Measurement of nitric oxide and 8-isoprostane in exhaled breath of children with atopic eczema.

Background: Leukotriene (LT) E(4) and 8-isoprostane concentrations are elevated in exhaled breath condensate in children with asthma. The effects of leukotriene receptor antagonists (LTRAs) on exhaled leukotriene and prostanoids in children with asthma are unknown. Objective: (1) To study the effect of montelukast, a LTRA, on exhaled LTE(4),8-isoprostane, and prostaglandin E(2) in children with asthma and atopic children; (2) to measure exhaled nitric oxide. Methods: An open-label study with oral montelukast (5 mg once daily for 4 weeks) was undertaken in 17 atopic children with asthma and 16 atopic children without asthma. Results: Pretreatment exhaled LTE(4) (P < .0001) and 8-isoprostane (P < .0001) values were higher in atopic children with asthma than in atopic children without asthma. In atopic children with asthma, montelukast reduced exhaled LTE4 by 33% (P < .001), and this reduction was correlated with pretreatment LTE(4) values (r = -0.90; P =.0001). Posttreatment exhaled LTE(4) levels in children with asthma were higher than pretreatment LTE(4) values in atopic children without asthma (P < .004). Montelukast had no effect on exhaled LTE(4) in atopic children without asthma (P =.74), or on exhaled 8-isoprostane (atopic children with asthma, P =.94; atopic children without asthma, P =.55) and PGE(2) (atopic children with asthma, P =.56; atopic children without asthma, P =.93) in both groups. In atopic children with asthma, exhaled nitric oxide concentrations were reduced by 27% (P <.05) after montelukast. Conclusion: Leukotriene receptor antagonists decrease exhaled LTE(4) in atopic children with asthma. This reduction is dependent on baseline exhaled LTE(4) values. Clinical implications: Measurement of exhaled LTE(4) might help identify children with asthma most likely to benefit from LTRAs.