Human herpesvirus-6 infection in a critically ill and immunocompetent patient: a case report

BACKGROUND

Human herpesvirus-6 is a rare infection in an immunocompetent adult. In existing literature, there is a dearth of knowledge that mainly exists as case reports and case series.

CASE PRESENTATION

In this case report, we described a 29-year-old female of Myanmarese descent patient from Myanmar who presented with altered mental status and non-specific respiratory and gastrointestinal symptoms. She was initially treated for pneumonia and discharged well. However, she re-presented to the hospital and was subsequently treated for severe central nervous system infection. Cerebrospinal fluid studies detected human herpesvirus-6 polymerase chain reaction with associated high serum human herpesvirus-6 concentration. This infection also triggered hemophagocytic lymphohistiocytosis. Treatment was initiated against both human herpesvirus-6 infection and hemophagocytic lymphohistiocytosis, and she responded to antiviral treatment and steroids, respectively.

CONCLUSION

This case study highlights the need for prompt diagnosis and treatment of this severe disease and the dangerous complications. Additionally, the authors share insights on the diagnostic challenges faced in the treatment of this patient.

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.

HHV-6 Infection in a 19-Year-Old Liver Transplant Recipient - Much More Than Roseola!

Human herpesvirus 6 (HHV-6) infections, most commonly occurring during childhood, are frequently mild and self-limited. However, immunosuppression due to transplantation may cause reactivation of HHV-6 with manifestations ranging from fever and skin exanthem to pneumonitis, hepatitis, encephalitis, and myelitis. Because these infections may be devastating for liver transplant recipients leading to transplant organ fibrosis and failure, it is imperative that internists recognize the manifestations, establish early diagnosis, institute appropriate therapy, and make timely referrals to transplant specialists. We present a case of a 19-year-old liver transplant recipient with HHV-6 viremia, encephalopathy, and hepatitis. The patient's symptoms improved with ganciclovir and intravenous immunoglobulin treatment, serum HHV-6 copies gradually decreased, and she was discharged with outpatient follow-up. After approximately one month of antiviral therapy, the patient's viral load was undetectable. Early recognition of HHV-6 viremia, appropriate laboratory assessment, and early institution of therapy is important for internal medicine physicians to decrease morbidity and mortality in liver transplant recipients.

Association analysis between symptomology and herpesvirus IgG antibody concentrations in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and multiple sclerosis

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and multiple sclerosis (MS) are two complex and multifactorial diseases whose patients experience persistent fatigue, cognitive impairment, among other shared symptoms. The onset of these diseases has also been linked to acute herpesvirus infections or their reactivations. In this work, we re-analyzed a previously-described dataset related to IgG antibody responses to 6 herpesviruses (CMV - cytomegalovirus; EBV - Epstein-Barr virus; HHV6 - human herpesvirus-6; HSV1 and HSV2 - herpes simplex virus-1 and -2, respectively; VZV - varicella-zoster virus) from the United Kingdom ME/CFS biobank. The primary goal was to report the underlying symptomology and its association with herpesvirus IgG antibodies using data from 4 disease-trigger-based subgroups of ME/CFS patients (n = 222) and patients with MS (n = 46). The secondary objective was to assess whether serological data could distinguish ME/CFS and its subgroup from MS using a SuperLearner (SL) algorithm. There was evidence for a significant negative association between temporary eye insight disturbance and CMV antibody concentrations and for a significant positive association between bladder problems and EBV antibody concentrations in the MS group. In the ME/CFS or its subgroups, the most significant antibody-symptom association was obtained for increasing HSV1 antibody concentration and brain fog, a finding in line with a negative impact of HSV1 exposure on cognitive outcomes in both healthy and disease conditions. There was also evidence for a higher number of significant antibody-symptom associations in the MS group than in the ME/CFS group. When we combined all the serological data in an SL algorithm, we could distinguish three ME/CFS subgroups (unknown disease trigger, non-infection trigger, and an infection disease trigger confirmed in the lab at the time of the event) from the MS group. However, we could not find the same for the remaining ME/CFS group (related to an unconfirmed infection disease). In conclusion, IgG antibody data explains more the symptomology of MS patients than the one of ME/CFS patients. Given the fluctuating nature of symptoms in ME/CFS patients, the clinical implication of these findings remains to be determined with a longitudinal study. This study is likely to ascertain the robustness of the associations during natural disease course.

Human herpesvirus 6 (HHV-6) associated permanent hyponatremia in umbilical cord blood transplant recipient

Long-term neurocognitive deficits after human herpesvirus-6 (HHV-6) infection are common in stem-cell transplant recipients, but SIADH (Syndrome of inappropriate antidiuretic hormone secretion) with persistent hyponatremia is rare. A 51-year-old woman presented with somnolence, hyponatremia (121 mmol/L) and HHV-6 viremia (80,330 copies/ml) on day +22 post umbilical cord blood transplant (UCBT). With waterrestriction, tolvaptan and combination of foscarnet and ganciclovir, patient's hyponatremia and HHV-6 viremia improved. On day +94 UCBT, hyponatremia and HHV-6 viremia recurred. Foscarnet was restarted and continued until day +269 UCBT due to multiple HHV-6 recurrences with persistent hyponatremia. At day +712, patient remains on water-restriction, tolvaptan for continuous hyponatremia from SIADH.

