Human herpesvirus type 6 in patients with systemic lupus erythematosus

Background and Objectives

Infectious agents are considered one of the possible etiological factors of systemic lupus erythematosus (SLE). It has been suggested that human herpesvirus type 6 (HHV-6) may trigger autoimmune disorders, but few studies have been conducted on the relationship between this virus and autoimmune diseases, especially SLE. The present study aimed to compare the frequency of HHV-6 infection between SLE patients and healthy individuals.

Materials and Methods

Serum samples were collected from 60 healthy people and 60 SLE patients referred to the rheumatology clinic of Shahid-Beheshti Hospital, Kashan, Iran, from January 2020 to January 2021. The following data were collected from the medical records of patients: sex; age; duration of disease; SLE clinical manifestations; and disease activity. After the extraction of viral DNA from samples, a nested polymerase chain reaction (PCR) test was performed to detect HHV-6.

Results

HHV-6 was detected in 12 SLE patients (20%) and in 8 healthy individuals (13.3%). A significant correlation was not obtained between SLE and the presence of HHV-6 (P = 0.09). There was no correlation between musculoskeletal involvements, skin lesions, renal manifestations, and hematological manifestations with the presence of HHV-6 (P>0.05). HHV-6 was detected more frequently in patients with active lupus than in patients with quiescent disease, but this difference was not significant (P=0.08).

Conclusion

Although patients with SLE had a higher prevalence of HHV-6 compared with healthy people, there is no strong link between HHV-6 infection and SLE. Future research is necessary because this data does not support the hypothesis that human herpesvirus 6 plays a role in the pathogenesis of SLE.

Time course of skin rash, computed tomography findings, and viral load in a rheumatoid arthritis patient with severe varicella pneumonia

Varicella-zoster virus (VZV) infection in adults or immunocompromised patients has a more severe presentation compared to the mild disease in children. To the best of our knowledge, no reports have described the clinical course of VZV pneumonia focusing on time course of skin rash, chest computed tomography (CT) findings, and viral load. Furthermore, no reports have described the reactivation of human herpes virus 6 (HHV-6) in VZV pneumonia. Here, we report a case of severe VZV pneumonia that resulted in reactivation of HHV-6 in a patient with rheumatoid arthritis (RA). A 66-year-old female treated for RA was admitted to our hospital with papules. Her chest CT showed granular infiltrates, micronodules, and ground-glass opacities. The day after admission, because the typical skin rashes and chest CT findings were observed, she was diagnosed with VZV pneumonia and treated with acyclovir. Her skin rash then crusted over five days and entered the healing process, whereas it took approximately two weeks for her respiratory condition and chest CT findings to improve. In addition, VZV deoxyribonucleic acid (DNA) gradually decreased with treatment. On the 34th day of admission, VZV DNA was not found in the serum sample but remained in the sputum sample. Furthermore, although reactivation of HHV-6 was observed, viremia resolved without treatment. Clinicians should be able to recognize the differences in the improvement of skin rashes, respiratory status, and chest CT findings. In addition, treatment for HHV-6 reactivation should be carefully determined for each case.

Recurrent herpes simplex virus encephalitis with presumptive Human Herpesvirus 6 chromosomal integration

Viral encephalitis can lead to encephalopathy, epileptic activity, focal neurological deficits, and death. Prompt recognition and a high index of clinical suspicion can lead to early initiation of appropriate management. We describe an interesting case of a 61-year-old presenting with fever and altered mental status, diagnosed with numerous episodes of viral encephalitis caused by divergent and recurrent viruses. On his initial presentation, lumbar puncture revealed lymphocytic pleocytosis and positivity for Human Herpesvirus 6 (HHV-6), and he was treated with ganciclovir. On subsequent admissions, he was diagnosed with recurrent HHV-6 encephalitis as well as Herpes Simplex Virus 1 encephalitis and treated with ganciclovir, foscarnet and acyclovir. Despite prolonged courses of treatment and resolution of symptoms, he continued to have persistently high plasma viral loads of HHV-6, consistent with probable chromosomal integration. In this report, we emphasize the clinical pearl of chromosomally integrated HHV-6 that can present in a patient with persistently high plasma viral loads of HHV-6, that are non-responsive to treatment. Individuals with chromosomally integrated HHV-6 may be more susceptible to other viral infections.

Epstein‒Barr virus and human herpesvirus 6 infection in patients with systemic lupus erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is a complex autoimmune disease, and the etiology is still unclear. Some studies have indicated that viral infection might contribute to the development of SLE.

METHODS

A total of 105 individuals with SLE and 110 matched healthy controls were tested for EBV-specific DNA fragments in peripheral blood monocytes by PCR-Southern blotting. The expression of EBV-encoded genes was determined by RT-PCR and Southern blotting in EBV-positive patients. Serum EBV-specific IgM antibody was determined by ELISA. HHV-6 DNA in peripheral blood monocytes of those SLE patients and normal controls was tested by nested PCR.

RESULTS

Statistical analysis showed that the EBV-positive rate of SLE patients was significantly higher than that of the control group (χ² = 87.329, P = 0), while the difference in the HHV-6-positive rate between the two groups was not significant (P > 0.05). An association of EBV and HHV-6 positivity in SLE patients was found (P = 0, r = 0.38). The EBV IgM level was significantly higher in SLE patients than in healthy controls (χ² = 25.184, P = 0). Forty-two of the 75 EBV DNA-positive specimens were positive for EBNA2 mRNA, and an association between EBV EBNA2 mRNA and anti-Sm antibody positivity was found (P = 0, r = 0.409). LMP1 mRNA was positive in 2 SLE patients with active phase, and no LMP2A mRNA expression was detected in EBV DNA-positive specimens. EBV early gene BARF1 mRNA was detected in 2 cases of EBV-positive SLE patients, and these 2 patients were also HHV-6 DNA positive. Thirty-eight patients were BcLF1 mRNA positive, and 33 of them were HHV-6 positive as well. These factors were associated (χ² = 15.734, P = 0). The expression of the EBV immediate early gene BZLF1 was negative in all 75 EBV-positive SLE patients.

CONCLUSIONS

The results suggest that EBV infection might be related to the occurrence of SLE. Although there is no direct evidence that HHV-6 infection is associated with the development of SLE, EBV and HHV-6 infection may have a coacceleration effect in SLE patients. This study provides a new theoretical and experimental basis for the study of viral etiology and the prevention and treatment of SLE.

Human herpesvirus-6 in hematopoietic stem cell transplant recipients: a prospective cohort study in Egypt

BACKGROUND

Immunocompromised patients face reactivation of latent viruses that increase the risk of morbidity.

AIM

The study aimed to detect human herpes virus 6 (HHV-6) reactivation among allogeneic (allo) and autologous (auto) hematopoietic stem cell transplant (HSCT) recipients and to correlate potentially attributed clinical manifestations to HHV-6 DNA plasma level.

METHODS

A prospective study included all (forty) patients undergoing allo and auto-HSCT from Jan 2020 till June 2022. Plasma samples were collected for HHV-6 serology, and for HHV-6 quantitative PCR at post-transplantation weeks 2, 4, 6. Demographic and clinical data were recorded.

RESULTS

Out of 40 peripheral blood stem cell transplant (PBSCT) recipients, 34 (85%) were HHV-6 IgG positive pre-HSCT. Of which, fourteen patients (14/34, 41.2%) showed positive HHV-6 DNaemia. HHV-6 DNAemia (15/40, 37.5%) was significantly higher among allo (8/12, 66.7%) versus auto (7/28, 25%) HSCT recipients (p = 0.030). Patients with HHV-6 DNAemia developed fever, delayed engraftment and bone marrow suppression in 6/15, 40%, thrombocytopenia (5/15, 33.3%), rash and pneumonitis (2/15, 13.3%), acute GVHD (aGVHD) (1/15, 6.7%). HHV-6 DNAemia ranged from 101 to 102,000 copies/mL. Univariate analysis identified conditioning with busulfan-cyclophosphamide as a significant risk (p = 0.043), while receiving BEAM protocol was a protective factor (p = 0.045). In multivariate analysis, receiving BEAM protocol retained significance (p = 0.040).

CONCLUSION

Frequent HHV-6 reactivation was detected after HSCT, especially in allo-HSCT recipients with clinical manifestations which could not be otherwise explained. To our best knowledge this is the first study of HHV6 reactivation in HSCT recipients from Egypt. Raising awareness for HHV-6 reactivation manifestations and screening in HSCT recipients could be lifesaving.

