The cytokine and chemokine profiles in patients with hand, foot and mouth disease of different severities in Shanghai, China, 2010

Enterovirus A71 infection-induced dry eye-like symptoms by damaging the lacrimal glands

Purpose

To determine the effects of EV-A71 (Enterovirus A71) infection on ocular surface and its mechanism.

Methods

AG6 mice aged two to three weeks were randomly divided into control and EV-A71 infected groups. Slit-lamp observation, fluorescein staining, and phenol red thread test were used to assess symptoms of ocular surface at 4 dpi (days post infection). The pathological changes of cornea and lacrimal gland were observed by H&E staining, PAS staining, TUNEL assay, IHC staining and qRT-PCR. Corneas and lacrimal glands from mice were obtained and processed for RNA sequencing analysis. Newly diagnosed HFMD patients caused by EV-A71 were recruited and ensured they met the inclusion criteria. Ocular surface parameters (TMH and NIKBUT) were measured using the OCULUS Keratograph 5M. Tear samples were taken to examine Cxcl1 and IL-6 levels through the ELISA method.

Results

Mice studies revealed that EV-A71 infection caused tear film instability, decreased tear secretions, decreased in lacrimal gland size, and distinct goblet cell loss. It also resulted in increased large vacuoles within acinar cells and structural damage in lacrimal gland. Apart from minor damage to the epidermis, there was no obvious inflammatory changes or apoptosis in the cornea. However, there were significant inflammatory injury and apoptosis in the lacrimal gland. RNA-seq analysis showed IL-17 and NF-κB signaling pathways were activated in the lacrimal glands of mice infected with EV-A71. In HFMD patients, the THM was in a low range and NITBUT was significantly shorter than the control group by Oculus Keratograph 5M. ELISA assay showed a higher tear Cxcl1 and IL-6 level in them.

Conclusion

EV-A71 infection affected lacrimal gland structure and function and induced dry eye-like symptoms.

Analysis of miRNAs Involved in Mouse Heart Injury Upon Coxsackievirus A2 Infection

Coxsackievirus A2 (CVA2) has recently been constantly detected, and is associated with viral myocarditis in children. Our previous study demonstrated that CVA2 led to heart damage in a neonatal murine model. However, the molecular mechanism of heart injury caused by CVA2 remains largely unknown. Emerging evidence suggests the significant functions of miRNAs in Coxsackievirus infection. To investigate potential miRNAs involved in heart injury caused by CVA2, our study, for the first time, conducted a RNA-seq in vivo employing infected mice hearts. In total, 87, 101 and 76 differentially expressed miRNAs were identified at 3 days post infection (dpi), 7 dpi and 7 dpi vs 3 dpi. Importantly, above 3 comparison strategies shared 34 differentially expressed miRNAs. These results were confirmed by quantitative PCR (qPCR). Next, we did GO, KEGG, and miRNA-mRNA integrated analysis of differential miRNAs. The dual-luciferase reporter assay confirmed the miRNA-mRNA pairs. To further confirm the above enriched pathways and processes, we did Western blotting and immunofluorescence staining. Our results suggest that inflammatory responses, T cell activation, apoptosis, autophagy, antiviral immunity, NK cell infiltration, and the disruption of tight junctions are involved in the pathogenesis of heart injury caused by CVA2. The dysregulated miRNAs and pathways recognized in the current study can improve the understanding of the intricate interactions between CVA2 and the heart injury, opening a novel avenue for the future study of CVA2 pathogenesis.

Translocating lipopolysaccharide correlates with the severity of enterovirus A71-induced HFMD by promoting pro-inflammation and viral IRES activity

Background

The increase of inflammation-inducing enterobacteria was recently observed in severe hand, foot, and mouth disease (HFMD) caused by Enterovirus A71 (EV-A71). This study aimed to verify the occurrence of bacterial translocation (BT) and further explore the contributory role of BT to severity of EV-A71-mediated HFMD cases.

Methods

Serum specimens from 65 mild and 65 severe EV-A71-associated HFMD cases and 65 healthy children were collected. EV-A71 VP1 in serum, inflammatory mediators including C-reactive protein, IL-1β, IL-6, interferon-γ and tumor necrosis factor-α, BT related biomarkers including Claudin-3, intestinal fatty acid binding protein, lipopolysaccharide (LPS), soluble CD14 (sCD14) and endotoxin core antibody were measured by ELISA. Bacterial DNA (BactDNA) fragments were quantified by quantified PCR (qPCR). Rhabdomyosarcoma (RD) or SH-SY5Y cells, infected with LPS-pre-incubated EV-A71 or transfected with plasmid containing viral 2A^pro or mRNA containing viral internal ribosomal entry site (IRES), were post-treated with or without LPS in vitro. EV-A71 RNA and viral or cellular proteins were determined by qPCR and western blot, respectively.

Results

Compared to mild HFMD patients, remarkably higher inflammatory mediators as well as BT-related biomarkers except BactDNA were observed in severe HFMD cases (all P < 0.05). In severe HFMD group, circulating concentrations of LPS and sCD14 showed statistical correlations with inflammation indices (all P < 0.05), serum levels of EV-A71 VP1 were found to be positively correlated with serum LPS (r = 0.341, P = 0.005) and serum sCD14 (r = 0.458, P < 0.001). In vitro, EV-A71 attachment and internalization were only slightly promoted by LPS pre-incubation; however, EV-A71 proliferation and viral 2A^pro-mediated IRES activity were significantly accelerated by LPS post-treatment.

Conclusions

Our results collectively indicate that gut-derived translocating LPS contributes to the severity of EV-A71-induced HFMD by driving inflammatory response and viral proliferation via viral 2A^pro-mediated IRES.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13099-021-00465-x.

