HHV-6B- and HHV-7-associated choroiditis secondary to acute myelogenous leukemia: a case report

We report a case of human herpes virus 6 (HHV-6)- and human herpes virus 7 (HHV-7)-associated choroiditis in an immunocompromised woman. A 42-year-old Chinese woman with a history of acute myelogenous leukemia presented with blurred vision and black floaters in her right eye. Anterior segment examination findings were normal. Ophthalmoscopic examination revealed a subretinal lesion in the superonasal peripapillary region with several punctate hemorrhages. Optical coherence tomography showed a crater-like choroidal protuberance, associated with retinal pigment epithelium rupture and full-thickness retinal edema in the involved area. Indocyanine green angiography demonstrated a broad hypofluorescent lesion in the choroid. The patient was diagnosed with choroiditis. Subsequently, metagenomic next-generation sequencing revealed HHV-6B and HHV-7 DNA in the aqueous humor. Therefore, antiviral therapy was initiated. The patient experienced resolution of all symptoms and signs after treatment with intravenous foscarnet and oral acyclovir. The findings in this case indicate that HHV-6 and HHV-7 can cause ocular infection, particularly in immunocompromised patients.

Meningitis associated with HHV-7 in an Iranian immunocompetent adolescent girl

There is limited literature regarding meningitis associated with HHV-7. This article reports an immunocompetent adolescent girl who developed fever, headache, and meningism which CSF molecular analysis with PCR was positive only for HHV-7. Interestingly, persistent cavum septum pellucidum and cavum vergae were observed on brain magnetic resonance imaging. The patient received antibiotics, dexamethasone, and acyclovir and then she gained full recovery. HHV-7 is a rare and yet possible pathogen in patients with meningitis, and this is the first described case report from Iran.

Development of a PCR assay for the detection of human herpes virus type 7

A PCR assay has been developed to identify the DNA of the human herpes virus type 7. The search and selection of conserved regions was carried out by comparing the whole genome nucleotide sequences of HHV-7. A fragment duplicated in the HHV-7 genomes was chosen as a target for amplification. The performance of the assay was tested on a synthetic matrix and clinical samples. The developed assay has high sensitivity and specificity and showed good efficiency in detecting HHV-7 DNA in clinical samples.

Metagenomic sequencing complements routine diagnostics in identifying viral pathogens in lung transplant recipients with unknown etiology of respiratory infection

Background

Lung transplant patients are a vulnerable group of immunosuppressed patients that are prone to frequent respiratory infections. We studied 60 episodes of respiratory symptoms in 71 lung transplant patients. Almost half of these episodes were of unknown infectious etiology despite extensive routine diagnostic testing.

Methods

We re-analyzed respiratory samples of all episodes with undetermined etiology in order to detect potential viral pathogens missed/not accounted for in routine diagnostics. Respiratory samples were enriched for viruses by filtration and nuclease digestion, whole nucleic acids extracted and randomly amplified before high throughput metagenomic virus sequencing. Viruses were identified by a bioinformatic pipeline and confirmed and quantified using specific real-time PCR.

Results

In completion of routine diagnostics, we identified and confirmed a viral etiology of infection by our metagenomic approach in four patients (three Rhinovirus A, one Rhinovirus B infection) despite initial negative results in specific multiplex PCR. Notably, the majority of samples were also positive for Torque teno virus (TTV) and Human Herpesvirus 7 (HHV-7). While TTV viral loads increased with immunosuppression in both throat swabs and blood samples, HHV-7 remained at low levels throughout the observation period and was restricted to the respiratory tract.

Conclusion

This study highlights the potential of metagenomic sequencing for virus diagnostics in cases with previously unknown etiology of infection and in complex diagnostic situations such as in immunocompromised hosts.

Acute myelitis by human herpes virus 7 in an HIV-infected patient

BACKGROUND

HHV7 reactivation has been occasionally reported as a cause of encephalitis or myelitis in transplant recipients, but to our knowledge it has never been associated with neurological disease in HIV-infected patients. We report a case of acute myelitis in an HIV-infected patient, with sustained HHV-7 DNA amplification in cerebrospinal fluid (CSF) and a favourable response to foscarnet.

CASE REPORT

A 40 year-old man with HIV infection was admitted with asymmetric hypoesthesia in legs and paraparesis. He was receiving treatment with efavirenz, emtricitabine and tenofovir, his CD4 count was 580/mm3 and HIV viral load was undetectable. Magnetic resonance imaging showed a focal central hyperintensity on T2 and STIR sequences, on the torathic spinal cord, with slight enhancement after intravenous gadolinium. All microbiological studies were negative except for HHV-7 DNA amplification in CSF. With a diagnosis of idiopathic transverse myelitis, treatment with high-dose intravenous methylprednisolone was initiated. However, paraparesis continued worsening, and a second CSF obtained 12 days after the first one resulted again in HHV-7 amplification.

RESULTS

The patient was treated with a 2 week course of foscarnet, and a rapid neurological improvement was noted. After treatment, PCR for HHV-7 in CSF was negative. Neurological exam was normal one month after treatment initiation.

CONCLUSION

HHV-7 reactivation may cause neurological disease in patients with HIV infection. Foscarnet is an effective treatment in HHV-7 associated myelitis.

Discovery and biological characterization of two novel pig-tailed macaque homologs of HHV-6 and HHV-7

Human herpesvirus-6 (HHV-6) and -7 (HHV-7) are Roseoloviruses within the Betaherpesvirus family, which have a high prevalence and suspected involvement in a number of diseases. Using CODEHOP-based PCR, we identified homologs of both viruses in saliva of pig-tailed macaques, provisionally named MneHV-6 and MneHV-7. This finding supports the existence of two distinct Roseolovirus lineages before the divergence of humans and macaques. Using specific qPCR assays, high levels of MneHV-6 and MneHV-7 DNA were detected in macaque saliva, although the frequency was greater for MneHV-7. A blood screen of 283 macaques revealed 10% MneHV-6 DNA positivity and 25% MneHV-7 positivity, with higher prevalences of MneHV-6 in older females and of MneHV-7 in younger males. Levels of MneHV-6 were increased in animals coinfected with MneHV-7, and both viruses were frequently detected in salivary gland and stomach tissues. Our discovery provides a unique animal model to answer unresolved questions regarding Roseolovirus pathology.