[Adult T-cell leukemia/lymphoma with multiple intracranial masses and CMV and HHV-6 reactivation at initial presentation]

A 55-year-old male was referred to our hospital after complaining of a sore throat for a month. Physical examination revealed a disturbance in consciousness, nuchal rigidity, painful multiple ulcers in the oral cavity, and erythema, the size of rice grains on the body. Hematological examination showed the following results: white blood cells, 7,910/µl (abnormal lymphocytes 2%), LDH, 203 U/l, corrected calcium, 11.2 mg/dl, soluble IL-2 receptor, 11,800 U/ml, and cytomegalovirus antigenemia assay (C10, C11) 43/49. Abnormal lymphocytes (CD4⁺CD25⁺) were discovered in the peripheral blood, bone marrow, and skin samples. Southern blotting of peripheral blood revealed monoclonal integration of human T-cell leukemia virus type 1 (HTLV-1) provirus DNA; and consequently, he was diagnosed with adult T-cell leukemia/lymphoma (ATLL). Multiple tumors with ringed contrast effect were observed in the brain parenchyma using contrast-enhanced computed tomography. The cell number in the cerebrospinal fluid was 1,320/mm³ (ATLL cells were 79% in flow cytometry), and the protein level was 244 mg/dl; moreover, the examination revealed a positive result for human herpesvirus 6 DNA. Despite herpesvirus genus treatment and modified LSG15 therapy combined with intrathecal chemotherapy, the patient became comatose and died on day 21 of hospitalization. A better understanding of the pathogenesis of ATLL, and the involvement with the central nervous system is needed along with the development of standard treatment.

Assessing and restoring adaptive immunity to HSV, VZV, and HHV-6 in solid organ and hematopoietic cell transplant recipients

BACKGROUND

Herpes simplex virus (HSV) 1 and 2, varicella zoster virus (VZV), and human herpesvirus 6 (HHV-6) cause severe infections in immunocompromised hosts. Interventions to optimize virus-specific adaptive immunity may have advantages over antivirals in the prophylaxis and treatment of these infections.

OBJECTIVES

We sought to review adaptive immune responses and methods for assessing and replenishing cellular and humoral immunity to HSV, VZV, and HHV-6 in solid organ transplant and hematopoietic cell transplant recipients.

SOURCES

We searched PubMed for relevant studies on immune responses to HSV, VZV, and HHV-6 as well as studies describing methods for evaluating and restoring cell-mediated immunity to other double-stranded DNA viruses in transplant recipients. Recent studies, randomized controlled trials, and investigations highlighting key concepts in clinical virology were prioritized for inclusion.

CONTENT

We describe the mechanisms of adaptive immunity to HSV, VZV, and HHV-6 and limitations of antivirals as prophylaxis and treatment for these infections in solid organ transplant and hematopoietic cell transplant recipients. We review methods for measuring and restoring cellular immunity to double-stranded DNA viruses; their potential applications to management of HSV, VZV, and HHV-6 in immunocompromised hosts; and barriers to clinical use. Vaccination and virus-specific T cell therapies are discussed in detail.

IMPLICATIONS

The growing repertoire of diagnostic and therapeutic techniques focused on virus-specific adaptive immunity provides a novel approach to management of viral infections in transplant recipients. Investigations to optimize such interventions specifically in HSV, VZV, and HHV-6 are needed.

Human herpesvirus 6 DNA was not detected in a brain specimen from a patient with mesial temporal sclerosis after status epilepticus due to human herpesvirus 6 infection

We performed virological analysis of resected brain tissues from a patient with temporal lobe epilepsy associated with mesial temporal sclerosis after febrile status epilepticus caused by human herpesvirus 6 infection. The patient had febrile status epilepticus at 9 months of age associated with human herpesvirus 6 infection. Magnetic resonance imaging revealed reduced water diffusion in the right temporal lobe and hippocampus. Polymerase chain reaction analysis detected 1.6 × 10⁵ copies/μg of human herpesvirus 6 DNA in whole blood, but none in the cerebrospinal fluid. The patient developed temporal lobe epilepsy associated with mesial temporal sclerosis at 67 months of age, necessitating surgical treatment. Anterior temporal lobectomy was performed at 171 months of age. Real-time polymerase chain reaction analysis of resected brain tissues revealed no viral DNA. In our patient, human herpesvirus 6 infection triggered febrile status epilepticus, while direct evidence to prove contribution of HHV-6 to the development of MTS was not obtained.

Association between human herpesvirus 6 (HHV-6) and cognitive function in the elderly population in Shenzhen, China

AIM

Human herpesvirus 6 (HHV-6) is neurophilic, and its relationship with Alzheimer's disease (AD) remains controversial. This study aimed to examine the relationships between HHV-6 and cognitive abilities in elderly people aged 60 years or above from communities in Shenzhen.

METHODS

We recruited participants from 10 community health service centers in Shenzhen. Participants were divided into case and control groups according to Mini-Mental State Examination (MMSE) scale standards and were included in this study with 1:1 matching based on sex and age (± 3 years). The HHV-6 gene was detected by real-time fluorescent quantitative PCR, and the HHV-6 copy number was quantified.

RESULTS

A total of 580 participants (cases, n = 290; controls, n = 290), matched for gender and age was included in this study. A positive HHV-6 test was not associated with a significant difference in global cognitive performance (OR_adjusted = 1.651, 95% CI = 0.671-4.062). After adjusting for gender, age, education, Pittsburgh Sleep Quality Index (PSQI) score, homocysteine (Hcy) and glycosylated hemoglobin (HbA1c), the results of multiple linear regression showed that there was a statistically negative correlation between HHV-6 copy number and orientation (β_adjusted = -0.974, p = 0.013), attention and calculation (β_adjusted = -1.840, p < 0.001), and language (β_adjusted = -2.267, p < 0.001). The restricted cubic spline (RCS) model results showed that there was a nonlinear dose-response relationship between HHV-6 log10-transformed copies and orientation (p_overall = 0.003, p_nonliner = 0.045), attention and calculation (p_overall < 0.001, p_nonliner < 0.001), and language (p_overall < 0.001, p_nonliner = 0.016).

CONCLUSIONS

HHV-6 infection significantly associated with orientation, attention and calculation, and language in elderly individuals.

Pityriasis rosea, human herpesvirus 6 infection and pregnancy

we read the interesting article by Bortolotti et al. on the relationship between human herpesvirus 6 (HHV-6) infection and intrauterine growth restriction (IUGR)¹ that prompted us to describe our experience about pityriasis rosea (PR) occurring during pregnancy. This article is protected by copyright. All rights reserved.

MicroRNA expression profiling of cerebrospinal fluid/serum exosomes in children with human herpesvirus 6-associated encephalitis/encephalopathy by high-throughput sequencing

Primary human herpesvirus 6 (HHV-6) infection is sometimes accompanied by acute encephalopathy with reduced subcortical diffusion (AED) in immunocompetent children. We investigated exosomal microRNA (miRNA) expression profiles in cerebrospinal fluid (CSF) and sera of patients with HHV-6-associated AED (n = 5) and febrile seizure (FS) (n = 5) using high-throughput sequencing. A total of 176 and 663 miRNAs were identified in CSF and serum exosomes, respectively. Comparative analysis determined that some miRNAs (miR-381-3p, miR-155) were exclusively expressed in the CSF exosomes of AED but not of FS patients, suggesting their potential application as novel diagnostic biomarkers for AED.

Envelope Glycoprotein based multi-epitope vaccine against a co-infection of Human Herpesvirus 5 and Human Herpesvirus 6 using in silico strategies

The Human Betaherpesviruses HHV-5 and HHV-6 are quite inimical in immunocompromised hosts individually. A co-infection of both has been surmised to be far more disastrous. This can be attributed to a synergetic effect of their combined pathologies. While there have been attempts to develop a vaccine against each virus, no efforts were made to contrive an effective prophylaxis for the highly detrimental co-infection. In this study, an ensemble of viral envelope glycoproteins from both the viruses was utilized to design a multi-epitope vaccine using immunoinformatics tools. A collection of bacterial protein toll-like receptor agonists (BPTAs) was screened to identify a highly immunogenic adjuvant for the vaccine construct. The constructed vaccine was analysed using an array of methodologies ranging from World population coverage analysis to Immune simulation, whose results indicate high vaccine efficacy and stability. Furthermore, codon optimization and in silico cloning analysis were performed to check for efficient expression in a bacterial system. Collectively, these findings demonstrate the potential of the constructed vaccine to elicit an immune response against HHV-5 and HHV-6, thus supporting the viability of in vitro and in vivo studies.