Response of Severe EV71-Infected Patients to Hyperimmune Plasma Treatment: A Pilot Study

Hand, foot, and mouth disease (HFMD) is highly prevalent in East and Southeast Asia. It particularly affects children under five years of age. The most common causative agents are coxsackieviruses A6 and A16, and enterovirus A71 (EV71). The clinical presentation is usually mild and self-limited, but, in some cases, severe and fatal complications develop. To date, no specific therapy or worldwide vaccine is available. In general, viral infection invokes both antibody and cell-mediated immune responses. Passive immunity transfer can ameliorate the severe symptoms of diseases such as COVID-19, influenza, MERS, and SARS. Hyperimmune plasma (HIP) from healthy donors with high anti-EV71 neutralizing titer were used to transfuse confirmed EV71-infected children with neurological involvement (n = 6). It resulted in recovery within three days, with no neurological sequelae apparent upon examination 14 days later. Following HIP treatment, plasma chemokines were decreased, whereas anti-inflammatory and pro-inflammatory cytokines gradually increased. Interestingly, IL-6 and G-CSF levels in cerebrospinal fluid declined sharply within three days. These findings indicate that HIP has therapeutic potential for HFMD with neurological complications. However, given the small number of patients who have been treated, a larger cohort study should be undertaken. Successful outcomes would stimulate the development of anti-EV71 monoclonal antibody therapy.

Effect of Emodin on Coxsackievirus B3m-Mediated Encephalitis in Hand, Foot, and Mouth Disease by Inhibiting Toll-Like Receptor 3 Pathway In Vitro and In Vivo

BACKGROUND

Encephalitis in hand, foot, and mouth disease (HFMD) is a serious threat to children's health and life. Toll-like receptor 3 (TLR3) is an innate immune-recognition receptor that can recognize virus and initiate innate immune responses. Emodin has the effects of anti-inflammatory and regulating immune function, but the mechanism is not very clear.

METHODS

Cells and mice were pretreated with coxsackievirus B3m (CVB3) and treated with emodin. The messenger ribonucleic acid (mRNA) and protein levels of TLR3 and downstream molecules were detected by quantitative real-time polymearse chain reaction and western blotting analysis, respectively. TLR3 expression was also downregulated by anti-TLR3 antibody (TLR3Ab) or small interfering RNA (siRNA). Pathological changes were assessed with hematoxylin and eosin staining. Immunohistochemistry was used to examine the expression of TLR3 in brain tissues. The expression of interleukin (IL)-6, nuclear factor (NF)-κB, and interferon (IFN)-β in serum were tested with enzyme-linked immunosorbent assay.

RESULTS

Emodin decreased the mRNA and protein levels of TLR3 and downstream molecules in vitro and in vivo. After downregulating TLR3 using anti-TLR3Ab or siRNA, emodin could still decrease the mRNA and protein levels of TLR3 and downstream molecules. Emodin also displayed notable effects on pathology, TLR3 protein in brain tissues, and expression of IL-6, NF-κB, IFN-β, in serum.

CONCLUSIONS

Emodin exerts a protective effect in CVB3-mediated encephalitis in HFMD by inhibiting the TLR3 pathway.

Host Immune Response to Enterovirus and Parechovirus Systemic Infections in Children

Background

Enterovirus (EV) and parechovirus type A3 (PeV-A3) cause infections ranging from asymptomatic to life-threatening. Host immune responses in children, particularly innate responses to PeV-A3, remain largely unknown. The aim of this study was to determine aspects of the cytokine/chemokine responses to EV and PeV-A3 in cerebrospinal fluid (CSF) and plasma obtained from children with systemic/central nervous system infection.

Methods

A total of 74 salvaged CSF samples (27 with EV, 23 with PeV-A3, and 24 with neither EV nor PeV-A3) and 35 paired blood samples (10 with EV, 14 with PeV-A3, and 11 with neither) were studied. Concentrations of cytokines and chemokines were measured using a customized 21-plex MILLIPLEX MAP Human Cytokine/Chemokine Magnetic Bead Panel. Additionally, clinical characteristics data for all the patients were collected from electronic medical records to evaluate the potential association between the immune response and presentations.

Results

We demonstrate that EV and PeV-A3 infections induce different cytokine/chemokine immune responses in children. EV induces more robust responses in CSF with significantly elevated levels of fractalkine, interferon (IFN)-α2, IFN-γ, interleukin (IL)-1Rα, IL-4, IL-8, and tumor necrosis factor α; PeV-A3 induces less robust or absent responses in CSF but robust responses in plasma, with significantly higher concentrations of IFN-α2, IL-15, IL-1Rα, interferon-γ-inducible protein–10, and monocyte chemoattractant protein–1.

Conclusions

High cytokine/chemokine concentrations in the plasma of PeV-A3 patients compared with EV patients could explain higher/more prolonged fever in PeV-A3 patients, whereas relatively low cytokine/chemokine concentrations in PeV-A3 CSF might explain the absence of CSF pleocytosis.

A neonatal murine model of coxsackievirus A4 infection for evaluation of vaccines and antiviral drugs

Coxsackievirus A4 (CVA4) infection can cause hand, foot and mouth disease (HFMD), an epidemic illness affecting neonatal and paediatric cohorts, which can develop to severe neurological disease with high mortality. In this study, we established the first ICR mouse model of CVA4 infection for the evaluation of inactivated vaccines and antiviral drug screening. The CVA4 YT226R strain was selected to infect the neonatal mice and three infectious factors were optimized to establish the infection model. The 3-day-old neonatal mice exhibited clinical symptoms such as hind limb paralysis and death. The severe inflammatory reactions were closely related to the abnormal expression of the acute phase response proinflammatory cytokine IL-6 and an imbalance in the IFN-γ/IL-4 ratio. Importantly, the inactivated CVA4 whole-virus vaccine induced humoral immune responses in adult females and the maternal antibodies afforded mice complete protection against lethal dose challenges of homologous or heterologous CVA4 strains. Both IFN-α2a and antiserum inhibited the replication of CVA4 and increased the survival rates of neonatal mice during the early stages of infection. This neonatal murine model of CVA4 infection will be useful for the development of prophylactic and therapeutic vaccines and for screening of antiviral drugs targeting CVA4 to decrease morbidity and mortality.

