leukotriene-c4 and Respiratory-Syncytial-Virus-Infections

It has been suggested that acute infantile bronchiolitis associated with respiratory syncytial virus (RSV) may share some pathogenic features with atopic asthma in that virus-specific IgE is produced and cysteinyl leukotrienes (cLTs) and eosinophil cationic protein (ECP) have been detected in airway secretions. ECP is a specific marker of eosinophil activation although leukotrienes can be released from a variety of cells including mast cells, eosinophils and monocytes.. To test the association between eosinophil activation and cysteinyl leukotriene production in the upper airway secretions of infants with RSV positive (RSV+ve) bronchiolitis.. Nasal lavage samples were performed in 78 infants (0.0-11.5 months) admitted to hospital with RSV+ve bronchiolitis soon after admission (0-48 h). Leukotriene C4 (LTC4) was assayed by enzyme immunoassay (EIA) and eosinophil cationic protein (ECP) by fluoroimmunoassay (FIA).. LTC4 was detectable in 51 and ECP in 57 of 78 samples with a significant positive relationship between LTC4 and ECP (r=0.557, P<0.001).. In the majority of our subjects with RSV+ve bronchiolitis ECP and LTC4 were detectable in upper airway secretions and were significantly associated with each other. In this clinical setting much of the detected LTC4 within upper airway secretions is likely to originate from the eosinophil, an observation that may have implications for clinical management and for delineation of the underlying mechanisms associated with this illness.

Topics: Blood Proteins; Bronchiolitis, Viral; Cysteine; Eosinophil Granule Proteins; Eosinophils; Female; Humans; Infant; Infant, Newborn; Leukotriene C4; Leukotrienes; Male; Nasal Lavage Fluid; Respiratory Syncytial Virus Infections; Respiratory Syncytial Virus, Human; Ribonucleases

One potential mechanism by which respiratory viruses trigger illness and complications is via the local elaboration of inflammatory mediators.. To determine whether there is an increase in local leukotriene C4 (LTC4) levels during experimental infection with influenza A virus (FLU), rhinovirus (RV), or respiratory syncytial virus (RSV).. Healthy adults were intranasally inoculated with a safety-tested strain of FLU (n = 29), RV (n = 16), or RSV (n = 21). Nasal lavage samples were collected, symptoms were recorded, and expelled nasal secretions were weighed before and then daily after challenge. Lavage samples were submitted for viral culture and assayed for LTC4 levels by radioimmunoassay. Serum antibody titers to the challenge viruses were assayed at baseline and 21 days after challenge.. All subjects were infected as evidenced by viral shedding and/or seroconversion. Following infection, significant increases (P < 0.05 by analysis of variance) in LTC4 levels were measured for each virus. Furthermore, there was a temporal association between the local LTC4 levels and the development of illness.. The results of this study, which used an adult experimental model, demonstrate elevations in locally produced LTC4 during respiratory infection with FLU, RV, and RSV. Future studies using antileukotriene agents may help elucidate the precise role of leukotrienes in mediating disease expression.

Topics: Adolescent; Adult; Cohort Studies; Humans; Influenza A virus; Influenza, Human; Leukotriene C4; Middle Aged; Nasal Lavage Fluid; Nasal Mucosa; Picornaviridae Infections; Respiratory Syncytial Virus Infections; Respiratory Syncytial Viruses; Respiratory Tract Infections; Rhinovirus; Time Factors