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Inherited Chromosomally Integrated Human Herpesvirus 6: Laboratory and Clinical Features. Microorganisms 2023; 11:microorganisms11030548. [PMID: 36985122 PMCID: PMC10052293 DOI: 10.3390/microorganisms11030548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 02/15/2023] [Indexed: 02/25/2023] Open
Abstract
Inherited chromosomally integrated human herpesvirus 6 (iciHHV-6) is a condition in which the complete HHV-6 genome is integrated into the chromosomes of the host germ cell and is vertically transmitted. The aims of this study were to identify iciHHV-6 prevalence in hospitalized patients and clinical features in individuals carrying this integration. HHV-6 PCR on hair follicles was used to confirm iciHHV-6 status when the blood viral load was more than 5 Log10 copies/mL. From January 2012 to June 2022, HHV-6 DNAemia was investigated in 2019 patients. In particular, 49 had a viral load higher than 6 Log10 copies/mL and HHV-6 DNA in hair follicles was positive. A viral load between 5.0 and 5.9 Log10 copies/mL was observed in 10 patients: 6 infants with acute HHV-6 infection and 4 patients with leukopenia and HHV-6 integration. Therefore, the iciHHV-6 prevalence in our population was 2.6% (53/2019). Adult patients with integration presented hematological (24%), autoimmune (11%), autoimmune neurological (19%), not-autoimmune neurological (22%), and other diseases (19%), whereas 5% had no clinically relevant disease. Although in our study population a high percentage of iciHHV-6 adult hospitalized patients presented a specific pathology, it is still unknown whether the integration is responsible for, or contributes to, the disease development.
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Abstract
Human roseoloviruses include three different species, human herpesviruses 6A, 6B, and 7 (HHV-6A, HHV-6B, HHV-7), genetically related to human cytomegalovirus. They exhibit a wide cell tropism in vivo and, like other herpesviruses, induce a lifelong latent infection in humans. In about 1% of the general population, HHV-6 DNA is covalently integrated into the subtelomeric region of cell chromosomes (ciHHV-6). Many active infections, corresponding to primary infections, reactivations, or exogenous reinfections, are asymptomatic. They also may cause serious diseases, particularly in immunocompromised individuals, including hematopoietic stem-cell transplant (HSCT) and solid-organ transplant recipients, and acquired immunodeficiency syndrome (AIDS) patients. This opportunistic pathogenic role is formally established for HHV-6 infection and less clear for HHV-7. It mainly concerns the central-nervous system, bone marrow, lungs, gastrointestinal tract, skin, and liver. As the best example, HHV-6 causes both exanthema subitum, a benign disease associated with primary infection, and severe encephalitis associated with virus reactivations in HSCT recipients. Diagnosis using serologic and direct antigen-detection methods currently exhibits limitations. The most prominent technique is the quantification of viral DNA in blood, other body fluids, and organs by means of real-time polymerase-chain reaction (PCR). The antiviral compounds ganciclovir, foscarnet, and cidofovir are effective against active infections, but there is currently no consensus regarding the indications of treatment or specifics of drug administration. Numerous questions about HHV-6A, HHV-6B, HHV-7 are still pending, concerning in particular clinical impact and therapeutic options in immunocompromised patients.