Prevalence and Management of Severe Hand, Foot, and Mouth Disease in Xiangyang, China, From 2008 to 2013

Therapeutic strategies for severe hand, foot, and mouth disease (HFMD) are currently either inconsequent or deficient in evidence. We retrospectively surveyed HFMD outbreaks in Xiangyang from June 2008 to December 2013. HFMD is staged from I to V according to clinical severity. Severe HFMD is defined as a case involving the central nervous system (CNS). We analyzed risk factors for fatality of severe cases and compared the efficiency and outcome of some therapies by binary logistic regression. The overall HFMD cases included 637 (1.26%) severe cases and 38 fatalities (0.075%). Analyses indicate that age (<3 years), enterovirus 71 (+), autonomic nervous system dysregulation, pulmonary edema/hemorrhage, C-reactive protein (CRP) (>40 mg/L), and cardiac troponin I (>0.04 ng/ml) are risk factors for fatality (all P < 0.05). Intravenous immunoglobulin (IVIG) and mechanical ventilation applied only in early stage IV significantly improved HFMD progression (both P < 0.05) with odds ratios of 0.24 (95% CI: 0.10-0.57) and 0.01 (95% CI: 0.00-0.10), respectively. Neither methylprednisolone nor milrinone administered in any stage made any significant difference on mortality (all P > 0.05). Precise recognition of the severe HFMD cases in early stage IV and prompt IVIG and mechanical ventilation application may reduce mortality. Mechanical ventilation training programs and dispatch of specialists to hospitals where there is no chance of transferring critical cases to the severe HFMD designated hospitals are two key measures to reduce fatality.

Global Gene Expression Analysis of the Brainstem in EV71- and CVA16-Infected Gerbils

Enterovirus 71 (EV71) and coxsackievirus A16 (CVA16) are the two most important pathogens of hand, foot, and mouth disease (HFMD). However, the neuropathogenesis of EV71 and CVA16 has not been elucidated. In our previous study, we established gerbils as a useful model for both EV71 and CVA16 infection. In this work, we used RNA-seq technology to analyze the global gene expression of the brainstem of EV71- and CVA16-infected gerbils. We found that 3434 genes were upregulated while 916 genes were downregulated in EV71-infected gerbils. In CVA16-infected gerbils, 1039 genes were upregulated, and 299 genes were downregulated. We also found significant dysregulation of cytokines, such as IP-10 and CXCL9, in the brainstem of gerbils. The expression levels of 10 of the most upregulated genes were confirmed by real-time RT-PCR, and the upregulated tendency of most genes was in accordance with the differential gene expression (DGE) results. Our work provided global gene expression analysis of virus-infected gerbils and laid a solid foundation for elucidating the neuropathogenesis mechanisms of EV71 and CVA16.

Characterization of inflammatory cytokine profiles in cerebrospinal fluid of hand, foot, and mouth disease children with enterovirus 71-related encephalitis in Hangzhou, Zhejiang, China

Enterovirus 71 (EV71) is an important etiological agent of hand, foot, and mouth disease (HFMD), which can also lead to severe neurological complications (eg, encephalitis) in young children. Although a series of reports on EV71 infection have been published, the pathogenic mechanism of EV71 infection is still not fully understood.We evaluated the cerebrospinal fluid (CSF) levels of the inflammatory cytokines interleukin (IL)-8, IL-1β, IL-6, IL-10, tumor necrosis factor (TNF)-α, and IL-12p70 in 88 children with EV71-related encephalitis and 19 children with febrile convulsion (FC) with the use of commercial cytometric bead array kits.The levels of IL-8, IL-1β, IL-6, and IL-10 in CSF were significantly higher in encephalitis group when compared with those observed in FC group, while no significant changes were noted in the levels of TNF-α and IL-12p70. In addition, significant and positive correlations among CSF IL-8, IL-1β, IL-6, and IL-10 were observed in encephalitis group. Furthermore, receiver operator characteristic analysis determined a cut-off value of 10.62 pg/mL for IL-6 to discriminate encephalitis patients from FCs with the sensitivity and specificity of 89.8% and 84.2%, respectively. Moreover, logistic regression analyses revealed that IL-6 was an independent predictor of EV71-related encephalitis (odds ratio = 23.241, P < .001).Our results indicate that 4 inflammatory cytokines (IL-8, IL-1β, IL-6, and IL-10) play important roles in the pathogenesis of EV71 infection. IL-6 may be used for the evaluation of EV71-related encephalitis and as a potential therapy candidate for EV71 infection.

Incidence, aetiology, and serotype spectrum analysis of adult hand, foot, and mouth disease patients: A retrospective observational cohort study in northern Zhejiang, China

BACKGROUND

Hand, foot, and mouth disease (HFMD) in adults has rarely been reported in the literature, although its clinical significance is underestimated. This study was performed to systematically elucidate the epidemiological characteristics of adult HFMD.

METHODS

A total of 266 adult patients with HFMD were recruited. The control group comprised 40 healthy adults. Swabs and serum samples were collected. Enterovirus strains were tested by RT-PCR, and cytokine expression was examined using commercial kits. Socio-demographic data were collected through follow-up telephone calls. Daily meteorological data were obtained from the China Meteorological Data Sharing Service System. Socio-economic data were collected from the statistical bureau.

RESULTS

This study identified several unique spatiotemporal patterns in adult HFMD. Having a child recently diagnosed with HFMD was a risk factor for HFMD, whereas keeping pets was a protective factor against HFMD. The results of this study indicate the existence of subclinical carriers or misdiagnosed patients who might be the latent infectious source of HFMD. Further, this study also indicated that adults may act as the main infectious source of trans-regional spread of HFMD.

CONCLUSIONS

This study revealed the potential hazards of adult HFMD and is a reminder of the vital clinical significance of further research into adult HFMD.

Clinical characteristics and managements of severe hand, foot and mouth disease caused by enterovirus A71 and coxsackievirus A16 in Shanghai, China

Background

Hand, foot and mouth disease (HFMD) is a transmissible infectious disease caused by human enteroviruses (EV). Here, we described features of children with severe HFMD caused by EV-A71 or coxsackievirus A16 (CV-A16) in Shanghai, China.

Methods

Severe EV-A71 or CV-A16 caused HFMD children admitted to the Xinhua Hospital from January 2014 and December 2016, were recruited retrospectively to the study. Symptoms and findings at the time of hospitalization, laboratory tests, treatments, length of stay and residual findings at discharge were systematically recorded and analyzed.

