In-vivo functions and regulation of polyphosphate in the vascular system.

PURPOSE OF REVIEW: Polyphosphate, an inorganic polymer consisting of linearly linked phosphate subunits, is ubiquitously found in living organisms. Functions and regulation of the polymer have been analyzed in plants, bacteria and yeast; however, the roles of polyphosphate in mammals are still emerging. RECENT FINDINGS: In contrast to synthetic polyphosphate that has been extensively utilized in ex-vivo studies, natural polyphosphate is complexed with bivalent cations (mostly Ca 2+ ) and regardless of chain length, forms microparticles that are retained on the surface of procoagulant platelets, platelet-derived microparticles and cancer extracellular vesicles. On cell surfaces, these Ca 2+ /polyphosphate aggregates initiate the factor XII-driven contact system, triggering proinflammatory and procoagulant reactions through the kallikrein kinin system and intrinsic pathway of coagulation, respectively. Polyphosphate inhibitors interfere with thrombosis while sparing hemostasis, replicating the effect of factor XII neutralizing agents. Furthermore, polyphosphate binds to platelet factor 4, which has implications for autoimmune thrombotic diseases, such as heparin-induced thrombocytopenia (HIT) and vaccine-induced thrombotic thrombocytopenia (VITT), potentially contributing to their pathogenesis. The metabolism and organ-specific distribution of the polymer remain incompletely defined and is the topic of ongoing research. SUMMARY: Polyphosphate acts as a procoagulant and proinflammatory mediator. Neutralizing polyphosphate provides well tolerated thromboprotection, mimicking the effects of factor XII deficiency.

Predicting severe enterovirus 71 infection: Age, comorbidity, and parental behavior matter.

OBJECTIVE: Enterovirus 71 (EV71) is one of the major pathogens that cause severe enteroviral infections. Our aim was to study the behavioral and household risk factors for its serious complications. METHODS: Between May 2011 and November 2012, we enrolled children who had symptoms of EV71 infection from six hospitals in Taiwan. The caregivers of each patient were interviewed to determine their hand hygiene habits in relation to EV71 infection. The severity of EV71 infection was classified as follows: Stage 1, hand-foot-mouth disease or herpangina; Stage 2, meningitis or myoclonic jerk; Stage 3A, encephalitis; Stage 3B, cardiopulmonary failure. Stages 2 to 3B were defined as severe EV71 infection. Children with Stages 3A and 3B infection were designated as the critical group. RESULTS: A total of 399 patients had laboratory-confirmed EV71 infection. Three risks factors were associated with the different degrees of severity in EV71 infection. Children <2 years old had much greater risks for severe EV71 infection [odds ratio (OR) 1.8; 95% confidence interval (CI), 1.2-2.8], delayed medical evaluation for critical infection (OR 9.4; 95% CI, 3.6-24.1), and developmental retardation for cardiopulmonary failure (OR 8.3; 95% CI, 2.0-33.7). Among all the habits and household factors, caregivers in the critical group had a significantly lower rate in terms of cleaning the faucet after washing their hands (OR 2.63; 95% CI, 1.14-6.08). CONCLUSIONS: Children <2 years old, developmental retardation, and delayed medical intervention were associated with severe EV71 infection. Cleaning water faucets after hand washing was a protective habit that reduced the risk of complications.

Galectin-3 and Its Genetic Variation rs4644 Modulate Enterovirus 71 Infection.

Galectin-3, a chimeric type ß-galactoside-binding protein, is known to modulate viral infection; however, its role in enterovirus 71 (EV71) infection has not been investigated. We generated galectin-3 null rhabdomyosarcoma (RD) cells and evaluated whether EV71 infection would be affected. In galectin-3 null cells, the released and intracellular EV71 viral loads were suppressed after 24 h of infection, and cell death rates were significantly lower, while cell proliferation remained unaltered. In addition, RD cells expressing a nonsynonymous genetic variant of galectin-3, rs4644 (LGALS3 +191C/A, P64H), produced lower virus titers than those with wild-type galectin-3 (C allele). To clarify whether the in vitro viral load reduction correlates with clinical severity, we enrolled children with laboratory-confirmed EV71 infection. Since hyperglycemia is an indicator of severe EV71 infection in children, 152 of 401 enrolled children had glucose examinations at admission, and 59 subjects had serum glucose levels ≥ 150 mg/dL. In comparison to the rs4644 AA genotype (2.2 ± 0.06 log10 mg/dL), serum glucose levels during EV71 infection were higher in patients with CC (2.4 ± 0.17 log10 mg/dL, p = 0.03) and CA (2.4 ± 0.15 log10 mg/dL, p = 0.02) genotypes, respectively. These findings suggest that the rs4644 AA genotype of galectin-3 might exert a protective effect. In summary, galectin-3 affects EV71 replication in our cellular model and its variant, rs4644, is associated with hyperglycemia in the clinical setting. The underlying mechanism and its potential therapeutic application warrant further investigation.

