Herpes simplex virus 1 (HSV-1) encephalitis (HSE) is the most common sporadic viral encephalitis in Western countries. Over the last 15 years, human genetic and immunological studies have provided ...proof-of-principle that childhood HSE can result from inborn errors of central nervous system (CNS)-specific, cell-intrinsic immunity to HSV-1. HSE-causing mutations of eight genes disrupt known (TLR3-dependent IFN-α/β immunity) and novel (dependent on DBR1 or snoRNA31) antiviral mechanisms. Monogenic inborn errors confer susceptibility to forebrain (TLR3-IFN or snoRNA31) or brainstem (DBR1) HSE. Most of these disorders display incomplete clinical penetrance, with the possible exception of DBR1 deficiency. They account for a small, but non-negligible proportion of cases (about 7%). These findings pave the way for the gradual definition of the genetic and immunological architecture of childhood HSE, with both biological and clinical implications.
OBJECTIVE:To report 14 patients with immune-mediated relapsing symptoms post–herpes simplex encephalitis (HSE) and to compare the clinical and immunologic features of the teenage and adult group with ...those of young children.
METHODS:Prospective observational study of patients diagnosed between June 2013 and February 2015. Immunologic techniques have been reported previously.
RESULTS:Among the teenage and adult group (8 patients, median age 40 years, range 13–69; 5 male), 3 had an acute symptom presentation suggesting a viral relapse, and 5 a presentation contiguous with HSE suggesting a recrudescence of previous deficits. Seven patients developed severe psychiatric/behavioral symptoms disrupting all social interactions, and one refractory status epilepticus. Blepharospasm occurred in one patient. Five patients had CSF antibodies against NMDA receptor (NMDAR) and 3 against unknown neuronal cell surface proteins. In 5/6 patients, the brain MRI showed new areas of contrast enhancement that decreased after immunotherapy and clinical improvement. Immunotherapy was useful in 7/7 patients, sometimes with impressive recoveries, returning to their baseline HSE residual deficits. Compared with the 6 younger children (median age 13 months, range 6–20, all with NMDAR antibodies), the teenagers and adults were less likely to develop choreoathetosis (0/8 vs 6/6, p < 0.01) and decreased level of consciousness (2/8 vs 6/6, p < 0.01) and had longer delays in diagnosis and treatment (interval relapse/antibody testing 85 days, range 17–296, vs 4 days, range 0–33, p = 0.037).
CONCLUSION:In teenagers and adults, the immune-mediated relapsing syndrome post-HSE is different from that known in young children as choreoathetosis post-HSE and is underrecognized. Prompt diagnosis is important because immunotherapy can be highly effective.
Herpes simplex virus type 1 (HSV-1) commonly causes orolabial ulcers, while HSV-2 commonly causes genital ulcers. However, HSV-1 is an increasing cause of genital infection. Previously, the World ...Health Organization estimated the global burden of HSV-2 for 2003 and for 2012. The global burden of HSV-1 has not been estimated.
We fitted a constant-incidence model to pooled HSV-1 prevalence data from literature searches for 6 World Health Organization regions and used 2012 population data to derive global numbers of 0-49-year-olds with prevalent and incident HSV-1 infection. To estimate genital HSV-1, we applied values for the proportion of incident infections that are genital.
We estimated that 3709 million people (range: 3440-3878 million) aged 0-49 years had prevalent HSV-1 infection in 2012 (67%), with highest prevalence in Africa, South-East Asia and Western Pacific. Assuming 50% of incident infections among 15-49-year-olds are genital, an estimated 140 million (range: 67-212 million) people had prevalent genital HSV-1 infection, most of which occurred in the Americas, Europe and Western Pacific.
The global burden of HSV-1 infection is huge. Genital HSV-1 burden can be substantial but varies widely by region. Future control efforts, including development of HSV vaccines, should consider the epidemiology of HSV-1 in addition to HSV-2, and especially the relative contribution of HSV-1 to genital infection.