Results

Of 19,995 children visited clinic service with probable HFMD, 574 children (2.87%) were admitted, 234 children (40.76%) were confirmed with EV-A71 (90/574) or CV-A16 (144/574) disease. Most (91.02%) of the patients were under 5 years. Initial clinical symptoms of EV-A71 and CV-A16 cases were: fever > 39 °C in 81 (90%) and 119 (82.63%), vomiting in 31 (34.44%) and 28 (19.44%), myoclonic twitching in 19 (21.11%) and 11(7.64%), startle in 21 (23.33%) and 20 (13.69%), respectively. Serum levels of interleukin-1β (IL-1β), IL-2, IL-6, IL-8, interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α) were significantly upregulated in severe HFMD subjects. Forty-seven children (20.08%) treated with intravenous gamma globulin (IVIG) showed decreased duration of illness episodes. All children were discharged without complications.

Conclusions

EV-A71 and CV-A16 accounted 40.76% of admitted HFMD during 2014 to 2016 in Xinhua Hospital. IVIG appeared to be beneficial in shortening the duration of illness episodes of severe HFMD.

Association of IL-13, S100B, and TLR-7 Gene Polymorphisms with Enterovirus 71 Infection in Hand, Foot, and Mouth Disease in China

AIM

This study was conducted to determine if single nucleotide polymorphisms within the interleukin (IL)-13 (rs20541 locus), the S100B (rs9722 locus), and the toll-like receptor (TLR)-7 (rs179019 and rs3853839 loci) genes are associated with the clinical severity of disease caused by enterovirus 71 (EV71) in children suffering from hand, foot, and mouth disease (HFMD).

MATERIALS AND METHODS

A total of 355 children, diagnosed with HFMD, were divided into two groups: severe (totaling 162 cases) and mild (totaling 193 cases). Three hundred healthy children were recruited as a control group. The gene polymorphisms of the rs20541 locus in the IL-13 gene; the rs9722 locus in the S100B gene; and the rs179019 and the rs3853839 loci in the TLR-7 gene were analyzed with Sanger sequencing. The expression levels of IL-13, S100B, interferon (IFN)-α, IL-6 and the relative expression level of TLR-7 were calculated for each genotype.

RESULTS

This study demonstrated that the T allele at the rs9722 locus of the S100B gene was a significant risk factor for severe HFMD. The rs3853839 C allele of the TLR-7 gene was also a risk factor for severe HFMD in both male and female patients. The G allele at the rs20541 locus of IL-13 gene and the A allele at the rs179019 locus of the TLR-7 gene were not risk factors for severe HFMD in either male or female patients.

CONCLUSION

The T allele at the rs9722 locus of S100B gene is a risk factor for the severe HFMD caused by EV71 infection, of which the mechanism may be due to the promotion of S100B protein secretion. The allele C at TLR-7 rs3853839 locus is a risk factor for the severe HFMD caused by EV71 infection, which may be related to a reduction of the relative expression of TLR-7, IFN-α, and IL-6.

Inflammatory profiles revealed the dysregulation of cytokines in adult patients of HFMD

BACKGROUND

Adult patients of HFMD might act as potential enterovirus reservoirs. As enterovirus infection will cause acute inflammatory response, identifying the association between the dysregulation of cytokines and the development and prognosis of HFMD in adult patients has vital clinical significance.

METHODS

60 patients from 266 laboratory-confirmed adult HFMD cases were included in this study, with 40 healthy adult subjects serving as the controls. Social-demographic data were collected through follow-up phone calls. Serum samples were collected from the participants. Enterovirus genotype was tested by RT-PCR, and the expression of cytokines were examined according to the manufacturer's instructions. Cases were classified using the cytokine profiles with machine learning algorithm.

RESULTS

Adult patients of HFMD presented with dysregulation of cytokines. 15 cytokines of adult patients were significantly elevated and 11 cytokines were decreased compared with those of controls. Correlation analysis showed some cytokines have positive correlation with the clinical characteristics and others have negative correlation. All of the enteroviral genotype presented cytokine dysregulation, and five cytokines were significantly different between genotypes. Using a random forest algorithm, we could classify the cytokine profiles into HFMD class and control class with a very high accuracy.

CONCLUSION

These findings suggested that cytokine expression was correlated with the enteroviral infection, genotype and clinical presentation. The inflammatory profiles could be developed as markers to identify HFMD cases with machine learning algorithm.

Chinese guidelines for the diagnosis and treatment of hand, foot and mouth disease (2018 edition)

BACKGROUND

Hand, foot, and mouth disease (HFMD) is a common infectious disease in childhood caused by an enterovirus (EV), and which is principally seen in children under 5 years of age. To promote diagnostic awareness and effective treatments, to further standardize and strengthen the clinical management and to reduce the mortality of HFMD, the guidelines for diagnosis and treatment have been developed.

METHODS

National Health Commission of China assembled an expert committee for a revision of the guidelines. The committee included 33 members who are specialized in diagnosis and treatment of HFMD.

RESULTS

Early recognition of severe cases is utmost important in diagnosis and treatment of patients with HFMD. The key to diagnosis and treatment of severe cases lies in the timely and accurate recognition of stages 2 and 3 of HFMD, in order to stop progression to stage 4. Clinicians should particularly pay attention to those EV-A71 cases in children aged less than 3 years, and those with disease duration less than 3 days. The following indicators should alert the clinician of possible deterioration and impending critical disease: (1) persistent hyperthermia; (2) involvement of nervous system; (3) worsening respiratory rate and rhythm; (4) circulatory dysfunction; (5) elevated peripheral WBC count; (6) elevated blood glucose and (7) elevated blood lactic acid. For treatment, most mild cases can be treated as outpatients. Patients should be isolated to avoid cross-infection. Intense treatment modalities should be given for those severe cases.

CONCLUSION

The guidelines can provide systematic guidance on the diagnosis and management of HFMD.

Siji Antiviral Mixture Protects against CA16 Induced Brain Injury through Inhibiting PERK/STAT3/NF-κB Pathway

Coxsackievirus 16 (CA16) causes hand, foot, and mouth disease (HFMD) in young children and infants, and it can lead to fatal neurological complications. This study investigated antiviral effects of Siji Antiviral Mixture (SAM) on CA16 in neonatal mice and the protective effects of SAM on CA16 induced brain injuries. Neonatal BALB/c mice and SH-SY5Y cells were used and injected with CA16 stains to study the efficacy. ELISA and Western blotting were used to measure the cytokines levels and proteins expression. Genes transduction was also used to verify interaction mechanism. As the results shown, SAM could reduce the clinical scores at the beginning and delay disease development in vivo. Treatment with SAM decreased the levels of LDH, CK-MB, caspase 3 and Bax, ER stress, and inflammatory reaction induced by CA16 infection. Further siRNA transfection results showed that CA16 induced ER stress and inflammatory reaction through PERK/STAT3/NF-κB signaling and the protective effects of SAM might be through inhibiting PERK/STAT3/NF-κB signaling. HPLC analysis showed fingerprint profiles of SAM had 42 chromatographic peaks. Collectively, our study highlighted distinct roles of SAM in inhibiting CA16 infection and brain injury. The molecular mechanism of SAM might be through inhibiting PERK/STAT3/NF-κB signaling.

