Background: Cysteinyl leukotrienes (CysLTs) are considered to play an important role in the pathogenesis of bronchial asthma. Leukotriene B4 (LTB4) is the most potent lipid chemotaxin known for neutrophils, which are implicated in sudden onset fatal asthma.
Objective: This study was conducted to study the activation of LTE4 and LTB4 in asthmatic patients and stable COPD patients and to determine whether the levels of these leukotrienes correlate with the degree of airway obstruction.
Subjects and methods: Seventy cases were included in this study, 30 cases with bronchial asthma, 30 cases with COPD and 10 age matched healthy subjects as a control.
Results: The mean values of urinary LTE4 /creatinine were significantly increased in asthmatic group compared to COPD and control groups. This increase was significantly higher during asthma attack as compared with remission state. The increase in urinary LTE4/creatinine in asthmatics was more significant in smokers than in nonsmokers. No significant difference was observed between smokers and nonsmokers in COPD or control groups. The increase of urinary LTE4/creatinine in asthmatics was associated with significant decrease in FEV1/ FVC % predicted. Serum LTB4 was above normal in all asthmatic and COPD groups. It was significantly higher in asthmatics during remission as compared to the control. However, patients with COPD had higher serum LTB4 levels than asthmatic group during attack.
Conclusion: Asthmatic patients present higher levels of urinary LTE4 as compared with COPD and control groups. This elevation was correlated with the degree of airway obstruction. Smoking habits significantly affect LTE4 levels only in asthmatics.
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