Association of fever and severe clinical course in bronchiolitis.
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Little attention has been given to the relation between fever and the severity of bronchiolitis. Therefore, the relation between fever and the clinical course of 90 infants (59 boys, 31 girls) hospitalised during one season with bronchiolitis was studied prospectively. Fever (defined as a single recording > 38.0 degrees C or two successive recording > 37.8 degrees C) was present in 28 infants. These infants were older (mean age, 5.3 v 4.0 months), had a longer mean hospital stay (4.2 v 2.7 days), and a more severe clinical course (71.0% v 29.0%) than those infants without fever. Radiological abnormalities (collapse/consolidation) were found in 60. 7% of the febrile group compared with 14.8% of the afebrile infants. These results suggest that monitoring of body temperature is important in bronchiolitis and that fever is likely to be associated with a more severe clinical course and radiological abnormalities. (+info)
Passive IgA monoclonal antibody is no more effective than IgG at protecting mice from mucosal challenge with respiratory syncytial virus.
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Respiratory syncytial virus (RSV) is a mucosally restricted pathogen that can cause severe respiratory disease. Although parenteral administration of sufficient RSV-specific IgG can reduce severity of lower respiratory tract infection in high-risk infants, delivery of antibody by direct airway administration is an attractive alternative. Topical and parenteral administration of an IgA monoclonal antibody (MAb) specific for the RSV F glycoprotein was compared with an IgG MAb, specific for the same antigenic site, for ability to protect mice against RSV infection. Administration of RSV-specific IgG was more effective in reducing RSV titers in lung (4.6 log10 pfu/g) than IgA MAb (3.6 log10 pfu/g) when given intranasally immediately prior to infection (P=.005). RSV titers in the nose were reduced only by prophylactic administration of IgG parenterally. Therefore, topical administration of IgA is no more effective than topically administered IgG and is less effective than systemically administered IgG for protecting against RSV infection. (+info)
Secreted respiratory syncytial virus G glycoprotein induces interleukin-5 (IL-5), IL-13, and eosinophilia by an IL-4-independent mechanism.
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The attachment glycoprotein G of respiratory syncytial virus (RSV) is produced as both membrane-anchored and secreted forms by infected cells. Immunization with secreted RSV G (Gs) or formalin-inactivated alumprecipitated RSV (FI-RSV) predisposes mice to immune responses involving a Th2 cell phenotype which results in more severe illness and pathology, decreased viral clearance, and increased pulmonary eosinophilia upon subsequent RSV challenge. These responses are associated with increased interleukin-4 (IL-4) production in FI-RSV-primed mice, and the responses are IL-4 dependent. RNase protection assays demonstrated that similar levels of IL-4 mRNA were induced after RSV challenge in mice primed with vaccinia virus expressing Gs (vvGs) or a construct expressing only membrane-anchored G (vvGr). However, upon RSV challenge, vvGs-primed mice produced significantly greater levels of IL-5 and IL-13 mRNA and protein than vvGr-primed mice. Administration of neutralizing anti-IL-4 antibody 11.B11 during vaccinia virus priming did not alter the levels of vvGs-induced IL-5, IL-13, pulmonary eosinophilia, illness, or RSV titers upon RSV challenge, although immunoglobulin G (IgG) isotype profiles revealed that more IgG2a was produced. vvGs-priming of IL-4-deficient mice demonstrated that G-induced airway eosinophilia was not dependent on IL-4. In contrast, airway eosinophilia induced by FI-RSV priming was significantly reduced in IL-4-deficient mice. Thus we conclude that, in contrast to FI-RSV, the secreted form of RSV G can directly induce IL-5 and IL-13, producing pulmonary eosinophilia and enhanced illness in RSV-challenged mice by an IL-4-independent mechanism. (+info)
Patients with multiple myeloma may safely undergo autologous transplantation despite ongoing RSV infection and no ribavirin therapy.
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Respiratory syncytial virus (RSV) has been reported as a cause of death among autologous peripheral blood stem cell (ASCT) and marrow recipients and recommendations for therapy with aerosolized ribavirin plus intravenous immunoglobulin (IVIG) made. This therapy is expensive, may be toxic, and causes a significant disruption of patient care. The purpose of this study was to evaluate the morbidity and mortality of RSV infections in patients with multiple myeloma undergoing ASCT without ribavirin therapy. During the months of February-April 1997, 10 consecutive patients (median age 57 years, seven males) with advanced and heavily pretreated myeloma underwent ASCT while having active RSV upper respiratory tract infection. After melphalan (200 mg/m2), all patients became neutropenic (<1000 cells/mm3) for a median of 7 days. Ribavirin was not given to any patient. No patient developed lower respiratory tract infection, required transfer to intensive care or died at a median follow-up of 8 months. One patient developed tracheobronchitis requiring oxygenation by nasal cannula. No delay in the treatment of the underlying myeloma was incurred. RSV infection may not necessarily be a contraindication for ASCT or an indication for therapy with aerosolized ribavirin. Additional studies are needed to confirm our preliminary findings. (+info)
Clinical characteristics of acute viral lower respiratory tract infections in hospitalized children in Seoul, 1996-1998.
