccination guidelines post-transplant. Vaccines were more commonly provided by the primary-care physician pretransplant (69%) rather than post-transplant (38%). Post-transplant, 50% of the centers recommend live vaccines for household contacts but not for the transplant recipient. Pretransplant monitoring of response to prior vaccination was performed inconsistently except for varicella (88%). Only 44% of the transplant centers measure for response to vaccination post-transplant, mostly hepatitis B. Current vaccination practices of pediatric lung transplant centers are heterogeneous. The lung transplant community would be well served by studies designed to evaluate the efficacy of vaccinations in this population.

Safety and efficacy of prolonged cytomegalovirus prophylaxis with intravenous ganciclovir in pediatric and young adult lung transplant recipients

CMV infection causes morbidity and mortality after transplantation. Despite a wide range of prevention strategies among pediatric lung transplant programs, the optimal duration of prophylactic therapy against CMV infection in pediatric lung transplantation is unknown. To assess the feasibility, safety, and short-term efficacy of extending intravenous ganciclovir administration from six wk duration to 12 wk duration in pediatric lung transplant recipients. An open-label pilot study was performed in primary pediatric lung transplant recipients with donor and/or recipient CMV seropositivity. Intravenous ganciclovir was given for 12 wk post-transplantation. Subjects were tracked for protocol completion. Toxicities monitored included renal dysfunction, myelosuppression, gastrointestinal and neurological complications, as well as infection related to indwelling catheter placement. Serial CMV levels were measured to determine short-term efficacy of the intervention. Nine of nine subjects enrolled completed the pilot study. Subjects' ages ranged from six to 18 yr. Indications for lung transplantation included cystic fibrosis (n = 7), idiopathic pulmonary hypertension (n = 1), and complex congenital heart disease with pulmonary hypertension (n = 1). Seven subjects underwent deceased donor bilateral lung transplantation and two subjects underwent heart-lung transplantation. No subjects had protocol-defined drug toxicity. No episodes of neutropenia, thrombocytopenia, or renal toxicity occurred. Five subjects had catheter-related infections (three after week 12 of ganciclovir). Seven of nine subjects had CMV detected by PCR (four prior to ganciclovir completion) with only one subject having a positive viral culture for CMV viremia (prior to ganciclovir completion). No subjects had UL-97 mutation for ganciclovir resistance detected. The use of prolonged prophylactic administration of ganciclovir for 12 wk duration is a feasible, safe, and effective treatment to prevent CMV viremia based on viral culture in at risk pediatric lung transplant recipients. Further clinical studies are underway to determine optimal CMV prevention strategies.

Quantitative analysis of procalcitonin after pediatric cardiothoracic surgery

Procalcitonin appears to be an early and sensitive marker of bacterial infection in a variety of clinical settings. The use of levels of procalcitonin to predict infection in children undergoing cardiac surgery, however, may be complicated by the systemic inflammatory response that normally accompanies cardiopulmonary bypass. The aim of our study was to estimate peri-operative concentrations of procalcitonin in non-infected children undergoing cardiac surgery. Samples of serum for assay of procalcitonin were obtained in 53 patients at baseline, 24, 48, and 72 hours following cardiac surgery. Concentrations were assessed using an immunoluminetric technique. Median concentrations were lowest at baseline at less than 0.5 nanograms per millilitre, increased at 24 hours to 1.8 nanograms per millilitre, maximized at 48 hours at 2.1 nanograms per millilitre, and decreased at 72 hours to 1.3 nanograms per millilitre, but did not return to baseline levels. Ratios of concentrations between 24, 48 and 72 hours after surgery as compared to baseline were 6.15, with 95 percent confidence intervals between 4.60 and 8.23, 6.49, with 95 percent confidence intervals from 4.55 to 9.27, and 4.26, with 95 percent confidence intervals between 2.78 and 6.51, respectively, with a p value less than 0.001. In 8 patients, who had no evidence of infection, concentrations during the period from 24 to 72 hours were well above the median for the group. We conclude that concentrations of procalcitonin in the serum increase significantly in children following cardiac surgery, with a peak at 48 hours, and do not return to baseline within 72 hours of surgery. A proportion of patients, in the absence of infection, had exaggerated elevations post-operatively.

Epidemiology of bloodstream infections in the first year after pediatric lung transplantation

BACKGROUND

Substantial morbidity and mortality rates are associated with infections in the first year after pediatric lung transplantation. To understand better the clinical significance of bloodstream infections (BSIs), we evaluated systematically the epidemiologic features of BSIs in the first year after transplantation.

