Intravenous Cidofovir therapy for disseminated adenovirus in a pediatric liver transplant recipient

Management strategies for common viral infections in pediatric renal transplant recipients

Viral infections have been considered as a major cause of morbidity and mortality after kidney transplantation in pediatric cohort. Children are at high risk of acquiring virus-related complications due to immunological immaturity and the enhanced alloreactivity risk that led to maintenance of high immunosuppressive regimes. Hence, prevention, early detection, and prompt treatment of such infe ctions are of paramount importance. Among all viral infections, herpes viruses (herpes simplex virus, varicella zoster virus, Epstein-Barr virus, cytomegalovirus), hepatitis B and C viruses, BK polyomavirus, and respiratory viruses (respiratory syncytial virus, parainfluenza virus, influenza virus and adenovirus) are common in kidney transplant recipients. These viruses can cause systemic disease or allograft dysfunction affecting the clinical outcome. Recent advances in tech nology and antiviral therapy have improved management strategies in screening, monitoring, adoption of prophylactic or preemptive therapy and precise trea tment in the immunocompromised host, with significant impact on the outcome. This review discusses the etiology, screening and monitoring, diagnosis, pre vention, and treatment of common viral infections in pediatric renal transplant recipients.

Impact of Respiratory Viral Infections in Transplant Recipients

Respiratory viral infections (RVIs) are among the leading cause of morbidity and mortality in pediatric hematopoietic stem cell transplant (HCT) and solid organ transplant (SOT) recipients. Transplant recipients remain at high risk for super imposed bacterial and fungal pneumonia, chronic graft dysfunction, and graft failure as a result of RVIs. Recent multicenter retrospective studies and prospective studies utilizing contemporary molecular diagnostic techniques have better delineated the epidemiology and outcomes of RVIs in pediatric transplant recipients and have advanced the development of preventative vaccines and treatment interventions in this population. In this review, we will define the epidemiology and outcomes of RVIs in SOT and HSCT recipients, describe the available assays for diagnosing a suspected RVI, highlight evolving management and vaccination strategies, review the risk of donor derived RVI in SOT recipients, and discuss considerations for delaying transplantation in the presence of an RVI.

A scoping review on acute gastrointestinal surgical complications in immunocompromised pediatric patients

Background

Gastrointestinal complications are becoming increasingly more common and pose a significant risk on the health of children with compromised immunity caused by various etiologies such as chemotherapy and posttransplantation immunosuppression. We aim to review abdominal complications in immunocompromised children and their respective management.

Main body

This is a scoping review of the literature. PubMed, MEDLINE, Google Scholar, and Scopus libraries were searched for relevant articles. Extracted data included the etiologies of immunocompromised immunity, gastrointestinal and abdominal complications in immunocompromised children, diagnosis, and treatment of these pathologies. Examples of gastrointestinal complications in immunocompromised children include, but not limited to, neutropenic enterocolitis, acute appendicitis, bowel perforation, acalculous cholecystitis, and acute pancreatitis. Our literature review showed that bacterial and fungal infections are the major causes of exacerbation and mortality. The main cause of immunosuppression in children with neutropenic enterocolitis and acute pancreatitis is chemotherapy, and management of these pathologies using intravenous fluids, antibiotic therapy, and granulocyte-stimulating factors is the current standard of care. Surgical intervention is uncommon and reserved for complicated cases. That said, in acute appendicitis and bowel perforation, laparoscopy is the mainstay treatment. However, in systemic infections, nonsurgical interventions such as transfusion and bowel rest are the gold standard. As for acalculous cholecystitis, percutaneous cholecystectomy is superior to laparotomy and other surgical interventions.

Conclusion

Timely diagnosis and management of gastrointestinal complications in the immunocompromised children is key in reducing mortality and morbidity. Both surgical and nonsurgical interventions are needed and should be further studied in order to improve outcomes.

Adenovirus Infection and Transplantation

Adenoviruses result in a wide array of clinical presentations, including primarily respiratory, gastrointestinal, genitourinary, or systemic infections. Although adenovirus causes mild disease limited to a single organ system in immunocompetent individuals, severe and life-threatening infections do rarely occur. Disseminated disease and severe localized disease resulting in significant morbidity and mortality have been well described in the immunocompromised populations. Although asymptomatic viremia, respiratory tract, and gastrointestinal infections are the most common disease in most transplant patients, renal transplant patients more commonly experience urinary tract infections, including hemorrhagic cystitis or nephritis. Diagnosis requires astute clinical awareness of the patient's clinical presentation that would be compatible with adenovirus combined with cultures, molecular testing, polymerase chain reaction, and tissue sampling. There is no Food and Drug Administration-approved treatment for adenovirus; however, several studies have evaluated therapeutic options including cidofovir, brincidofovir, and immunotherapy. This article will summarize our current understanding of adenovirus in the transplant population.

Case presentation: persistent adenovirus B3 infections associated with bronchiolitis obliterans treated with cidofovir in a child with mosaic tetrasomy 9p

Background

Adenoviruses (AdV) are non-enveloped, double-stranded DNA viruses with multiple serotypes, which cause a variety of end-organ disease in both immunocompetent and immunocompromised individuals. Some adenoviruses can become latent in the mucosa-associated lymphoid tissue (e.g. adenoids and tonsils), with the potential to reactivate sporadically, leading to upper or lower respiratory tract infection and disease. Bronchiolitis Obliterans (BO) is a rare chronic lung disorder which usually follows a severe insult to the respiratory tract. In children, it is a complication of severe infections (as post-infectious BO), typically manifesting after a severe respiratory infection, in previously healthy pre-school children. Symptoms and signs of air trapping (hyperinflated chest, expiratory wheeze) with persistent oxygen requirement are characteristic. The presence of the unusual mosaic tetrasomy 9p genotype in this case, despite standard cidofovir therapy for persistent or chronic adenovirus infection, may have impacted on the child’s long-term clinical outcomes.