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Human Herpesvirus 6 (HHV-6) necrotizing encephalitis, a rare condition in immunocompromised patients: The importance of brain biopsy associated with HHV-6 testing. J Neurol Sci 2017; 377:112-115. [PMID: 28477677 DOI: 10.1016/j.jns.2017.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 04/04/2017] [Accepted: 04/05/2017] [Indexed: 11/23/2022]
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Agut H, Bonnafous P, Gautheret-Dejean A. Update on infections with human herpesviruses 6A, 6B, and 7. Med Mal Infect 2016; 47:83-91. [PMID: 27773488 DOI: 10.1016/j.medmal.2016.09.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 09/19/2016] [Indexed: 11/19/2022]
Abstract
Human herpesviruses 6A, 6B, and 7 (HHV-6A, HHV-6B, HHV-7) are genetically related to cytomegalovirus. They belong to the Roseolovirus genus and to the Betaherpesvirinae subfamily. They infect T cells, monocytes-macrophages, epithelial cells, and central nervous system cells. These viruses are ubiquitous and are responsible for lifelong chronic infections, most often asymptomatic, in the vast majority of the general adult population. HHV-6B is responsible for exanthema subitum, which is a benign disease of infants. HHV-6A and HHV-6B also cause opportunistic infections in immunocompromised patients: encephalitis, hepatitis, bone marrow suppression, colitis, and pneumonitis. Their etiological role in chronic diseases such as multiple sclerosis, cardiomyopathy, and thyroiditis is still controversial. The pathogenicity of HHV-7 is less clear and seems to be much more restricted. Chromosomal integration of HHV-6A and HHV-6B is transmissible from parents to offspring and observed in about 1% of the general population. This integration raises the question of potential associated diseases and can be a confounding factor for the diagnosis of active infections by both viruses. The diagnosis of HHV-6A, HHV-6B, and HHV-7 infections is rather based on gene amplification (PCR), which allows for the detection and quantification of the viral genome, than on serology, which is mainly indicated in case of primary infection. Ganciclovir, foscarnet, and cidofovir inhibit the replication of HHV-6A, HHV-6B, and HHV-7. Severe infections may thus be treated but these therapeutic indications are still poorly defined.
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Affiliation(s)
- H Agut
- Service de virologie, CERVI, hôpitaux universitaires La Pitié Salpêtrière-Charles-Foix, Assistance publique-Hôpitaux de Paris, 83, boulevard de l'Hôpital, 75651 Paris cedex 13, France; Inserm, CIMI-Paris UMR 1135, Équipe 1 PVI, Sorbonne universités, UPMC université Paris 6, 75013 Paris, France.
| | - P Bonnafous
- Inserm, CIMI-Paris UMR 1135, Équipe 1 PVI, Sorbonne universités, UPMC université Paris 6, 75013 Paris, France.
| | - A Gautheret-Dejean
- Service de virologie, CERVI, hôpitaux universitaires La Pitié Salpêtrière-Charles-Foix, Assistance publique-Hôpitaux de Paris, 83, boulevard de l'Hôpital, 75651 Paris cedex 13, France; Inserm, CIMI-Paris UMR 1135, Équipe 1 PVI, Sorbonne universités, UPMC université Paris 6, 75013 Paris, France; Faculté de pharmacie, université Paris-Descartes, 75006 Paris, France.
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Agut H, Bonnafous P, Gautheret-Dejean A. Laboratory and clinical aspects of human herpesvirus 6 infections. Clin Microbiol Rev 2015; 28:313-35. [PMID: 25762531 PMCID: PMC4402955 DOI: 10.1128/cmr.00122-14] [Citation(s) in RCA: 177] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Human herpesvirus 6 (HHV-6) is a widespread betaherpesvirus which is genetically related to human cytomegalovirus (HCMV) and now encompasses two different species: HHV-6A and HHV-6B. HHV-6 exhibits a wide cell tropism in vivo and, like other herpesviruses, induces a lifelong latent infection in humans. As a noticeable difference with respect to other human herpesviruses, genomic HHV-6 DNA is covalently integrated into the subtelomeric region of cell chromosomes (ciHHV-6) in about 1% of the general population. Although it is infrequent, this may be a confounding factor for the diagnosis of active viral infection. The diagnosis of HHV-6 infection is performed by both serologic and direct methods. The most prominent technique is the quantification of viral DNA in blood, other body fluids, and organs by means of real-time PCR. Many active HHV-6 infections, corresponding to primary infections, reactivations, or exogenous reinfections, are asymptomatic. However, the virus may be the cause of serious diseases, particularly in immunocompromised individuals. As emblematic examples of HHV-6 pathogenicity, exanthema subitum, a benign disease of infancy, is associated with primary infection, whereas further virus reactivations can induce severe encephalitis cases, particularly in hematopoietic stem cell transplant recipients. Generally speaking, the formal demonstration of the causative role of HHV-6 in many acute and chronic human diseases is difficult due to the ubiquitous nature of the virus, chronicity of infection, existence of two distinct species, and limitations of current investigational tools. The antiviral compounds ganciclovir, foscarnet, and cidofovir are effective against active HHV-6 infections, but the indications for treatment, as well as the conditions of drug administration, are not formally approved to date. There are still numerous pending questions about HHV-6 which should stimulate future research works on the pathophysiology, diagnosis, and therapy of this remarkable human virus.
