Systemic Leukotriene Levels in COPD: Insights into Disease Pathogenesis and Severity

<bold>Introduction:</bold> Chronic obstructive pulmonary disease (COPD) arises from persistent inflammation that remains unresolved. However, the specific leukotrienes involved in COPD have yet to be fully characterized. We aimed to evaluate systemic leukotriene (LT) levels in both COPD patients and control subjects, and to analyze these levels based on COPD severity and clinical parameters. <bold>Methods:</bold> We conducted a case-control study at the Pulmonology Department of La Rabta Hospital between March and September 2022, involving 40 male patients diagnosed with confirmed stable COPD. This group was matched with a control group. Patients with COPD-related respiratory diseases and/or receiving immunosuppressive treatment were excluded. Patients underwent interviews, examinations, and disease severity was assessed using the 2022 GOLD guidelines. Blood samples were collected for Leukotrienes B4, D4, E4, and F4, and spirometry was performed. <bold>Results:</bold> The mean age was 64 years ±8 in the COPD group versus 59 years ±7 in the control group. COPD staging revealed that 17% of cases were classified as stage 3, and an equal proportion were classified as stage 4. A significantly higher level of LTB4 (p< 10^-3) and LTE4 (p=0,028) was found in the COPD group. The ROC curve analysis showed a significant diagnostic value of the following biomarkers in COPD: LTB4 (AUC=0,837, P< 10^-3) and LTE4 (AUC=0,847, p=0,028). The risk of COPD was 7 times higher for LTB4 and LTF4. A significant correlation between LTF4 and FEV1 (r=-0,360, p=0,023). No significant correlation was found between LT and the number of acute exacerbation of COPD. <bold>Conclusion:</bold> This study provides valuable insights into the underlying etiopathogenic mechanisms of COPD.