Background: Dysregulation of eicosanoids is associated with asthma and a composite of oxylipins, including exhaled LTB4, but their potential utility in monitoring the therapeutic outcomes has not been comprehensively assessed. Objectives: We aimed to examine the levels of major eicosanoids representing different metabolic pathways in exhaled breath condensates (EBCs) of children with asthma during exacerbation and after treatment. Methods: Levels of 6 exhaled eicosanoid species in asthmatic children and healthy subjects were evaluated using ELISA. Results: In addition to those previously reported, including LTB4, LTE4, LXA4 and PGE2, the levels of exhaled 15-HETE, but not TXB2, showed significant difference between asthmatics (N=318) and healthy controls (N=97). When the asthmatic population was stratified into different severity groups, the severe group was characterized by significantly lower levels of 15-HETE and 15-HETE/LTB4 ratio, as compared to the mild and control groups. Receiver Operating Characteristic (ROC) analyses revealed similar distinguishing power for the level of exhaled 15-HETE and those of FEV1 and FeNO. Analysis of asthmatics (N=75) during exacerbation and convalescence showed significant improvement in lung function (FEV1; p<0.001), but not FeNO, concomitant with significantly increased levels of 15-HETE (p<0.001) and reduced levels of TXB2 (p<0.05) after therapy, particularly for those who at the top 30% level during exacerbation. Further, decreased LTB4 and LXA4 at convalescence were noted only in those at the top 30 percentile during exacerbation. Conclusion: The exhaled 15-HETE was found to discriminate childhood asthma while decreased levels of exhaled TXB2 and increased levels of 15-HETE were prominent after treatment.

Background: Dysregulation of eicosanoids is associated with asthma and a composite of oxylipins, including exhaled LTB4, characterizes childhood asthma. While FeNO has been used as the standard for monitoring steroid responsiveness, the potential utility of eicosanoids in monitoring the therapeutic outcomes remains unclear. We aimed to examine the levels of major eicosanoids representing different metabolic pathways in exhaled breath condensates (EBCs) of children with asthma during exacerbation and after treatment. Methods: Levels of 6 exhaled eicosanoid species in asthmatic children and healthy subjects were evaluated using ELISA. Results: In addition to those previously reported, including LTB4, the levels of exhaled 15-HETE, but not TXB2, showed significant difference between asthmatics (N=318) and healthy controls (N=97), particularly the severe group showed the lowest levels of exhaled 15-HETE. Receiver Operating Characteristic (ROC) analyses revealed similar distinguishing power for the levels of 15-HETE, FEV1 and FeNO, whilethe 15-HETE/LTB4 ratio was significantly lower in subjects with severe asthma (p<0.01). Analysis of asthmatics (N=75) during exacerbation and convalescence showed significant improvement in lung function (FEV1; p<0.001), but not FeNO, concomitant with significantly increased levels of 15-HETE (p<0.001) and reduced levels of TXB2 (p<0.05) after therapy, particularly for those who at the top 30% level during exacerbation. Further, decreased LTB4 and LXA4 at convalescence were noted only in those at the top 30 percentile during exacerbation. Conclusion: The exhaled 15-HETE was found to discriminate childhood asthma while decreased levels of exhaled TXB2 and increased levels of 15-HETE were prominent after treatment.

Background: Serum or cord blood soluble Fas ligand (FasL) has been related to asthma, allergic rhinitis, and atopic dermatitis in cross-sectional and short-term follow-up studies. However, the association of cord blood soluble FasL with long-term allergic outcomes has seldom been investigated. Thus, this study investigated the relationship between cord blood soluble FasL and long-term allergic outcomes in a follow-up birth cohort. Methods: The Prediction of Allergies in Taiwanese Children birth cohort study recruited healthy newborns upon delivery. At birth, blood was collected from the umbilical cords of these children, and the cord blood soluble Fas ligand levels were measured. At the age of seven years, the allergic outcome of each child was diagnosed by pediatric allergists and pulmonologists. Tests were conducted to measure the specific immunoglobulin E, fractional exhaled nitric oxide (FeNO), and pulmonary function levels of each child. Results:Cord blood soluble FasL levels were higher in 7-year-old children with allergic rhinitis (Odds ratio [OR] = 2.41, p = .012) and expiratory airway obstruction (the highest forced expiratory volume in 1 second/ forced vital capacity < 90%, OR = 2.11, p = .022). The FeNO and Dermatophagoides pteronyssinus-specific immunoglobulin E levels of 7-year-old children were positively correlated with cord blood soluble FasL levels (p = .006 and .02, respectively). Conclusion: In this birth cohort, the cord blood soluble FasL levels were associated with allergic rhinitis, obstructive-type lung function, FeNO, and house dust mite sensitization in 7-year-old children. The cord blood soluble FasL level might be used as a predictor for allergic diseases in children who are 7 years old.