Usefulness of the FilmArray Meningitis/Encephalitis Panel in diagnosis of central nervous system infection after allogeneic hematopoietic stem cell transplantation

PURPOSE

The BioFire FilmArray® Meningitis/Encephalitis Panel (FAMEP) is designed to rapidly and accurately detect common multiple pathogens that cause central nervous system (CNS) infection, including viruses, bacteria, and yeast. The FAMEP's usefulness in the setting of allogeneic hematopoietic stem cell transplantation (HSCT) has not been fully evaluated. This retrospective study evaluated the usefulness of the FAMEP in the screening for CNS infection after allogeneic HSCT.

METHODS

Cerebrospinal fluid (CSF) was obtained from 12 patients to evaluate the causes of CNS disorders after allogeneic HSCT, and the FAMEP was applied.

RESULTS

The median day of the FAMEP evaluations was 27 days post-transplant (range, 0-390). Human herpesvirus 6 (HHV-6) was detected in three patients and cytomegalovirus was detected in one patient, leading to the diagnosis of encephalitis/myelitis. In three patients (HHV-6, n = 2; CMV, n = 1), the presence of the viruses was confirmed by conventional real-time polymerase chain reaction (PCR). However, in the remaining patient with HHV-6 detected by the AMEP, HHV-6 was not detected by real-time PCR at the onset but was detected 7 days later. The treatments for the detected viruses improved the clinical conditions in the four patients.

CONCLUSIONS

Our results suggest that the FAMEP can be a useful sensitive assay in the screening and diagnosis of CNS viral infections after allogeneic HSCT.

Targeted treatment in viral-associated inflammatory cardiomyopathy

Detection of viruses like HHV-6 in endomyocardial biopsy or serum serology of patients with myocarditis or heart failure features unresponsive to conventional heart failure therapies could be a potential targeted treatment especially in refractory cases.

Human Herpesvirus 6 Infection and Risk of Chronic Fatigue Syndrome: A Systematic Review and Meta-Analysis

INTRODUCTION

Chronic fatigue syndrome (CFS) is a neurological disease that is accompanied by excessive fatigue or tiredness. There are several reports confirming the association between human herpesvirus 6 (HHV-6) infection and CFS illness. This systematic review and meta-analysis was performed to integrate the information of published studies with regard to this association until May 2021.

METHODS

The literature search was based on keywords including "chronic fatigue syndrome and HHV 6," "chronic fatigue syndrome and HHV-6," "chronic fatigue syndrome and HHV6," "chronic fatigue syndrome and Herpes virus 6," and "chronic fatigue syndrome and Herpesvirus6" in MEDLINE (PubMed), Web of Science, and EMBASE.

RESULTS

The literature search identified 17 studies to be included in the systematic review and 11 studies in meta-analysis. The symmetry funnel plot and Egger's test (p value = 0.2) identified no publication bias among studies. Moreover, the low level of I2 revealed homogeneity across studies.

DISCUSSION

In conclusion, the association between the HHV-6 infection and CFS incidence was substantiated. However, the results of this study also suggest that further comprehensive studies are needed to solidify the association between HHV-6 and CFS. Future studies should consider additional factors that may have affected the significance of such a correlation.

Association of Inherited Chromosomally Integrated Human Herpesvirus 6 with Neurologic Symptoms and Management after Allogeneic Hematopoietic Cell Transplantation

Reactivation of human herpesvirus 6 (HHV-6) after allogeneic hematopoietic cell transplantation (HCT) is associated with neurologic complications, but the impact of donor and/or recipient inherited chromosomally integrated HHV-6 (iciHHV-6) on post-HCT central nervous system (CNS) symptoms and diagnostic and therapeutic interventions is not well understood. The aims of the present study were (1) to compare the cumulative incidence of CNS symptoms in the first 100 days following allogeneic HCT among patients with donor and/or recipient iciHHV-6 (iciHHV-6^pos)with that of patients with neither donor nor recipient iciHHV-6 (iciHHV-6^neg) and (2) to assess the role of HHV-6 detection in driving potentially unnecessary interventions in iciHHV-6^pos patients. We performed a retrospective matched cohort study of 87 iciHHV-6^pos and 174 iciHHV-6^neg allogeneic HCT recipients. HHV-6 testing was performed at the discretion of healthcare providers, who were unaware of iciHHV-6 status. The cumulative incidence of CNS symptoms was similar in iciHHV-6^pos (n = 37; 43%) and iciHHV-6^neg HCT recipients (n = 81; 47%; P = .63). HHV-6 plasma testing was performed in similar proportions of iciHHV-6^pos (n = 6; 7%) and iciHHV-6^neg (9%) patients and was detected in all tested iciHHV-6^pos HCTs and 2 (13%) iciHHV-6^neg HCTs. This resulted in more frequent HHV-6-targeted antiviral therapy after iciHHV-6^pos HCT (odds ratio, 12.8; 95% confidence interval, 1.5 to 108.2) with associated side effects. HHV-6 plasma detection in 2 iciHHV-6^pos patients without active CNS symptoms prompted unnecessary lumbar punctures. The cumulative incidence of CNS symptoms was similar after allogeneic HCT involving recipients or donors with and without iciHHV-6. Misattribution of HHV-6 detection as infection after iciHHV-6^pos HCT may lead to unnecessary interventions. Testing for iciHHV-6 may improve patient management.

Human herpesvirus 6 and central nervous system disease in oncology patients: A retrospective case series and literature review

BACKGROUND

Human herpesvirus 6 (HHV-6) can reactivate with immunosuppression and cause central nervous system (CNS) dysfunction. Much of the literature describes cases after hematopoietic stem cell transplantation (HSCT), ranging from encephalitis to a post-transplant acute limbic encephalitis syndrome (PALE). Outside of HSCT, studies of HHV-6 encephalitis are limited to case reports.

OBJECTIVES

This study was designed to review HHV-6 CNS infection, and evaluate all patients admitted to MD Anderson Cancer Center between March 2016 and December 2018 with detectable HHV-6 DNA in the cerebrospinal fluid (CSF).

STUDY DESIGN

Patients with HHV-6 DNA detected in the CSF using the Viracor or Biofire® Meningitis Encephalitis Panel platforms and no other identified etiology were identified and demographic features, known risk factors, imaging findings, CSF analysis, treatments and patient outcomes were extracted from medical records.

RESULTS

725 patients underwent HHV-6 testing during the study timeframe, with 19 cases (2.6 %) of HHV-6 mediated CNS disease identified. Most patients, 13/19 (68 %), had undergone HSCT with median time to presentation of 31 days after transplant. Survival at 240 days after transplant was 62 %. CSF had lymphocyte predominance and nearly all patients had peripheral lymphopenia. Other at risk populations identified included patients who received chimeric antigen receptor (CAR) T-cell therapy and biologic immunotherapy. Notable discordance among testing platforms was found in 5/9 (55 %) instances.

CONCLUSIONS

In addition to HSCT patients, HHV-6 reactivation leading to CNS disease also occurs in settings such as following adoptive T cell therapy or biologic immunotherapy. Significant diagnostic discordance exists between testing platforms.

Human herpesvirus 6 reactivation in unmanipulated haploidentical hematopoietic stem cell transplantation predicts the occurrence of grade II to IV acute graft-versus-host disease

BACKGROUND

Human herpesvirus 6 (HHV-6) reactivation is relatively common after allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, the incidence of HHV-6 reactivation and the clinical outcomes following unmanipulated haploidentical HSCT (haplo-HSCT) remain unknown.

METHOD

We prospectively monitored blood HHV-6 DNA using real-time quantitative polymerase chain reaction weekly until day 100 post unmanipulated haplo-HSCT in patients with hematological malignancies.

RESULTS

From November 2016 to March 2017, 102 patients (58 male and 44 female, median age 25(2-58) years old) were enrolled. Within 100 days post-transplantation, 27 patients (27/136, 19.9%) developed HHV-6 viremia with a median onset time of 14 (7-98) days. The cumulative incidence of HHV-6 reactivation on day 100 post-HSCT was 25.5 ± 4.3% in haplo-HSCT. The median HHV-6 copy number was 1.45 × 10³ (5.48 × 10² -2.00 × 10⁴ ) copies/ml. The HHV-6 viremia duration time was 7 days in 23 patients, 14 days in one patient and 21 days in one patient. In multivariate analysis, prior HHV-6 reactivation was an independent risk factor for grade 2-4 graft-versus-host disease (GVHD). But it did not influence the overall survival (OS)(HR 1.624, 95%CI 0.768-3.432, P = .204), disease-free survival (DFS) (HR 1.640, 95%CI 0.799-3.367, P = .177) and non-relapse mortality (NRM) (HR 1.644, 95%CI 0.670-4.038, P = .278).