Case presentation

We present a case of persistent AdV B3 infection in a 14-month old boy with mosaic tetrasomy 9p, which persisted for 10 weeks, resulting in radiologically-confirmed BO, requiring cidofovir to control the persistent AdV B3 infection and standard therapy with pulsed steroids. We argue that in the presence of the mosaic tetrasomy 9p, earlier antiviral therapy may have decreased the severity of BO, as this mutation is known to be associated with some degree of immune dysregulation.

Conclusions

Adenovirus infections are common in children and may persist as latent infections, with subsequent reactivations during loss of immune control, related to systemic illness arising from other causes. In chronic, reactivated AdV infection with pneumonia, BO is a recognised complication. However, in this case, with the presence of the mosaic tetrasomy 9p mutation, earlier antiviral therapy may have reduced such longer term complications, due to the immune dysregulatory nature of this mutation.

Antiviral Therapies for Herpesviruses: Current Agents and New Directions

PURPOSE

The objective of this review was to summarize the recent literature describing the current burden of disease due to herpesviruses in the antiviral and transplant era; describe mechanisms of action of antiviral agents and the development of resistance; summarize the literature of recent antiviral agents brought to market as well as agents under development; and to present literature on future strategies for herpesvirus therapeutics.

METHODS

An extensive search of the medical literature related to antiherpesviral therapy was conducted to compose this narrative review. Literature searches were performed via PubMed and ultimately 137 articles were included as most relevant to the scope of this article.

FINDINGS

Herpesviruses are a family of DNA viruses that are ubiquitous throughout human populations and share the feature of establishing lifelong infections in a latent phase with the potential of periodic reactivation. With the exception of herpes simplex virus, varicella zoster virus, and Epstein-Barr virus, which have a significant disease burden in individuals with normal immune function, the morbidity and mortality of the remaining viruses are primarily associated with the immunocompromised host. Over the last half-century, several agents have been tested in large randomized, placebo-controlled trials that have resulted in safe and effective antiviral agents for the treatment of many of these infections.

IMPLICATIONS

With increasing use of antiherpesviral agents for extended periods, particularly in immunocompromised hosts, the emergence of resistant viruses has necessitated the development of newer agents with novel targets and better side-effect profiles.

Successful treatment of disseminated adenovirus infection with cidofovir and intravenous immunoglobulin in an infant following heart transplant

For most patients, adenoviruses cause few acute health concerns and are often self-limiting. Patients who are immunocompromised or immunosuppressed, however, are at risk for disseminated adenovirus and suffer high morbidity and mortality, without well-defined treatment options. We report the case of a 9-month-old boy who was successfully treated for disseminated adenovirus infection with intravenous immunoglobulin and cidofovir 3 months post heart transplant, tailored to serum adenoviral load and clinical response. We emphasise the importance of early identification, monitoring, and a potentially novel treatment in the paediatric cardiac transplant population with disseminated adenovirus infection.

Antiviral Drugs in Newborn and Children

This article focuses on the clinically relevant approved antiviral medications available for the treatment of infants and children. A brief overview of drug categories, mechanism of action, resistance, pharmacokinetics, and side effects is provided for the more commonly prescribed antivirals. The patient categories addressed are treatment and prophylaxis of influenza, neonatal herpes simplex virus and congenital cytomegalovirus, treatment and prophylaxis of viral disease in the immunocompromised host, and a brief introduction to the antivirals available to treat hepatitis B and hepatitis C in children.

Adenovirus

Adenoviruses are a highly prevalent infection that can cause a range of clinical syndromes in immunocompromised patients, ranging from localized disease of the respiratory tract, gastrointestinal tract, or urinary tract to disseminated disease. Adenovirus infections may develop in this unique population as the result of primary infection or reactivation of latent virus. Disease can be potentially progressive with high rates of mortality in patients with pneumonia and disseminated disease. Fortunately, cidofovir and its lipid ester, brincidofovir, appear to be effective for the treatment of adenovirus, although neither is specifically approved for this indication. Adenovirus should always be considered when immunocompromised patients present with any clinical syndrome that could be compatible with adenoviral infection. Once disease is suspected, cultures or molecular testing of appropriate specimens should be obtained and blood should be sent for adenovirus polymerase chain reaction (PCR) whenever adenovirus is suspected. Monitoring of quantitative viral loads in blood is helpful in predicting response to therapy with a significant drop (>1 log) associated with a higher probability of clinical response.

Viral Hepatitis: Other Viral Hepatides

Non-hepatotropic viruses cause acute hepatitis and/or acute liver failure, without causing any chronic damage to the liver. These viruses do not primarily target the liver. These viruses include the herpes viruses (Epstein-Barr virus, cytomegalovirus, and herpes simplex virus), parvovirus, adenovirus, influenza, and severe acute respiratory syndrome (SARS)-associated coronavirus.

The risk of acquiring infection from any of the non-hepatotropic viruses is specific to each virus. Infection with the herpesviruses is ubiquitous, with clinically significant hepatitis being less common. Considerations for determining the risk of hepatitis from non-hepatotropic viruses include prior exposure (risk of reactivation), host immune status (increase severity in immunosuppressed), and duration of infection in the contact.