Insights into the knowledge of complex diseases: Environmental infectious/toxic agents as potential etiopathogenetic factors of systemic sclerosis

Systemic sclerosis (SSc) is a connective tissue disease secondary to three cardinal pathological features: immune-system alterations, diffuse microangiopathy, and fibrosis involving the skin and internal organs. The etiology of SSc remains quite obscure; it may encompass multiple host genetic and environmental -infectious/chemical-factors. The present review focused on the potential role of environmental agents in the etiopathogenesis of SSc based on epidemiological, clinical, and laboratory investigations previously published in the world literature. Among infectious agents, some viruses that may persist and reactivate in infected individuals, namely human cytomegalovirus (HCMV), human herpesvirus-6 (HHV-6), and parvovirus B19 (B19V), and retroviruses have been proposed as potential causative agents of SSc. These viruses share a number of biological activities and consequent pathological alterations, such as endothelial dysfunction and/or fibroblast activation. Moreover, the acute worsening of pre-existing interstitial lung involvement observed in SSc patients with symptomatic SARS-CoV-2 infection might suggest a potential role of this virus in the overall disease outcome. A variety of chemical/occupational agents might be regarded as putative etiological factors of SSc. In this setting, the SSc complicating silica dust exposure represents one of the most promising models of study. Considering the complexity of SSc pathogenesis, none of suggested causative factors may explain the appearance of the whole SSc; it is likely that the disease is the result of a multifactorial and multistep pathogenetic process. A variable combination of potential etiological factors may modulate the appearance of different clinical phenotypes detectable in individual scleroderma patients. The in-deep investigations on the SSc etiopathogenesis may provide useful insights in the broad field of human diseases characterized by diffuse microangiopathy or altered fibrogenesis.

Human herpesvirus 6 myelitis after chimeric antigen receptor T-cell therapy

This article reports a fatal case of human herpesvirus 6 (HHV-6) myelitis following CD19-targeted chimeric antigen receptor T-cell therapy. Infection from HHV-6 reactivation after haematopoietic stem cell transplant is established, and outside of this population is limited to case reports. The patient developed cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome that responded to corticosteroids both clinically and on imaging. Subsequently, ascending flaccid paralysis developed, leading to neuromuscular respiratory failure and, ultimately, death. Disease progression was refractory to foscarnet and multiple immunomodulating agents. HHV-6 should be considered in patients with encephalitis and myelitis after adoptive T-cell therapy.

Hemolytic uremic syndrome related to Shiga-like toxin-producing Escherichia coli with encephalitis hiding a human herpesvirus-6 infection: a case report

BACKGROUND

Cardiac and neurological involvement in hemolytic uremic syndrome are life-threatening complications. The most frequent complications of cardiac involvement in hemolytic uremic syndrome are myocarditis and cardiac dysfunction due to fluid overload. Pericarditis remains very rare in hemolytic uremic syndrome. To our knowledge, only five cases of cardiac tamponade associated with hemolytic uremic syndrome have been described in literature. A 27-month-old Caucasian girl presented with symptoms of nonbloody diarrhea and tonic-clonic seizures. The diagnosis of Shiga-like toxin-producing Escherichia coli hemolytic uremic syndrome with central nervous system involvement was made, and stool examination revealed infection with a Shiga-like toxin-producing Escherichia coli. She did not need renal replacement therapy but had severe neurological impairment. The patient's course was complicated by pericardial effusion. A pericardiocentesis was performed via an apical approach because the pericardial effusion was predominantly surrounding the left ventricle. Effusion analysis showed an exudate and positivity for human herpesvirus-6B on polymerase chain reaction with viremia. This finding was consistent with primary human herpesvirus-6 infection with encephalitis.

CONCLUSION

We report this uncommon case of Shiga-like toxin-producing Escherichia coli hemolytic uremic syndrome associated with a severe human herpesvirus-6 infection. Secondary isolated pericardial effusion and atypical neurological involvement are uncommon in Shiga-like toxin-producing Escherichia coli hemolytic uremic syndrome and should lead the physician to perform additional investigations.

Risk Factor and Long-Term Outcome Analyses for Acute Limbic Encephalitis and Calcineurin Inhibitor-Induced Encephalopathy in Adults following Allogeneic Hematopoietic Cell Transplantation

