IL6 and chronic obstructive pulmonary disease: Among other cytokines, IL-33 is markedly elevated in COPD patients with lung cancer, showing negative correlation with FEV1/FVC and increasing with GOLD staging (150), Conversely, IL-6/IL-1β rise in tuberculosis patients, positively correlating with total lung capacity (TLC) and RV/TLC, respectively—collectively serving as disease severity indicators.