Hand-foot-mouth disease and use of steroids, intravenous immunoglobulin, and traditional Chinese herbs in a tertiary hospital in Shantou, China

BACKGROUND

In contrast to the guidelines of World Health Organization (WHO) and United States-Centers for Disease Control and prevention (US-CDC), the Chinese national guidelines recommend the use of steroids, intravenous immunoglobulin (IVIG), or traditional Chinese herbs (TCHs) in hand-foot-mouth disease (HFMD) management. Their use and therapeutic efficacies are, however, unclear. We aimed to describe their use in and the clinical outcomes of hospitalized HFMD cases.

METHODS

A retrospective review of hospital medical records for HFMD cases during 2008-2016 was conducted in a medical school-affiliated tertiary hospital in Shantou, Guangdong, China.

RESULTS

Hospitalized children with the discharge diagnosis of HFMD (n = 3778), comprising mild (58.4%), severe (41.5%), and very severe (0.1%) cases, were enrolled in the study. Steroids, IVIG, and antiviral TCH Lan-Qin were respectively prescribed in 60.5, 37.1, and 71.0% of cases. Most cases (99.8%) recovered and six died. Recovery rate was lower with the use of IVIG and higher with Lan-Qin (alone or in combination with steroid) in the mild cases (Ps < 0.05). Longer hospital stay was observed with steroid/IVIG with or without Lan-Qin in the severe cases (Ps < 0.05).

CONCLUSIONS

This nine-year retrospective review shows 1) an increase in the incidence of HFMD as well as the use of steroids, IVIG, and TCH over time, 2) no significant advantage of using steroids and IVIG, either alone or in combination, in the management of mild HFMD cases, and 3) a higher recovery rate in mild HFMD cases with the use of antiviral TCH (Lan-Qin). Our findings need verification in a larger prospect study with cases from hospitals in other regions of China. Lan-Qin efficacy should be evaluated in randomized trials. Meanwhile, caution should be exercised in the extensive use of steroids and IVIG in HFMD management.

Correlation analysis on serum inflammatory cytokine level and neurogenic pulmonary edema for children with severe hand-foot-mouth disease

Objective

This study aims to discuss the correlation between serum inflammatory cytokines and neurogenic pulmonary edema (NPE) in children with severe hand–foot–mouth disease (HFMD).

Methods

A total of 89 patients with severe HFMD were enrolled into this study. These patients were divided into two groups, according to the presence of NPE: central nervous system disease (CNSD) group and NPE group. Serum IL-4, IL-10, IL-6, IL-17, tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ) levels were measured in patients by enzyme-linked immunosorbent assay at 1, 3, and 5 days after admission. Furthermore, risk factors for NPE were screened using multivariable logistic regression analysis.

Results

IL-6, TNF-α, IL-10, and interferon-γ (IFN-γ) levels in the NPE group were higher than in the CNSD group. TNF-α, IL-10, and IFN-γ levels reached a peak on the 3rd day of admission. Age, continuous fever, blood sugar, white blood cell count, and IL-10 were risk factors for the occurrence of NPE in severe HFMD.

Conclusion

The dynamic unbalance of inflammatory cytokines is related to the occurrence and progress of NPE.

Caspase-3 Inhibition Attenuates the Cytopathic Effects of EV71 Infection

Previous studies demonstrate that human enterovirus 71 (EV71), a primary causative agent for hand, foot, and mouth disease, activates caspase-3 through the non-structural viral 3C protein to induce host cell apoptosis; however, until now it was unclear how 3C activates caspase-3 and how caspase-3 activation affects viral production. Our results demonstrate that 3C binds caspase-8 and caspase-9 but does not directly bind caspase-3 to activate them, and that the proteolytic activity of 3C is required by the activation of caspase-8, caspase-9, and caspase-3. Inhibition of caspase-3 activity attenuates apoptosis in 3C-transfected cells. Furthermore, caspase-3 inhibitor protects host cells from the cytopathic effect of EV71 infection and prevents cell cycle arrest, which is known to be favored for EV71 viral replication. Inhibition of caspase-3 activity decreases EV71 viral protein expression and viral production, but has no effect on viral entry, replication, even polyprotein translation. Therefore, caspase-3 is exploited functionally by EV71 to facilitate its production, which suggests a novel therapeutic approach for the treatment and prevention of hand, foot, and mouth disease.

Cytokine and Chemokine Profiling in Patients with Hand, Foot and Mouth Disease in Singapore and Malaysia

Hand, foot and mouth disease (HFMD) is a prevalent contagious childhood disease typically associated with fever, oral lesions and limb exanthema. While HFMD is caused by a plethora of serotypes of viruses under the genus Enterovirus within the Picornaviridae family, Coxsackievirus A16 (CV-A16) and Enterovirus 71 (EV-A71) are considered the main etiological agents. In recent years however, other viruses have also been isolated in considerable numbers from infected individuals in many regions, joining the legion commonly associated with HFMD. The present study investigated the cytokine and chemokine profiles of HFMD patients from Singapore and Malaysia for the first time. Comparative cohort studies of EV-A71-associated HFMD cases revealed that the Malaysia cohort had a distinct profile from the Singapore cohort, and this could be partly attributed by different EV-A71 genotypes. As the isolation of CV-A6, instead of CV-A16, had become prevalent in the Singapore cohort, it was also of particular interest to study the differential cytokine and chemokine profiles. Our data revealed that overlapping as well as unique profiles exist between the two major causative clinical isolates in the Singapore cohort. Having a better understanding of the respective immunological profiles could be useful for more accurate HFMD diagnosis, which is imperative for disease transmission control until multi-valent vaccines and/or broad-spectrum anti-viral drugs become available.