Post-transplantation acute limbic encephalitis (PALE) is a rare, severe inflammatory disorder in the bilateral limbic system, including the hippocampus. To date, only a few studies have reported details, including risk factors for PALE; however, further clinical evidence of PALE, especially in cerebrospinal fluid human herpesvirus 6-negative cases, is warranted. In addition, data are sparse regarding the risk factors for calcineurin inhibitor (CNI)-induced encephalopathy (CNIE) following allogeneic hematopoietic cell transplantation (allo-HCT) in adults. Therefore, we examined the risk factors for and clinical details of PALE and CNIE. We retrospectively analyzed consecutive patients who underwent allo-HCT between January 2005 and November 2017. A total of 485 patients age 46 years (median) were eligible. In total, 14 PALE cases and 11 CNIE cases were identified. Multivariable analyses identified older age, use of an HLA-mismatched unrelated donor (URD), graft-versus-host disease (GVHD) prophylaxis with CNI and mycophenolate mofetil, and grade II-IV acute GVHD as significantly associated with an increased risk of PALE. In 13 patients who received high-dose methylprednisolone (mPSL) therapy, 6 (46%) responded to mPSL therapy, and 3 (23%) achieved complete remission at day 90 after mPSL administration. Furthermore, myelodysplastic syndrome (MDS), HLA-mismatched URD, and grade II-IV acute GVHD were significantly associated with an increased risk of CNIE. The 5-year nonrelapse mortality rate was 50% in PALE and 63% in CNIE, suggesting a very poor prognosis. In conclusion, this study provides evidence that HLA-mismatched URD and acute GVHD may independently contribute to the development of PALE, possibly in part through HLA-mismatch-derived alloimmune responses. Other than acute GVHD, we have identified MDS and HLA-mismatched URD as novel predictors of CNIE after allo-HCT.

The role of human herpesvirus-6 and inflammatory markers in the pathogenesis of multiple sclerosis

Multiple sclerosis (MS) is a destructive autoimmune neuroinflammatory and neurodegenerative disorder of the central nervous system (CNS) with unknown etiology and mechanism of pathogenesis. Pathogens, especially human herpes viruses, have been suggested as environmental factors of the MS and other neuroinflammatory disorders. This study aimed to determine the prevalence of HHV-6 antibody response in MS patients and investigate the levels of pro/anti-inflammatory cytokine and chemokines in MS patients in comparison with healthy subjects. Two hundred sixty-three patients with clinically defined MS (140 females and 123 males), along with 263 healthy subjects (140 females and 123 males), were recruited for this study. After the analysis of HHV-6 seropositivity/seronegativity, the levels of some pro/anti-inflammatory cytokines, including TNF-α, IFN-γ, IL-1β, IL-6, and IL-12 as well as two chemokines, namely CCL-2 and CCL-5 were determined by the enzyme-linked immunosorbent assay (ELISA) method in HHV-6 seropositive/seronegative MS patients and healthy subjects. Our results showed that the serum concentrations of TNF-α, IFN-γ, IL-1β, IL-6, and CCL-5 elevated in HHV-6 seropositive compared with seronegative MS patients (P < .05). Moreover, the levels of IL-12, IL-10, and CCL-2 levels were significantly lower in seropositive MS patients when compared with seronegative MS patients (P < .05). Also, our results revealed that the mean values of the expanded disability status scale (EDSS) were significantly higher in HHV-6 seropositive versus seronegative MS patients (P < .05). In conclusion, we proposed that HHV-6 infection may play a role in MS pathogenesis by changing cytokine signaling in MS patients that may lead to peripheral inflammation.

Acute encephalopathy with biphasic seizures and late reduced diffusion in a Spanish girl

We report a case of a 22-month-old Spanish girl who presented acute encephalopathy with biphasic seizures and late reduced diffusion (AESD). Serum procalcitonin (PCT) reached a maximum of 50.5 ng/mL on the first day whereas C-reactive protein (CRP) peaked at 1.21 mg/dL on the second. At the time of discharge, right spastic hemiparesis persisted. MR spectroscopy on day 23 revealed a decrease in N-acetylaspartate and an increase in choline. To our knowledge, we report the first case of AESD in Europe. These findings support the role of PCT and PCT/CRP ratio in the early diagnosis of AESD and correlation of MR spectroscopy findings with neurological outcome.

Human herpesvirus-6 is present at higher levels in the pancreatic tissues of donors with type 1 diabetes

Human herpesvirus-6 (HHV-6) is a ubiquitous pathogen associated with nervous and endocrine autoimmune disorders. The aim of this study was to investigate the presence of HHV-6 in pancreatic tissue sections from non-diabetic, auto-antibody positive (AAB+), and donors with type 1 diabetes (T1D) and explore whether there is any association between HHV-6 and MHC class I hyperexpression and CD8 T cell infiltration. HHV-6 DNA was detected by PCR and its protein was examined by indirect immunofluorescence assay followed by imaging using high-resolution confocal microscopy. Viral DNA (U67) was found in most pancreata of non-diabetic (3 out of 4), AAB+ (3 out of 5) and T1D donors (6 out of 7). Interestingly, HHV-6 glycoprotein B (gB) was more expressed in islets and exocrine pancreas of donors with T1D. However, gB expression was not directly associated with other pathologies. Out of 20 islets with high gB expression, only 3 islets (15%) showed MHC class I hyperexpression. Furthermore, no correlation was found between gB expression and CD8 T cell infiltration on a per-islet basis in any of the groups. Our observations indicate that HHV-6 DNA and protein are present in the pancreas of non-diabetic subjects but gB expression is higher in the pancreas of donors with T1D. The possible role of HHV-6 as a contributory factor for T1D should therefore be further investigated.