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Affiliation(s)
- Henri Agut
- Sorbonne Universités, UPMC, CIMI-Paris UMRS CR7, PVI Team, Paris, France INSERM, CIMI-Paris U1135, PVI Team, Paris, France AP-HP, Hôpitaux Universitaires Pitié Salpêtrière-Charles Foix, Service de Virologie, Paris, France
| | - Pascale Bonnafous
- Sorbonne Universités, UPMC, CIMI-Paris UMRS CR7, PVI Team, Paris, France INSERM, CIMI-Paris U1135, PVI Team, Paris, France
| | - Agnès Gautheret-Dejean
- Sorbonne Universités, UPMC, CIMI-Paris UMRS CR7, PVI Team, Paris, France INSERM, CIMI-Paris U1135, PVI Team, Paris, France AP-HP, Hôpitaux Universitaires Pitié Salpêtrière-Charles Foix, Service de Virologie, Paris, France Université René Descartes, Faculté de Pharmacie, Laboratoire de Microbiologie UPRES EA 4065, Paris, France
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Nefzi F, Ben Salem NA, Khelif A, Feki S, Aouni M, Gautheret-Dejean A. Quantitative analysis of human herpesvirus-6 and human cytomegalovirus in blood and saliva from patients with acute leukemia. J Med Virol 2014; 87:451-60. [PMID: 25163462 DOI: 10.1002/jmv.24059] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2014] [Indexed: 01/24/2023]
Abstract
Human herpesvirus-6 (HHV-6) and human cytomegalovirus (HCMV) DNAs were quantified by real-time PCR assays in blood and saliva obtained from 50 patients with acute leukemia at the time of diagnosis (50 of each matrix), aplasia (65 of each matrix), remission (55 of each matrix), and relapse (20 of each matrix) to evaluate which biological matrix was more suitable to identify a viral reactivation, search for a possible link between HHV-6 and HCMV reactivations, and evaluate the relations between viral loads and count of different leukocyte types in blood. The median HHV-6 loads were 136; 219; 226, and 75 copies/million cells in blood at diagnosis, aplasia, remission and relapse, respectively. The HCMV loads were 193 and 317 copies/million cells in blood at diagnosis and remission. In the saliva samples, the HHV-6 loads were 22,165; 15,238; 30,214, and 17,454 copies/million cells at diagnosis, aplasia, remission, and relapse, respectively. The HCMV loads were 8,991; 1,461; 2,980, and 4,283 copies/million cells at diagnosis, aplasia, remission, and relapse, respectively. The HHV-6 load in the blood was correlated to the counts of polymorphonuclear leukocytes (R(2) = 0.5; P < 0.0001) and lymphocytes (R(2) = 0.4; P = 0.001) and was not correlated to the monocyte counts (R(2) = 0.07; P = 0.7). Saliva appears to be a more sensitive biological matrix than whole blood in the detection of HHV-6 or HCMV reactivations. The HHV-6 and HCMV reactivations were linked only in saliva.