Atypical hand-foot-mouth disease in children: a hospital-based prospective cohort study.

BACKGROUND: In 2010, we observed children with atypical presentations of hand-foot-mouth disease (HFMD), such as rashes on earlobes and faces, or bullae on trunks and bilateral limbs. Hyperpigmentation later developed as the bullous lesions crusted. Thus, we intended to study the etiology of the illness and the phylogeny of the pathogens. METHOD: Patients were prospectively enrolled in a tertiary medical center in Taipei, Taiwan. The definition of atypical HFMD includes symptoms of acute viral infection with either of the following presentations: (1) maculopapular rashes presenting on the trunks, buttocks or facial areas, or (2) large vesicles or bullae on any sites of the body. Patients were classified into two groups according to vesicle sizes by two pediatricians at different points in time. The large vesicle group was defined as having vesciculobullous lesions ≥ 1 cm in diameter; the small rashes group had maculopapular rashes < 1cm in diameter. Two throat swabs were collected from each patient for virus isolation and reverse transcription polymerase chain reactions. RESULTS: We enrolled 101 patients between March and December 2010. The mean age of the participants was 3.3 ± 3.0 years (median age: 2.5 years, range: 21 days-13.5 years). The ratio of males to females was 1.8 to 1. All samples were enterovirus-positive, including coxsackievirus A6 (80%), coxsackievirus A16 (6%), enterovirus 71 (1%), coxsackievirus A5 (1%) and 12 non-typable enterovirus (12%). Bullous fluid aspirated from 2 patients also grew coxsackievirus A6. Among the patients infected with coxsackievirus A6, 54% (45/81) had bullae, compared to 25% (5/20) of those having non-coxsackievirus A6 infections (P=0.02). Fourteen cases had myoclonic jerks and one boy was diagnosed with febrile convulsions. None had complications or sequelae. Phylogenetic analysis showed the strains in Taiwan in 2010 shared more commonality with strains from Finland in 2009 (GenBank: FJ870502-FJ870508), and were close to those circulating in Japan in 2011 (GenBank: AB649286-AB649291). CONCLUSIONS: Coxsackievirus A6 infections may cause atypical manifestations of HFMD, including vesicles or papules on faces or bullae on trunks. These features could provide valuable information to distinguish this versatile enterovirus infection from other virus-induced vesiculobullous diseases.

Clinical features and phylogenetic analysis of Coxsackievirus A9 in Northern Taiwan in 2011.

BACKGROUND: Coxsackievirus A9 (CA9) was one of the most prevalent serotype of enteroviral infections in Taiwan in 2011. After several patient series were reported in the 1960s and 1970s, few studies have focused on the clinical manifestations of CA9 infections. Our study explores and deepens the current understanding of CA9. METHODS: We analyzed the clinical presentations of 100 culture-proven CA9-infected patients in 2011 by reviewing their medical records and depicted the CA9 phylogenetic tree. RESULTS: Of the 100 patients with culture-proven CA9 infections, the mean (SD) age was 4.6 (3.4) years and the male to female ratio was 1.9. For clinical manifestations, 96 patients (96%) had fever and the mean (SD) duration of fever was 5.9 (3.4) days. Sixty one patients (61%) developed a skin rash, and the predominant pattern was a generalized non-itchy maculopapular rash without vesicular changes. While most patients showed injected throat, oral ulcers were found in only 19 cases (19%), among whom, 6 were diagnosed as herpangina. Complicated cases included: aseptic meningitis (n=8), bronchopneumonia (n=6), acute cerebellitis (n=1), and polio-like syndrome (n=1). Phylogenetic analysis for current CA9 strains is closest to the CA9 isolate 27-YN-2008 from the border area of mainland China and Myanmar. CONCLUSIONS: The most common feature of CA9 during the 2011 epidemic in Taiwan is generalized febrile exanthema rather than herpangina or hand, foot, and mouth disease. Given that prolonged fever and some complications are possible, caution should be advised in assessing patients as well as in predicting the clinical course.

Seroprevalence of enterovirus 71 and no evidence of crossprotection of enterovirus 71 antibody against the other enteroviruses in kindergarten children in Taipei city.