Joint association of carrying HLA-B*13:01 gene and human herpesvirus-6 with occupational trichloroethylene hypersensitivity syndrome

PURPOSE

Occupational trichloroethylene hypersensitivity syndrome (OTHS) clinically manifests as generalized severe rash resembling drug-induced hypersensitivity syndrome (DIHS) and afflicts predominantly HLA-B*13:01 gene carriers after their exposure to trichloroethylene. Meanwhile, OTHS may also be associated with human herpesvirus such as herpesvirus-6 (HHV6) and cytomegalovirus (HCMV) reported to participate in the pathology of DIHS. This study explored the association of carrying HHV6 and HCMV, and the joint association of carrying HLA-B*13:01 and HHV6 and HCMV with OTHS.

METHODS

We recruited 30 OTHS patients and 40 trichloroethylene-exposed healthy workers as cases and controls, respectively. HLA-B*13:01 was genotyped and HHV6 and HCMV DNA were detected in the DNA extracted from whole-blood sample of each participant with PCR techniques. Positive rates of HLA-B*13:01 gene and HHV6 and HCMV DNA and their association with OTHS were then analyzed.

RESULTS

The OTHS cases showed significantly higher positive rates of HLA-B*13:01 gene and HHV6 DNA, but not HCMV DNA, than the controls (83.3% vs. 25.0% and 56.7% vs. 10.0%, respectively, both P < 0.001). Positive rate of HHV6 DNA was significantly higher in HLA-B*13:01 carriers than in non-carriers in the cases (68.0% vs. 0, P = 0.005), but not in the controls. Carrying HLA-B*13:01 and HHV6 had an interactive effect on OTHS (OR = 91.80, P < 0.001).

CONCLUSIONS

Carrying HLA-B*13:01 and HHV6 may be associated with OTHS; furthermore, carrying HLA-B*13:01 and HHV6 may be jointly associated with OTHS.

Human Herpesvirus-6 corneal Endotheliitis after intravitreal injection of Ranibizumab

BACKGROUND

To report the first case of human herpesvirus-6 (HHV-6) corneal endotheliitis that developed after intravitreal ranibizumab injections.

CASE PRESENTATION

A 63-year-old man with a medical history of diabetes and systemic steroid treatment for bullous pemphigoid had been receiving intravitreal injections of ranibizumab in the left eye for 2 years according to a Pro Re Nata treatment regimen for macular edema associated with branch retinal vein occlusion. Twenty days after the last injection, the patient presented with pain and decreased visual acuity in his left eye. His best corrected visual acuity in the left eye was 2/200, and intraocular pressure was 45 mmHg with edema of the central stromal cornea, mild conjunctival injection, intermediate keratic precipitates, and mild anterior chamber reaction. HHV-6 DNA was detected in the aqueous humor using multiplex strip polymerase chain reaction, and it was identified as variant A, HHV-6A. A diagnosis of HHV-6A-associated corneal endotheliitis was made. Oral valganciclovir and topical ganciclovir therapy was initiated with good resolution of all symptoms and signs.

CONCLUSIONS

HHV-6A can be a possible complication of intravitreal ranibizumab therapy. To the best of our knowledge, this is the first reported case of HHV-6A corneal endotheliitis following intravitreal ranibizumab injection.

High Incidence of Early Human Herpesvirus-6 Infection in Children Undergoing Haploidentical Manipulated Stem Cell Transplantation for Hematologic Malignancies

Human herpesvirus-6 (HHV-6) infection is increasingly recognized among allogeneic hematopoietic stem cell transplantation (HSCT) recipients, with 30% at risk of reactivation in the haploidentical setting. It has been associated with encephalitis, acute graft-versus-host disease, and graft failure. Here we report 2 cohorts of pediatric haploidentical manipulated HSCT in which, despite many differences, HHV-6 reactivation and disease occurred with very high incidence compared with data reported in the literature and represented the main early post-transplant infectious complication compared with other viral, bacterial, or fungal infections. The 2 cohorts were recruited at the pediatric transplant centers of Perugia (n = 13), Barcelona (n = 10), and Madrid (n = 15). All patients received myeloablative conditioning regimens and 2 different types of ex vivo graft manipulation: CD34⁺ selection and regulatory T cell/conventional T cell infusion in 13 patients and CD45RA T cell depletion in 25 patients. Antiviral prophylaxis was acyclovir in 33 and foscarnet in 5 patients. HHV-6 DNAemia was checked by quantitative or qualitative PCR. In vitro experiments demonstrated that donor CD4⁺ T cells are the reservoir of HHV-6 and suggested a role of the graft composition in both transplant settings (rich in CD4⁺ T cells) in the high rate of HHV-6 infections. All patients presented very early HHV-6 DNAemia after transplantation, and although viremic, 9 patients (24%) developed symptomatic limbic encephalitis. All patients responded to antiviral treatment, and none died of infection, although 2 experienced long-term neurologic sequelae (22%). Moreover, 6 patients presented organ involvement in absence of other causes: 1 hepatitis, 1 pneumonia, 2 gastroenteritis, and 2 multiorgan involvement(1 encephalitis, pneumonia, and gastritis; 1 pneumonia and enteritis). Incidences of other viral, bacterial, and fungal diseases were lower in both cohorts. In vitro, HHV-6 was found to infect only CD4⁺ fraction of the graft. Co-culturing CD4⁺ T cells with CD56⁺ natural killer (NK) cells eliminated the virus, demonstrating the main role of NK cells in the antiviral immune response. All 38 pediatric patients undergoing these manipulated haploidentical HSCTs showed HHV-6 reactivation, and 14 of 38 developed HHV-6 disease with similar features in terms of timing, morbidity, response to treatment, and outcome. The graft composition in both transplant platforms, rich in CD4⁺ T cells and poor in NK cells, seems to play a key role. HHV-6 DNAemia surveillance was useful to diagnose and treat preemptively HHV-6 infection.