Diagnosis is made with a combination of serology, polymerase chain reaction, or liver biopsy. Treatment is supportive in the majority. In certain clinical scenarios, such as cytomegalovirus infection in transplant patients, and acute liver failure from herpes simplex virus, specific antiviral therapy is warranted.

Use of cidofovir in pediatric patients with adenovirus infection

Background: Adenoviruses contribute to morbidity and mortality among immunocompromised pediatric patients including stem cell and solid organ transplant recipients. Cidofovir (CDV), an antiviral compound approved by the FDA in 1996, is used for treatment of adenoviral (ADV) infections in immunocompromised patients despite concern of potential nephrotoxicity.   Methods: We conducted a retrospective 5-year review at Boston Children's Hospital of 16 patients (mean age = 6.5 years) receiving 19 courses of CDV. During therapy all pertinent data elements were reviewed to characterize potential response to therapy and incidence of renal dysfunction.   Results: Of the 19 CDV courses prescribed, 16 courses (84%) were in patients who had a positive blood ADV Polymerase chain reaction (PCR) alone or in combination with positive ADV PCR/ Direct Immunofluorescence Assay (DFA) at another site. Respiratory symptoms with or without pneumonia were the most common presentation (10/19, 53%). In the majority of blood positive courses (10/16, 63%), viral clearance was also accompanied by clinical response. This was not the case in four courses where patients expired despite viral clearance, including one in which death was directly attributable to adenovirus. There was reversible renal dysfunction observed during the use of CDV. Conclusions:  CDV appeared safe and reasonably tolerated for treatment of ADV in this pediatric population and was associated with viral response and clinical improvement in the majority of patients but reversible renal dysfunction was a side effect. Further studies of the efficacy of CDV for immunocompromised children with ADV infection are warranted.

Use of cidofovir in pediatric patients with adenovirus infection

Background: Adenoviruses contribute to morbidity and mortality among immunocompromised pediatric patients including stem cell and solid organ transplant recipients. Cidofovir (CDV), an antiviral compound approved by the FDA in 1996, is used for treatment of adenoviral (ADV) infections in immunocompromised patients despite concern of potential nephrotoxicity.   Methods: We conducted a retrospective 5-year review at Boston Children's Hospital of 16 patients (mean age = 6.5 years) receiving 19 courses of CDV. During therapy all pertinent data elements were reviewed to characterize potential response to therapy and incidence of renal dysfunction.   Results: Of the 19 CDV courses prescribed, 16 courses (84%) were in patients who had a positive blood ADV Polymerase chain reaction (PCR) alone or in combination with positive ADV PCR/ Direct Immunofluorescence Assay (DFA) at another site. Respiratory symptoms with or without pneumonia were the most common presentation (10/19, 53%). In the majority of blood positive courses (10/16, 63%), viral clearance was also accompanied by clinical response. This was not the case in four courses where patients expired despite viral clearance, including one in which death was directly attributable to adenovirus. There was reversible renal dysfunction observed during the use of CDV. Conclusions:  CDV appeared safe and reasonably tolerated for treatment of ADV in this pediatric population and was associated with viral response and clinical improvement in the majority of patients but reversible renal dysfunction was a side effect. Further studies of the efficacy of CDV for immunocompromised children with ADV infection are warranted.

Cidofovir in pediatric solid organ transplant recipients: University of Nebraska experience

BACKGROUND

Clinical experience with cidofovir in pediatric solid organ transplantation is limited. We assessed the effect of cidofovir use on renal function in pediatric solid organ transplant recipients.

METHODS

Wilcoxon signed-rank tests were used to determine if changes in renal function were significant, Wilcoxon rank-sum tests to test the association between changes in glomerular filtration rate and potential confounding factors, and MacNemar tests to compare the proportions of patients at different time points.

RESULTS

We included 25 patients with a mean age of 4.2 years (SD 4.6). More patients were receiving renal replacement therapy while being treated with cidofovir compared with baseline (24% vs. 4%; P = 0.03). For patients not receiving renal replacement therapy, there was no evidence of a significant median change in glomerular filtration rate from baseline to 1 month after cidofovir treatment (P = 0.32) or to the end of cidofovir treatment (P = 0.23) or in creatinine from baseline to the end of cidofovir therapy (P = 0.2). There was a marginal decreased median change in creatinine from baseline to 1 month after cidofovir treatment (P = 0.06). Fewer patients had proteinuria (72.2% vs. 27.8%; P = 0.02) and hematuria (22.2% vs. 0%) after cidofovir treatment.

CONCLUSION

In our pediatric transplant cohort, cidofovir did not significantly change renal function reflected by creatinine, glomerular filtration rate, hematuria or proteinuria, but a significant number of patients required renal replacement therapy because of fluid overload.

Monitoring and managing viral infections in pediatric renal transplant recipients

Viral infections remain a significant cause of morbidity and mortality following renal transplantation. The pediatric cohort is at high risk of developing virus-related complications due to immunological naiveté and the increased alloreactivity risk that requires maintaining a heavily immunosuppressive environment. Although cytomegalovirus is the most common opportunistic pathogen seen in transplant recipients, numerous other viruses may affect clinical outcome. Recent technological advances and novel antiviral therapy have allowed implementation of viral and immunological monitoring protocols and adoption of prophylactic or preemptive treatment approaches in high-risk groups. These strategies have led to improved viral infection management in the immunocompromised host, with significant impact on outcome. We review the major viral infections seen following kidney transplantation and discuss strategies for preventing and managing these pathogens.