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This study was performed to investigate the etiologic agents, age distribution, clinical manifestations and seasonal occurrence of acute viral lower respiratory tract infections in children. We confirmed viral etiologies using nasopharyngeal aspirates in 237 patients of the ages of 15 years or younger who were hospitalized for acute lower respiratory tract infection (ALRI) from March 1996 to February 1998 at Samsung Seoul Hospital, Seoul, Korea. The overall isolation rate was 22.1%. The viral pathogens identified were adenovirus (12.7%), influenza virus type A (21.1%), -type B (13.9%), parainfluenza virus type 1 (13.5%), -type 2 (1.3%), -type 3 (16.0%) and respiratory syncytial virus (21.5%). The occurrence of ALRIs was highest in the first year of life, although parainfluenza virus type 1 infection occurred predominantly in the second year of life and influenza virus caused illnesses in all age groups. The specific viruses are frequently associated with specific clinical syndromes of ALRI. The respiratory agents and associated syndromes frequently have characteristic seasonal patterns. This study will help us to estimate the etiologic agents of ALRI, and establish a program for the prevention and treatment. An annual nationwide survey is necessary to understand the viral epidemiology associated with respiratory illnesses in Korea. (+info)
IL-8 and neutrophil elastase levels in the respiratory tract of infants with RSV bronchiolitis.
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The aim of this study was to determine whether interleukin (IL)-8 is released within the upper respiratory tract of infants during respiratory syncytial virus (RSV) bronchiolitis and whether the large number of polymorphonuclear neutrophils (PMNs) present in the respiratory tract of these infants are contributing to the inflammation through release of inflammatory mediators. Twenty-seven infants with acute bronchiolitis were recruited during one winter epidemic and 20 infant control subjects were recruited from a cohort participating in a community-based vaccine study. Samples of airways fluid were obtained using nasal lavage. The lavage fluid was spun to remove the cells, and the supernatant was stored at -70 degrees C. The supernatants were subsequently assayed for the presence of IL-8, total human neutrophil elastase (HNE) and neutrophil elastase activity. In the children with bronchiolitis compared with control infants, elevated levels of IL-8 (median (range) 1.53 (0-153) versus 0 (0-5.6) ng x mL(-1)) HNE (136 (32-694) versus 14 (0-516) ng x mL(-1)) and elastase activity (4 (1-220) versus 1 (0-339) mU x mL(-1)) were found. These results indicate that interleukin-8 is released in the upper respiratory tract in response to respiratory syncytial virus infection and suggest that polymorphonuclear neutrophil products are playing an important role in the inflammatory response to respiratory syncytial virus infection in infants with acute bronchiolitis. This contrasts with the predominantly eosinophilic response evident in atopic upper and lower respiratory tract disease. (+info)
Peripheral blood cytokine responses and disease severity in respiratory syncytial virus bronchiolitis.
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The role of cellular immunity in disease severity in respiratory syncytial virus (RSV) bronchiolitis is largely unknown. This study investigated the association between disease severity and systemic cytokine responses in hospitalized ventilated and nonventilated RSV bronchiolitis patients. In whole blood cultures stimulated with phytohaemagglutinin (PHA), lymphoproliferative responses and interferon (IFN)-gamma and interleukin (IL)-4 production during acute illness were measured. In addition, plasma cytokines were measured. Measurements were repeated in the convalescent phase, 3-4 weeks after admission. Fifty patients were included. The median age in ventilaled patients was significantly lower than in nonventilated patients (1 versus 4 months, p<0.05). In comparison with nonventilated patients, the ventilated patients had significantly lower lymphoproliferative responses and a lower production of IFN-gamma and IL-4. In fact, IFN-gamma and IL-4 production in ventilated patients was almost completely undetectable. Plasma IL-8 levels in ventilated patients were significantly higher than in nonventilated patients. In the convalescent phase, lymphoproliferative and cytokine responses as well as plasma IL-8 levels were normal in both patient groups. Since RSV bronchiolitis is associated with the subsequent development of asthma, the possible skewing of the T-helper (Th1/Th2) cytokine balance was investigated. This was found neither in the acute nor in the convalescent phase. In conclusion, the data indicate that depressed lymphocyte function and elevated plasma interleukin-8 levels are markers of severe disease. It is suggested that age and maturation related immune mechanisms could explain the occurrence of severe respiratory syncytial virus bronchiolitis requiring mechanical ventilation in young infants. (+info)
Pre-emptive use of aerosolized ribavirin in the treatment of asymptomatic pediatric marrow transplant patients testing positive for RSV.
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Respiratory syncytial virus is a common virus which frequently causes severe lower tract disease in immunocompromised patients. The mortality rate in bone marrow transplant patients with lower tract disease varies from 31% to 100%, depending upon the treatment used, time before initiation of treatment, and whether patients are pre- or post-engraftment. Therapy with inhaled ribavirin has been used with limited success in decreasing mortality rate. Because of concern about conversion from upper respiratory tract disease to lower respiratory tract disease, we conducted a pilot study using aerosolized ribavirin in asymptomatic RSV-positive patients. Patients had NP washes performed on a weekly basis during the RSV season, for the presence of RSV. If patients were positive, but asymptomatic, and could have their transplant postponed, they were treated with ribavirin until negative. Patients who could not be postponed received aerosolized ribavirin, and began transplant conditioning. During this study, we performed 145 nasal aspirations for RSV on 25 patients; 10 aspirates were positive in seven asymptomatic patients. All positive events were successfully treated with ribavirin, which cleared the RSV for a minimum of 3 weeks. No patients became symptomatic. Thus, we conclude that ribavirin can clear asymptomatic infections in immunocompromised pediatric transplant patients. (+info)