Unexpected High Incidence of Human Herpesvirus-6 Encephalitis after Naive T Cell-Depleted Graft of Haploidentical Stem Cell Transplantation in Pediatric Patients

The CD45RA T cell depletion (TCD) method has been used to deplete naive T cells, preventing graft-versus-host disease (GVHD) but preserving memory cells, providing immediate functional T cells with anti-infection, antileukemia, and antirejection effects. We describe a series of 25 consecutive high-risk patients with leukemia who received haploidentical hematopoietic stem cell transplantation (haplo-HSCT) with CD45RA TCD. Each patient received 2 cell products: 1 created by CD34 positive selection and the other through CD45RA depletion from the CD34 negative fraction by a CliniMACS device. CD45RA-depleted haplo-HSCT was well tolerated, with rapid engraftment and low risk of severe acute GVHD and chronic GVHD. Although this treatment achieved a good control of viral reactivations, such as cytomegalovirus and adenovirus, we observed an unexpectedly high rate of limbic encephalitis due to human herpesvirus-6 (HHV-6; 8 cases). Characteristically, the infection appeared early in almost all patients, just after the engraftment. Although no patient died from encephalitis, 1 patient showed neuropsychological sequelae, and another experienced secondary graft failure just after the HHV-6 reactivation.

Human Herpesvirus-6B Reactivation Is a Risk Factor for Grades II to IV Acute Graft-versus-Host Disease after Hematopoietic Stem Cell Transplantation: A Systematic Review and Meta-Analysis

Graft-versus-host disease (GVHD) is an important cause of morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT). Many studies have suggested that human herpesvirus-6B (HHV-6B) plays a role in acute GVHD (aGVHD) after HCT. Our objective was to systematically summarize and analyze evidence regarding HHV-6B reactivation and development of aGVHD. PubMed and EMBASE databases were searched using terms for HHV-6, HCT, and aGVHD, yielding 865 unique results. Case reports, reviews, articles focusing on inherited chromosomally integrated HHV-6, poster presentations, and articles not published in English were excluded. The remaining 467 articles were reviewed for the following requirements: a statistical analysis of HHV-6B reactivation and a GVHD was described, HHV-6B reactivation was defined by PCR, and blood (plasma, serum, or peripheral blood mononuclear cells) was used for HHV-6B PCR. Data were abstracted from publications that met these criteria (n = 33). Publications were assigned to 1 of 3 groups: (1) HHV-6B reactivation was analyzed as a time-dependent risk factor for subsequent aGVHD (n = 14), (2) aGVHD was analyzed as a time-dependent risk factor for subsequent HHV-6B reactivation (n = 1), and (3) analysis without temporal specification (n = 18). A statistically significant association (P < .05) between HHV-6B reactivation and aGVHD was observed in 10 of 14 studies (71%) in group 1, 0 of 1 study (0%) in Group 2, and 8 of 18 studies (44.4%) in Group 3. Of the 14 studies that analyzed HHV-6B as a risk factor for subsequent aGVHD, 11 performed a multivariate analysis and reported a hazard ratio, which reached statistical significance in 9 of these s tudies. Meta-analysis of these 11 studies demonstrated a statistically significant association between HHV-6B and subsequent grades II to IV aGVHD (hazard ratio, 2.65; 95% confidence interval, 1.89 to 3.72; P < .001).HHV-6B reactivation is associated with aGVHD, and when studies have a temporal component to their design, HHV-6B reactivation is associated with subsequent aGVHD. Further research is needed to investigate whether antiviral prophylaxis reduces incidence or severity of aGVHD.