Treatment of adenovirus hepatitis with cidofovir in a pediatric liver transplant recipient

AdV hepatitis is a rarely reported complication after pediatric liver transplantation that is associated with high rates of morbidity, mortality and graft failure. Successful treatment of AdV relies on early diagnosis of disease by quantitative PCR measurement of adenoviral DNA in blood and histological evidence in tissue biopsy. Pharmacologic treatment largely consists of antiviral therapy with CDV, an acyclic nucleoside phosphonate analog and reduction in immunosuppression. This report describes a case of AdV hepatitis in a pediatric liver transplant recipient successfully treated with a modified, renal sparing dosing of CDV.

Donor-transmitted adenovirus infection causing kidney allograft nephritis and graft loss

Adenovirus (AdV) infection can occur early after transplantation, especially with potent immunosuppression for induction or acute rejection treatment. We present the largest case series of adult renal recipients from a single institution with AdV infection, and the first apparent case of transferred AdV infection from 1 deceased donor to 2 kidney recipients. Three patients received kidneys from 2 deceased donors: 2 from a 23-year-old donor, and the third from a 4-year-old donor. The recipients with the same donor both displayed early rejection. One who eventually lost his graft to AdV nephritis required treatment with plasmapheresis, intravenous immunoglobulin, rituximab, and anti-thymocyte globulin for severe antibody-mediated rejection. The second required only steroids for acute cellular rejection and has good renal function at 7 years. The third recipient was discovered to have AdV and microabscesess on renal biopsy and required nephrectomy. In the 2 cases of graft loss, we observed sudden deterioration of graft function with rising creatinine and subsequent necrosis resulting in nephrectomy within 40 days after transplantation. AdV was detected by polymerase chain reaction in urine or serum and/or renal tissue. AdV activation after potent immunosuppression can lead to systemic infection and may trigger rejection and/or early graft loss.

Successful Treatment of Biliary Atresia in Very Small Infants through Living Related Liver Transplantation

Improving outcomes in very small children is a major goal of pediatric liver transplantation. This report describes our experience of living related liver transplantation in an infant weighing 3.98 kg. The recipient, a 80-day-old male infant with congenital biliary atresia, was treated with living donor liver transplantation and then followed up for 6 months. The left lateral segment (segment II, III) with reduced size from the donor, his 26-year-old mother, was used as the graft. The graft weighed 200 g. The graft weight to recipient body weight ratio was 5.025%. The donor regained her liver function within 3 days and was discharged on day 8. The patient showed good results. Liver function returned to normal 9 days after the operation with bilirubin level almost decreased to normal. Cyclosporin, mycophenolate mofetil and prednisone were used for postoperative immunosuppression. No bleeding, thrombosis, infection or bile leakage occurred. The patient had slight fever because of a little collection in the abdomen and recovered after paracentesis and drainage. He was discharged on day 16. The donor and recipient are in satisfactory condition at present. Improvement of technique in hepatic surgery, microsurgical technique in vascular surgery and postoperative intensive care are the keys to ensure the success of the procedure.

Adenovirus infections in solid organ transplant recipients

PURPOSE OF REVIEW

Adenoviruses are emerging as important viral pathogens in solid organ transplant recipients, impacting morbidity, graft survival and even mortality. This review will discuss the current understanding of the epidemiology, diagnosis and therapy of adenovirus infection in transplant recipients.

RECENT FINDINGS

Advances in the field include the use of polymerase chain reaction in the diagnosis of adenoviral infection, a better understanding of the epidemiology, immune response and potential new therapies, including preemptive and adoptive immunotherapy strategies. Adenoviral infections appear to be common, especially in pediatric solid organ transplant. Generally well tolerated, some high-risk patients may develop disseminated disease causing graft failure, which may lead to retransplant and/or death. Antiviral therapy and immunotherapy may play a role in these patients, although prospective controlled data are not available at this time.

SUMMARY

Although new tools and a better understanding of the epidemiology, risk factors and therapies for adenovirus are beginning to materialize, prospective, controlled trials, using careful definitions, and standardized methodologies need to be performed to more fully clarify these issues in solid organ transplant recipients.

Adenovirus infection and treatment with cidofovir in children after liver transplantation

In a retrospective study, serum samples from 21 pediatric liver transplant recipients were analysed by quantitative real-time PCR for ADV infection up to 24 wk after Tx. ADV DNA was detected in serum of eight children after Tx, one of whom developed life-threatening fulminant hepatitis and sepsis. None of these children were symptomatic at the time of first detection of ADV DNA in serum after Tx. Seven children with positive ADV PCR had low adenoviral loads, showed no increase in viral load and remained clinically asymptomatic in the follow-up period of 24 wk. After 10 wk under immunosuppression one child presented clinically with adenoviral sepsis and severe necrotizing hepatitis. This patient revealed a dramatic increase of ADV from baseline titers up to 1.3 x 10(9 )copies/mL serum within 10 wk after Tx. ADV was also detected in a liver biopsy of this child at 1.2 x 10(4) copies/cell and typed by sequence analysis as human ADV species C, type 6, a rarely detected ADV type and first described in a liver transplant patient. Immunosuppression was reduced in this patient immediately and the antiviral drug cidofovir administered intravenously followed by viral suppression and clinical improvement of the child.