Herpes simplex encephalitis can trigger autoimmune encephalitis that leads to neurological worsening. We aimed to assess the frequency, symptoms, risk factors, and outcomes of this complication.
We ...did a prospective observational study and retrospective analysis. In the prospective observational part of this study, we included patients with herpes simplex encephalitis diagnosed by neurologists, paediatricians, or infectious disease specialists in 19 secondary and tertiary Spanish centres (Cohort A). Outpatient follow-up was at 2, 6, and 12 months from onset of herpes simplex encephalitis. We studied another group of patients retrospectively, when they developed autoimmune encephalitis after herpes simplex encephalitis (Cohort B). We compared demographics and clinical features of patients who developed autoimmune encephalitis with those who did not, and in patients who developed autoimmune encephalitis we compared these features by age group (patients ≤4 years compared with patients >4 years). We also used multivariable binary logistic regression models to assess risk factors for autoimmune encephalitis after herpes simplex encephalitis.
Between Jan 1, 2014, and Oct 31, 2017, 54 patients with herpes simplex encephalitis were recruited to Cohort A, and 51 were included in the analysis (median age 50 years IQR 5–68). At onset of herpes simplex encephalitis, none of the 51 patients had antibodies to neuronal antigens; during follow-up, 14 (27%) patients developed autoimmune encephalitis and all 14 (100%) had neuronal antibodies (nine 64% had NMDA receptor NMDAR antibodies and five 36% had other antibodies) at or before onset of symptoms. The other 37 patients did not develop autoimmune encephalitis, although 11 (30%) developed antibodies (n=3 to NMDAR, n=8 to unknown antigens; p<0·001). Antibody detection within 3 weeks of herpes simplex encephalitis was a risk factor for autoimmune encephalitis (odds ratio OR 11·5, 95% CI 2·7–48·8; p<0·001). Between Oct 7, 2011, and Oct 31, 2017, there were 48 patients in Cohort B with new-onset or worsening neurological symptoms not caused by herpes simplex virus reactivation (median age 8·8 years IQR 1·1–44·2; n=27 male); 44 (92%) patients had antibody-confirmed autoimmune encephalitis (34 had NMDAR antibodies and ten had other antibodies). In both cohorts (n=58 patients with antibody-confirmed autoimmune encephalitis), patients older than 4 years frequently presented with psychosis (18 58% of 31; younger children not assessable). Compared with patients older than 4 years, patients aged 4 years or younger (n=27) were more likely to have shorter intervals between onset of herpes simplex encephalitis and onset of autoimmune encephalitis (median 26 days IQR 24–32 vs 43 days 25–54; p=0·0073), choreoathetosis (27 100% of 27 vs 0 of 31; p<0·001), decreased level of consciousness (26 96% of 27 vs seven 23% of 31; p<0·001), NMDAR antibodies (24 89% of 27 vs 19 61% of 31; p=0·033), and worse outcome at 1 year (median modified Rankin Scale 4 IQR 4–4 vs 2 2–3; p<0·0010; seizures 12 63% of 19 vs three 13% of 23; p=0·001).
The results of our prospective study show that autoimmune encephalitis occurred in 27% of patients with herpes simplex encephalitis. It was associated with development of neuronal antibodies and usually presented within 2 months after treatment of herpes simplex encephalitis; the symptoms were age-dependent, and the neurological outcome was worse in young children. Prompt diagnosis is important because patients, primarily those older than 4 years, can respond to immunotherapy.
Mutua Madrileña Foundation, Fondation de l'Université de Lausanne et Centre Hospitalier Universitaire Vaudois, Instituto Carlos III, CIBERER, National Institutes of Health, Generalitat de Catalunya, Fundació CELLEX.