Roseolovirus molecular biology: recent advances

Human herpesviruses 6A, 6B, and 7 (HHV-6A, HHV-6B, and HHV-7) are classified within the roseolovirus genus of the betaherpesvirus subfamily. Most humans likely harbor at least two of these large DNA viruses, and 1% of humans harbor germline chromosomally integrated (ci) HHV-6A or HHV-6B genomes. Differences at the genetic level manifest as distinct biologic properties during infection and disease. We provide a brief synopsis of roseolovirus replication and highlight the unique properties of their lifecycle and what is known about the viral gene products that mediate these functions. In the nearly 30 years since their discovery, we have only begun to unlock the molecular strategies these highly evolved pathogens employ to establish and maintain chronic infections in humans.

Possible interference of human beta-herpesviruses-6 and -7 in gastrointestinal cancer development

AIM

The high incidence of gastrointestinal cancer combined with high mortality from the disease if diagnosed at a late stage, signifies the need for better diagnostic, prognostic and predictive tools. Human beta-herpesviruses have been suggested as possible cofactors in the development of gastrointestinal cancer.

METHODS

Sixty five patients with gastrointestinal cancer before surgery and without any treatment were enrolled in this study and divided into two groups depending on lymphocytes' count: I group (n = 35) -- lymphocytes > 1400x10(6)/L and II group (n = 30) -- lymphocytes < 1400x10(6)/L. Nested polymerase chain reaction was used to detect latent and active stage of persistent human herpesvirus-6 and -7 infection, laser flow cytometry with monoclonal antibodies -- to determine immunological parameters.

RESULTS

Activation of herpesvirus-6 and -7 was more frequently observed in the patients' group with lymphopenia (HHV-6 1/1 (100%), HHV-7 4/8 (50%) and HHV-6 + HHV-7 6/9 (66%); p < 0.05). Cellular immune parameters were analysed in immunocompromised II group's patients dependently on beta-herpevirus infection. Although number of leukocytes was higher in patients with active HHV-6/-7 infection (p = 0.01), number of lymphocytes CD3(+), CD4(+), CD8(+) and CD38(+) in patients with active HHV-6/-7 infection tended to decrease (p < 0.0001, P = 0.0002, p = 0.0001 and p < 0.0001, respectively). However, number of CD19(+) had tendency to increase (p = 0.03).

CONCLUSION

Activation of herpesvirus-6 and -7 may lead to decrease of lymphocytes total count and develop immunosuppression in patients with gastrointestinal cancer.

[Meningomyelitis associated with infection by human herpes virus 7: report of two cases]

Human herpesvirus 7 (HHV-7) may cause encephalomyelitis in immune competent adults. We report two patients infected by the virus. A 34-year-old male presenting with paraparesis and a sensitive deficiency located in D6 dermatome. Cerebrospinal fluid had 35 white blood cells per mm³ and 75 mg protein per dl. A PCR-microarray examination was positive for HHV-7. The patient was treated with prednisolone and ganciclovir with full recovery. A 27-year-old male presenting with headache, fever and diarrhea. Cerebrospinal fluid analysis showed 160 cells per mm³ and 75 mg protein per dl. Viral RNA detection was positive for HHV-7. The patient was managed with analgesia and rest and was discharged with the diagnosis of viral meningitis. Our communication supports the notion that HHV-7 may be considered as pathogen factor in humans, even in immune competent ones.

Progressive multifocal leukoencephalopathy following fludarabine treatment in a chronic lymphocytic leukemia patient

Progressive multifocal leukoencephalopathy (PML) is a neurological disease caused by infection of the central nervous system (CNS) with the JC polyomavirus (JCV). JCV is endemic and infects a large proportion (70-90%) of healthy individuals worldwide, but infection is latent. JCV reactivation may occur, if the immune function is compromised.

AIM

To present a PML case in a CLL patient after a long course of disease and treatment with fludarabine. JCV virus infection in this patient was proven both in brain biopsy material and blood.

METHODS

Patient with a nine-year history of CLL was hospitalized with the weakness in the right leg and left hand, tremors, speech difficulties. An MRI diagnosed infiltrative glial tumor of the left hemisphere, proliferating predominantly in the frontal lobe, more in the gyrus frontalis superior region. CNS tumor biopsy performed.

RESULTS

Morphology and immunoprofile of the lesion consistent with progressive multifocal leukoencephalopathy. The material from biopsy was diagnosed as positive for JCV DNA. JCV and HHV-7 genomic sequences were found in patient's PBL DNA sample. In a plasma DNA sample, only genomic sequences were detected.

CONCLUSION

The present case draws attention to the fact that the use of fludarabine and its combinations in CLL therapy increases the risk of JCV infection reactivation and development of serious complications like PML.

Lymphotropic herpesvirus DNA detection in patients with active CMV infection - a possible role in the course of CMV infection after hematopoietic stem cell transplantation

BACKGROUND

The natural history of cytomegalovirus (CMV) infection and disease in transplant recipients prompts researchers to look for other factors contributing to this infection. The ubiquity of lymphotropic herpesviruses (EBV, HHV-6, and HHV-7) and the possibility of their activation during immunosuppression may suggest their participation in progression of CMV infection in patients after hematopoietic stem cell transplantation (HSCT).

