Surveillance of the Middle East respiratory syndrome (MERS) coronavirus (CoV) infection in healthcare workers after contact with confirmed MERS patients: incidence and risk factors of MERS-CoV seropositivity.

Given the mode of transmission of Middle East respiratory syndrome (MERS), healthcare workers (HCWs) in contact with MERS patients are expected to be at risk of MERS infections. We evaluated the prevalence of MERS coronavirus (CoV) immunoglobulin (Ig) G in HCWs exposed to MERS patients and calculated the incidence of MERS-affected cases in HCWs. We enrolled HCWs from hospitals where confirmed MERS patients had visited. Serum was collected 4 to 6 weeks after the last contact with a confirmed MERS patient. We performed an enzyme-linked immunosorbent assay (ELISA) to screen for the presence of MERS-CoV IgG and an indirect immunofluorescence test (IIFT) to confirm MERS-CoV IgG. We used a questionnaire to collect information regarding the exposure. We calculated the incidence of MERS-affected cases by dividing the sum of PCR-confirmed and serology-confirmed cases by the number of exposed HCWs in participating hospitals. In total, 1169 HCWs in 31 hospitals had contact with 114 MERS patients, and among the HCWs, 15 were PCR-confirmed MERS cases in study hospitals. Serologic analysis was performed for 737 participants. ELISA was positive in five participants and borderline for seven. IIFT was positive for two (0.3%) of these 12 participants. Among the participants who did not use appropriate personal protective equipment (PPE), seropositivity was 0.7% (2/294) compared to 0% (0/443) in cases with appropriate PPE use. The incidence of MERS infection in HCWs was 1.5% (17/1169). The seroprevalence of MERS-CoV IgG among HCWs was higher among participants who did not use appropriate PPE.

Thermal stability of MnBi magnetic materials.

MnBi has attracted much attention in recent years due to its potential as a rare-earth-free permanent magnet material. It is unique because its coercivity increases with increasing temperature, which makes it a good hard phase material for exchange coupling nanocomposite magnets. MnBi phase is difficult to obtain, partly because the reaction between Mn and Bi is peritectic, and partly because Mn reacts readily with oxygen. MnO formation is irreversible and harmful to magnet performance. In this paper, we report our efforts toward developing MnBi permanent magnets. To date, high purity MnBi (>90%) can be routinely produced in large quantities. The produced powder exhibits 74.6 emu g(-1) saturation magnetization at room temperature with 9 T applied field. After proper alignment, the maximum energy product (BH)max of the powder reached 11.9 MGOe, and that of the sintered bulk magnet reached 7.8 MGOe at room temperature. A comprehensive study of thermal stability shows that MnBi powder is stable up to 473 K in air.

An important role of tumor necrosis factor receptor-2 on natural killer T cells on the development of dsRNA-enhanced Th2 cell response to inhaled allergens.

BACKGROUND: Recent evidence indicates that TNF-α is a key mediator of the development of dsRNA-enhanced Th2 cell response to inhaled allergens. Natural killer T (NKT) cells may be a candidate source of Th2-polarizing cytokines. OBJECTIVE: The objective of this study was to evaluate the role of lung NKT cells on the development of TNF-α-mediated Th2 cell response. METHODS: A virus-associated asthma mouse model was generated by the administration of ovalbumin (OVA, 75 µg) and poly[I:C] (0.1 µg). Role of NKT and type I NKT cells was evaluated using CD1d- and Jα18-deficient mice. TNF-α receptors (TNFRs) were antagonized by using TNFR blocking peptides. RESULTS: The number of infiltrated NKT cells was increased in a virus-associated asthma mouse model. Increase in Th2 and Th17 cytokine levels in wild-type mice were abolished in both CD1d- and Jα18-deficient mice. In vitro co-culture experiments with alveolar macrophages and NKT cells showed that TNF-α produced by macrophages in the presence of poly[I:C] acts on NKT cells, inducing production of Th2-polarizing cytokines. Moreover, the induction of Th2-polarizing cytokines by poly[I:C] or recombinant TNF-α was impaired in both CD1d- and Jα18-deficient mice and that the above effect was reversed by a TNF-α receptor-2 (TNFR2) blocking peptide, but not by a TNFR1 blocker. CONCLUSIONS: These findings suggest that NKT cells play a key role in the development of Th2 cell response to inhaled allergens and that TNF-α produced by alveolar macrophages induces Th2 cell response, via TNFR2 on NKT cells.