Molecular characterization of adenoviral infections in Cuba: report of an unusual association of species D adenoviruses with different clinical syndromes

Adenoviruses are common pathogens that are responsible for a wide variety of infectious syndromes. The objectives of this study were to identify and characterize members of different adenovirus species at the molecular level and to describe the correlation between viruses and clinical syndromes during a period of 4 years. Between 2002 and 2006, 45 of 512 respiratory specimens (8%) from patients with acute respiratory tract infection tested positive for adenovirus. Four adenovirus isolates from samples sent for enterovirus isolation were also analyzed. This research identified 49 confirmed cases of human adenovirus infection by PCR and/or viral culture. The most common diagnosis was upper respiratory infection (44%). Human adenovirus D was the major species found (59%), followed by Human adenovirus C (36%) and Human adenovirus B (4%). Human adenovirus 5 was the major serotype found producing bronchiolitis, followed by human adenovirus 6. In patients with upper respiratory infection, the major serotype found was human adenovirus 17. Viruses of the species Human adenovirus D were identified in seven (77%) cases of acute febrile syndrome. Four isolates from clinical materials obtained from patients with encephalitis, acute flaccid paralysis and meningoencephalitis were identified as belonging to the species Human adenovirus D. Our data demonstrate a surprising result about the identification of an unusual association of viruses of the species Human adenovirus D with different clinical syndromes. This observation could be evaluated as a possible indicator of the emergence of a novel strain but further studies are required.

Fatal adenovirus hepatitis during maintenance therapy for childhood acute lymphoblastic leukemia

Disseminated adenoviral infection with hepatitis is rare in children undergoing standard chemotherapy. We report on a 3(1/2)-year-old male with fatal adenovirus hepatitis receiving maintenance chemotherapy for acute lymphoblastic leukemia (ALL). Adenoviral hepatitis was proven by histology, viral culture, and PCR in a liver biopsy. Quantitative real-time PCR in the peripheral blood showed adenoviral DNA copy number >10(9)/ml. Despite aggressive supportive care and antiviral treatment with cidofovir, the patient died rapidly due to fulminant liver failure. Diagnostic and treatment options for adenovirus infection remain unsatisfactory for these patients. We propose suggestions for diagnosis and therapy.

Treatment of adenovirus pneumonia with cidofovir in pediatric lung transplant recipients

BACKGROUND

Adenovirus pneumonia results in significant morbidity and mortality in lung transplant recipients. Cidofovir allows for directed therapy but can result in nephrotoxicity. We report our experience with cidofovir for the treatment of adenovirus pneumonia in pediatric lung transplant recipients.

METHODS

In a retrospective review, we identified four cases of culture-proven adenovirus pneumonia in children who underwent lung transplantation at Texas Children's Hospital (TCH). All patients received cidofovir 1 mg/kg every other day or three times a week for a total of 4 weeks. Probenecid and intravenous hydration were administered in conjunction with the cidofovir. Intravenous immunoglobulin (IVIg) was given as adjunctive therapy, and immunosuppression was not modified during the treatment course.

RESULTS

The four cases of adenovirus pneumonia comprised 4 of the 54 (7%) lung transplantations performed at TCH from 2002 to 2006, and all were in children <3 years of age. All patients developed pneumonia within 2 months after transplantation. With cidofovir treatment, three of the four children survived. Among the survivors, two developed early bronchiolitis obliterans within 1 year after transplant, and one has continued to have good graft function at 2 years after transplant. All patients maintained normal renal function throughout the treatment course.

CONCLUSIONS

Pediatric lung transplant recipients <3 years of age are at increased risk of adenovirus pneumonia early after transplantation. Cidofovir, when used in the modified dosing regimen and in combination with IVIg and renal protection measures, is a safe and potentially effective treatment option for adenovirus pneumonia in lung transplant recipients.

Liver transplantation in very small infants

BACKGROUND

This study examines the results of liver transplantation (LT) in children 5 kg or less. Reports suggest an increased morbidity and mortality in children weighing 5 kg or less as compared to larger children. However, over half of all children needing LT are <1 year old. Improving outcomes in very small children is a major goal of liver transplantation.

METHODS

All children under 21 years of age transplanted from January 1990 to June 2005 were included in this study. One hundred sixty-eight primary liver transplants were done: 61 in children less than one year of age and 20 in infants weighing 5 kg or less at LT (2 to 5 kg). These 20 infants underwent 23 transplants. Whole organs were used in 39% of transplants, and reduced or split grafts were used in 61%. Arterial reconstruction using aortic conduits was done in 22%. Analysis included Fischer's exact or Chi square test for non-parametric analysis while patient survival was calculated using the Kaplan-Meier method test with differences in survival assessed using the log rank test.

RESULTS

Five-year survival for infants 5 kg or less was 74%, and graft survival was 60%, which was not different from patients transplanted that were >5 kg. There were three perioperative deaths, one from primary graft non-function, and two from portal vein thrombosis. There were no bile leaks or hepatic artery thromboses. Bacterial, fungal, and viral infections made up the vast majority of the postoperative complications (65%), with viral infections resulting in two graft losses requiring re-transplantation. Rejection occurred in 25% of patients, of which one required OKT3. Five of the 23 liver transplants in infants less than 5 kg were done prior to 1996, with a five-year graft survival of only 20%. Improvements in technique and postoperative care after 1996 led to improved graft and patient survival of 77% and 86% respectively.

CONCLUSIONS

Liver transplantation for infants weighing less than 5 kilograms can be technically challenging but can have equivalent graft and patient survival when compared to larger children requiring liver transplantation. Infants should not be denied liver transplantation based on weight alone.