CONCLUSION

The reactivation of HHV-6 after unmanipulated haploidentical transplantation predicts the occurrence of grade 2-4 a-GVHD, but it may not influence the overall survival (OS), disease-free survival (DFS) and non-relapse mortality (NRM).

Impact of Specific Antibody Level on Human Herpesvirus 6 Reactivation after Allogeneic Stem Cell Transplantation

The majority of adults are seropositive for human herpesvirus 6 (HHV-6). HHV-6 reactivation can occur after allogeneic hematopoietic stem cell transplantation (HSCT) and lead to life-threatening central nervous system disorders. In this prospective study, we evaluated the relationship between HHV-6 reactivation and anti-HHV-6 IgG antibody levels in recipients of allogeneic HSCT. The HHV-6 viral load in the plasma was quantitatively measured weekly after allogeneic HSCT by real-time polymerase chain reaction. The level of anti-HHV-6 IgG antibody was measured by enzyme-linked immunosorbent assay before and serially after transplantation. In 28 of the 56 evaluated patients (50%), HHV-6 reactivation was detected after transplantation. In a multivariate analysis, cord blood as the stem cell source was the only significant factor associated with HHV-6 reactivation (odds ratio, 8.6; 95% confidence interval, 2.3 to 32.6; P < .01). When evaluated in the recipients of cord blood transplantation (CBT), the anti-HHV-6 antibody level before transplantation was significantly lower in the patients with HHV-6 reactivation compared with those without (sample positivity index: median, 2.04 [range, 0.95 to 5.98] versus 4.15 [range, 3.93 to 5.65]; P < .05). The anti-HHV-6 antibody level was significantly decreased at 3 months post-transplantation compared with before transplantation (P < .01). Such differences were not observed in other stem cell sources. Our results demonstrate that the low anti-HHV-6 antibody level before transplantation was associated with the reactivation of HHV-6 after CBT, and that the anti-HHV-6 antibody level was significantly decreased specifically after CBT. These results suggest that HHV-6-specific humoral immunity plays a role in HHV-6 reactivation after CBT.

Clinically Mild Encephalopathy With a Reversible Splenial Lesion Type 2 Caused by Human Herpesvirus 6 Infection

BACKGROUND

Clinically mild encephalopathy with a reversible splenial lesion (MERS) is the second commonest cause of encephalopathy. Several pathogens have been detected in patients with MERS type 2, such as influenza A and B, but little is known about the proportion of cases of MERS type 2 with this pathogenesis. Human herpesvirus 6 (HHV6) is the second commonest pathogen causing acute encephalopathy. However, HHV6 has not been previously reported in patients with MERS type 2.

PATIENT DESCRIPTION

In this report, we describe a five-year-old boy with MERS type 2 caused by HHV6 infection. The present case was diagnosed with MERS type 2 caused by HHV6 infection based on the characteristic clinical course, the results of the virus testing, and imaging findings.

DISCUSSION

This is the first description of MERS type 2 caused by HHV6 infection. Although there is a report of MERS type 1 caused by HHV6 infection, there are no detailed reports in the literature about MERS type 2 associated with HHV6 infection. Thus the clinical findings associated with MERS type 2 caused by HHV6 infection are poorly understood. This report indicates that HHV6 can cause MERS type 2.

Inherited chromosomally integrated human herpesvirus 6 and autoimmune connective tissue diseases

BACKGROUND

Entire genome of human herpesvirus 6 (HHV-6) that integrates into human chromosomes is called chromosomally integrated HHV-6 (ciHHV-6). Several viral infections have been suggested to be involved in autoimmune connective tissue diseases (CTDs). Reactivated HHV-6 from the integrated viral genome can induce immune responses against the virus. Thus, it is plausible that ciHHV-6 is associated with autoimmune CTDs.

OBJECTIVES

We sought to determine whether the prevalence of ciHHV-6 was significantly higher in patients with autoimmune CTDs than in a healthy population.

STUDY DESIGN

A total of 846 peripheral blood samples collected from autoimmune CTD patients were analyzed. Since there was a large number of samples, they were pooled into 24 samples per group. Copy numbers of HHV-6 DNA were measured by real-time PCR. The threshold level for distinguishing between ciHHV-6 and active viral infection and the reliability of pooled DNA analysis were examined as initial validation experiments.

RESULTS

The threshold level was 1.6 × 10^6 copy/mL in whole blood. The reliability of pooled DNA analysis to identify one ciHHV-6 sample among 23 HHV-6 DNA-negative samples was high. No HHV-6 DNA was detected in any of the pooled DNA samples collected from the patients. The probability of the present study including the 846 autoimmune CTD patient's samples was statistically not different with a healthy Japanese population which was 0.2 % or 0.6 %.

CONCLUSIONS

There was no significant difference in the prevalence of ciHHV-6 between a healthy population and patients with autoimmune CTDs.

Human herpesvirus 6 encephalitis in a patient treated with everolimus for renal cell carcinoma

INTRODUCTION

Everolimus is a mammalian target of rapamycin inhibitor and is approved as second-line treatment or beyond for renal cell carcinoma. We report a case of a 75-year-old male treated with everolimus for metastatic renal cell carcinoma, after sunitinib treatment, who was diagnosed with human herpesvirus 6 encephalitis.

CASE REPORT

After 39 months of everolimus, 10 mg per day, our patient was admitted with fever, consciousness disorders and a partial epileptic crisis. Laboratory tests revealed lymphopenia (170 lymphocytes/mm³), and polymerase chain reaction in cerebrospinal fluid was positive for human herpesvirus 6. Brain magnetic resonance imaging study demonstrated hippocampal abnormality and a pontine lesion.

MANAGEMENT AND OUTCOME

The patient stopped everolimus treatment indefinitely. He received ganciclovir initially intravenously, with a rapid clinical improvement, as well as polyvalent immunoglobulins were given to correct hypogammaglobulinemia. Two months later, antiviral therapy was switched to oral ganciclovir, which was never stopped. A new lumbar puncture was performed one month after the initiation of antiviral treatment, which did not reveal human herpesvirus 6 DNA anymore.

DISCUSSION

Human herpesvirus 6 encephalitis is more common in hematopoietic stem cell transplant recipients and HIV patients. This is the first case probably associated to everolimus treatment. In contrast to most patients diagnosed with this infection, who either die or develop neurologic sequelae, our patient almost fully recovered two months later.

Inherited chromosomally integrated HHV-6 possibly modulates human gene expression

Approximately, 1% of human population possesses a copy of human herpesvirus 6A and 6B (HHV-6A/B) in the genome. This viral element is referred to as inherited chromosomally integrated HHV-6A/B (iciHHV-6A/B) and is encoded in all of their cells. A recent study revealed that iciHHV-6A/B potentially increases the immune responses against HHV-6. However, it remains unclear whether iciHHV-6A/B affects human gene expression. Here, we perform global transcriptome analysis using the datasets obtained from various human tissues. We detected two and four individuals positive for iciHHV-6A and iciHHV-6B, respectively, and revealed that the transcriptional expression of iciHHV-6A/B was sporadic in the human body. Transcriptome analysis identified the human genes differentially expressed between iciHHV-6A/B-positive and -negative individuals. Particularly, the expression of some genes encoding immunoglobulins decreased in sigmoid colon of iciHHV-6A/B-positive individuals. Our findings suggest that iciHHV-6A/B may be associated with human health maintenance.

Current understanding of human herpesvirus 6 (HHV-6) chromosomal integration

Human herpesvirus 6A (HHV-6A) and 6B (HHV-6B) are members of the genus Roseolovirus in the Betaherpesvirinae subfamily. HHV-6B infects humans in the first years of life, has a seroprevalence of more than 90% and causes Roseola Infantum, but less is known about HHV-6A. While most other herpesviruses maintain their latent genome as a circular episome, HHV-6A and HHV-6B (HHV-6A/B) have been shown to integrate their genome into the telomeres of infected cells. HHV-6A/B can also integrate into the chromosomes of germ cells, resulting in individuals carrying a copy of the virus genome in every nucleated cell of their bodies. This review highlights our current understanding of HHV-6A/B integration and reactivation as well as aspects that should be addressed in the future of this relatively young research area. It forms part of an online symposium on the prevention and therapy of DNA virus infections, dedicated to the memory of Mark Prichard.