Effects of Prophylactic Foscarnet on Human Herpesvirus-6 Reactivation and Encephalitis in Cord Blood Transplant Recipients: A Prospective Multicenter Trial with an Historical Control Group

Cord blood transplantation (CBT) is a distinct risk factor for human herpesvirus-6 (HHV-6) reactivation and HHV-6 encephalitis. In a prospective multicenter trial we investigated the effects of prophylactic foscarnet (90 mg/kg i.v. infusion from days 7 to 27 after CBT) on the occurrence of HHV-6 reactivation, HHV-6 encephalitis, and acute graft-versus-host disease (aGVHD) in CBT recipients. Between 2014 and 2016, 57 patients were included in a foscarnet-prophylaxis group. Outcomes were compared with an historical control group who received CBT between 2010 and 2014 (standard-treatment group, n = 63). The cumulative incidence of high-level HHV-6 reactivation, defined as plasma HHV-6 DNA ≥ 10⁴ copies/mL, at 60 days after CBT was significantly lower in the foscarnet-prophylaxis group than in the standard-treatment group (18.3% versus 57.3%, P < .001). Multivariate analysis revealed that myeloablative preconditioning and standard treatment were significant risk factors for high-level HHV-6 reactivation. The cumulative incidence of HHV-6 encephalitis at 60 days after CBT was not different between the groups (foscarnet-prophylaxis group, 12.4%; standard-treatment group, 4.9%; P = .14). The cumulative incidences of grades II to IV and grades III to IV aGVHD at 60 days after CBT were not different between the groups (grades II to IV aGVHD: foscarnet-prophylaxis group, 42.0%; standard-treatment group, 40.5%; P = .96; grades III to IV aGVHD: foscarnet-prophylaxis group, 14.5%; standard-treatment group, 14.5%; P = 1.00). In the setting of this study foscarnet significantly suppressed systemic HHV-6 reactivation in CBT recipients but failed to prevent the development of HHV-6 encephalitis. Suppression of HHV-6 reactivation by foscarnet did not show any effects against the incidence of aGVHD.

Analysis of five cases of human herpesvirus-6 myelitis among 121 cord blood transplantations

Reports of myelitis associated with human herpesvirus-6 (HHV-6) following allogeneic transplantation are rare. Of 121 cases of cord blood transplantation (CBT) performed at Nagano Red Cross Hospital, five cases (4.1%) of HHV-6 myelitis developed at around the time of engraftment. The major symptom identified in all five patients was superficial pain or pruritus linked to segmental levels of the spinal cord. Other identified symptoms were fever or low-grade fever in all five patients, autonomic nerve disorder in four patients, bladder and rectal disturbance in two patients, and extrapyramidal disorder in two patients. These symptoms were experienced primarily 16-39 days after CBT. HHV-6 PCR tests were all positive for cerebrospinal fluid and for plasma. Of the four cases tested by magnetic resonance imaging (MRI), three showed spinal cord abnormality. Antiviral therapy using foscarnet or ganciclovir was effective in every case. Although one case treated from 12 days after onset experienced long-term pain resembling postherpetic neuralgia, symptoms in the four cases were completely relieved after antiviral therapy. In summary, the major symptoms of HHV-6 myelitis were superficial pain linked to segmental levels of the spinal cord. Prognosis may be improved by early initiation of antiviral therapy.

Increased interleukin-1β and basic fibroblast growth factor levels in the cerebrospinal fluid during human herpesvirus-6B (HHV-6B) encephalitis

Human herpesvirus 6B (HHV-6B) causes exanthema subitum in infants and is known to be mildly pathogenic. However, HHV-6B infection can induce febrile seizures in a high percentage of patients, and in rare cases, result in encephalitis. We detected higher levels of interleukin (IL)-1β and basic fibroblast growth factor (bFGF) in the cerebrospinal fluid (CFS) of patients with HHV-6B encephalitis when compared to those in patients with non-HHV-6B-induced febrile seizures. In vitro, IL-1β and bFGF enhanced HHV-6B gene expression in infected U373 astrocytes during the initial and maintenance phases of infection, respectively. These findings indicated that IL-1β and bFGF contribute to HHV-6B growth and the onset of encephalitis.

Hippocampal signal abnormality on the first day of illness in acute encephalopathy with biphasic seizures and late reduced diffusion caused by HHV-6 infection

We report a 13-month-old girl who developed acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) with transient reduced diffusion in the hippocampus and anterior commissure on diffusion-weighted imaging (DWI), which was performed on the first day after febrile status epilepticus (FSE) as the initial neurological symptom of AESD. DWI just after late seizures showed high signal intensity lesions in both left hippocampus and anterior commissure, and left extratemporal and occipital subcortical white matter. HHV-6 DNA was positive in both blood and cerebrospinal fluid samples. DWI at two months after onset showed atrophy in the left mesial temporal lobe and extratemporal and occipital lobe without the signal abnormalities. Although it has been reported that magnetic resonance images tend to show no acute abnormality during the first two days in typical AESD, transient reduced diffusion could be found on the DWI performed on the first day of AESD.