T Cell Immunity To Enterovirus 71 Infection In Humans And Implications For Vaccine Development

Enterovirus 71 (EV-A71) is one of the major pathogens causing hand, foot and mouth disease (HFMD). Some strains can lead to neurological disease and fatality in children. Up to date, there is no FDA-approved vaccine to prevent severe HFMD and mortality. Although the inactivated vaccine has advanced to production in China, lack of long-term protection and the requirement of multiple boosters have necessitated the development of other types of vaccines. Recent studies indicate that cellular and not humoral immunity determines the clinical outcome of EV-A71 infections. High levels of cytokines such as IL-1β, IL-6, IL-10 and IFN-γ tend to correlate with clinical severity in patients with pulmonary edema and encephalitis. The live attenuated vaccine may serve as the preferred choice as it can induce excellent humoral and cellular immunity as well as live-long immunity. Expression of certain HLA alleles such as TNF-α promoter type II (-308 allele), HLA-A33 and HLA-DR17 responses have been linked to severe HFMD. However, the high variability of MHC genes could restrict T cell recognition and be a major obstacle in the design of peptide vaccines. Hence, the development of a T cell universal vaccine (incorporating both CD4⁺ and CD8⁺ T cell epitopes) that induces broad, multifunctional and cross-reactive CD8⁺ T cell responses maybe desirable.

Interleukin-35 Modulates the Imbalance Between Regulatory T Cells and T Helper 17 Cells in Enterovirus 71-Induced Hand, Foot, and Mouth Disease

Interleukin (IL)-35 modulates the imbalance between regulatory T cells (Tregs) and T helper (Th) 17 cells, which played vital roles in the pathogenesis of autoimmune and infectious diseases. However, the role of Tregs/Th17 cell imbalance and the regulatory functions of IL-35 have remained largely unknown in enterovirus 71 (EV71)-induced hand, foot, and mouth disease (HFMD). In this study, a total of 47 HFMD patients (30 with mild HFMD and 17 with severe HFMD) and 13 healthy individuals were enrolled. The frequencies of CD4⁺CD25⁺CD127^dim/- Tregs and CD4⁺IL-17⁺ Th17 cells, as well as IL-35 expression levels, were measured. Cellular proliferation and cytokine production was also determined in purified Tregs following recombinant IL-35 stimulation. An imbalance between Tregs and Th17 cells was observed in children with severe HFMD, which manifested as a reduction in the Tregs population and an elevation in the Th17 population. Serum IL-35 concentrations were also decreased in case of severe HFMD, which correlated with the Tregs:Th17 cell ratios. Recombinant IL-35 stimulation increased the proportion of Tregs, but downregulated that of Th17 cells. Treatment with IL-35 enhanced Tregs suppressive function and IL-35 and IL-10 expression, but reduced IL-22 secretion in both healthy individuals and those with severe HFMD. The Tregs:Th17 cell ratio was increased in the convalescent patients, however, a significant reduction in serum IL-35 was not observed. Our findings indicated that EV71 infection shifted the Tregs:Th17 cell ratio through IL-35 by downregulating inhibitory cytokine production and reducing the cell-to-cell contact inhibition of effector T cells. Regulation of IL-35 as it relates to the Tregs/Th17 balance may play a critical role in the pathogenesis of EV71-associated HFMD.

Rheum emodin inhibits enterovirus 71 viral replication and affects the host cell cycle environment

Human enterovirus 71 (EV71) is the primary causative agent of recent large-scale outbreaks of hand, foot, and mouth disease (HFMD) in Asia. Currently, there are no drugs available for the prevention and treatment of HFMD. In this study, we compared the anti-EV71 activities of three natural compounds, rheum emodin, artemisinin and astragaloside extracted from Chinese herbs Chinese rhubarb, Artemisia carvifolia and Astragalus, respectively, which have been traditionally used for the treatment and prevention of epidemic diseases. Human lung fibroblast cell line MRC5 was mock-infected or infected with EV71, and treated with drugs. The cytotoxicity of the drugs was detected with MTT assay. The cytopathic effects such as cell death and condensed nuclei were morphologically observed. The VP1-coding sequence required for EV71 genome replication was assayed with qRT-PCR. Viral protein expression was analyzed with Western blotting. Viral TCID50 was determined to evaluate EV71 virulence. Flow cytometry analysis of propidium iodide staining was performed to analyze the cell cycle distribution of MRC5 cells. Rheum emodin (29.6 μmol/L) effectively protected MRC5 cells from EV71-induced cytopathic effects, which resulted from the inhibiting viral replication: rheum emodin treatment decreased viral genomic levels by 5.34-fold, viral protein expression by less than 30-fold and EV71 virulence by 0.33107-fold. The fact that inhibition of rheum emodin on viral virulence was much stronger than its effects on genomic levels and viral protein expression suggested that rheum emodin inhibited viral maturation. Furthermore, rheum emodin treatment markedly diminished cell cycle arrest at S phase in MRC5 cells, which was induced by EV71 infection and favored the viral replication. In contrast, neither astragaloside (50 μmol/L) nor artemisinin (50 μmol/L) showed similar anti-EV71 activities. Among the three natural compounds tested, rheum emodin effectively suppressed EV71 viral replication, thus is a candidate anti-HFMD drug.

Glucocorticoids Prevent Enterovirus 71 Capsid Protein VP1 Induced Calreticulin Surface Exposure by Alleviating Neuronal ER Stress

Severe hand-foot-and-mouth disease (HFMD) caused by Enterovirus 71 (EV71) always accompanies with inflammation and neuronal damage in the central nervous system (CNS). During neuronal injuries, cell surface-exposed calreticulin (Ecto-CRT) is an important mediator for primary phagocytosis of viable neurons by microglia. Our data confirmed that brainstem neurons underwent neuronophagia by glia in EV71-induced death cases of HFMD. EV71 capsid proteins VP1, VP2, VP3, or VP4 did not induce apoptosis of brainstem neurons. Interestingly, we found VP1-activated endoplasmic reticulum (ER) stress and autophagy could promote Ecto-CRT upregulation, but ER stress or autophagy alone was not sufficient to induce CRT exposure. Furthermore, we demonstrated that VP1-induced autophagy activation was mediated by ER stress. Meaningfully, we found dexamethasone treatment could attenuate Ecto-CRT upregulation by alleviating VP1-induced ER stress. Altogether, these findings identify VP1-promoted Ecto-CRT upregulation as a novel mechanism of EV71-induced neuronal cell damage and highlight the potential of the use of glucocorticoids to treat severe HFMD patients with CNS complications.

