TF and infection: In the study by Roland et al., examining TF levels in patients with COPD, during COPD exacerbation and 4–6 weeks later, TF levels were significantly higher during COPD exacerbation, while there was no correlation observed between the rise in TF, infection symptoms, and oxygen saturation during exacerbation; treatment with antibiotics or corticosteroids and TF levels during and after COPD exacerbation [77].