Summary Objectives We aimed to investigate the incidence and mortality of herpes simplex encephalitis (HSE) in a nationwide cohort. Methods From the Danish National Patient Registry, we identified ...all adults hospitalised with a first-time diagnosis of HSE in Denmark during 2004–2014. The HSE diagnoses were verified using medical records and microbiological data. Patients were followed for mortality through the Danish Civil Registry System. We estimated age-standardised incidence rates of HSE and 30-day, 60-day, and 1-year cumulative mortality. Furthermore, we assessed whether calendar year, age, gender, level of comorbidity, virus type, and department type was associated with HSE mortality. Results We identified a total of 230 cases of HSE. Median age was 60.7 years (interquartile range: 49.3–71.6). The overall incidence rate was 4.64 cases per million population per year (95% confidence interval: 4.06–5.28). The cumulative mortality within 30 days, 60 days, and 1 year of the HSE admission was 8.3%, 11.3%, and 18.6%, respectively. Advanced age and presence of comorbidity were associated with increased 60-day and 1-year mortality. Conclusions This nationwide study of verified HSE found a higher incidence than reported in previous nationwide studies. Presence of comorbidity was identified as a novel adverse prognostic factor. Mortality rates following HSE remain high.
Herpes simplex virus-1 (HSV-1) encephalitis (HSE) is typically sporadic. Inborn errors of TLR3- and DBR1-mediated central nervous system cell-intrinsic immunity can account for forebrain and ...brainstem HSE, respectively. We report five unrelated patients with forebrain HSE, each heterozygous for one of four rare variants of SNORA31, encoding a small nucleolar RNA of the H/ACA class that are predicted to direct the isomerization of uridine residues to pseudouridine in small nuclear RNA and ribosomal RNA. We show that CRISPR/Cas9-introduced bi- and monoallelic SNORA31 deletions render human pluripotent stem cell (hPSC)-derived cortical neurons susceptible to HSV-1. Accordingly, SNORA31-mutated patient hPSC-derived cortical neurons are susceptible to HSV-1, like those from TLR3- or STAT1-deficient patients. Exogenous interferon (IFN)-β renders SNORA31- and TLR3- but not STAT1-mutated neurons resistant to HSV-1. Finally, transcriptome analysis of SNORA31-mutated neurons revealed normal responses to TLR3 and IFN-α/β stimulation but abnormal responses to HSV-1. Human SNORA31 thus controls central nervous system neuron-intrinsic immunity to HSV-1 by a distinctive mechanism.
Summary
Herpes simplex virus (HSV) can cause oral or genital ulcerative lesions and even encephalitis in various age groups with high infection rates. More seriously, HSV may lead to a wide range of ...recurrent diseases throughout a lifetime. No vaccines against HSV are currently available. The accumulated clinical research data for HSV vaccines reveal that the effects of HSV interacting with the host, especially the host immune system, may be important for the development of HSV vaccines. HSV vaccine development remains a major challenge. Thus, we focus on the research data regarding the interactions of HSV and host immune cells, including dendritic cells (DCs), innate lymphoid cells (ILCs), macrophages, and natural killer (NK) cells, and the related signal transduction pathways involved in immune evasion and cytokine production. The aim is to explore possible strategies to develop new effective HSV vaccines.
In the course of primary infection with herpes simplex virus 1 (HSV-1), children with inborn errors of toll-like receptor 3 (TLR3) immunity are prone to HSV-1 encephalitis (HSE). We tested the ...hypothesis that the pathogenesis of HSE involves non-haematopoietic CNS-resident cells. We derived induced pluripotent stem cells (iPSCs) from the dermal fibroblasts of TLR3- and UNC-93B-deficient patients and from controls. These iPSCs were differentiated into highly purified populations of neural stem cells (NSCs), neurons, astrocytes and oligodendrocytes. The induction of interferon-β (IFN-β) and/or IFN-λ1 in response to stimulation by the dsRNA analogue polyinosinic:polycytidylic acid (poly(I:C)) was dependent on TLR3 and UNC-93B in all cells tested. However, the induction of IFN-β and IFN-λ1 in response to HSV-1 infection was impaired selectively in UNC-93B-deficient neurons and oligodendrocytes. These cells were also much more susceptible to HSV-1 infection than control cells, whereas UNC-93B-deficient NSCs and astrocytes were not. TLR3-deficient neurons were also found to be susceptible to HSV-1 infection. The rescue of UNC-93B- and TLR3-deficient cells with the corresponding wild-type allele showed that the genetic defect was the cause of the poly(I:C) and HSV-1 phenotypes. The viral infection phenotype was rescued further by treatment with exogenous IFN-α or IFN-β ( IFN-α/β) but not IFN-λ1. Thus, impaired TLR3- and UNC-93B-dependent IFN-α/β intrinsic immunity to HSV-1 in the CNS, in neurons and oligodendrocytes in particular, may underlie the pathogenesis of HSE in children with TLR3-pathway deficiencies.