Incidence of and risk factors for active tuberculosis in human immunodeficiency virus-infected patients in South Korea.

BACKGROUND: In South Korea, a high-income country with an intermediate tuberculosis (TB) burden and low human immunodeficiency virus (HIV) prevalence, studies on incidence and risk factors of TB in HIV-infected persons have rarely been reported. OBJECTIVE: To investigate the incidence of and risk factors for active TB in HIV-infected persons in South Korea. METHODS: A retrospective analysis was conducted of 1265 HIV-1 infected patients who visited four hospitals in South Korea between 1985 and 2012. We analysed the incidence of TB during the follow-up period. To investigate risk factors associated with active TB, we conducted a 1:2 matched case-control study of HIV-infected patients with newly active TB and controls without active TB who had similar CD4(+) T-cell counts and dates of first visit. RESULTS: Over a total of 4457 person-years (py), 185 (14.6%) subjects were diagnosed with active TB; the incidence was 4.2 cases/100 py. In multivariate analysis, low body mass index (P = 0.033) and current smoking (P = 0.003) were independent risk factors for TB in HIV-infected patients. CONCLUSION: Further strategies on prevention and treatment of active TB among HIV-infected patients should be implemented in South Korea. Encouraging smoking cessation and supporting good nutrition may be ways to reduce the incidence of active TB in HIV-infected patients.

TNF-alpha is a key mediator in the development of Th2 cell response to inhaled allergens induced by a viral PAMP double-stranded RNA.

BACKGROUND: Viral pathogen-associated molecular patterns, such as dsRNA, disrupt airway tolerance to inhaled allergens. Specifically, the Th2 and Th17 cell responses are induced by low-dose dsRNA and the Th1-dominant response by high-dose dsRNA. OBJECTIVE: In this model, we evaluate the role of TNF-α in the development of adaptive immune dysfunction to inhaled allergens induced by airway sensitization with dsRNA-containing allergens. METHODS: A virus-associated asthma mouse model was generated via simultaneous airway administration of ovalbumin (OVA) and low (0.1 µg) or high (10 µg) doses of polyinosine-polycytidylic acid (poly[I:C]). The effect of TNF-α on Th2 airway inflammation was evaluated using TNF-α-deficient mice and recombinant TNF-α. RESULTS: TNF-α production was enhanced by airway exposure to low and high doses of poly[I:C]. After airway sensitization with OVA plus low-dose poly[I:C], TNF-α-deficient mice exhibited less OVA-induced airway inflammation than did wild-type (WT) mice. However, this did not occur upon sensitization with high-dose poly[I:C]. In terms of T-cell response, the production of IL-4 from lung T cells after OVA challenge was enhanced by airway sensitization with OVA plus low-dose poly[I:C] in WT mice, and this phenotype was inhibited by the absence of TNF-α. Moreover, the Th2 cell response induced by sensitization with OVA plus low-dose poly[I:C], which was abolished in TNF-α-deficient mice, was restored in these mice upon addition of recombinant TNF-α. CONCLUSION: The results of this study suggest that TNF-α produced by airway exposure to low-dose dsRNA is a key mediator in the development of Th2 cell response to inhaled allergens.

A viral PAMP double-stranded RNA induces allergen-specific Th17 cell response in the airways which is dependent on VEGF and IL-6.