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Affiliation(s)
- Faten Nefzi
- Laboratory of Infectious Diseases and Biological Agents, Faculty of Pharmacy, University of Monastir, Monastir, Tunisia
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Coinfection of human herpesviruses 6A (HHV-6A) and HHV-6B as demonstrated by novel digital droplet PCR assay. PLoS One 2014; 9:e92328. [PMID: 24663487 PMCID: PMC3963908 DOI: 10.1371/journal.pone.0092328] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 02/20/2014] [Indexed: 01/23/2023] Open
Abstract
The human herpesviruses HHV-6A and HHV-6B have been associated with various neurologic disorders partly due to the detection of elevated viral DNA levels in patients compared to controls. However the reported frequency of these viruses varies widely, likely reflecting differences in PCR methodologies used for detection. Digital droplet PCR (ddPCR) is a third generation PCR technology that enables the absolute quantification of target DNA molecules. Mounting evidence of the biological differences between HHV-6A and HHV-6B has led to their recent reclassification as separate species. As it is now especially relevant to investigate each virus, our objectives were to first design a multiplex HHV-6A and HHV-6B ddPCR assay and then to investigate the incidence of HHV-6A and HHV-6B coinfection in samples from healthy donors and patients with MS, a disease in which HHV-6 is thought to play a role. In our assessment of healthy donors, we observed a heretofore-underappreciated high frequency of coinfection in PBMC and serum, and found that our assay precisely detects both HHV-6A and HHV-6B chromosomally integrated virus, which has important implications in clinical settings. Interestingly, upon comparing the saliva from MS patients and healthy donors, we detected a significantly elevated frequency of coinfection in MS saliva; increased detection of HHV-6A in MS patients is consistent with other studies suggesting that this viral species (thought to be more neurotropic than HHV-6B) is more prevalent among MS patients compared to healthy donors. As the biology and disease associations between these two viral species differ, identifying and quantifying both species of HHV-6 may provide clinically relevant information, as well as enhance our understanding of the roles of each in health and disease.
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Quantitation of human herpesvirus-6A, -6B and -7 DNAs in whole blood, mononuclear and polymorphonuclear cell fractions from healthy blood donors. J Clin Virol 2012; 53:151-5. [DOI: 10.1016/j.jcv.2011.10.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 10/17/2011] [Accepted: 10/26/2011] [Indexed: 01/22/2023]
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Pellett PE, Ablashi DV, Ambros PF, Agut H, Caserta MT, Descamps V, Flamand L, Gautheret-Dejean A, Hall CB, Kamble RT, Kuehl U, Lassner D, Lautenschlager I, Loomis KS, Luppi M, Lusso P, Medveczky PG, Montoya JG, Mori Y, Ogata M, Pritchett JC, Rogez S, Seto E, Ward KN, Yoshikawa T, Razonable RR. Chromosomally integrated human herpesvirus 6: questions and answers. Rev Med Virol 2011; 22:144-55. [PMID: 22052666 PMCID: PMC3498727 DOI: 10.1002/rmv.715] [Citation(s) in RCA: 235] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 09/02/2011] [Accepted: 09/15/2011] [Indexed: 12/14/2022]
Abstract
Chromosomally integrated human herpesvirus 6 (ciHHV-6) is a condition in which the complete HHV-6 genome is integrated into the host germ line genome and is vertically transmitted in a Mendelian manner. The condition is found in less than 1% of controls in the USA and UK, but has been found at a somewhat higher prevalence in transplant recipients and other patient populations in several small studies. HHV-6 levels in whole blood that exceed 5.5 log10 copies/ml are strongly suggestive of ciHHV-6. Monitoring DNA load in plasma and serum is unreliable, both for identifying and for monitoring subjects with ciHHV-6 due to cell lysis and release of cellular DNA. High HHV-6 DNA loads associated with ciHHV-6 can lead to erroneous diagnosis of active infection. Transplant recipients with ciHHV-6 may be at increased risk for bacterial infection and graft rejection. ciHHV-6 can be induced to a state of active viral replication in vitro. It is not known whether ciHHV-6 individuals are put at clinical risk by the use of drugs that have been associated with HHV-6 reactivation in vivo or in vitro. Nonetheless, we urge careful observation when use of such drugs is indicated in individuals known to have ciHHV-6. Little is known about whether individuals with ciHHV-6 develop immune tolerance for viral proteins. Further research is needed to determine the role of ciHHV-6 in disease. Copyright © 2011 John Wiley & Sons, Ltd.
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Affiliation(s)
- Philip E Pellett
- Department of Immunology and Microbiology, Wayne State University School of Medicine, Detroit, MI 48201, USA.
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Agut H. Deciphering the clinical impact of acute human herpesvirus 6 (HHV-6) infections. J Clin Virol 2011; 52:164-71. [DOI: 10.1016/j.jcv.2011.06.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Revised: 06/09/2011] [Accepted: 06/24/2011] [Indexed: 02/07/2023]
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