Acute meningoencephalitis caused by adenovirus serotype 26

Adenoviridae are rare causes of meningoencephalitis in both immunocompetent and immunocompromised hosts. In this article the authors report a case of adenoviral meningoencephalitis caused by serotype 26 and its identification, not described previously, in cerebrospinal fluid (CSF) by PCR and brain tissue by immunohistochemical staining.

Infections in pediatric solid organ transplant recipients

Despite the progress made in graft and patient survival in recent years, infectious complications remain a major source of morbidity and mortality in pediatric solid organ transplant recipients. The risk of infection after transplant is determined by the interaction of several factors, including age, type of organ transplanted, type and intensity of immunosuppression, environmental exposures, and the consequences of invasive procedures. Compared with adult transplant recipients, children are at higher risk of developing primary infection with various organisms after transplantation, as they often lack previous immunity from natural exposure to many microbes and often have not completed their primary immunization series at the time of transplantation. This article provides an overview of the risk factors, timing, and types of infectious complications associated with organ transplantation in children.

Adenovirus infections in transplant recipients

Adenoviruses are increasingly recognized as contributors to morbidity and mortality among stem cell and solid-organ transplant recipients. Clinical presentations range from asymptomatic viremia to respiratory and gastrointestinal disease, hemorrhagic cystitis, and severe disseminated illness. The limited clinical data available support the use of cidofovir for many of these illnesses. Prospective studies are needed to better understand the pathogenesis of and therapeutic options for adenoviral infections in this patient population.

Disseminated adenovirus infection with respiratory failure in pediatric liver transplant recipients: impact of intravenous cidofovir and inhaled nitric oxide

Adenoviruses (AdV) are opportunistic pathogens that can lead to severe infections and respiratory failure (acute respiratory distress syndrome, ARDS) with high mortality in immunosuppressed patients. Cidofovir (CDV) has been used in adenoviral disease in bone marrow transplant recipients. Two pediatric liver transplant recipients with disseminated adenoviral disease and ARDS were treated with reduction of immunosuppression, CDV, and inhaled nitric oxide (iNO). CDV 1 mg/kg was given three times per week intravenously with intravenous hydration and oral probenecid. Viral suppression and clinical improvement was achieved. AdV hepatitis did not occur, and graft function was preserved, although acute rejection occurred in both patients. Adverse effects were mild and transient not requiring dose modification. Severe hypoxemia was reversed with iNO 10-20 p.p.m. CDV treatment of AdV infections in organ transplant recipients and other immunocompromised patients should be further investigated in prospective studies.

Adenoviral disease in pediatric solid organ transplant recipients

Adenoviral disease in pediatric SOT recipients is emerging as an important viral pathogen, with serious consequences impacting morbidity, mortality and graft survival. The optimal diagnostic techniques, as well as therapy have yet to be established. This article reviews the current epidemiology of AdV in orthotopic liver, intestinal, cardiothoracic and renal transplant recipients. Issues related to diagnosis, notably the use of newer non-culture based viral detection methods and therapy, including anti-adenoviral agents and adoptive immunotherapy are discussed.

Adenovirus fulminant hepatic failure: disseminated adenovirus disease after unrelated allogeneic stem cell transplantation for acute lymphoblastic leukemia

Adenovirus is one of the major causes of non-relapse morbidity and mortality after allogeneic hematopoietic stem cell transplantation for hematological malignancy. Fulminant hepatic failure is a rare manifestation of post-transplant complication with adenovirus. Extremely high mortality and aggressiveness of the clinical course have been posing clinical challenges for the diagnosis as well as for the treatment. Here, we report a case with disseminated adenovirus disease presenting with fulminant hepatic failure after bone marrow transplantation for acute lymphoblastic leukemia.

Clinical and In Vitro Evaluation of Cidofovir for Treatment of Adenovirus Infection in Pediatric Hematopoietic Stem Cell Transplant Recipients

Post-hematopoietic stem cell transplantation (HSCT) adenovirus infections were identified in 31 of 204 consecutive pediatric HSCT patients, 18 of whom had severe manifestations of infection. Cidofovir treatment led to clinical improvement in 8 of 10 patients with severe infection and to virologic clearance in 9 patients. In vitro susceptibility to cidofovir was demonstrated in 12 clinical adenovirus isolates. Cidofovir is a promising treatment option for this population.

Emerging viral infections after hematopoietic cell transplantation

This overview summarizes recent data on emerging viruses after hematopoietic cell transplantation (HCT), including adenovirus, BK virus, human metapneumovirus (hMPV), and human herpesvirus (HHV) 6. The increased recognition of these infections is due to improved molecular detection methods, increased surveillance and more profound immunosuppression in the host. Adenovirus can cause serious disease especially in T-cell depleted transplant recipients. Adenovirus viremia is an important risk factor for disease in this setting. BK virus has been associated with hemorrhagic cystitis in HCT recipients. BK viremia is significantly associated with hemorrhagic cystitis. hMPV shows a seasonal distribution and can cause fatal pneumonia in HCT recipients. hMPV may be the etiology of some cases previously categorized as idiopathic pneumonia syndrome. HHV-6 commonly leads to viremia in HCT recipients. HHV-6 has been strongly associated with encephalitis and delayed platelet engraftment. Prospective studies are needed to further examine epidemiology, disease associations, and management strategies for these viruses.