METHODS

A retrospective case-cohort study of pediatric primary lung transplant recipients was performed. The frequency of BSIs and the organisms isolated were determined through medical and laboratory record review. We assessed variations in causative organisms and rates of BSIs in 3 time periods after transplantation, ie, early (0-30 days), intermediate (31-90 days) and late (91-365 days).

RESULTS

Between July 1990 and November 2000, 190 pediatric patients received primary lung transplants. Twenty-six percent (49 of 190) of recipients had at least 1 BSI. The most commonly isolated organisms were coagulase-negative Staphylococcus (n = 25, 28.4%), Pseudomonas aeruginosa (n = 14, 16.0%) and Candida spp. (n = 9, 10.2%). The overall rate of BSIs was 2.1 episodes per 1000 catheter-days. The highest rate of BSIs occurred in the early period, compared with the intermediate and late periods (5.5, 1.3 and 1.6 episodes per 1000 catheter-days, respectively; P = 0.21). Early BSIs were associated with death in the first year after transplantation (relative risk, 3.9; 95% confidence interval, 1.6-9.4; P = 0.002).

CONCLUSIONS

BSIs occur frequently after primary pediatric lung transplantation, with the highest rate being in the first 30 days after transplantation. Early BSIs are associated with death in the first year after transplantation.

Variability in standard care for cytomegalovirus prevention and detection in pediatric lung transplantation: survey of eight pediatric lung transplant programs

Cytomegalovirus (CMV) infection after pediatric lung transplantation is a significant risk factor for morbidity and mortality in the first year after transplantation. Multiple strategies have been reported for CMV prevention among adult lung transplant programs. In contrast, little information has been reported regarding protocols for prevention and detection of CMV from pediatric programs. We conducted a survey to better understand the range of practice patterns for CMV prevention and detection at pediatric lung transplant centers. A self-administered questionnaire was distributed to 11 pediatric lung transplant centers identified through the International Pediatric Lung Transplant Collaborative in September 2002. A member of the lung transplant team from each institution was asked to provide the methods of CMV prevention and surveillance. Eight of 11 centers surveyed responded to the questionnaire accounting for 45.6% (26 of 57) and 100% (three of three) of the pediatric lung transplants performed in the US and UK in 2001, respectively. All centers used prophylactic therapy against CMV with either ganciclovir or valganciclovir with duration ranging from 3.5 wk to indefinitely. Most centers (six of eight) prescribed a prophylactic regimen based on donor and recipient CMV serostatus. Half (four of eight) of the centers report using CMV hyperimmune globulin in addition to an antiviral agent. Method for CMV detection varied widely, including use of conventional viral culture (n = 1), antigenemia (n = 7), and polymerase chain reaction (n = 2). A wide range of strategies is used to prevent and detect CMV in pediatric lung transplant recipients with little empiric evidence demonstrating the optimal approach. A retrospective analysis among these centers is being conducted to evaluate the efficacy of these approaches.

Cytomegalovirus viremia associated with death or retransplantation in pediatric lung-transplant recipients

BACKGROUND

Cytomegalovirus (CMV) infection is a frequent complication of lung transplantation. However, there is limited information regarding the incidence and sequelae of CMV infections in pediatric lung-transplant recipients. On the basis of case series suggesting that CMV infection was associated with excess morbidity and mortality in lung-transplant recipients, we hypothesize that CMV viremia increases the risk of bronchiolitis obliterans (BOS) or death and retransplantation in the first year following transplantation.

METHODS

A case-cohort study of pediatric primary lung-transplant recipients was performed. Univariate analysis was used to assess whether CMV viremia was associated with BOS or death and retransplantation within 1 year after transplantation. Patients at high risk for CMV infection received ganciclovir prophylaxis for 42 days posttransplantation.

RESULTS

From July 1990 to November 2000, 194 pediatric patients received primary lung transplants. Twenty-three percent of patients developed CMV viremia. Eighty percent of CMV viremia episodes occurred before 120 days posttransplant. A first episode of CMV viremia was associated with retransplantation or death between days 90 and 365 (RR=4.1, 95% confidence interval [CI] 1.1-14.5) and was not associated with BOS (RR=1.3, 95% CI 0.5-3.3).

CONCLUSIONS

CMV viremia in the first year after pediatric primary lung transplantation is associated with increased risk of death or retransplantation between 90 and 365 days posttransplant, when CMV prophylaxis has stopped. A phase II pilot trial is warranted to assess safety and short-term efficacy of increasing the duration of CMV prophylaxis from 42 to 120 days.