Detection frequency of human herpesviruses-6A, -6B, and -7 genomic sequences in central nervous system DNA samples from post-mortem individuals with unspecified encephalopathy

In this autopsy-based study, human herpesvirus-6 (HHV-6) and -7 (HHV-7) genomic sequence frequency, HHV-6 variants, HHV-6 load and the expression of HHV-6 antigens in brain samples from the individuals, with and without unspecified encephalopathy (controls), using nested and real-time polymerase chain reactions, restriction endonuclease, and immunohistochemical analysis were examined. GraphPad Prism 6.0 Mann-Whitney nonparametric and chi-square test and Fisher's exact test were used for statistical analysis. The encephalopathy diagnoses were shown by magnetic resonance imaging made during their lifetime and macro- and microscopically studied autopsy tissue materials. Widespread HHV-6 and/or HHV-7 positivity was detected in the brain tissue of various individuals with encephalopathy, as well as in controls (51/57, 89.4 % and 35/51, 68.6 %, respectively; p = 0.009). Significantly higher detection frequency of single HHV-6 and concurrent HHV-6 + HHV-7 DNA was found in pia mater meninges, frontal lobe, temporal lobe, and olfactory tract DNAs in individuals with encephalopathy compared to the control group. HHV-6 load and higher frequency of the viral load >10 copies/10(6) cells significantly differed in samples from individuals with and without encephalopathy. The expression of HHV-6 antigens was revealed in different neural cell types with strong predominance in the encephalopathy group. In all HHV-6-positive autopsy samples of individuals with and without encephalopathy, HHV-6B was revealed. Significantly higher detection frequency of beta-herpesvirus DNA, more often detected HHV-6 load >10 copies/10(6) cells, as well as the expression of HHV-6 antigens in different brain tissue samples from individuals with encephalopathy in comparison with control group indicate on potential involvement of these viruses in encephalopathy development.

Fulminant hepatic failure attributed to infection with human herpesvirus 6 (HHV-6) in an immunocompetent woman: A case report and review of the literature

Mild disease due to human herpesvirus-6 (HHV-6) has been reported in healthy children. Severe disease due to this virus can occur in immunocompromised patients but is rarely reported in previously healthy adults. We report the case of a previously healthy woman who presented with a skin rash, mild upper respiratory symptoms, and abdominal pain and succumbed to fulminant hepatic failure attributed to infection with HHV-6B. HHV-6 may be more commonly associated with fulminant hepatitis in immunocompetent patients than previously thought and should be considered in the differential diagnosis of patients presenting with skin rash, upper respiratory symptoms, and unexplained hepatitis.

Human herpesvirus-6 infection-associated acute encephalopathy without skin rash

BACKGROUND

Human herpesvirus-6 (HHV-6) is the etiological agent of exanthema subitum-associated encephalopathy, which usually occurs in children younger than 3 years. Brain imaging shows various abnormalities.

PATIENT

A previously healthy 4-year-old girl developed acute encephalopathy with clinical features consisting of fever, repetitive seizures, and a disturbance of consciousness. The patient did not show skin rash suggestive of exanthema subitum during the course of her illness. The primary HHV-6 infection was diagnosed based on the absence of IgG against HHV-6 and identification of the virus DNA in the acute phase serum and a significant increase of the anti-HHV-6 IgG titers in the convalescent phase sera. Diffusion-weighted images showed transient high signal intensity in the bilateral periventricular white matter and splenium of the corpus callosum and in the gray matter structures such as the bilateral basal ganglia and thalami. Upon therapy with steroid and γ-globulin, the patient recovered without any neurological deficits.

CONCLUSION

Primary HHV-6 infection can cause acute encephalopathy without exanthema subitum. The etiological diagnosis is possible only by examining the blood and cerebrospinal fluid, when the patient shows no skin rash. This condition should be included in the differential diagnosis of acute encephalopathy even in patients older than 3 years.

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.

HHV-6-positivity in diseases with demyelination

BACKGROUND

The triggering agent of multiple sclerosis is still unknown and many viruses, including human herpesvirus-6 (HHV-6), are under suspicion. In earlier study we found patients who had HHV-6 reactive OCBs in their CSF. We wanted to investigate whether HHV-6 has an active role in diseases with demyelination.

OBJECTIVE

To analyze the HHV-6-reactive cases in detail and investigate the possible independent role of HHV-6 in the development of central nervous system involvements with demyelination.

STUDY DESIGN

We studied serum and CSF samples that were collected over a period of one year, from all patients who had oligoclonal bands (OCB) in cerebrospinal fluid (CSF) and were examined in the Department of Neurology, University Central Hospital of Helsinki, Finland. Clinical evaluation was accomplished blinded of HHV-6 analysis and follow-up time was two years. All patients underwent MRI of the head and clinically indicated CSF analysis.

RESULTS

The 17 patients with HHV-6-reactive OCBs were significantly younger and had significantly more IgG-OCBs in comparison to patients without HHV-6-reactive OCBs. Initial diagnoses in patients with HHV-6-reactive OCBs remained the same during the follow-up time.

CONCLUSION

Patients with HHV-6-positive OCBs appear to form a separable group. In progressive neurological diseases HHV-6 may have a role in long-term infection with demyelination.