BACKGROUND/PURPOSE: Enterovirus 71 (EV71) infection may cause severe neurological and cardiopulmonary complications, especially in preschool children. This study is to investigate the seroprevalence and seroconversion of EV71, and the crossprotection of EV71 antibody against other enteroviruses among kindergarteners. METHODS: Overall 228 children in a public kindergarten were enrolled during two academic years, 2006 and 2007, in Taipei, Taiwan and we measured their EV71 neutralizing antibody. When the participants had herpangina; hand, foot and mouth disease (HFMD); febrile illness or respiratory symptoms, throat swabs were sampled and processed for viral culture and enterovirus real-time reverse transcriptase polymerase chain reaction (RT-PCR). Questionnaires, completed by the participants' guardians, surveyed the history of allergy and annual incidence of symptoms related to enterovirus infection. RESULTS: Seropositive rates of EV71 were 20% (32/163) in 2006 and 6% (4/65) in 2007. The rate of EV71 seropositivity increased with age (p < 0.01) in 2006 but it did not differ between genders (p = 0.14). No seroconversion was observed from 2006 to 2007. Herpangina occurred in 64% of children with EV71 seropositivity and 48% of those without EV71 antibodies (p = 0.12). Non-71 enterovirus infection, confirmed by viral study, occurred in 53% (19/36) of the EV71-seropositive children and in 53% (102/192) of EV71-seronegative children (p = 0.89). No participants had EV71 infection during the study period. CONCLUSION: EV71 did not frequently circulate in Taipei City from September 2006 to June 2008. Presence of EV71 neutralizing antibody was not associated with lower incidence of enterovirus infection caused by non-71 serotypes.

Varicella breakthrough infection and vaccine effectiveness in Taiwan.

We performed this nationwide retrospective investigation among the recipients of varicella vaccine to evaluate the breakthrough varicella infection rate, factors associated with breakthrough infection and the vaccine effectiveness. The recipients of these vaccinations were identified through Taiwan's National Immunization Information System and data on breakthrough infections among these recipients were collected by using Taiwan's National Health Insurance Claims Database. From 2000 to 2007, 1,057,345 persons received varicella vaccinations in Taiwan. Varicella breakthrough infection occurred among 22,640 (2.1%) vaccinees and 170 (0.016%) required hospitalization for varicella disease. Annual breakthrough infection rates ranged from 0.12% to 2.04%. The mean age of vaccination was 1.6 years (median 1.3 years) and the mean age at breakthrough infection was 3.9 years. The mean interval between vaccination and the breakthrough infection was 2.3 years. The rate was significantly lower in regions where free varicella vaccinations were available than in regions where they were not (P<0.001). Varicella breakthrough infection was significantly more likely to occur at 5 and 6 years of age among the vaccinees, who received vaccination between 12 months and 23 months of age (P<0.001). The vaccine effectiveness against varicella was 82.6% and against varicella-related hospitalization was 85.4% from 2000 to 2005.

Epidemiologic features of Kawasaki disease in Taiwan, 2003-2006.

OBJECTIVE: Kawasaki disease is the leading cause of acquired heart disease in children worldwide. This study characterizes the epidemiology of Kawasaki disease in Taiwan between 2003 and 2006. METHODS: Using Taiwan's 2003-2006 national health insurance claims, we investigated the epidemiologic features of Kawasaki disease (ICD-9-CM code 446.1) and coronary artery aneurysm formation (International Classification of Diseases, Ninth Revision, Clinical Modification code 414.11) and compared the incidences of these diseases with those occurring between 1996 and 2002 in Taiwan and those reported by other countries. RESULTS: During our 4-year study period, 3877 children and adolescents <20 years of age were hospitalized for Kawasaki disease. Ninety percent of these children were <5 years of age, and the male/female ratio was 1.62:1. The annual incidence of Kawasaki disease was 153 in 100000 children <1 year of age, 111 in children 1 year of age, 58 in children 2 years of age, 30 in children 3 years of age, 19 in children 4 years of age, and 5.2 in children 5 to 9 years of age. The overall incidence was 69 cases per 100000 for children <5 years of age. Kawasaki disease recurred in 1.5% of all cases. Kawasaki disease occurred most frequently in the summer and least frequently in the winter. Coronary artery aneurysm occurred in 7.2% (279 of 3877) of all Kawasaki disease cases. CONCLUSIONS: The overall incidence of Kawasaki disease was 69 in 100000 children <5 years of age between 2003 and 2006 in Taiwan, comparable with the incidence of 66 in 100000 children between 1996 and 2002. Taiwan has the third highest incidence of Kawasaki disease in the world, after Japan and Korea. In Taiwan, it occurs more frequently during the summer.