MATERIAL/METHODS

The presence of CMV, EBV, HHV-6 and HHV-7 was confirmed through detection of viral DNA isolated from leukocytes. Allo-HSCT recipients (n=55) were examined repeatedly within the average period of 14±7.3 months post-transplant.

RESULTS

CMV DNA was detected in 24% of samples, while EBV, HHV-6 and HHV-7 were detected in 20%, 15% and 14% of samples, respectively. Based on the presence of CMV infection at particular time-points (months) after transplantation, the recipients were divided into 3 groups: Group I (N=15) with persistent infection, Group II (N=20) with transient infection, and Group III (N=20) without CMV infection. In Group I, the mean CMV load was significantly higher than in Group II, and the clinical condition of Group I patients was poorer. All these patients manifested clinical symptoms, and all had episodes of GvHD. All Group I patients developed multiple infections; EBV in 80%, HHV-6 in 47% and HHV-7 in 87% of patients. In the remaining groups, with the exception of HHV-6 in group II, the frequency of infected patients was lower. In addition, CMV presence was often preceded by another herpesvirus.

CONCLUSIONS

The results suggest that other herpesviruses, mainly HHV-7, could predispose CMV to cause chronic infection.

Quantitative detection of HHV-6 and HHV-7 in transbronchial biopsies from lung transplant recipients

The occurrence and significance of HHV-6 and HHV-7 were investigated in pulmonary tissue from lung transplant recipients. Eighty-seven transbronchial biopsies from 30 patients were studied by quantitative real-time PCR; the association with histopathological features was investigated. HHV-6 and HHV-7-DNA were detected in 6.9% and 9.2% transbronchial biopsies, respectively. A significant association between HHV-6 detection on transbronchial biopsies and interstitial pneumonia was found, in contrast to the lack of association between viral detection on bronchoalveolar lavage and any histopathological feature. No association was evidenced in terms of acute and chronic rejection. The finding of HHV-6 and/or HHV-7-DNA positivity in all the cases with ischemia-reperfusion injury suggests a possible role in favouring ?-herpesviruses reactivation, as previously described for HCMV in renal transplantation.

[One case of correlation between the human herpesvirus 7 DNA load and the hemo hagocytic syndrome]

OBJECTIVE

To research the relationship between human herpesvirus 7 (HHV-7) viral Load and the etiopathogenisis of hemophagocytic syndrome, in order to provide evidence for the clinical diagnosis of hemophagocytic syndrome and anti-virus therapy.

METHODS

Peripheral blood of patient with hemophagocytic syndrome during different treatment periods, extracted DNA, Syntheticed the primers of HHV-7, gene sequence of PCR amplified fragments detected, determined HHV-7 viral Load by Real-time fluorescent quantitative PCR and the ferritin concentration in peripheral blood detected by chemiluminescence.

RESULT

The sequence result indicated that PCR amplified fragment was a part of HHV-7 gene, the ferritin concentration viried with the load of HHV-7.

CONCLUSION

The occurrence of hemophagocytic syndrome is connetted with the load of HHV-7.

[Application of real-time PCR and LightCycler system for investigating the presence of human herpesvirus 7 DNA]

Human herpesvirus 7 (HHV-7) is a beta-herpesvirus widely spread within a population and has been recognized as a potential pathogen in immunocompromised hosts. The goal of the study was development of real-time PCR assay for detection of human herpesvirus 7 DNA in clinical samples, using primers targeting a conserved region of the viral DNA major capside proteine gene and a specific TaqMan hydrolyzing probe. Sixty four plasma samples taken from a group of adult recipients of allogeneic HSCT, during detectable CMV viremia or neutropenic fever, were tested for the presence of viral DNA in the LightCycler system with method described above. HHV-7 DNA was detected in 40 specimens (62.5%). The conclusion is that developed TaqMan-based probes real-time PCR test is very reliable and valuable tool for detection of HHV-7 viremia in plasma samples. The high level of sensitivity and accuracy provided by the LightCycler instrument is favorable for the use of this method in the detection of human herpesvirus 7 DNA in clinical specimens.

Characterization of the lymphotropic amplicons-6 and tamplicon-7 vectors derived from HHV-6 and HHV-7

Amplicon-6 and Tamplicon-7 are novel non-integrating vectors derived from the lymphotropic Human Herpesviruses 6 and 7 (HHV-6 and HHV-7). In the presence of helper viruses the amplicon vectors replicate to yield packaged defective genomes of size approximately 150 kb and consisting of multiple repeat units containing (i) the oriLyt DNA replication origin (ii) the pac-1 and pac-2 cleavage and packaging signals (iii) bacterial plasmid DNA sequences (iv) the chosen transgene(s). Employing CD46 as a receptor HHV-6 gains entry into varied cells, including lymphocytes and dendritic cells, whereas HHV-7 employs the CD4 receptor to target CD4+ cells. The amplicon-based vectors have facilitated the characterization of viral DNA replication and packaging. Following electroporation and helper virus superinfection, the vectors can be transmitted as cell associated and as cell-free virions secreted into the medium. Analyses by flow cytometry have shown good cell spread and efficient gene expression. Exemplary transgenes have included: (i) The Green Fluorescence Protein (GFP) (ii) Genes for potential use in anti-viral vaccination e.g., the HSV-1 glycoprotein D (gD) with and without the trans-membrane region, expressed intracellularly, at the cell membrane or as secreted proteins. (iii) Tumor cell antigens. (iv) Apoptotic genes for development of oncolytic vectors. Due to their cell tropism, their structure as concatemeric genomes, with less than 1.5 kb of viral DNA sequences, the HHV-6 and 7 amplicons have the potential to become unique vectors for immunization and lymphotropic gene therapy.