IMPORTANCE: Approximately 1 in 5 adults in the US had a sexually transmitted infection (STI) in 2018. This review provides an update on the epidemiology, diagnosis, and treatment of gonorrhea, ...chlamydia, syphilis, Mycoplasma genitalium, trichomoniasis, and genital herpes. OBSERVATIONS: From 2015 to 2019, the rates of gonorrhea, chlamydia, and syphilis increased in the US; from 1999 to 2016, while the rates of herpes simplex virus type 1 (HSV-1) and HSV-2 declined. Populations with higher rates of STIs include people younger than 25 years, sexual and gender minorities such as men and transgender women who have sex with men, and racial and ethnic minorities such as Black and Latinx people. Approximately 70% of infections with HSV and trichomoniasis and 53% to 100% of extragenital gonorrhea and chlamydia infections are asymptomatic or associated with few symptoms. STIs are associated with HIV acquisition and transmission and are the leading cause of tubal factor infertility in women. Nucleic acid amplification tests have high sensitivities (86.1%-100%) and specificities (97.1%-100%) for the diagnosis of gonorrhea, chlamydia, M genitalium, trichomoniasis, and symptomatic HSV-1 and HSV-2. Serology remains the recommended method to diagnose syphilis, typically using sequential testing to detect treponemal and nontreponemal (antiphospholipid) antibodies. Ceftriaxone, doxycycline, penicillin, moxifloxacin, and the nitroimidazoles, such as metronidazole, are effective treatments for gonorrhea, chlamydia, syphilis, M genitalium, and trichomoniasis, respectively, but antimicrobial resistance limits oral treatment options for gonorrhea and M genitalium. No cure is available for genital herpes. Effective STI prevention interventions include screening, contact tracing of sexual partners, and promoting effective barrier contraception. CONCLUSIONS AND RELEVANCE: Approximately 1 in 5 adults in the US had an STI in 2018. Rates of gonorrhea, chlamydia, and syphilis in the US have increased, while rates of HSV-1 and HSV-2 have declined. Ceftriaxone, doxycycline, penicillin, moxifloxacin, and the nitroimidazoles are effective treatments for gonorrhea, chlamydia, syphilis, Mycoplasma genitalium, and trichomoniasis, respectively, but antimicrobial resistance limits oral therapies for gonorrhea and Mycoplasma genitalium, and no cure is available for genital herpes.
Infections are a major threat to human reproductive health, and infections in pregnancy can cause prematurity or stillbirth, or can be vertically transmitted to the fetus leading to congenital ...infection and severe disease. The acronym 'TORCH' (Toxoplasma gondii, other, rubella virus, cytomegalovirus, herpes simplex virus) refers to pathogens directly associated with the development of congenital disease and includes diverse bacteria, viruses and parasites. The placenta restricts vertical transmission during pregnancy and has evolved robust mechanisms of microbial defence. However, microorganisms that cause congenital disease have likely evolved diverse mechanisms to bypass these defences. In this Review, we discuss how TORCH pathogens access the intra-amniotic space and overcome the placental defences that protect against microbial vertical transmission.
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