Adenovirus infection rates in pediatric recipients of alternate donor allogeneic bone marrow transplants receiving either antithymocyte globulin (ATG) or alemtuzumab (Campath)

Infectious complications due to adenovirus are of increasing concern after allogeneic stem cell transplantation. Over the past 4 years, we have modified our conditioning regimens to use alemtuzumab in preference to anti-thymocyte globulin (ATG) for pediatric patients receiving stem cell transplants from alternate donors. Recent reports in adult studies implicate alemtuzumab as a risk factor for adenovirus infection. We therefore evaluated the incidence of adenovirus infection in pediatric patients receiving either ATG or alemtuzumab in their conditioning regimens. Of the 111 patients evaluated, a total of 54 patients received ATG and 57 patients received alemtuzumab. In total, 35/111 (32%) patients were infected by adenovirus, and 9/111 (8%) had adenovirus disease (AD). Adenovirus infection was greater in the alemtuzumab group than the ATG group (23/57 vs 12/54) (P=0.039) and disseminated AD was more frequent in the alemtuzumab group vs the ATG group (8/57 and 1/54 respectively) (P=0.032). The presence of Grade 3-4 graft-versus-host disease was a risk factor for adenovirus infection. Our findings highlight the fact that adenovirus infection is a frequent complication after stem cell transplantation from alternate donors in the pediatric population and that alemtuzumab increases the risk of infection compared to ATG. This work will help in identifying at-risk populations for our upcoming immunotherapy trial using adoptively transferred donor-derived adenovirus-specific cytotoxic T lymphocytes.

Prospects for adenovirus antivirals

Adenoviruses cause a number of self-limiting but often highly infectious diseases that affect multiple organs, most commonly those associated with respiratory, genitourinary and gastrointestinal tracts and the ocular surface. Many factors have driven a search for effective topical and systemic antivirals to adenoviruses. These include patient morbidity, economic losses and chronic visual disturbances associated with epidemic keratoconjunctivitis; and the startling recent trend of high morbidity and rising mortality associated with systemic adenoviral infections in the immunosuppressed, particularly paediatric bone marrow transplant recipients. The development of effective antivirals has proven to be a complex task, owing to the fact that multiple and often genetically divergent adenovirus serotypes can cause similar diseases. Currently, there remains no licensed systemic or topical treatment in the USA or Europe. However, many compounds have been explored for activity against adenoviruses, and some have been evaluated clinically in either a topical setting for ocular disease or in the setting of systemic treatment in the face of life-threatening adenovirus infections. This article outlines such compounds, discusses the potential for their clinical development, and highlights some problems that may be faced in evaluating their efficacy clinically.

Open lung biopsy in pediatric patients with respiratory failure after abdominal transplantation

To understand the utility of open lung biopsy (OLB) in the evaluation of respiratory failure in pediatric abdominal organ transplant we reviewed the records of nine children in this patient population who underwent an OLB. Eight of nine patients had undergone a previous non-diagnostic bronchoalveolar lavage. Biopsies were performed at the bedside in the pediatric intensive care unit and tissue was processed by the Department of Pathology with special stains for infectious agents. There were no significant complications of OLB. A specific treatable etiology was identified in four patients (respiratory syncytial virus, adenovirus, graft-vs.-host disease and post-transplant lymphoproliferative disease), leading to a change in therapy and survival in two. Overall survival was 44%. Given the low morbidity, OLB as performed in this study appears appropriate in this patient population.

Invasive adenoviral infection in a recipient of unrelated bone marrow transplantation: Problems with diagnostic PCR

A hematopoietic stem cell transplantation (SCT) recipient developed severe diarrhea and fever. A rapid test for the presence of adenovirus (AdV)-specific antigen in the patient's stools was positive; however, AdV genome was not detected by conventional or real-time polymerase chain reaction (PCR). AdV was confirmed by specific PCR for AdV serotype 7 and by an AdV hexon/fiber gene DNA sequence homology search of the PCR product. We suspect that conventional/real-time PCR failed to detect AdV due to nine silent single base substitutions in the extracted AdV genome. Treatment with 1 mg/kg cidofovir (CDV) intravenously three times a week was effective.

Innate immune responses to adenoviral vector-mediated acute pancreatitis

OBJECTIVES

The role of innate immunity in the development of acute viral pancreatitis is not well understood. The aim of the study was to characterize the role of the innate immune system, especially macrophages, natural killer (NK), and NK T (NKT) cells, in the generation of immune responses to intrapancreatic delivery of recombinant adenoviral vector.

METHODS

Adenoviral vectors expressing beta-galactosidase or green fluorescent protein genes with viral capsid conjugated covalently with carbocyanine dye were directly injected into the pancreas of C57Bl/6 mice.

RESULTS

Fluorescent microscopy of the pancreas showed that 30 minutes after vector administration, adenoviral particles localized to cell membranes, internalized, and localized to the nucleus by 4 hours, and transgene expression began at 24 hours. Immunohistochemical staining showed macrophages entering the pancreas shortly after vector administration, with maximal infiltration at day 4, and then disappearing as antigen-expressing cells were eliminated. Intrapancreatic macrophages appeared to deliver viral capsid proteins to the spleen. Flow cytometry showed that NK and NKT cells migrate to the pancreas and persist. Serum cytokines IL-6, IL-10, and IL-12 were all elevated.

CONCLUSION

Macrophages and NK and NKT cells play a major role in the development of acute adenovirus-mediated pancreatitis.