Detection and monitoring of human herpesvirus 7 in adult liver transplant patients: impact on clinical course and association with cytomegalovirus

We herein have described HCMV and HHV-7 detection during the follow-up of 29 adult liver recipients in our transplant unit. For basic immunosuppression, the patients received cyclosporine and symptomatic HCMV infection was treated with gancyclovir. The most prevalent etiology for liver transplantation was hepatitis C or alcohol abuse (45% of patients). The laboratory monitoring to 180 days after transplantation was performed by nested-polymerase chain reaction to HCMV or HHV-7. HCMV DNA was detected in 19/29 of patients (65.5%) and HHV-7 DNA, in 14/29 of patients (48.2%). The time-related appearance of HHV-7 and HCMV DNA differed significantly (P = .02); their detection was considered independent (P = .2). The results showed that few patients remained free of HHV-7 or HCMV after liver transplantation, indicating that most patients were actively infected with more then one virus sequentially and not concurrently. Graft dysfunction, fever, gastrointestinal system abnormalities, and interstitial pneumonitis dominated the clinical pictures. Thirteen of 29 patients (44.8%) developed symptomatic HCMV active infections. The relationship between the detection of HCMV DNA, and HCMV disease development was significant (P = .0004). In HCMV-free patients, no symptoms or significant laboratory findings were linked with HHV-7. However, HHV-7 was frequently detected sequentially after HCMV, and an interaction of HCMV and/or HHV-6 to increase their pathogenic effects could not be excluded. Further studies should be performed including HHV-6 to evaluate the relationship, among beta herpesviruses.

[Human herpesvirus 7 infection in patients after allogeneic hematopoietic stem cell transplantation]

OBJECTIVE

To study the prevalence of human herpesvirus 7 (HHV-7) infection in recipients following allogeneic hematopoietic stem cell transplantation (allo-HSCT).

METHODS

Peripheral blood samples were collected before and weekly after allo-HSCT from 72 consecutive recipients and 53 donors. Nested polymerase chain reaction (nPCR) was used to monitor HHV-7 DNAemia.

RESULTS

HHV-7 DNAemia was detected at least once in 86.1% (62/72) of the 72 patients on the median day 15.6 (7 approximately 56 days) after allo-HSCT. Continuing HHV-7 DNAemia (HHV-7 DNAemia maintained at least 4 weeks) was evidenced in 40.3% (29/72) of the patients after allo-HSCT. The prevalence of continuing HHV-7 DNAemia in the patients receiving HLA mismatched or HLA matched unrelated allo-HSCT who underwent conditioning with anti-thymocyte globulin (ATG) was 48.9% (23/47), significantly higher than that in the patients receiving HLA matched related allo-HSCT with conditioning without ATG [24% (6/25), P = 0.040]. Enhanced incidence the prevalence of HHV-7 DNAemia in the patients receiving corticosteroid after allo-HSCT was 44.6% (39/65), significantly higher than that in the patients who did not receive corticosteroid [0% (0/7), P = 0.037]. No relationship was observed between HHV-7 infection and transplant-related complications including acute graft versus host disease, hemorrhagic cystitis, cytomegalovirus and HHV-6 infection.

CONCLUSION

Common in allo-HSCT recipients, HHV-7 DNAemia is closely associated with conditioning with ATG and application of corticosteroid after allo-HSCT.

Reciprocal roles of cellular chemokine receptors and human herpesvirus 7-encoded chemokine receptors, U12 and U51

Human herpesvirus 7 (HHV-7) is a member of the subfamilyBetaherpesvirinaethat exhibits a restricted cell tropism, preferentially infecting CD4+T cellsin vitro. HHV-7 encodes two functional chemokine receptors, U12 and U51. The human chemokines that act as ligands for these receptors have been identified as CCL22 (the natural ligand for CCR4) and CCL19 (the natural ligand for CCR7). It was found that murine L1.2 cells co-expressing CCR4 or CCR7 and U12 responded to both CCL22 and CCL19 in calcium-mobilization assays, but migrated in response only to the appropriate ligand for the expressed cellular receptor. Similar results were obtained with L1.2 cells co-expressing CCR4 or CCR7 with U51. These results suggest that the HHV-7 U12 and U51 receptors can function in concert with CCR4 and CCR7 in host-cell signalling pathways.

Lichen planus remission is associated with a decrease of human herpes virus type 7 protein expression in plasmacytoid dendritic cells

The cause of lichen planus is still unknown. Previously we showed human herpes virus 7 (HHV-7) DNA and proteins in lesional lichen planus skin, and significantly less in non-lesional lichen planus, psoriasis or healthy skin. Remarkably, lesional lichen planus skin was infiltrated with plasmacytoid dendritic cells. If HHV-7 is associated with lichen planus, then HHV-7 replication would reduce upon lichen planus remission. HHV-7 DNA detection was performed by nested PCR and HHV-7 protein by immunohistochemistry on lesional skin biopsies from lichen planus patients before treatment and after remission. Biopsies were obtained from lichen planus lesions before treatment (n = 18 patients) and after remission (n = 13). Before treatment 61% biopsies contained HHV-7 DNA versus 8% after remission (P = 0.01). HHV-7-protein positive cell numbers diminished significantly after remission in both dermis and epidermis. Expression of HHV-7 was mainly detected in BDCA-2 positive plasmacytoid dendritic cells rather than CD-3 positive lymphocytes. HHV-7 replicates in plasmacytoid dendritic cells in lesional lichen planus skin and diminishes after remission. This study further supports our hypothesis that HHV-7 is associated with lichen planus pathogenesis.

Human herpesvirus-6 (HHV-6) DNA in plasma reflects the presence of infected blood cells rather than circulating viral particles

BACKGROUND

The presence of HHV-6 DNA in plasma or serum is considered a good marker of active infection. However, it is ignored whether this DNA corresponds to virus particles produced by lymphoid tissue infection or virus-free DNA released from infected circulating blood cells.

