Concentrations of LTB₄, LTC₄, LTD₄ and LTE₄ in bronchiolitis due to respiratory syncytial virus

Fifty‐five infants with bronchiolitis due to respiratory syncytial virus were evaluated for the presence of leukotriene B₄, C₄, D₄ and E₄ in nasopharyngeal secretions. An attempt was made to correlate concentrations of leukotrienes to arterial oxygen tension. Forty participants received conventional therapy consisting primarily of aerosolized albuterol and occasional aminophylline therapy. The other 15 individuals received ribavirin therapy in addition to conventional therapy, and leukotriene concentrations were compared among individuals in these groups. RSV infection was documented by standard methods, and leukotrienes were measured by reverse‐phase high pressure liquid chromatography. The leukotriene detected most commonly was LTC₄ (up to 83% of subjects); LTD₄ and LTB₄ were present in approximately 30% of individuals. The mean partial pressure of oxygen was found to be lower in those individuals with detectable LTB₄ than in those without detectable LTB₄ (p < 0.025), and an overall inverse correlation of LTB₄ concentrations with initial pO₂ values was observed (r = 0.318, p < 0.05). The presence and quantity of other leukotrienes did not correlate with the severity of illness. During the first week of illness, the concentration of leukotrienes declined sharply in ribavirin recipients. Individuals receiving conventional therapy during the same time interval exhibited stable or increasing leukotriene concentrations. These observations suggest that LTB₄ may be important in the pathogenesis of bronchiolitis, and that ribavirin therapy may inhibit leukotriene release in the respiratory tract.