Coxsackievirus A16 induced neurological disorders in young gerbils which could serve as a new animal model for vaccine evaluation

Coxsackievirus A16 (CA16) is one of the major pathogens associated with human hand, foot, and mouth disease (HFMD) in the Asia-pacific region. Although CA16 infections are generally mild, severe neurological manifestations or even death has been reported. Studies on CA16 pathogenesis and vaccine development are severely hampered because the small animal models that are currently available show major limitations. In this study, gerbils (Meriones unguiculatus) were investigated for their suitability as an animal model to study CA16 pathogenesis and vaccine development. Our results showed that gerbils up to the age of 21 days were fully susceptible to CA16 and all died within five days post-infection. CA16 showed a tropism towards the skeletal muscle, spinal cord and brainstem of gerbils, and severe lesions, including necrosis, were observed. In addition, an inactivated CA16 whole-virus vaccine administrated to gerbils was able to provide full protection to the gerbils against lethal doses of CA16 strains. These results demonstrate that gerbils are a suitable animal model to study CA16 infection and vaccine development.

Antiviral activity of Lactobacillus reuteri Protectis against Coxsackievirus A and Enterovirus 71 infection in human skeletal muscle and colon cell lines

Background

Recurrence of hand, foot and mouth disease (HFMD) pandemics continues to threaten public health. Despite increasing awareness and efforts, effective vaccine and drug treatment have yet to be available. Probiotics have gained recognition in the field of healthcare worldwide, and have been extensively prescribed to babies and young children to relieve gastrointestinal (GI) disturbances and diseases, associated or not with microbial infections. Since the faecal-oral axis represents the major route of HFMD transmission, transient persistence of probiotic bacteria in the GI tract may confer some protection against HFMD and limit transmission among children.

Methods

In this work, the antiviral activity of two commercially available probiotics, namely Lactobacillus reuteri Protectis (L. reuteri Protectis) and Lactobacillus casei Shirota (L. casei Shirota), was assayed against Coxsackieviruses and Enterovirus 71 (EV71), the main agents responsible for HFMD. In vitro infection set-ups using human skeletal muscle and colon cell lines were designed to assess the antiviral effect of the probiotic bacteria during entry and post-entry steps of the infection cycle.

Results

Our findings indicate that L. reuteri Protectis displays a significant dose-dependent antiviral activity against Coxsackievirus type A (CA) strain 6 (CA6), CA16 and EV71, but not against Coxsackievirus type B strain 2. Our data support that the antiviral effect is likely achieved through direct physical interaction between bacteria and virus particles, which impairs virus entry into its mammalian host cell. In contrast, no significant antiviral effect was observed with L. casei Shirota.

Conclusions

Should the antiviral activity of L. reuteri Protectis observed in vitro be translated in vivo, such probiotics-based therapeutic approach may have the potential to address the urgent need for a safe and effective means to protect against HFMD and limit its transmission among children.

Clinical and Associated Immunological Manifestations of HFMD Caused by Different Viral Infections in Children

Hand, foot, and mouth disease (HFMD), with vesiculae on the hands, feet and mouth, is an infectious disease caused by many viral pathogens. However, the differences of immune response induced by these pathogens are unclear. We compared the clinical manifestations and the levels of immunologic indicators from 60 HFMD patients caused by different viral pathogens to analyze the differences in the immune response. It was shown that Th2 cytokines (IL-4 and IL-10) increased significantly in EV71-infected children; Th1 cytokines (IL-2 and IFN-γ) rose in CA16-infected children; both Th1 and Th2 cytokines elevated in non-EVG-infected children; only individual cytokines (such as IL-10) went up in EVG-infected children. Meanwhile, the antibodies induced by viral infection could not cross-interfere between the different pathogens. These differences might be due to variations in the immune response induced by the individual pathogens or to the pathogenesis of the infections by the individual pathogens.

Enterovirus 71 mediates cell cycle arrest in S phase through non-structural protein 3D

Many viruses disrupt the host cell cycle to facilitate their own growth. We assessed the mechanism and function of enterovirus 71 (EV71), a primary causative agent for recent hand, foot, and mouth disease outbreaks, in manipulating cell cycle progression. Our results suggest that EV71 infection induces S-phase arrest in diverse cell types by preventing the cell cycle transition from the S phase into the G2/M phase. Similar results were observed for an alternate picornavirus, Coxsackievirus A16. Synchronization in S phase, but not G0/G1 phase or G2/M phase, promotes viral replication. Consistent with its ability to arrest cells in S phase, the expression of cyclin A2, CDK 2, cyclin E1, and cyclin B1 was regulated by EV71 through increasing transcription of cyclin E1, promoting proteasome-mediated degradation of cyclin A2 and regulating the phosphorylation of CDK 2. Finally, a non-structural protein of EV71, the RNA-dependent RNA polymerase 3D, was demonstrated to mediate S-phase cell cycle arrest. These findings suggest that EV71 induces S-phase cell cycle arrest in infected cells via non-structural protein 3D, which may provide favorable conditions for virus production.

Expression profile and kinetics of cytokines and chemokines in patients with chronic hepatitis C

Cytokines and chemokines play an important role in defense against viral infection and modulating immune response. However, expression prolife of serum cytokines and chemokines, which were associated with the outcome of patients in response to anti-HCV treatment have not been fully elucidated. The current study aimed to determine the expression pattern of cytokines and chemokines in chronic HCV infection and their association with outcome in response to therapy. Seventy-two patients with HCV infection were enrolled, and fifty-one received peg-interferon α-2a and ribavirin therapy for 48 weeks. Thirty-nine cytokines and chemokines were analyzed by Luminex 200 and ELISA. In comparison to healthy individuals, production of IL-8 and IL-10 were increased in chronic hepatitis C patients. In contrast, IFN-γ, IL-7, and IL-15 were remarkably decreased, especially in HCV genotype 1b infection. HCV RNA load is closely associated with IL-10 and IL-15 expressions, and inhibition of HCV replication was accompanied by reduction in IL-10 and elevation in IL-7 and IL-15. Skewed cytokines and chemokines expression existed in chronic HCV infection, and might play an important role in persistent HCV infection. Exploiting the expression pattern of cytokines and chemokines may help to develop a better understanding of the pathogenesis of chronic HCV infection.