BACKGROUND: Innate immune response by a viral pathogen-associated molecular pattern dsRNA modulates the subsequent development of adaptive immune responses. Although virus-associated asthma is characterized by noneosinophilic inflammation, the role of Th17 cell response in the development of virus-associated asthma is still unknown. OBJECTIVE: To evaluate the role of the Th17 cell response and its underlying polarizing mechanisms in the development of an experimental virus-associated asthma. METHODS: An experimental virus-associated asthma was created via airway sensitization with ovalbumin (OVA, 75 µg) and a low (0.1 µg) or a high (10 µg) doses of synthetic dsRNA [polyinosine-polycytidylic acid; poly(I:C)]. Transgenic (IL-17-, IL-6-deficient mice) and pharmacologic [a vascular endothelial growth factor receptor (VEGFR) inhibitor] approaches were used to evaluate the roles of Th17 cell responses. RESULTS: After cosensitization with OVA and low-dose poly(I:C), but not with high-dose poly(I:C), inflammation scores after allergen challenge were lower in IL-17-deficient mice than in wild-type (WT) mice. Moreover, inflammation enhanced by low-dose poly(I:C), but not by high-dose poly(I:C), was impaired in IL-6-deficient mice; this phenotype was accompanied by the down-regulation of IL-17 production from T cells from both lymph nodes and lung tissues. Airway exposure of low-dose poly(I:C) enhanced the production of VEGF and IL-6, and the production of IL-6 was blocked by treatment with a VEGFR inhibitor (SU5416). Moreover, the allergen-specific Th17 cell response and subsequent inflammation in the low-dose poly(I:C) model were impaired by the VEGFR inhibitor treatment during sensitization. CONCLUSIONS: Airway exposure of low-level dsRNA induces an allergen-specific Th17 cell response, which is mainly dependent on VEGF and IL-6.

15-lipoxygenase metabolites play an important role in the development of a T-helper type 1 allergic inflammation induced by double-stranded RNA.

BACKGROUND: We recently demonstrated that the T-helper type 1 (Th1) immune response plays an important role in the development of non-eosinophilic inflammation induced by airway exposure of an allergen plus double-stranded RNA (dsRNA). However, the role of lipoxygenase (LO) metabolites in the development of Th1 inflammation is poorly understood. OBJECTIVE: To evaluate the role of LO metabolites in the development of Th1 inflammation induced by sensitization with an allergen plus dsRNA. METHODS: A Th2-allergic inflammation mouse model was created by an intraperitoneal injection of lipopolysaccharide-depleted ovalbumin (OVA, 75 microg) and alum (2 mg) twice, and the Th1 model was created by intranasal application of OVA (75 microg) and synthetic dsRNA [10 microg of poly(I : C)] four times, followed by an intranasal challenge with 50 microg of OVA four times. The role of LO metabolites was evaluated using two approaches: a transgenic approach using 5-LO(-/-) and 15-LO(-/-) mice, and a pharmacological approach using inhibitors of cysteinyl leucotriene receptor-1 (cysLTR1), LTB4 receptor (BLT1), and 15-LO. RESULTS: We found that the Th1-allergic inflammation induced by OVA+dsRNA sensitization was similar between 5-LO(-/-) and wild-type (WT) control mice, although Th2 inflammation induced by sensitization with OVA+alum was reduced in the former group. In addition, dsRNA-induced Th1 allergic inflammation, which is associated with down-regulation of 15-hydroxyeicosateraenoic acids production, was not affected by treatment with cysLTR1 or BLT1 inhibitors, whereas it was significantly lower in 12/15-LO(-/-) mice compared with WT control mice. Moreover, dsRNA-induced allergic inflammation and the recruitment of T cells following an allergen challenge were significantly inhibited by treatment with a specific 15-LO inhibitor (PD146176). CONCLUSION: 15-LO metabolites appear to be important mediators in the development of Th1-allergic inflammation induced by sensitization with an allergen plus dsRNA. Our findings suggest that the 15-LO pathway is a novel therapeutic target for the treatment of virus-associated asthma characterized by Th1 inflammation.