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Guidelines for HHV-6 infections
who received foscarnet and significantly higher in patients who received ganciclovir, but this was in unad- justed descriptive analyses.
Information on the clinical use of cidofovir for the treat- ment of HHV-6 encephalitis is limited to two case reports;96,97 in one cidofovir was interrupted due to drug toxicity and in the other the drug was combined with fos- carnet.
• Intravenous foscarnet or ganciclovir are recommend- ed for treatment of HHV-6B encephalitis. Drug selection should be dictated by the drug’s side effects and the patient’s comorbidities (AIIu).
• The recommended doses are 90 mg/kg b.d. for foscar- net and 5 mg/kg b.d. for ganciclovir (AIIu).
• Antiviral therapy should be for at least three weeks and until testing demonstrates clearance of HHV-6 DNA from blood and, if possible, CSF (CIII).
• Combined ganciclovir and foscarnet therapy can be considered (CIII).
• Immunosuppressive medications should be reduced if possible (BIII).
• There are insufficient data on the use of cidofovir to make a recommendation.
Treatment of human herpesvirus 6B associated end-organ diseases other than encephalitis
Since the strength of associations with other end-organ diseases is moderate or weak, there are insufficient data to guide a recommendation for antiviral treatment.
Conclusions
Human herpesvirus 6B is the primary cause of infectious encephalitis after allogeneic HSCT. Studies of prevention and treatment strategies for this disease are urgently required to improve outcomes using novel therapeutic approaches, such as new antiviral drugs and immunother- apy.
As regards other possible HHV-6B end-organ diseases post-HSCT, improved RNA diagnostic tests are necessary to demonstrate active viral replication (in situ hybridiza- tion and/or reverse transcription PCR).
Understanding the pathogenic potential of HHV-6 and CIHHV-6 requires that all prospective studies on HSCT patients and health outcomes use tests on both donor and recipient that distinguish HHV-6A from HHV-6B.
Funding
The ECIL meeting (Sept 21-23, 2017) was supported by unrestricted grants from Astellas, Basilea, Chimerix, Clinigen, Gilead, MSD, Pfizer and Shire. None of these pharmaceutical companies had any role in the selection of experts and the scope and purpose of the guidelines, or the collection, analysis, and interpretation of the data and editing the guidelines.
Acknowledgments
The authors would like to thank Thierry Calandra for chairing the ECIL HHV-6 session and the ECIL participants. We also thank GL events, Lyon, France for organizing the meeting.
• No recommendation can be made.
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