Cytokine responses and correlations thereof with clinical profiles in children with enterovirus 71 infections

BACKGROUND

Severe complications associated with EV71 infections caused many infants death. However, the pathogenesis of EV71 infection in the severe cases remained poorly understood.

METHODS

In this study we collected plasma and cerebrospinal fluid (CSF) specimens drawn in the acute and/or recovery phases from EV71-infected individuals, and plasma specimens from healthy children served as normal controls. We compared the levels of cytokines and chemokines determined by a Luminex-based cytokine bead array.

RESULTS

The plasma levels of IL-1β and IL-6 were significantly higher in severe and critical cases than in mild patients and normal controls. Higher plasma levels of IL-6, IL-10, and IL-8 were evident in critical than severe cases. The CSF levels of IL-6, IL-8, and IP-10 were higher, and that of RANTES lower (compared to plasma), in severe and critical patients. Significantly lower CSF levels of cytokines and chemokines were recorded in the recovery than the acute phase in severe and critical cases treated with intravenous immunoglobulin (IVIG) and glucocorticoids. Only the CSF levels of IL-6, IP-10, and IL-8 were significantly correlated with white blood cell counts, and absolute neutrophil and monocyte counts, in severe cases. Furthermore, the CSF levels of IL-6 were correlated with temperature in both cases.

CONCLUSIONS

These data indicate that a major cytokine response and inflammation, in both plasma and the CNS, are features of disease caused by EV71 infection. Systemic inflammation caused by EV71 infection exacerbated the deterioration of the disease, and resulted in the disease progression to the critical illness stage.

Serum inflammatory cytokine levels correlate with hand-foot-mouth disease severity: a nested serial case-control study

Background

Hand-food-mouth disease (HFMD) cases can be fatal. These cases develop rapidly, and it is important to predict the severity of HFMD from mild to fatal and to identify risk factors for mild HFMD. The objective of this study was to correlate the levels of serum inflammatory cytokines with HFMD severity.

Methods

This study was designed as a nested serial case-control study. The data collected included general information, clinical symptoms and signs, laboratory findings and serum cytokine levels.

Results

The levels of IL-4, IL-6, IL-10, TNF-α and IFN-γ in patients with severe HFMD were significantly higher than in mild patients during the 2nd to 5th day after disease onset. The levels of IL-4, IL-6, IL-10 and IFN-γ increased from the 2nd day to the 4th day and later decreased. The levels of TNF-α were high on the first two days and subsequently decreased. The changes of IL-10, TNF-α and IFN-γ in the controls were similar for all cases. The levels of IL-4, IL-6 and IL-17 in the controls were not significantly different with the progression of HFMD.

Conclusions

Our findings indicate that the IL-4, IL-6, IL-10, TNF-α and IFN-γ levels correlate with HFMD severity.

Expression profiles of circulating cytokines, chemokines and immune cells in patients with hepatitis B virus infection

BACKGROUND

Immune cells and molecules play a vital role in initiating, maintaining, regulating immunological homeostasis and inflammation in many pathological and physiological processes; however, the changes on expressions and functions of these cells and molecules in hepatitis B virus (HBV) infection have not been elucidated well.

OBJECTIVES

The current study aimed to determine the expression pattern of different cytokines, chemokines, immune cells in HBV infection and their association with disease progression.

PATIENTS AND METHODS

Sixty-nine patients with chronic HBV infection were enrolled. Five immune cell subsets and 46 cytokines and chemokines were analyzed by flow cytometry and Luminex 200.

RESULTS

In comparison to healthy individuals and asymptomatic HBV carriers, expression of CXCL9, CXCL10, CXCL11, and IL-10 were elevated in patients with chronic active HBV and had positive correlation with ALT levels. In contrast, G-CSF, MCP-3, and IFN-γ levels were significantly decreased in patients with chronic active HBV infection in contrast to carriers and healthy individuals; however, these down regulations did not show any correlation with either virological findings or liver inflammation. Although the proportion of CD4(+) CD25 (high) regulatory T cells (Tregs) was higher in patients with HBV infection than in healthy controls, no correlations were found between Tregs and other cytokines or chemokines.

CONCLUSIONS

CXCR3-associated chemokines might contribute to liver inflammation in chronic hepatitis B, while MCP-3 and G-CSF were inhibited by HBV infection. Host immune response was suppressed as manifested by an increase in CD4(+) CD25(high) Tregs and IL-10 as well as a decrease in IFN-γ. Exploiting the expression pattern of cytokine and chemokine may help to develop a better understanding of chronic HBV infection pathogenesis.

Coxsackievirus A16 infection induces neural cell and non-neural cell apoptosis in vitro

Coxsackievirus A16 (CA16) is one of the main causative pathogens of hand, foot and mouth disease (HFMD). Viral replication typically results in host cell apoptosis. Although CA16 infection has been reported to induce apoptosis in the human rhabdomyosarcoma (RD) cell line, it remains unclear whether CA16 induces apoptosis in diverse cell types, especially neural cells which have important clinical significance. In the current study, CA16 infection was found to induce similar apoptotic responses in both neural cells and non-neural cells in vitro, including nuclear fragmentation, DNA fragmentation and phosphatidylserine translocation. CA16 generally is not known to lead to serious neurological symptoms in vivo. In order to further clarify the correlation between clinical symptoms and cell apoptosis, two CA16 strains from patients with different clinical features were investigated. The results showed that both CA16 strains with or without neurological symptoms in infected patients led to neural and muscle cell apoptosis. Furthermore, mechanistic studies showed that CA16 infection induced apoptosis through the same mechanism in both neural and non-neural cells, namely via activation of both the mitochondrial (intrinsic) pathway-related caspase 9 protein and the Fas death receptor (extrinsic) pathway-related caspase 8 protein. Understanding the mechanisms by which CA16 infection induces apoptosis in both neural and non-neural cells will facilitate a better understanding of CA16 pathogenesis.