A Case of Salazosulfapyridine-Induced Hypersensitivity Syndrome in a Rheumatoid Arthritis Patient with Relapse of Skin Erythema

We experienced a rare case of drug-induced hypersensitivity syndrome (DIHS) in which salazosulfapyridine (SASP) reactivated human herpesvirus 6 (HHV-6) and cytomegalovirus (CMV), which resulted in a relapse of skin symptoms after changing to mizoribine. At the time of recurrence of skin erythema after the initiation of mizoribine, the serum DNA titers of not HHV-6 but CMV were elevated. A drug-induced lymphocyte stimulation test was negative for mizoribine but positive for SASP. In this case, DIHS developed with SASP in association with HHV-6 and CMV reactivation. The immunocompromised state induced by herpes virus reactivation and mizoribine might have caused the relapse of skin erythema.

Betaherpesvirus assembly and egress: Recent advances illuminate the path

The human betaherpesviruses, human cytomegalovirus (HCMV; species Human betaherpesvirus 5) and human herpesviruses 6A, 6B, and 7 (HHV-6A, -6B, and -7; species Human betaherpesviruses 6A, 6B, and 7) are highly prevalent and can cause severe disease in immune-compromised and immune-naive populations in well- and under-developed communities. Herpesvirus virion assembly is an intricate process that requires viral orchestration of host systems. In this review, we describe recent advances in some of the many cellular events relevant to assembly and egress of betaherpesvirus virions. These include modifications of host metabolic, immune, and autophagic/recycling systems. In addition, we discuss unique aspects of betaherpesvirus virion structure, virion assembly, and the cellular pathways employed during virion egress.

Inherited Chromosomally Integrated Human Herpesvirus 6 Demonstrates Tissue-Specific RNA Expression In Vivo That Correlates with an Increased Antibody Immune Response

HHV-6A and -6B are human herpesviruses that have the unique property of being able to integrate into the telomeric regions of human chromosomes. Approximately 1% of the world’s population carries integrated HHV-6A/B genome in every cell of their body. Whether viral genes are transcriptionally active in these individuals is unclear. By taking advantage of a unique tissue-specific gene expression data set, we showed that the majority of tissues from iciHHV-6 individuals do not show HHV-6 gene expression. Brain and testes showed the highest tissue-specific expression of HHV-6 genes in two separate data sets. Two HHV-6 genes, U90 (immediate early 1 protein) and U100 (glycoproteins Q1 and Q2), were found to be selectively and consistently expressed across several human tissues. Expression of U90 translates into an increase in antigen-specific antibody response in iciHHV-6A/B⁺ subjects relative to controls. Future studies will be needed to determine the mechanism of gene expression, the effects of these genes on human gene transcription networks, and the pathophysiological impact of having increased viral protein expression in tissue in conjunction with increased antigen-specific antibody production.

Human herpesviruses 6A and 6B (HHV-6A and HHV-6B) are human viruses capable of chromosomal integration. Approximately 1% of the human population carries one copy of HHV-6A/B integrated into every cell in their body, referred to as inherited chromosomally integrated human herpesvirus 6A/B (iciHHV-6A/B). Whether iciHHV-6A/B is transcriptionally active in vivo and how it shapes the immunological response are still unclear. In this study, we screened DNA sequencing (DNA-seq) and transcriptome sequencing (RNA-seq) data for 650 individuals available through the Genotype-Tissue Expression (GTEx) project and identified 2 iciHHV-6A- and 4 iciHHV-6B-positive candidates. When corresponding tissue-specific gene expression signatures were analyzed, low levels HHV-6A/B gene expression was found across multiple tissues, with the highest levels of gene expression in the brain (specifically for HHV-6A), testis, esophagus, and adrenal gland. U90 and U100 were the most highly expressed HHV-6 genes in both iciHHV-6A- and iciHHV-6B-positive individuals. To assess whether tissue-specific gene expression from iciHHV-6A/B influences the immune response, a cohort of 15,498 subjects was screened and 85 iciHHV-6A/B⁺ subjects were identified. Plasma samples from iciHHV-6A/B⁺ and age- and sex-matched controls were analyzed for antibodies to control antigens (cytomegalovirus [CMV], Epstein-Barr virus [EBV], and influenza virus [FLU]) or HHV-6A/B antigens. Our results indicate that iciHHV-6A/B⁺ subjects have significantly more antibodies against the U90 gene product (IE1) than do non-iciHHV-6-positive individuals. Antibody responses against EBV and FLU antigens or HHV-6A/B gene products either not expressed or expressed at low levels, such as U47, U57, and U72, were identical between controls and iciHHV-6A/B⁺ subjects. CMV-seropositive individuals with iciHHV-6A/B⁺ have more antibodies against CMV pp150 than do CMV-seropositive controls. These results argue that spontaneous gene expression from integrated HHV-6A/B leads to an increase in antigenic burden that translates into a more robust HHV-6A/B-specific antibody response.

IMPORTANCE HHV-6A and -6B are human herpesviruses that have the unique property of being able to integrate into the telomeric regions of human chromosomes. Approximately 1% of the world’s population carries integrated HHV-6A/B genome in every cell of their body. Whether viral genes are transcriptionally active in these individuals is unclear. By taking advantage of a unique tissue-specific gene expression data set, we showed that the majority of tissues from iciHHV-6 individuals do not show HHV-6 gene expression. Brain and testes showed the highest tissue-specific expression of HHV-6 genes in two separate data sets. Two HHV-6 genes, U90 (immediate early 1 protein) and U100 (glycoproteins Q1 and Q2), were found to be selectively and consistently expressed across several human tissues. Expression of U90 translates into an increase in antigen-specific antibody response in iciHHV-6A/B⁺ subjects relative to controls. Future studies will be needed to determine the mechanism of gene expression, the effects of these genes on human gene transcription networks, and the pathophysiological impact of having increased viral protein expression in tissue in conjunction with increased antigen-specific antibody production.

Human herpesvirus 6A active infection in patients with autoimmune Hashimoto's thyroiditis

BACKGROUND

Hypothyroidism due to Hashimoto's thyroiditis (HT) is the commonest autoimmune endocrine illness in which antibodies against thyroid organ result in inflammation. The disease has a complex etiology that involves genetic and environmental influences. Viral infections may be involved in triggering of the disease as their molecular mimicry enhance autoimmune responses. Human herpesvirus-6 (HHV-6) is recognized for its contribution to some autoimmune diseases.

OBJECTIVE

In the current study, the prevalence of HHV-6 active infection in patients with HT and with non-autoimmune thyroid disorders were compared with patients with euthyroidism. In addition, a correlation between presence of HHV-6 infections and HT was investigated.

METHODS

A total of 151 patients with clinically and laboratory confirmed HT, 59 patients with non-autoimmune thyroid disorders, and 32 patients with normal thyroid function were included in the study. For further confirmation of HT disease, all the precipitants were tested for anti-thyroid peroxidase (TPO), and anti-thyroglobulin (TG) antibodies. For detection of both HHV-6 types A and B, nested PCR and restriction enzyme digestion were used. HHV-6 DNA positive samples were further investigated by DNA sequencing analysis.

RESULTS

HHV-6A DNA was found in serum sample of 57 out of 151 patients (38%) with HT, which was significantly more often than in patients with non-autoimmune thyroid disorders (p=0.001). However, HHV-6 DNA was not detected in serum samples of euthyroid subjects.

CONCLUSIONS

The results support a possible role for active HHV-6A infection, demonstrated by the presence of HHV-6 DNA in sera, in the development of HT.

Delayed aminopenicillin reaction associated to human herpes virus 6 infection mimicking DRESS syndrome

BACKGROUND

DRESS syndrome (rash with eosinophilia and systemic symptoms) is an uncommon and severe drug-induced reaction.

CLINICAL CASE

An 8-year-old boy was diagnosed with tonsillopharyngitis, and treatment with amoxicillin was started. One day later, he presented bilateral malar rash which evolved to generalized erythroderma in two days. He was referred to the emergency room and then he was discharged after the treatment with amoxicillin was discontinued. Five days later, he still had fever, progressive facial and acral edema, and ecchymotic lesions. The laboratory studies showed 6220 leukocytes/mm3 (970 eosinophils/mm3). The pharyngeal culture tested positive to human herpesvirus 6 (HHV-6). The fever, rash and edema disappeared with supportive measures. Based on the results of the allergy tests, a diagnosis of delayed reaction to aminopenicillin associated to HHV-6 mimicking DRESS syndrome was made, with the recommendation to avoid penicillin antibiotics.