OBJECTIVES

To investigate whether HHV-6 DNA in whole plasma is nonencapsidated and its amount is correlated to cellular and human herpesvirus-7 (HHV-7) DNA loads in plasma subfractions as well as in corresponding peripheral blood mononuclear cells (PBMCs).

STUDY DESIGN

Whole plasma samples from immunocompromised patients were submitted to a DNase-resistance test. Plasma samples from a second group of patients were split up into three subfractions: P1 (pellet of clarification), P2 (pellet of ultracentrifugation), and S (supernatant of ultracentrifugation). HHV-6, HHV-7, and cellular DNA loads were determined in each fraction and PBMCs using specific real-time PCR.

RESULTS

Among 14 whole plasma samples, the majority of HHV-6 DNA detected was unprotected against DNase, i.e. nonencapsidated. The study of 35 other plasma samples revealed that cellular DNA was present in all subfractions from all samples whereas HHV-6 DNA was detected in 13 P1, 12 P2, 10 S fractions, and HHV-7 DNA in only one P1 fraction. Accordingly, median HHV-6 DNA load was significantly higher in P1 than in P2 and S fractions. The detection of HHV-6 DNA in plasma subfractions was statistically associated with a higher HHV-6 viral load in PBMCs (p<or=0.0003).

CONCLUSIONS

Taken together, these data tend to favour the hypothesis of a release of HHV-6 and cellular DNA into plasma following the lysis of infected PBMCs. HHV-6 DNA in plasma does not necessarily reflect the amount of virus produced by the active infection of distant lymphoid tissue and organs.

Drug-Induced Hypersensitivity Syndrome due to Mexiletine Hydrochloride Associated with Reactivation of Human Herpesvirus 7

It has been suggested that reactivation of human herpesvirus 6 (HHV-6) infection may be involved in the pathogenesis of drug-induced hypersensitivity syndrome. We report a 45-year-old Japanese man who developed a generalized papuloerythematous rash, fever, hepatitis, lymphadenopathy and lymphocytosis with an increased number of atypical lymphocytes. He was diagnosed with DIHS due to mexiletine hydrochloride based on laboratory data, results of a patch test and the clinical course of his complaint, and was treated with systemic steroids. In order to determine whether HHV-6 or -7 was associated with the patient's disease, serological assays and PCR were carried out. Significant increases in antibody titers against HHV-6 and -7 were observed from day 12 to 24. From PCR analysis, none of the peripheral blood mononuclear cells or skin tissue samples contained HHV-6 DNA. All samples, however, were found to contain HHV-7 DNA. Reactivation of HHV-7 could be responsible for drug-induced hypersensitivity syndrome.

Detection of β-herpesviruses in allogenic stem cell recipients by quantitative real-time PCR

The aim of this study was to investigate the clinical impact of reactivation of human herpes virus-6 (HHV-6) and HHV-7 infections in stem cell transplantation recipients, and to examine a possible increase in virulence of the two roseoloviruses when a reactivation of CMV (HHV-5) simultaneously occurs. For this purpose, quantitative real-time PCR systems were developed to assess the viral load of CMV, HHV-6, or HHV-7 in the plasma of haematopoetic stem cell recipients. One hundred and ninety-eight plasma samples from 37 patients who underwent allogeneic stem cell transplantation were tested for CMV, HHV-6, and HHV-7 by a 5'-exonuclease (TaqMan) quantitative real-time PCR. The CMV load obtained by the real-time PCR assay was compared retrospectively with results generated previously with a commercially available test (COBAS AMPLICOR CMV MONITOR Test, Roche). The results suggest that CMV and HHV-6 may be associated with post-transplantation end-organ disease, while HHV-7 reactivation had no impact on the patients included in this study. No evidence for a potential interaction of the roseoloviruses and CMV infections was found.

Association of anticonvulsant hypersensitivity syndrome with Herpesvirus 6, 7

BACKGROUND

Anticonvulsant hypersensitivity syndrome (AHS) is one of the most severe forms of drug eruption with potentially lethal, and multiorgan involvement. Recently, it has been suggested that Human Herpesvirus (HHV) infection has been involved in this syndrome, although the pathogenesis of this syndrome remains still unclear.

METHODS

The objective of this study was to determine the clinical characteristics of AHS and the possible role of viral infection as a co-factor. We prospectively analyzed clinical, laboratory and virological findings for 23 cases of AHS. A viral study including viral serology and a polymerase chain reaction (PCR) was performed.

RESULTS

The most common anticonvulsant was carbamazepine (12) followed by phenytoin (6), phenobarbital (4) and gabapentin (1). All patients met fulfill the clinical criteria of AHS. Even though internal organ involvement such as liver (52%), kidney (34%), and lung (13%) has been observed, involvement of heart, lung, thyroid, muscle, pancreas, spleen, and brain was less frequent. We also noted two patients who died due to multiorgan failure. No association with viral infection including HSV, VZV, HHV-8, CMV, EBV, measles, rubella and parvovirus B19 was detected in the current series. Increased serum anti-HHV-6 IgG and HHV-7 titers and presence of HHV-6 and -7 DNA in serum, revealed by PCR analysis, suggested reactivation of HHV-6. In contrast to the control groups, DNA for HHV-6 was detected in serum in 5 out of the 23 patients while HHV-7 was seen in two patients. We found an evidence to link reactivation of HHV-6 or HHV-7 in the development of only carbamazepine-induced AHS.

CONCLUSIONS

We propose that some cases of AHS are accompanied by reactivation of not only HHV-6 but also HHV-7. HHV infection may contribute to the severity, prolongation, or relapse of AHS and may possibly have fatal consequences in some susceptible individuals receiving the anticonvulsants.

