Outcomes of human adenovirus infection and disease in a retrospective cohort of pediatric solid organ transplant recipients

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.

Update on Epidemiology and Outcomes of Infection in Pediatric Organ Transplant Recipients

Pediatric solid organ transplant (SOT) recipients are at risk for infection following transplantation. Data from adult SOT recipients are often used to guide prevention and treatment of infections associated with organ transplantation in children. This article highlights key recent pediatric SOT-specific publications for an array of infectious complications of organ transplantation. Attention is given to areas of need for future study.

Adenovirus Infection in Hematopoietic and Solid Organ Paediatric Transplant Recipients: Treatment, Outcomes, and Use of Cidofovir

BACKGROUND

human adenovirus (hAdV) infection constitutes an important cause of morbidity and mortality in transplant recipients, due to their immune status. Among drugs currently available, cidofovir (CDF) is the most prescribed.

METHODS

Retrospective study of hAdV infection in paediatric transplant recipients from a tertiary paediatric centre, describing characteristics, management, and outcomes, and focused on the role of CDF.

RESULTS

49 episodes of infection by hAdV were detected during a four-year period: 38 episodes in patients that received allogeneic hematopoietic stem cell transplantation (77.6%) and 11 in solid organ transplant recipients (22.4%). Twenty-five patients (52.1%) were symptomatic, presenting mainly fever and/or diarrhoea. CDF was prescribed in 24 patients (49%), with modest results. CDF use was associated with the presence of symptoms resulting in lower lymphocyte count, paediatric intensive care unit admission, and high viral load. Other therapeutic measures included administration of intravenous immunoglobulin, reducing immunosuppression, and T-lymphocyte infusion. Despite treatment, 22.9% of patients did not resolve the infection and there were three deaths related to hAdV infection. All-cause mortality was 16.7% (8 episodes) by 30 days, and 32.7% (16 episodes) by 90 days, of which, 3 episodes (3/16, 18.8%) were attributed to hAdV directly.

CONCLUSIONS

hAdV infection had high morbidity and mortality in our series. CDF use is controversial, and available therapeutic options are limited. Transplant patients with low lymphocyte count are at higher risk of persistent positive viremias, and short-term survival of these patients was influenced by the resolution of hAdV infection.

Brincidofovir for the treatment of human adenovirus infection in pediatric solid organ transplant recipients: A case series

HAdV viremia can cause significant morbidity among pediatric recipients of SOT with variability in incidence and severity of disease based on the type of allograft. Currently, there are no US FDA-approved treatments for HAdV infections, and historically, the mainstay of treatment has been decreasing immunosuppression, with antiviral therapies reserved for those with severe disease. We describe the treatment of four pediatric SOT recipients (two kidney, one combined kidney-liver, and one liver) presenting with HAdV disease at our institution using brincidofovir. Our case series highlights the variability in presentation and the potential for severe disease in pediatric SOT recipients as we review disease presentation, disease course, complications, and treatment with brincidofovir.

Isolation of a novel intertypic recombinant human mastadenovirus B2 from two unrelated bone marrow transplant recipients

Human adenoviruses (HAdV) are well-known opportunistic pathogens of immunocompromised adult and pediatric patients but specific associations between HAdV species or individual HAdV types and disease are poorly understood.

In this study we report the isolation of a novel HAdV-B2 genotype from two unrelated immunocompromised patients, both recipients of a hematopoietic cell transplant. In both patients, the course of HAdV infection is consistent with a scenario of reactivation of a latent virus rather than a primary opportunistic infection.

Archived HAdV PCR-positive plasma, urine, and stool specimens were processed for virus isolation and detailed molecular characterization. Virus isolates were recovered from patient 1 from PCR-positive urine specimens obtained at days 103 and 116 after transplant in association with gross hematuria, and from a stool specimen obtained 138 days after transplant in association with diarrhea. An isolate was recovered from patient 2 from a PCR-positive urine specimen. Hexon and fiber gene amplification and sequencing were carried out for initial molecular typing, identifying the isolates as an intertypic recombinant with a HAdV-11-like hexon gene and a HAdV-77-like fiber gene. Comprehensive restriction fragment length polymorphism (RFLP) analysis was performed on viral DNA purified from urine and stool isolates, and next generation whole genome sequencing was carried out on purified viral genomic DNA. The genomes of the two isolated strains are 99.5% identical and represent the same RFLP genomic variant. The identified virus is a novel HAdV-B2 genotype designated HAdV-78 exhibiting a HAdV-11-like penton base, a HAdV-11-like hexon and a HAdV-77-like fiber (P11H11F77).

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A novel HAdV-B2 type was isolated from 2 unrelated stem cell transplant recipients.

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The two isolated strains are 99.5% identical and represent the same genomic variant.

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The virus is an intertypic recombinant P11H11F77 designated HAdV-78.

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Genotype HAdV-78 is closely related to HAdV-77 with a 99% sequence similarity.

Adenovirus persistence, reactivation, and clinical management

Adenoviral infections continue posing a major threat in severely immunocompromised patients including particularly allogeneic stem cell transplant recipients. Although exogenous infections occur in some instances, the majority of invasive events appear to arise from viral reactivation. In the pediatric setting, adenoviruses were demonstrated to persist in the gastrointestinal tract, and the intestinal epithelium serves as the main site of viral replication preceding invasive infection. Regular monitoring of serial stool samples for the presence and load of adenoviruses has therefore become a routine diagnostic tool for post-transplant patient surveillance, and can serve as a trigger for early initiation of treatment. In the adult setting, the source of infection or reactivation is less clear, and monitoring of peripheral blood specimens is the predominant approach for patient surveillance. Timely initiation of antiviral treatment is reportedly required for prevention or successful control of disseminated disease mediated by adenoviruses, and appropriate diagnostic monitoring is therefore of paramount importance. Currently available antiviral agents and immune therapeutic approaches have not been able to entirely overcome the life-threatening courses of invasive adenoviral infections in the immunocompromised clinical setting.