Table 1 Typical COPD and CF biomarkers.
Biomarker | Illness | Classification | Characteristics |
|---|---|---|---|
Forced Expiratory Volume in 1 second (\(FEV_1\)) | COPD, CF | Severity and prognosis | Measures lung activity and air flow. Reduction, irreversibility and chronicity of the \(FEV_1\) differentiate COPD and CF33,34. |
Exhaled Breath Condensate (EBC) | COPD | Exacerbations | Recollected by cooling exhaled air. pH of EBC from COPD patients is lower than that of healthy individuals, providing a biomarker based on the acidity of the breath condensate27. |
Neutrophils | COPD, CF | Exacerbations | These are inflammatory cells which activity serve to monitor lung function. They are related to airway obstruction, mucus hypersecretion and alveolar destruction.35,36,39 |
C-Reactive Protein (CRP) | COPD | Prognosis, mortality and exacerbations | This protein takes part on systematic inflammatory response. COPD patients present higher concentrations of CRP than healthy individuals27,36. |
Interleukin 6 (IL-6) | COPD | Exacerbations | This protein regulates the immunological response. COPD patients display higher IL-6 concentrations than healthy individuals27,36. |
Fibrinogen | COPD | Exacerbations | Predicts moderate and severe exacerbations in COPD, accompanied by an increment of concentration in inflammation phases27,36. |
Clara cell protein (CC16) | COPD | Severity and exacerbations | This protein possesses anti-inflammatory properties and its concentration decreases in COPD patients27. |
Surfactant Protein D (SP-D) | COPD | Therapeutic response | This protein protects against infections and oxidizing agents. COPD patients experiment relatively higher levels of SP-D and its concentration decreases when administrating corticosteroids27. |
Sweat-chloride concentration | CF | Therapeutic response | Reliable test for discriminating between minimal, partial and full CF transmembrane-conductance regulator (CFTR) protein function. Still needs clinical studies to support it as a biomarker for drug development35. |
Nasal Potential Difference (NPD) | CF | Therapeutic response | Isolates CFTR activity in nasal mucus and it is sensitive enough to detect dose-dependent bioactivity. Requires specialised equipment35. |
Intestinal Current Measurement (ICM) | CF | Therapeutic response | Tracks CFTR-dependent ion transport. Requires a rectal biopsy35. |
Bacterial density in sputum | CF | Therapeutic response | The most common bacteria linked to infection and morbidity on CF patients are P. aeruginosa, Burkholderia cepacia complex and Staphylococcus aureus. The presence of these bacteria is a sign of disease and it can be useful to determine the infection degree35. |
