Ganciclovir is effective for prophylaxis and treatment of human herpesvirus-6 in allogeneic stem cell transplantation

Human herpesvirus 6 in bronchalveolar lavage fluid after lung transplantation: a risk factor for bronchiolitis obliterans syndrome?

Bronchiolitis obliterans syndrome (BOS) is the limiting factor to long-term survival after lung transplantation. Previous studies suggested respiratory viral tract infections are associated with the development of BOS. To identify the impact of virus detection in bronchoalveolar lavage (BAL) fluid, we analyzed BAL samples from 87 consecutive lung transplant recipients for human herpesvirus (HHV)-6, Epstein-Barr virus, Herpes simplex virus 1/2, Cytomegalovirus, respiratory syncytical virus and adenovirus by PCR. Acute rejection, BOS and death were recorded for a mean follow-up time of 3.27 +/- 0.47 years. Results of PCR analysis and other potential risk factors were entered into a Cox regression analysis of BOS predictors and death. Only acute rejection was a distinct risk factor for BOS of all stages, death and death from BOS. HHV-6 was detected in 20 patients. Univariate and multivariate analysis revealed that HHV-6 was associated with an increased risk to develop BOS > orb = stage 1 and death, separate from the risk attributable to acute rejection. Identification of HHV-6 DNA in BAL fluid is a potential risk factor for BOS. Our results warrant further studies to elucidate a possible causal link between HHV-6 and BOS.

HHV-6-related acute liver failure in two immunocompetent adults: favourable outcome after liver transplantation and/or ganciclovir therapy

Fulminant hepatitis of unknown origin remain a significant cause of mortality, for which liver transplantation is often considered as the only therapeutic option. In retrospective studies, human herpesvirus 6 (HHV-6) infections have been associated with such diseases, but the diagnosis of HHV-6 infection of the liver is rarely established during the acute phase of liver failure. Using real-time polymerase chain reaction (PCR), we diagnosed two cases of severe acute liver failure (ALF) related to HHV-6 occurring in immunocompetent young adults. Both cases had a favourable outcome, one after valganciclovir therapy, one after liver transplantation associated with ganciclovir. Viral origin was evidenced in each case by the detection of high amounts of HHV-6 DNA in liver tissue by the PCR assay. The decrease of intrahepatic viral load after therapeutic intervention was also monitored by quantitative PCR and paralleled in the two cases the clinical improvement. Diagnosis of HHV-6 infection must be systematically evoked in case of unexplained ALF, since it might lead to specific therapeutic interventions, in addition of liver transplantation.

Postinfantile giant cell hepatitis with autoimmune features following a human herpesvirus 6-induced adverse drug reaction

Giant cell hepatitis (GCH) is frequently found in neonates, but rarely in adults. Diagnosis is made on the basis of the presence of hepatocellular multinucleate giant cells. The disease often takes a fulminant course with the development of cirrhosis within months, requiring transplantation or leading to death in a high percentage of cases. The aetiology and pathogenesis are unclear. Association with autoimmune disorders, viral infections and drug reactions, but also with congenital metabolic diseases such as alpha1-antitrypsin deficiency or haemosiderosis has been described. In some cases, no causative event has been found. Therefore, therapeutic options are controversially discussed. We present a patient with GCH with autoimmune features after a human herpesvirus 6 (HHV6)-induced adverse drug reaction, a combination that has not been reported before. High-dose immunosuppression led to dramatic improvements over the past year.

Interactions between viruses in transplant recipients

Viral coinfections may modulate disease expression, enhance pathogenicity, and lead to greater cumulative immunosuppression in the host. The pathophysiological basis of these may be direct virus-virus interactions, effect of cohabitating viruses on host cell function, or impaired host immune responses. The interrelationship between viral pathogens has become increasingly more relevant and its scope wider as new or previously unrecognized viruses continue to emerge as pathogens in transplant recipients. The pathways and mediators that modulate biological activity represent potential targets for immunomodulatory interventions as adjunctive therapies for transplant recipients.

Update on human herpesvirus 6 biology, clinical features, and therapy

Human herpesvirus 6 (HHV-6) is a betaherpesvirus that is closely related to human cytomegalovirus. It was discovered in 1986, and HHV-6 literature has expanded considerably in the past 10 years. We here present an up-to-date and complete overview of the recent developments concerning HHV-6 biological features, clinical associations, and therapeutic approaches. HHV-6 gene expression regulation and gene products have been systematically characterized, and the multiple interactions between HHV-6 and the host immune system have been explored. Moreover, the discovery of the cellular receptor for HHV-6, CD46, has shed a new light on HHV-6 cell tropism. Furthermore, the in vitro interactions between HHV-6 and other viruses, particularly human immunodeficiency virus, and their relevance for the in vivo situation are discussed, as well as the transactivating capacities of several HHV-6 proteins. The insight into the clinical spectrum of HHV-6 is still evolving and, apart from being recognized as a major pathogen in transplant recipients (as exemplified by the rising number of prospective clinical studies), its role in central nervous system disease has become increasingly apparent. Finally, we present an overview of therapeutic options for HHV-6 therapy (including modes of action and resistance mechanisms).

Impact of Small Bowel Exploration Using Video-Capsule Endoscopy in the Management of Acute Gastrointestinal Graft-versus-Host Disease

BACKGROUND

The purpose of this study was to evaluate the impact of the global diagnostic approach on the outcome of patients suspected of having acute (a) gastrointestinal (GI) graft-versus-host disease (GVHD).