Encephaloradiculomyelitis associated to HHV-7 and CMV co-infection in immunocompetent host

An active co-infection with CMV and HHV-7 has been never described in immunocompetent patients. The authors describe a case of encephaloradiculomyelitis in an immunocompetent man. Polymerase chain reaction (PCR) performed on cerebrospinal fluid (CSF) showed positivity for DNA of Cytomegalovirus (CMV) and Herpes-virus type 7 (HHV-7), whereas the same test applied on peripheral blood mononuclear cells gave negative result. These results are highly supportive of an infection of the central and peripheral nervous systems, caused by CMV and HHV7. Such viral co-infection has only been described in immune-depressed patients with CMV disease, in which HHV-7 was supposed to act as a cofactor, enhancing clinical manifestations. The same mechanism is presumably responsible for the development of encephaloradiculomyelitis clinical signs in the present case. This is the second case in which DNA of HHV-7 has been found in the CSF of an adult immunocompetent patient. This novel observation suggests that the search for viral DNA in the CSF should be performed also in immunocompetent patients.

Anatomical mapping of human herpesvirus reservoirs of infection

Following primary infection, all eight human herpesviruses persist lifelong in the human host. However, a mapping of all anatomic sites of human herpesvirus persistence is lacking. Fresh tissue specimens representing approximately 40 major anatomic sites from eight autopsies were screened using a recently developed real-time PCR method for detection of all eight human herpesviruses. Patients with evidence of active herpesvirus infection (herpes simplex 1 (HSV-1), herpes simplex 2 (HSV-2), varicella-zoster virus (VZV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), herpesvirus 6 (HHV-6), herpesvirus 7 (HHV-7), and herpesvirus 8 (HHV-8)) at the time of death were excluded to avoid detection of widely disseminated infection. Despite this precaution, widespread HSV-1 positivity (with blood positivity) was detected in one case-an elderly male who died of cardiac arrest. In a middle-aged male with HIV-AIDS, HSV-1 was found in neural and pharyngeal tissues, skin, cartilage, bone, and urinary bladder, whereas in two other cases, HSV-1 was restricted to neural tissues. HSV-2 was detected in a single site, the anus, in the male with HIV-AIDS. VZV was detected only twice, once in the adrenal gland and once in the small intestine. CMV was detected in three cases, most commonly in nasal mucosa, trachea, thyroid, intestine, and liver. EBV was detected in all eight cases, especially in nasal mucosa, tonsil, spleen, lymph node, tongue, and intestine, but in only two of six whole-blood specimens. HHV-6, like EBV, was detected in all eight cases, most commonly in salivary glands, thyroid, stomach, intestines, liver, and pancreas. HHV-7, like EBV and HHV-6, was detected in all eight cases, most commonly in salivary glands, tonsil, lymph nodes, and bone marrow. HHV-8 was detected in only two sites (both lymph nodes) from two cases. Herpesviruses were detected in three of six whole-blood specimens, including HSV-1, EBV, HHV-6, and HHV-7. These results represent the most comprehensive mapping of herpesvirus tissue distribution in humans reported to date.

Characteristics and Acquisition of Human Herpesvirus (HHV)–7 Infections in Relation to Infection with HHV‐6

Although both human herpesvirus (HHV) 6 and HHV-7 infections are ubiquitous during childhood, few acute HHV-7 infections are identified. It is unknown whether HHV-7 viremia indicates primary infection, as with HHV-6, or reactivation, and if these differ clinically. We studied, in otherwise healthy children < or =10 years old, HHV-7 and HHV-6 infections and their interaction by serologic assessment, viral isolation, and polymerase chain reaction. In children < or =24 months of age, HHV-7 infections occurred less often than HHV-6 infections (P< or =.002). Of 2806 samples from 2365 children < or =10 years old, 30 (1%) showed evidence of HHV-7 viremia; 23 (77%) of these were primary and 7 (23%) were reactivated HHV-7 infections. Four (13%) showed concurrent HHV-6 viremia, 2 associated with primary HHV-7 infections. The clinical manifestations of primary and reactivated HHV-7 infections were similar, except that seizures occurred more frequently in reactivated infections. These findings, previously unrecognized in otherwise healthy children, suggest that HHV-7 viremia could represent primary or reactivated infection and may be affected by the interaction between HHV-6 and HHV-7.

Latent infection of human herpesvirus 7 in CD4(+) T lymphocytes

To determine the cell populations in peripheral blood that are infected latently with human herpesvirus 7 (HHV-7), the real-time polymerase chain reaction (PCR) was used to determine the quantities of viral DNA in adherent and non-adherent cells from 71 healthy volunteers. Real-time PCR, which detected the U31 gene of HHV-7, was developed to measure viral load. The majority of non-adherent cells (14/16; 87.5%) contained HHV-7 DNA, while most of the adherent cells did not (1/16; 6.3%). HHV-7 viral load in non-adherent cells was significantly higher than that in adherent cells (P < 0.0001). Then, HHV-7 DNA load was compared between the CD4-positive and -negative cell fractions derived from the non-adherent cells of 26 healthy adults. As in the previous experiment, only 2 (7.7%) of the 26 adherent cell specimens contained small amounts of HHV-7 DNA (27.7 copies/1 x 10(6) cells and 208.7 copies/1 x 10(6) cells). In contrast, 88.5% of CD4(+) T cell samples (23/26 specimens) were positive for HHV-7 DNA, ranging from 0.4 to 3,542.8 copies/1 x 10(6) cells. Viral DNA was detected in only 3 (11.5%) of the 26 CD4(-) T cell specimens, with 8.4, 63.5, and 74.1 copies/1 x 10(6) cells. HHV-7-positive DNA loads were significantly higher in the CD4(+) T cells than those observed in the CD4(-) T cells (P = 0.0005). The relationship between HHV-7 viral loads in non-adherent cells and those in saliva was investigated. Comparison of HHV-7 DNA load between blood CD4(+) T cells and saliva revealed that the HHV-7 DNA load in saliva correlated with that present in CD4(+) T cells (r = 0.415; P = 0.0174).