CONCLUSION

The diagnosis of delayed reactions to aminopenicillin and DRESS syndrome requires a high index of suspicion in order to promptly withdraw the offending medication and to avoid delays in the diagnosis.

Herpesviridae Seropositivity in Patients with Multiple Sclerosis: First Polish Study

BACKGROUND

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system that leads to inflammation, demyelination and neurodegeneration. Viral aetiology has been suspected to be an MS trigger for a long time, and herpesviruses (HSs) are among the potential pathogens involved.

OBJECTIVES

The present investigation aims to detect the presence of antibodies against the herpes simplex virus (HSV), varicella-zoster virus, Epstein-Barr virus (EBV), human cytomegalovirus (CMV) and human herpesvirus 6 (HHV6) in the serum of MS patients and control individuals in north-eastern Poland.

METHOD

Plasma was collected from 141 MS patients and 44 blood donors who served as the control group. These individuals were assessed for the presence of antibodies using an enzyme-linked immunosorbent assay.

RESULTS

The statistical analysis showed a higher probability of EBV (p = 0.037, OR 4.359) and HHV6 (p = 0.020, OR 3.343) antibody presence in patients with MS compared to that in the control group. In the MS patient group, the prevalence of CMV IgG antibodies was significantly higher in females (p = 0.025). Patients who tested positive for anti-EBV IgG were diagnosed 7.9 years earlier than patients who tested negative for anti-EBV IgG (p = 0.048).

CONCLUSIONS

The study showed that MS patients in north-eastern Poland were more likely to be seropositive for EBV and HHV6 than healthy individuals. Further work should be undertaken in other regions of Poland and other European countries with particular attention paid to testing seropositivity in all HSs, particularly in the MS patient population, to evaluate the impact of HSs on MS patients in different environments.

Reactivation of human herpesviruses 6 and 7 in Kawasaki disease

Objectives: Kawasaki disease (KD) is one of the most common childhood vasculitides. Some serological studies have suggested an etiological relationship between KD and human herpesvirus (HHV)-6 or HHV-7. However, primary or reactivated HHV-6 and -7 has not been fully investigated in patients with KD. Methods: Twenty-three patients with KD were prospectively enrolled in this study. Peripheral blood was collected in the acute and convalescence phases, and HHV-6 and -7 viral loads were measured by real-time PCR. Results: In the acute phase, HHV-6 and -7 DNA was detected in 7 (30%) patients each, compared to 13 (57%) and 9 (39%) patients in the convalescence phase, respectively. HHV-6 and -7 DNA loads were significantly higher in the convalescence phase than in the acute phase. Significant increases in HHV-6 and -7 DNA loads were not observed in disease control patients. Taking into account HHV-6 and -7 serostatus, reactivation of HHV-6 and -7 was observed in 7 and 9 patients, respectively. KD patients with HHV-6 reactivation showed higher C-reactive protein levels and more frequently required steroid therapies than patients without reactivation. Conclusion: HHV-6 and -7 reactivation is frequent in KD patients. HHV-6 reactivation might exacerbate the severity of KD.

Pityriasis Rosea during Pregnancy: Major and Minor Alarming Signs

BACKGROUND

Pityriasis rosea (PR) is a self-limiting exanthematous disease associated with human herpesvirus (HHV)-6 and/or HHV-7 reactivation. In pregnant women, PR may be associated with pregnancy complications.

OBJECTIVE

To determine relevant risk factors in the development of negative pregnancy outcome in PR.

METHODS

Between 2005 and 2017 at the Department of Dermatology, University of Genoa, we recruited 76 women who developed PR during pregnancy. In 60 patients without known risk factors for intrauterine fetal death (30 with pregnancy complications and 30 without) we analyzed the pregnancy week of PR onset, presence of enanthem and of constitutional symptoms, PR body surface area involvement, age, and in 50 patients (20 with pregnancy complications and 30 without), the viral load of HHV-6 and HHV-7 (copies/mL).

RESULTS

In logistic regression analysis, early onset of PR (p = 0.0017) and enanthem (p = 0.0392) proved to be significantly associated with pregnancy complications. HHV-6 viral load (copies/mL) (p < 0.0001), constitutional symptoms (p < 0.001), and PR body surface area involvement (p < 0.004) were also significantly associated with pregnancy complications.

CONCLUSION

The onset of PR before week 15 and enanthem may be considered major risk factors that should alarm the dermatologist. Constitutional symptoms and involvement of > 50% of the body area may be considered minor risk factors.

Comparative genomic, transcriptomic, and proteomic reannotation of human herpesvirus 6

Background

Human herpesvirus-6A and -6B (HHV-6) are betaherpesviruses that reach > 90% seroprevalence in the adult population. Unique among human herpesviruses, HHV-6 can integrate into the subtelomeric regions of human chromosomes; when this occurs in germ line cells it causes a condition called inherited chromosomally integrated HHV-6 (iciHHV-6). Only two complete genomes are available for replicating HHV-6B, leading to numerous conflicting annotations and little known about the global genomic diversity of this ubiquitous virus.

Results

Using a custom capture panel for HHV-6B, we report complete genomes from 61 isolates of HHV-6B from active infections (20 from Japan, 35 from New York state, and 6 from Uganda), and 64 strains of iciHHV-6B (mostly from North America). HHV-6B sequence clustered by geography and illustrated extensive recombination. Multiple iciHHV-6B sequences from unrelated individuals across the United States were found to be completely identical, consistent with a founder effect. Several iciHHV-6B strains clustered with strains from recent active pediatric infection. Combining our genomic analysis with the first RNA-Seq and shotgun proteomics studies of HHV-6B, we completely reannotated the HHV-6B genome, altering annotations for more than 10% of existing genes, with multiple instances of novel splicing and genes that hitherto had gone unannotated.

Conclusion

Our results are consistent with a model of intermittent de novo integration of HHV-6B into host germline cells during active infection with a large contribution of founder effect in iciHHV-6B. Our data provide a significant advance in the genomic annotation of HHV-6B, which will contribute to the detection, diversity, and control of this virus.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-4604-2) contains supplementary material, which is available to authorized users.

Human CD134 (OX40) expressed on T cells plays a key role for human herpesvirus 6B replication after allogeneic hematopoietic stem cell transplantation

BACKGROUND

CD134 (OX40), which is a cellular receptor for human herpesvirus-6B (HHV-6B) and expresses on activated T cells, may play a key role for HHV-6B replication after allogeneic hematopoietic stem cell transplantation (allo-HSCT).

OBJECTIVES

Therefore, we examined the CD134 expression on T cells and HHV-6B replication after allo-HSCT, and analyzed the correlation between them.

STUDY DESIGN

Twenty-three patients after allo-HSCT were enrolled. The percentages of CD134-positive cells within the CD4⁺ and CD8⁺ cell populations were measured by flow cytometry, and the viral copy number of HHV-6B was simultaneously quantified by real-time PCR. The correlation between CD134 and HHV-6B viral load was then statistically analyzed.

RESULTS

HHV-6B reactivation occurred in 11 of 23 patients (47.8%). CD134 expression was seen on T cells and was coincident with the time of peak viral load. The percentage of CD134-positive cells decreased significantly when HHV-6B DNA disappeared (p = .005 in CD4⁺ T cells, p = .02 in CD8⁺ T cells). In the 4 patients who underwent umbilical cord blood transplantation (UCBT), the viral load varied with the percentage of CD134-positive cells. In the comparison between the HHV-6B reactivation group and non-reactivation group, maximum percentages of CD134-positive cells among CD4⁺ T cells in reactivation group were significantly higher than those in non-reactivation group (p = .04).

CONCLUSIONS

This is the first study to show that a correlation of CD134 expression on T cells with HHV-6B replication after allo-HSCT, especially in UCBT. The results possibly indicate that CD134 on T cells plays a key role for HHV-6B replication after allo-HSCT.