METHODS

Ten consecutive patients with suspected aGI-GVHD were prospectively explored with an exhaustive approach including video-capsule endoscopy (VCE). Images observed with VCE were compared with results obtained with other GI investigations including duodenal biopsies. RESULTS.: Five patients had a normal VCE examination: four were successfully treated symptomatically, but one died as a result of toxoplasmosis. VCE disclosed aGI-GVHD lesions in all five remaining patients, and two of the five were considered normal by upper GI endoscopy. All of these patients experienced improvement in their GI symptoms within 2 weeks of adjustments to their immunosuppressive treatment.

CONCLUSIONS

This approach has enhanced the authors' ability to adapt immunosuppressive treatments in patients suffering from suspected aGI-GVHD. Further investigation of the apparently high negative predictive value of VCE will be of great interest, particularly with a view to avoiding unnecessary immunosuppressive treatment.

Thrombotic microangiopathy (TMA) and stroke due to human herpesvirus-6 (HHV-6) reactivation in an adult receiving high-dose melphalan with autologous peripheral stem cell transplantation

We report an adult autologous stem cell transplant (ASCT) patient who developed transplant-associated thrombotic microangiopathy (TMA) due to human herpesvirus-6 (HHV-6) reactivation. A 58-year-old female with Stage IIIA IgGkappa multiple myeloma received a melphalan (200 mg/m2) ASCT with discharge home after resolution of ASCT-related toxicities. She presented on D+20 with dyspnea, rash, and fever to 105 degrees F, followed by worsening dyspnea, hypotension, and capillary leak. Mental status (MS) changes were noted on D+23, but head CT and EEG were unremarkable. On D+29, a generalized seizure occurred with decline in platelet count and haptoglobin. TMA was noted on peripheral blood smear and therapeutic plasma exchange (TPE) was initiated on D+31. Lumbar puncture (LP) revealed CSF protein 74 mg/dL and white blood count 7,000/mm3 with 74% lymphocytosis. TPE was continued without improvement in her MS or thrombocytopenia despite improvement in microangiopathy. An MRI of the brain showed a left hippocampus abnormality, and an EEG was consistent with encephalopathy. Serum polymerase chain regimen (PCR) was negative for CMV, HSV1, and HSV2 but was strongly positive for HHV-6. Repeat LP protein was 597 mg/dL. Foscarnet was initiated, and cerebrospinal fluid (CSF) PCR for HHV-6 revealed 1,400 DNA copies/mL. Her MS greatly improved within 48 hr of antiviral therapy, serum HHV-6 became negative, and TPE was tapered without recurrence of her TMA. TMA with HHV-6 reactivation is likely an underdiagnosed entity. Given its fulminant course and favorable response to therapy, HHV-6 reactivation should be considered a potential etiology in patients with TMA after ASCT.

Human herpesvirus 6 (HHV6) infection

Human herpes virus-6 was first reported in 1986 and is the sixth member of the herpes virus family. HHV-6 consists of two closely related variants HHV-6A and HHV-6B. The majority of infections occur in healthy infants with most infections caused by HHV-6B. The virus preferentially infects CD4+T-lymphocytes and the surface marker CD46 acts as a co-receptor. Infection is followed by persistence and latency in different cells and organs including monocytes/macrophages, salivary glands, the brain and the kidneys. In this article we will discuss the clinical manifestations of HHV-6 infection in healthy children and the syndromes associated with HHV-6 reactivation in immunocompromised patients. Evidence of association between HHV-6 infection and different clinical entities such as multiple sclerosis, malignancy, infectious momononucleosis, drug hypersensitivity syndromes and skin eruptions is discussed. Published data on the use and efficacy of antiviral agents in complicated infections and infections in immunocompromised patients is presented.

Significance of human herpesviruses to transplant recipients

PURPOSE OF REVIEW

Despite recent great advances in transplantation techniques, herpesvirus infections remain a major cause of morbidity and mortality in transplant recipients. While improvement in immunosuppressive drug regimens have decreased the risk of graft-versus-host disease and rejection in bone marrow transplant recipients and solid organ transplant recipients, all such drugs carry with them an increased risk of herpesvirus reactivation. The following review consolidates recent findings in this field, covering reports published from January 2002 to August 2003.

RECENT FINDINGS

Real-time polymerase chain reaction has improved the ability to distinguish between latent and active herpesvirus infection, which had been a major difficulty in the diagnosis of such conditions. It has been suggested that evaluation of virus-specific cytotoxic T lymphocyte activity is important for prediction of viral diseases. Development of new antiviral drugs has provided other therapeutic options. However, neither prophylactic nor preemptive administration of antiviral drugs can completely abolish the risk of herpesvirus infection. Transfusion of virus-specific cytotoxic T lymphocytes has been suggested to be a useful treatment for recipients with continuous viral replication due to severe immunosuppression.

SUMMARY

Recent progress has been made in learning more about the role of virus-specific cytotoxic T lymphocytes, and developing better diagnostic procedures and therapeutic protocols that are efficient and have reduced adverse side effects. Reliable monitoring methods for viral load, in combination with evaluation of virus-specific cytotoxic T cells, has made possible the prediction of viral diseases and furthered understanding of the role of these cells in controlling viral infections. Furthermore, adoptive immunotherapy has been improved by analyzing host immune responses.

Neonatal liver failure

Liver failure in the neonatal period is challenging to diagnose and manage, and still carries a high mortality. With ongoing developments in the field of metabolic disorders and antiviral therapy, and the ability to offer liver transplantation to small babies, an overall survival of 40% has been achieved. Early recognition of liver failure, good supportive care and prompt referral to a paediatric liver transplant centre are essential elements in improving the outcome for these babies. Decisions about contra-indications to and timing of transplantation are complex as many of the disease processes are still evolving in the neonatal period, and extrahepatic disease, which cannot be corrected by a transplant, may appear later.