Frequent human herpesvirus-6 viremia but low incidence of encephalitis in double-unit cord blood recipients transplanted without antithymocyte globulin

Cord blood transplantation (CBT) is a known risk factor for human herpesvirus-6 (HHV-6) infection. We analyzed the nature of HHV-6 infections in 125 double-unit CBT recipients (median age, 42 years) transplanted for hematologic malignancies with calcineurin inhibitor/mycophenolate mofetil prophylaxis and no antithymocyte globulin. One hundred seventeen patients (94%) reactivated HHV-6 by quantitative plasma PCR (median peak, 7600 copies/mL; range, 100 to 160,000) at a median of 20 days (range, 10 to 59) after transplantation. HHV-6 encephalitis occurred in 2 patients (1.6%), of whom 1 died and 1 recovered with therapy. No association was found between high-level HHV-6 viremia (≥10,000 or ≥25,000 copies/mL) and age, diagnosis, conditioning intensity, or dominant unit characteristics or between high-level viremia and transplant outcomes (engraftment, cytomegalovirus reactivation, day 100 grades II to IV acute graft-versus-host disease, day 100 transplant-related mortality, or 1-year disease-free survival). HHV-6 therapy delayed the onset of cytomegalovirus reactivation. Interestingly, HHV-6 resolution was observed in untreated patients, and resolution of viremia correlated with absolute lymphocyte count recovery. We observed a low incidence of encephalitis and no association with CBT outcomes. Our data suggest therapy in uncomplicated viremia may not be warranted. However, further investigation of the risk-to-benefit of HHV-6 viremia treatment and standardization of PCR testing is required.

Low prevalence of human herpesvirus-6 and varicella zoster virus in blood of multiple sclerosis patients, irrespective of inflammatory status or disease progression

Herpesviruses, including human herpesvirus-6 and varicella zoster virus, have been implicated in the disease aetiology of multiple sclerosis. These viruses are capable of reactivation, reminiscent of the relapsing-remitting nature of multiple sclerosis. However, viral DNA has also been reported present in healthy controls, often at similar prevalence rates. This study aimed to determine whether prevalence could be associated with different stages of activity of the disease as well as the inflammatory status of the patients. Polymerase chain reaction assays were used to screen for human herpesvirus-6 and varicella zoster virus DNA in blood from 31 Caucasian patients with multiple sclerosis and 30 healthy age, sex and race matched control subjects. The patients were screened for inflammation using C-reactive protein as a marker and were also categorized according to their remitting/relapsing status. Results were positive for human herpesvirus-6 in blood from only one patient (3.2%) and human herpesvirus-6 DNA was not present in any control subjects. Varicella zoster virus was not detected in either the patients or control subjects. Similar to some other studies we saw an absence or very low viral positivity in blood from both patients and controls. These findings were irrespective of relapse episodes, increased inflammatory status or duration of the disease. Results therefore do not support a causative role for either human herpesvirus-6 or varicella zoster virus in the disease aetiology of multiple sclerosis, but rather that prevalence in patients may be linked to that of the general population.

Human herpesvirus-6 DNAemia is a sign of impending primary CMV infection in CMV sero-discordant renal transplantations

BACKGROUND

Human herpesvirus-6 (HHV-6) frequently reactivates in immunocompromized individuals. Most commonly HHV-6 DNA is detected without organ localized disease. This HHV-6 DNAemia usually occurs in patients who also have CMV reactivations. The question if reactivation of one virus causes reactivation of the other, or whether both viruses reactivate independently, cannot be answered in populations with high seroprevalence for both viruses. Our study is the first in which 35 patients have been included who were CMV seronegative prior to transplantation.

OBJECTIVE

We investigated the occurrence of HHV-6 reactivations in relation to the CMV-serostatus of renal transplantation donor and recipient.

STUDY DESIGN

9 consecutive patients receiving a renal transplantation were included. All available stored whole blood samples were tested for HHV-6 DNA by quantitative PCR. Details including CMV serostatus of donor and recipient were recorded.

RESULTS

CMV-seropositive recipients have a 68% chance of developing HHV-6 DNAemia if the kidney came from a CMV-seropositive donor, compared to 26% if the kidney came from a CMV-seronegative donor. CMV-seronegative recipients, who are bound to undergo primary CMV infections following transplantation with a renal graft from a CMV-seropositive donor, have 88% chance of developing HHV-6 DNAemia. If they receive a graft from a CMV-seronegative donor the chance of developing HHV-6 DNAemia is 22%.

CONCLUSION

Receiving a renal transplant from a CMV-seropositive donor increases the chance of developing HHV-6 DNAemia. HHV-6 DNAemia is a sign of impending primary CMV infections following sero-discordant renal transplantations.

Recent progress of elucidating the mechanisms of drug hypersensitivity

Recent technical approaches to investigating drug hypersensitivity have provided a great deal of information to solve the mechanisms that remain poorly understood. First, immunological investigations and in silico analysis have revealed that a novel interaction between T cells and antigen-presenting cells, namely the pharmacological interaction concept, is involved in drug recognition and the hapten theory. Second, progress in immunology has provided a new concept of CD4+ T cell subsets. Th17 cells have proven to be a critical player in acute generalized exanthematous pustulosis. Our recent findings suggest that this subset might contribute to the pathogenesis of Stevens-Johnson syndrome/toxic epidermal necrolysis. Third, alarmins, molecules associated with innate immunity, are also associated with exaggeration and the persistence of severe drug hypersensitivity. The latest innovative techniques are providing a new landscape to examine drug hypersensitivity.