Betaherpesvirus Virion Assembly and Egress

Virions are the vehicle for cell-to-cell and host-to-host transmission of viruses. Virions need to be assembled reliably and efficiently, be released from infected cells, survive in the extracellular environment during transmission, recognize and then trigger entry of appropriate target cells, and disassemble in an orderly manner during initiation of a new infection. The betaherpesvirus subfamily includes four human herpesviruses (human cytomegalovirus and human herpesviruses 6A, 6B, and 7), as well as viruses that are the basis of important animal models of infection and immunity. Similar to other herpesviruses, betaherpesvirus virions consist of four main parts (in order from the inside): the genome, capsid, tegument, and envelope. Betaherpesvirus genomes are dsDNA and range in length from ~145 to 240 kb. Virion capsids (or nucleocapsids) are geometrically well-defined vessels that contain one copy of the dsDNA viral genome. The tegument is a collection of several thousand protein and RNA molecules packed into the space between the envelope and the capsid for delivery and immediate activity upon cellular entry at the initiation of an infection. Betaherpesvirus envelopes consist of lipid bilayers studded with virus-encoded glycoproteins; they protect the virion during transmission and mediate virion entry during initiation of new infections. Here, we summarize the mechanisms of betaherpesvirus virion assembly, including how infection modifies, reprograms, hijacks, and otherwise manipulates cellular processes and pathways to produce virion components, assemble the parts into infectious virions, and then transport the nascent virions to the extracellular environment for transmission.

Using Droplet Digital PCR to Detect Coinfection of Human Herpesviruses 6A and 6B (HHV-6A and HHV-6B) in Clinical Samples

Droplet digital™ polymerase chain reaction (ddPCR™) is a unique digital PCR technique that allows for absolute quantification of nucleic acid samples. This technique operates on the basis of amplification within water-oil emulsion droplets and can detect very small quantities of target molecules, yielding extremely precise data. Here, we describe in detail a ddPCR procedure for multiplexed detection of two clinically relevant herpesviruses, HHV-6A and HHV-6B.

Comparative evaluation of a laboratory developed real-time PCR assay and the RealStar® HHV-6 PCR Kit for quantitative detection of human herpesvirus 6

BACKGROUND

HHV-6 reactivation in immunocompromised patients is common and may be associated with serious morbidity and mortality; therefore, early detection and initiation of therapy might be of benefit. Real-time PCR assays allow for early identification of HHV-6 reactivation to assist in providing a timely response. Thus, we compared the performance of an in-house developed HHV-6 quantitative PCR assay with a commercially available kit, the RealStar^® HHV-6 PCR Kit.

METHOD

The analytical sensitivity, analytical specificity, linearity, precision and accuracy of the in-house developed HHV-6 qPCR assay were evaluated. The diagnostic performance of the in-house HHV-6 qPCR assay was compared with the RealStar^® HHV-6 PCR Kit, using 72 clinical specimens and 17 proficiency testing samples.

RESULTS

Linear regression analysis of the quantitative results showed a dynamic range from 2 to 10 log₁₀ copies/ml and a coefficient of determination (R²) of 0.999 for the in-house assay. A dilution series demonstrated a limit of detection and a limit of quantification of 1.7 log₁₀ and 2 log₁₀ copies/ml, respectively. The precision of the assay was highly reproducible among runs with coefficients of variance (CV) ranging from 0.27% to 4.37%. A comparison of 27 matched samples showed an excellent correlation between the quantitative viral loads measured by the in-house HHV-6 qPCR assay and the RealStar^® HHV-6 PCR Kit (R²=0.926; P<0.0001), with an average bias of -0.24 log₁₀ copies/ml.

CONCLUSIONS

The in-house developed HHV-6 qPCR method is a sensitive and reliable assay with lower cost for the detection and quantification of HHV-6 DNA when compared to the RealStar^® HHV-6 PCR Kit.

Divergent tropism of HHV-6AGS and HHV-6BPL1 in T cells expressing different CD46 isoform patterns

CD46 is a receptor for HHV-6A, but its role as a receptor for HHV-6B is controversial. The significance of CD46 isoforms for HHV-6A and HHV-6B tropism is unknown. HHV-6A_GS was able to initiate transcription of the viral genes U7 and U23 in the CD46⁺CD134^- T-cell lines Peer, Jurkat, Molt3, and SupT1, whereas HHV-6B_PL1 was only able to do so in Molt3 and SupT1, which expressed a CD46 isoform pattern different from Peer and Jurkat. The HHV-6B_PL1-susceptible T-cell lines were characterized by low expression of the CD46 isoform BC2 and domination of isoforms containing the cytoplasmic tail, CYT-1. A HHV-6B_PL1 susceptible cell line, Be13, changed over time its CD46 isoform pattern to resemble Peer and Jurkat and concomitantly lost its susceptibility to HHV-6B_PL1 but not HHV-6A_GS infection. We propose that isoforms of CD46 impact on HHV-6B infection and thereby in part explain the distinct tropism of HHV-6A_GS and HHV-6B_PL1.

Association between human herpesvirus & human endogenous retrovirus and MS onset & progression

This review discusses the role of Epstein-Barr virus (EBV), human herpesvirus 6 (HHV6) and human endogenous retroviruses (HERVs) in the onset and progression of multiple sclerosis (MS). Although EBV has been established as one of the causal factors in MS onset, its role in MS progression is still uncertain. Moreover, interactions between EBV and other risk factor on MS development still need more investment. With less consistent evidence than EBV, HHV6 has also been implicated in the pathogenesis of MS; moreover, it showed a closer connection with the disease activity. Recent studies found that HERVs were associated with the development and progression of MS. Some antiviral treatments have shown promise for clinical interventions in the future. Future studies are yet needed to fully clarify the role of these agents in MS onset and disease course and the modes by which they realise these effects.

Human Herpesvirus 6 Infection Following Haploidentical Transplantation: Immune Recovery and Outcome

Human herpesvirus 6 (HHV-6) is increasingly recognized as a potentially life-threatening pathogen in allogeneic hematopoietic stem cell transplantation (alloSCT). We retrospectively evaluated 54 adult patients who developed positivity to HHV-6 after alloSCT. The median time from alloSCT to HHV-6 reactivation was 34 days. HHV-6 was present in plasma samples from 31 patients, in bone marrow (BM) of 9 patients, in bronchoalveolar lavage fluid and liver or gut biopsy specimens from 33 patients, and in cerebrospinal fluid of 7 patients. Twenty-nine patients developed acute graft-versus-host disease (GVHD), mainly grade III-IV, and 15 had concomitant cytomegalovirus reactivation. The median absolute CD3⁺ lymphocyte count was 207 cells/µL. We reported the following clinical manifestations: fever in 43 patients, skin rash in 22, hepatitis in 19, diarrhea in 24, encephalitis in 10, BM suppression in 18, and delayed engraftment in 11. Antiviral pharmacologic treatment was administered to 37 patients; nonetheless, the mortality rate was relatively high in this population (overall survival [OS] at 1 year, 38% ± 7%). A better OS was significantly associated with a CD3⁺ cell count ≥200/µL at the time of HHV-6 reactivation (P = .0002). OS was also positively affected by the absence of acute GVHD grade III-IV (P = .03) and by complete disease remission (P = .03), but was not significantly influenced by steroid administration, time after alloSCT, type of antiviral prophylaxis, plasma viral load, or organ involvement. Although HHV-6 detection typically occurred early after alloSCT, better T cell immune reconstitution seems to have the potential to improve clinical outcomes. Our findings provide new insight into the interplay between HHV-6 and the transplanted immune system.

Central nervous system infection following allogeneic hematopoietic stem cell transplantation

OBJECTIVE/BACKGROUND

Here, we described the clinical characteristics and outcomes of central nervous system (CNS) infections occurring after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in a single institution over the previous 6 years.

METHODS

Charts of 353 consecutive allogeneic transplant recipients were retrospectively reviewed for CNS infection.

RESULTS

A total of 17 cases of CNS infection were identified at a median of 38 days (range, 10-1028 days) after allo-HSCT. Causative pathogens were human herpesvirus-6 (n=6), enterococcus (n=2), staphylococcus (n=2), streptococcus (n=2), varicella zoster virus (n=1), cytomegalovirus (n=1), John Cunningham virus (n=1), adenovirus (n=1), and Toxoplasma gondii (n=1). The cumulative incidence of CNS infection was 4.1% at 1 year and 5.5% at 5 years.

CONCLUSION

Multivariate analysis revealed that high-risk disease status was a risk factor for developing CNS infection (p=.02), and that overall survival at 3 years after allo-HSCT was 33% in patients with CNS infection and 53% in those without CNS infection (p=.04).