Fatal adenovirus hepatitis during standard chemotherapy for childhood acute lymphoblastic leukemia

Fulminant hepatitis is a rare complication of adenoviral infection that has not previously been reported in children receiving standard chemotherapy for acute leukemia. The authors have observed fatal adenovirus hepatitis in three children receiving first-line chemotherapy for acute lymphoblastic leukemia (ALL). The patients presented 10, 17, and 8 months into therapy according to the UKALL XI (third intensification), UKALL 97/99 (maintenance), and pilot UKALL 2003 (delayed intensification II) protocols, respectively. All patients received aggressive supportive care and intravenous immunoglobulins. The second and third patients were also treated with intravenous cidofovir. Despite these measures, all three children deteriorated rapidly and died of fulminant liver failure. Although rare, adenovirus infection should be considered in the differential diagnosis of acute hepatitis in children receiving standard chemotherapy for ALL.

Comprehensive detection and serotyping of human adenoviruses by PCR and sequencing

Human adenoviruses are common pathogens associated with many diseases, including respiratory, gastrointestinal, and ocular infections. Because they are now being increasingly recognized as agents of life-threatening disseminated infection in immunocompromised patients, robust and sensitive laboratory detection methods are needed for their rapid diagnosis. We describe here a PCR assay using a single primer pair, targeting a region of the hexon gene containing hypervariable region 7, that can detect all known human adenovirus serotypes and allows for serotype determination through the analysis of the nucleotide sequence. This comprehensive assay has proven effective for diagnosing adenoviruses at the serotype level in a broad range of patient specimens, including conjunctival, nasopharyngeal, stool, blood, and urine specimens.

Monitoring of adenovirus infection in pediatric transplant recipients by quantitative PCR: report of six cases and review of the literature

Adenoviral (AdV) infections after transplantation remain a challenge in pediatric patients. Qualitative and quantitative PCR offer new approaches to early diagnosis and monitoring. However, their role in the management of AdV infections in pediatric transplant recipients remains to be determined. We report six children with positive qualitative serum-PCR for AdV on routine follow-up after transplantation (liver n = 4, hematopoetic stem cells (HSCT) n = 1, combined liver and HSCT n = 1). None of these children were symptomatic at the time of first detection of AdV. Two patients remained asymptomatic, one developed hemorrhagic cystitis and enteritis. Three children with positive PCR developed high viral load on quantitative PCR, all developed clinical AdV sepsis with further rising virus load. Despite antiviral therapy with cidofovir, these three patients died of septic multiorgan failure. Positive qualitative AdV-PCR from blood after pediatric transplantation is not necessarily followed by clinical disease. In case of positive AdV-PCR, monitoring by serial quantitative PCR is useful regarding treatment decision and prevention of fatal disease.

Adenoviral infections in children: the impact of rapid diagnosis

BACKGROUND

Adenovirus (ADV) infections were difficult to diagnose in the past, and many infections were unrecognized. Direct fluorescent assay (DFA) for the rapid diagnosis of ADV infection, as part of a viral respiratory panel, became available at Primary Children's Medical Center (Salt Lake City, UT) in December 2000.

OBJECTIVE

To describe children with ADV infection diagnosed by DFA and viral culture and document the impact of rapid ADV testing on patient care.

METHODS

DFA testing for respiratory viruses including ADV was performed on nasal wash specimens with parallel viral culture. Chart review was performed for all ADV-positive patients identified from microbiology records between December 2000 and May 2002.

RESULTS

Of 1901 patients positive for respiratory viruses, 143 (7.5%) were ADV-positive by DFA or culture. The mean age of ADV-positive children was 23 months; 90% were <or=60 months old. Eighty percent were previously healthy, and 56% required admission with a mean length of stay of 3.4 days. The most common diagnoses included fever (31%), bronchiolitis (24%), and pneumonia (14%). Other conditions included suspected Kawasaki disease (KD) and hepatitis. Forty-six percent of ADV-positive children were given antibiotics at presentation, but only 2 (1.4%) had documented bacterial infection (one had Escherichia coli urinary tract infection and one had Moraxella catarrhalis bacteremia). Thirty-six percent of children had a change in management based on positive ADV DFA. In children with suspected KD (n = 5), 100% had positive ADV DFA, and immune globulin was withheld in 4. One immunocompetent patient with fulminant liver failure received cidofovir treatment after a positive ADV DFA and recovered before liver transplant.

CONCLUSIONS

ADV is a common infection in young children and often results in admission and unnecessary antibiotic therapy. Identifying ADV as the cause of illness can favorably impact care and in some instances may be life-saving. DFA testing for ADV should be considered for infants and children requiring admission for fever, respiratory illness, suspected KD, and hepatitis.

Real-time blood plasma polymerase chain reaction for management of disseminated adenovirus infection

We evaluated the usefulness of quantifying blood plasma adenovirus DNA loads for the management of adenovirus infection. Quantification of adenovirus A, B, and C DNA loads was done with real-time polymerase chain reaction (PCR) assays. Blood plasma specimens obtained from 44 immunocompromised patients were screened prospectively with this method. PCR findings for 36 patients were negative, and none of the patients developed disseminated adenoviral disease. PCR findings for 8 patients were positive; all 8 had invasive adenoviral disease and were treated with cidofovir. Sequential measurements of adenovirus DNA loads were performed to monitor the effect of cidofovir therapy. Decrease in the blood plasma DNA load was significantly higher in patients with a good response to cidofovir than in patients with a poor response and was therefore correlated with survival. Detection of adenovirus DNA in blood plasma appears to be useful for identifying patients at risk for invasive disease. Moreover, quantification of adenovirus DNA loads in plasma is helpful for monitoring the efficacy of antiviral therapy.