Development of the loop-mediated isothermal amplification method for rapid detection of cytomegalovirus DNA

Cytomegalovirus (CMV) loop-mediated isothermal amplification (LAMP) was performed on DNA extracted from CMV (AD-169)-, herpes simplex virus (HSV) 1 (KOS)-, HSV-2 (186)-, varicella-zoster virus (Oka-vaccine)-, human herpesvirus (HHV)-6 A (U1102)-, HHV-6 B (Z29)-, and HHV-7 (RK)-infected cells. Although amplified CMV demonstrated typical ladder patterns, no LAMP product was detected in reactions performed with other viral DNAs. The sensitivity of the CMV LAMP was 500 copies/tube, as determined by either agarose gel electrophoresis or turbidity assay. To determine whether CMV LAMP could be used for quantitative analysis of viral DNA, threshold times, defined as the time (in seconds) to reach the threshold level (0.1), were measured by amplification of serial dilutions of the plasmid DNA. The standard curve exhibited a correlation coefficient of 0.944, a slope of -208.1, and a y-intercept of 3261.4. Following these initial validation experiments, we analyzed 180 samples collected serially from 20 pediatric hematopoietic stem cell transplant recipients. Detection of CMV DNA in whole blood (WB) was tested by CMV LAMP and real-time polymerase chain reaction (PCR). When >500 copies/tube (>5000 copies/200 microl of WB) was defined as positive for CMV infection, the sensitivity, specificity, positive predictive value, and negative predictive values of the CMV LAMP were 80.0, 98.9, 66.7, and 99.4%, respectively.

Analysis of Shedding of 3 β‐Herpesviruses in Saliva from Patients with Connective Tissue Diseases

BACKGROUND

Whether an association exists between infection with beta -herpesviruses and connective tissue diseases remains unclear, as are the mechanisms for the regulation of these infections in the salivary glands.

METHODS

Human herpesvirus (HHV)-7 was isolated and viral DNA was quantified by real-time polymerase chain reaction (PCR) in serially collected saliva samples, to determine whether viral load correlated with infectivity. Then, to examine the role played by beta -herpesviruses in connective tissue diseases, cytomegalovirus, HHV-6, and HHV-7 DNA loads were examined by real-time PCR in serially collected saliva samples from 21 patients with connective tissue diseases.

RESULTS

Although subjects with frequent HHV-7 shedding were more likely to have a high viral load than were other subjects, high viral loads were detected in saliva samples from a portion of the subjects with low viral shedding rates. No significant difference between the quantity of HHV-7 DNA in saliva samples from which active virus was isolated and that amplified from samples without detectable virus was observed. Patients with adult-onset Still disease consistently had high HHV-7 DNA loads, in contrast to patients with other connective tissue diseases (P=.0003) and healthy adults (P=.0224). The mean HHV-6 (P=.012) and HHV-7 (P<.0001) DNA loads in patients with connective tissue diseases were lower than those in healthy adults.

CONCLUSION

These data suggest that a number of host factors in patients with adult-onset Still disease may function to accelerate HHV-7 replication in the salivary glands.

Investigating the presence of human herpesvirus 7 and 8 in multiple sclerosis and normal control brain tissue

Multiple sclerosis (MS) is an important demyelinating disease of the central nervous system, the aetiology of which is thought to have a possible viral component. In this study we investigated the possible involvement in MS of two herpes viruses: the neurotropic human herpesvirus 7 (HHV-7) and the related human herpesvirus 8 (HHV-8). Utilising fluorescent in situ hybridisation (FISH) techniques, we examined human post mortem tissues for the presence of immediate early and late viral gene or protein expression in MS patient normal appearing white matter (NAWM), lesional tissue and normal control brain samples. HHV-7 and/or HHV-8 mRNA or protein was detected in some individuals in all three sample categories and was restricted to oligodendrocytes, as determined by double mRNA FISH analysis or immuno fluorescence (IF). No samples showed evidence of viral mRNA when subjected to RT-PCR on extracted ribonucleic acid. We therefore conclude that there is little evidence in our particular sample cohort to suggest involvement of either HHV-7 or HHV-8 in MS.

Prevalence of herpes simplex virus (types 1 and 2), varicella-zoster virus, cytomegalovirus, and human herpesvirus 6 and 7 DNA in cerebrospinal fluid of Middle Eastern patients with encephalitis

HSV-1 DNA was detected in 32 (30%) of 106 cerebrospinal fluid samples from patients with encephalitis. Cytomegalovirus, varicella-zoster virus, and human herpesvirus 6 (HHV-6) DNAs were each detected in three patients (3%); herpes simplex virus type 2 (HSV-2) and HHV-7 PCRs were negative. HSV detection was associated with seizure (P = 0.02), especially focal seizure (P = 0.0002), and pathological computed tomography (P = 0.02) with focal lesions (P = 0.0004).

Additional evidence that pityriasis rosea is associated with reactivation of human herpesvirus-6 and -7

To elucidate the role of human herpesvirus (HHV)-6 and -7 (HHV-7) in pityriasis rosea (PR), we measured their DNA load in plasma, peripheral blood mononuclear cells (PBMC), and tissues using a calibrated quantitative real-time PCR assay. We also studied HHV-6- and HHV-7-specific antigens in skin by immunohistochemistry and anti-HHV-7 neutralizing activity using a syncytia-inhibition test. Plasma and PBMC were obtained from 31 PR patients (14 children, 17 adults), 12 patients with other dermatites, and 36 blood donors. Skin biopsies were obtained from 15 adults with PR and 12 with other dermatites. HHV-6 and HHV-7 DNA were detected in 17% and in 39% of PR plasmas, respectively, but in no controls. HHV-7 viremia was associated with a higher PBMC load and, in adults, with systemic symptoms. HHV-7, but not HHV-6, levels in PBMC were higher in PR patients than in controls. HHV-6 and HHV-7 antigens were found only in PR skin (17% and 67% of patients analyzed, respectively), indicating a productive infection. Syncytia-neutralizing antibodies were found in PR patients and controls, but their titers were lower in patients with HHV-7 viremia. These data confirm the causal association between PR and active HHV-7 or, to a lesser extent, HHV-6 infection.