Drug-Induced Hypersensitivity Syndrome Followed by Subacute Thyroiditis

Drug-induced hypersensitivity syndrome (DIHS) is a severe multiorgan system adverse drug reaction with reactivation of human herpesviruses (HHVs) such as HHV-6, HHV-7, cytomegalovirus (CMV) and Epstein-Barr virus. Various complications, including autoimmune diseases, sometimes appear during the course of DIHS. We report a case of salazosulfapyridine-induced DIHS associated with HHV-6 reactivation. Two and a half months after the onset of DIHS, subacute thyroiditis occurred, possibly associated with CMV reactivation. Prednisolone (20 mg/day) was effective for subacute thyroiditis. Long-term follow-up is needed in patients with DIHS because of the possible onset of autoimmune diseases.

Overlapping MERS and mild AESD caused by HHV-6 infection

We report the case of an overlapping encephalopathy syndrome consisting of clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) and a mild form of acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) caused by human herpesvirus-6. A previously healthy 17-month-old girl was admitted to our hospital as a precaution because of seizures that had developed more than 25 hours (h) after fever. Brain diffusion-weighted images (DWI) showed high signal intensity in the central splenial region on Day 2. She regained consciousness 16 h after the second seizure. On Day 6, she had a secondary cluster of partial seizures. DWI showed resolution of the splenial lesion and revealed reduced diffusion in the fronto-subcortical white matter. She regained consciousness 36 h after the secondary cluster of seizures without any sequelae. A third DWI performed on Day 15 showed that the fronto-subcortical white matter lesions had completely disappeared. Based on the clinicoradiological findings, we diagnosed the patient with overlapping MERS and mild AESD. Our case, together with previous reports, suggests that patients can develop combined encephalopathy syndromes as a phenotype. Many encephalopathy syndromes have been established and classified; however, some may not present as independent syndromes.

Human herpesvirus 6 is associated with status epilepticus and hyponatremia after umbilical cord blood transplantation

This article describes a case involving a 65-year-old man who experienced nonconvulsive status epilepticus after undergoing an allogenic hematopoietic cell transplantation to treat chronic lymphocytic leukemia. The authors describe the diagnostic work-up and treatment of human herpesvirus 6 infection, and discuss other potential causes of nonconvulsive status epilepticus in similar scenarios.

Status epilepticus after allogeneic hematopoietic cell transplantation (alloHCT) is rare. The authors report a case involving a 65-year-old man with nonconvulsive status epilepticus 34 days after umbilical cord blood transplantion for chronic lymphocytic leukemia. Cerebrospinal fluid and serum were positive for human herpesvirus 6 (HHV6). Magnetic resonance imaging of the brain showed symmetric T2 hyper-intensity bilaterally in the mesial temporal lobes, and T2 hyperintensi-ties and restricted diffusion of bilateral putamina. Despite aggressive anticonvulsive therapy, his seizures only abated with initiation of ganciclovir therapy. The patient completed six weeks of combination antiviral therapy (ganciclovir and foscarnet). His cognitive function gradually improved and, after prolonged rehabilitation, the patient was discharged home with residual intermittent memory loss but otherwise functional. HHV6 should be considered in the differential diagnosis of nonconvulsive status epilepticus after alloHCT, especially in patients with hyponatremia. Empirical antiviral therapy targeting HHV6 should be administered to these patients.

Evidence for human herpesvirus-6B infection of regulatory T-cells in acute systemic lymphadenitis in an immunocompetent adult with the drug reaction with eosinophilia and systemic symptoms syndrome: a case report

We describe a fatal case of drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome with human herpesvirus-6B (HHV-6B)-associated lymphadenitis and virus-associated hemophagocytic syndrome triggered by an over-the-counter medication to treat respiratory and influenza-like symptoms. Histologically, the structure of the lymph node was disrupted with infiltration of large lymphocytes carrying intranuclear acidophilic inclusion bodies. Immunohistochemistry and real-time PCR analysis revealed that these large lymphocytes were positive for HHV-6B. Numerous HHV-6 particles were detected in the inclusion body of the lymphocytes by electron microscopy. Interestingly, immunohistochemistry revealed that HHV-6B-infected cells in the lymph node were CD3(+), CD4(+), CD25(+), and FoxP3(+) T cells, indicating a phenotypic resemblance to regulatory T-cells. This case provides direct evidence of HHV-6 infection in CD25(+)/FoxP3(+) T cells in a case of acute lymphadenitis of DRESS syndrome, suggesting a significant role of HHV-6 infection of regulatory T-cells in the pathogenesis of DRESS syndrome.

Quantification of two viral transcripts by real time PCR to investigate human herpesvirus type 6 active infection

BACKGROUND

Human herpesvirus 6 (HHV-6) causes exanthema subitum and is associated with symptomatic reactivations in immunocompromised patients, particularly after hematopoietic stem cell transplantation. The detection of viral mRNA can help to make the difference between latent, chromosomally integrated and true replicating virus. It can also be a useful tool to investigate viral multiplication in different cell types.

OBJECTIVES

To develop molecular tools for the detection and quantification HHV-6 transcripts that can be used in a clinical setting.

STUDY-DESIGN

Two one-step reverse-transcriptase quantitative real-time PCR (RT-qPCR) were developed for the quantification of the immediate early U90 and the late U100 mRNAs. Viral mRNA loads were compared to viral DNA loads during infection in vitro and in blood samples collected from stem cell transplanted patients.

RESULTS

Analytical performances of the two quantitative real-time PCR were good. In vitro, kinetics of both transcripts was well correlated with DNA levels. Sixty blood samples from patients with active HHV-6 infection were analyzed. Overall agreement of qualitative results for HHV-6 DNA, U90 RNA and U100 RNA was good. HHV-6 DNA loads were significantly higher than mRNA loads. In clinical samples, the amounts of U100 and U90 mRNAs were low and their detection was mainly associated to viral DNA loads upper than 1000 copies/ml of blood.

CONCLUSION

The new assays are sensitive and reliable methods for the monitoring of viral transcription in vitro and in vivo. As their detection is associated to high DNA loads in vivo, they can be helpful tools for the diagnosis of active infection.

Human herpesvirus-6 and cytomegalovirus DNA in liver donor biopsies and their correlation with HLA matches and acute cellular rejection

Herpesvirus reactivation is common after liver transplantation.

Objective

Analyze the presence of cytomegalovirus (HCMV) and human herpesvirus-6 (HHV-6) DNA in liver donor biopsies, seeking to better understand issues involving human donor leukocyte antigens (HLA)-A, B and DR, as well as correlations with acute cellular rejection.

Methods

Fifty-nine liver transplantation patients were investigated for the presence of HCMV and HHV-6 DNA in liver donor biopsies, using the Nested-PCR technique. The clinical donor information and HLA matches were obtained from the São Paulo State Transplant System. The recipients’ records regarding acute cellular rejection were studied.

Results

Seven (11.8%) biopsies were positive for HCMV DNA and 29 (49%) were positive for HHV-6 DNA. In 14 donors with HLA-DR 15 nine had HHV-6 DNA positive liver biopsy with a tendency for significant association (p = 0.09), 22 recipients developed acute cellular rejection and 9/22 were positive for HLA-DR 15 (p = 0.03; χ² = 4.51), which was statistically significant in univariate analysis and showed a tendency after multivariate analysis (p = 0.08).

Conclusion

HHV-6 DNA was prevalent in liver donors studied as well as HLA-DR 15. These findings suggest that patients with HLA-DR 15 in liver donor biopsies develop more rejection after liver transplantation.

Acute hepatitis with periportal confluent necrosis associated with human herpesvirus 6 infection in liver transplant patients

OBJECTIVES

To correlate human herpesvirus 6 (HHV-6) viral load with pathologic features in graft acute hepatitis of unknown origin.

METHODS

Liver frozen samples from 26 patients with graft hepatitis of unknown origin were available for HHV-6 DNA quantification.

RESULTS

In 10 (38.5%) of 26 liver samples, HHV-6 DNA was detectable, with a median viral load of 3.84 log10 copies/10⁶ cells. Confluent periportal necrosis was observed in 4 of 10 patients and associated with high viral load. These 4 patients responded to antiviral therapy. Mild unspecific hepatitis was observed in 4 patients with low intragraft viral load and in 2 patients with high viral load in a context of deep immunosuppression. Patients with HHV-6-negative graft hepatitis disclosed lobular necrotico-inflammatory activity without periportal necrosis.

CONCLUSIONS

Our study provides data supporting the pathogenic role of HHV-6 for liver allografts. The presence of confluent periportal necrosis could be a clue for prompt diagnosis of HHV-6-induced graft hepatitis.