leukotriene-b4 and Respiratory-Syncytial-Virus-Infections

Respiratory syncytial virus (RSV) bronchiolitis is a very common infection in infants and, after the acute phase, a number of patients develop a reactive airway disease that lasts for years. Although the pathogenesis of the lung damage after RSV bronchiolitis is still largely unknown, previous studies suggest that leukotrienes may play an active part in it. The aim of this study was to measure leukotriene levels in the nasal lavage fluid (NLF) collected in infants during RSV bronchiolitis and 1 month later. Cysteinyl leukotrienes (Cys-LTs) and leukotriene B(4) (LTB(4)) were measured in the NLF of 22 infants with their first episode of RSV bronchiolitis and 16 healthy infants. A second NLF sample was collected to measure leukotriene levels 1 month after the acute disease. NLF Cys-LT levels were significantly higher in infants with RSV bronchiolitis than in healthy controls [950 pg/ml (285.5-2155.9) vs. 110.5 pg/ml (66.5-451.3), p = 0.01], and they remained so a month after the acute infection (p = 0.02). A subanalysis showed no difference in Cys-LTs concentrations, either between bronchiolitis infants with and without a family history of atopy, or between those with and without passive exposure to cigarette smoke. No significant difference was found between the LTB(4) levels measured in the bronchiolitis cases and the control children. Cys-LTs are significantly increased in the NLF of infants with acute RSV bronchiolitis, and remain so at 1-month follow-up, suggesting a possible role of these eicosanoids in the pathogenesis of the disease.

Topics: Bronchiolitis; Cysteine; Female; Follow-Up Studies; Humans; Infant; Leukotriene B4; Leukotrienes; Male; Nasal Lavage Fluid; Respiratory Syncytial Virus Infections; Respiratory Syncytial Virus, Human

We prospectively studied the levels of eicosanoids in intubated patients with severe bronchiolitis and compared them to electively intubated non-infected infants. LeukotrieneE(4) (LTE(4)), leukotrieneB(4) (LTB(4)), and prostaglandinE(2) (PGE(2)) levels were significantly increased (P <.01) from endotracheal (ET) aspirates of infants with bronchiolitis compared with controls, as were urinary LTE(4) levels (P <.001). We conclude that eicosanoids are increased in the tracheal aspirates and urine of children with bronchiolitis.

Topics: Acute Disease; Bronchiolitis, Viral; Case-Control Studies; Child, Preschool; Dinoprostone; Female; Humans; Infant; Intubation, Intratracheal; Leukotriene B4; Leukotriene E4; Male; Prospective Studies; Respiratory Syncytial Virus Infections

Large numbers of neutrophils in the airway of infants infected by respiratory syncytial virus (RSV) are recruited by chemokines, such as interleukin-8, and specific inflammatory molecules can delay apoptosis increasing their longevity. The aim of this study was to investigate whether airway secretions in RSV bronchiolitis contain factors that influence neutrophil apoptosis. Nasal lavage fluid (NLF) was obtained from 24 infants with RSV bronchiolitis (31 infant controls and 12 adults). Neutrophils isolated from healthy adult volunteers were incubated with the NLF in Dulbecco modified Eagle medium (DMEM) for 24 h, and apoptosis and necrosis were quantified using Hoechst 33342 and propidium iodide viability dyes. The presence of putative factors that delay neutrophil apoptosis was investigated using inhibitors to leukotriene-B4, lipopolysaccharide and the IL-8 receptor CXCR2, and blocking antibodies to granulocyte-monocyte colony-stimulating factor. Characterisation of NLF involved tests of thermal instability, proteolysis, deoxyribonuclease digestion and molecular filtration. NLF from infants with RSV bronchiolitis and controls significantly delayed neutrophil apoptosis, whereas NLF from healthy adults did not. None of these inhibitor molecules blocked this delay in apoptosis but activity was heat liable and >3 kDa. The study showed that nasal lavage fluid from infants significantly delays neutrophil apoptosis. The speculation is that the prolonged survival of neutrophils in the infant airway contributes to the characteristic accumulation of neutrophils in the airways of infants with respiratory infections.

Topics: Adult; Apoptosis; Bronchiolitis, Viral; Cell Survival; Granulocyte-Macrophage Colony-Stimulating Factor; Humans; Infant; Interleukin-8; Leukotriene B4; Nasal Lavage Fluid; Neutrophils; Polymyxin B; Receptors, Interleukin-8B; Respiratory Syncytial Virus Infections; Respiratory System

To determine whether measurement of an inflammatory mediator in exhaled condensate could provide a noninvasive method for evaluating lungs of calves.. 84 calves < or = 2 months old.. Concentration of leukotriene B4 (LTB4) was evaluated in the exhaled condensate of healthy calves and calves with experimentally induced respiratory tract infections. For collection of samples of exhaled condensate, the total amount of exhaled air was directed into a cooled double-jacketed tube. Each tube was sealed and stored at -80 C. The LTB4 concentration was measured, using an ELISA.. In exhaled condensates of clinically healthy calves, normally distributed and highly reproducible LTB4 concentrations (mean +/- SD, 116.1 +/- 55.4 pg/ml) were measured. After experimentally induced infection with Pasteurella multocida serovar D, LTB4 in exhaled condensate increased significantly (mean, 179% increase), compared with basal concentrations before infection; this increase in LTB4 was significantly correlated with deterioration in lung function. In 2 of 4 calves experimentally infected with bovine respiratory syncytial virus, the LTB4 concentration in exhaled condensate increased (300 to 400% increase), compared with baseline values, which was associated with development of bronchial hyperresponsiveness after infection.. Collection of exhaled condensate is tolerated well by calves and is an acceptable method for obtaining fluid from exhaled air originating from the lungs. This method provides alternatives for diagnosing and evaluating treatment of naturally acquired and experimentally induced diseases of the lungs and airways in calves.

Topics: Animals; Breath Tests; Bronchoalveolar Lavage; Bronchoalveolar Lavage Fluid; Carbachol; Cattle; Cell Count; Enzyme-Linked Immunosorbent Assay; Leukotriene B4; Linear Models; Lung Diseases; Pasteurella Infections; Pasteurella multocida; Regression Analysis; Reproducibility of Results; Respiratory Function Tests; Respiratory Syncytial Virus Infections; Respiratory Syncytial Virus, Bovine; Statistics, Nonparametric