Human herpesvirus 7 open reading frames U12 and U51 encode functional beta-chemokine receptors

Human herpesvirus 7 (HHV-7), which belongs to the betaherpesvirus subfamily and infects mainly CD4+ T cells in vitro, infects children during infancy. HHV-7 contains two genes, U12 and U51, that encode putative homologs of cellular G-protein-coupled receptors. To analyze the biological function of the U12 and U51 genes, we cloned these genes and expressed the proteins in cells. U12 and U51 encoded functional calcium-mobilizing receptors for beta-chemokines, which include thymus and activation-regulated chemokine (TARC), macrophage-derived chemokine (MDC), EBI1-ligand chemokine (ELC), and secondary lymphoid-tissue chemokine (SLC), but not for other chemokines, suggesting that the chemokine selectivities of the U12 and U51 products were distinct from those of the known mammalian chemokine receptors. ELC and SLC induced migration in Jurkat cells stably expressing U12, but TARC and MDC did not. In contrast, none of these chemokines induced migration in Jurkat cells stably expressing U51. Together, these data indicate that the products of U12 and U51 may play important and different roles in the pathogenesis of HHV-7 through transmembrane signaling.

Human herpesviruses-6 and -7 infections

PURPOSE OF REVIEW

To summarize the biology and clinical consequences of infection with the closely related human herpesviruses-6 and -7 (HHV-6/7) in children.

RECENT FINDINGS

Over the last year there has been a paucity of paediatric publications on HHV-6 and only two studies focused on HHV-7. Steady progress has been made regarding the biology and clinical consequences of HHV-6 infection whereas the effect of HHV-7 infection remains a neglected topic. However, both viruses have been shown to contribute significantly and equally to the burden of disease in young children with suspected encephalitis or severe convulsions with fever. There continues to be uncertainty as to the effects of HHV-6 infection after stem cell transplant, although there is general agreement that it contributes to encephalitis. In contrast, HHV-7 seems to have little clinical impact after stem cell transplant, although central nervous system infection and disease have recently been reported in children. Understanding the contribution of chromosomal integration and inheritance of both HHV-6 variants A and B (HHV-6A/B) and their effect on diagnosis is emerging.

SUMMARY

There is an urgent need for more research on HHV-6 and -7 in children, particularly in relation to chromosomal integration of HHV-6A and B, and clinical consequences of HHV-7 infection.

Human herpesviruses 6 and 7 and central nervous system infection in children

Human herpesviruses 6 and 7 were infrequently found in cerebrospinal fluid of children with central nervous system infection.

The role and frequency of human herpesviruses (HHV)-6 and -7 in central nervous system (CNS) diseases of children are unclear. Cerebrospinal fluid samples from 245 pediatric patients (median age 43 days), submitted for evaluations of possible sepsis or of neurologic symptoms, were tested for HHV-6 and HHV-7 DNA by polymerase chain reaction. HHV-6 DNA was found in 3 of 245 samples, and HHV-7 was found in 0 of 245 samples. The three patients with HHV-6 DNA were <2 months of age. HHV-6 was likely pathogenic in two patients with meningitis who lacked evidence of another microbiologic cause. HHV-6 and HHV-7 are uncommon causes of CNS infection in children. HHV-6 may occasionally cause meningitis in young infants.

[A study of the relationship between initial febrile seizures and human herpes virus 6, 7 infections]

The DNA detection of human herpes virus (HHV) 6, 7 was performed in the patients who visited to the Nakano children's hospital because of their initial febrile seizures (FS). Those patients included 35 boys and 21 girls under 3 years of age (mean: 1 year 4 months). DNAs of HHV 6, 7 in the mononuclear cells extracted from peripheral blood were detected in 84% of the patients. This study proved that at least 34% of initial FS are caused by HHV 6 or 7 infections. Forty-seven percents of the patients who were clinically diagnosed as exanthema subitum showed complex type FS. In conclusion, HHV 6 and 7 infections are often related to the occurrence of initial FS, which may be in part caused by their direct invasion to the central nervous system.

Detection of human herpesvirus 7 DNA by loop-mediated isothermal amplification

The reliability of loop-mediated isothermal amplification (LAMP), initially developed for the detection of human herpesvirus 7 (HHV-7), was evaluated in this study. Although a LAMP product was detected in HHV-7 DNA, neither HHV-6 nor human cytomegalovirus DNA produced a product. When agarose gel electrophoresis was used for the detection of LAMP products, the sensitivity of a 30-min HHV-7 LAMP reaction reached 250 copies/tube. The use of turbidity for the detection of the LAMP products gave a sensitivity of 500 and 250 copies/tube for 30- and 60-min reactions, respectively. Following these initial validation studies, clinical samples collected from two patients with primary HHV-7 infections were examined by HHV-7 LAMP. By use of agarose gel electrophoresis, HHV-7 LAMP products could be detected in acute-phase plasma samples but no LAMP product was detectable in convalescent-phase plasma samples from either patient. Since a turbidity assay is less sensitive than agarose gel electrophoresis, no HHV-7 LAMP product could be detected in plasma samples after a 30-min LAMP reaction. After a 60-min LAMP reaction, HHV-7 LAMP product could be detected in acute-phase plasma samples.