Roles of Inflammatory Biomarkers in Exhaled Breath Condensates in Respiratory Clinical Fields

Abstract

Background: Exhaled condensates contain inflammatory biomarkers; however, their roles in the clinical field have been under-investigated.

Methods: We prospectively enrolled subjects admitted to pulmonology clinics. We collected exhaled breath condensates (EBC) and analysed the levels of 6 and 12 biomarkers using conventional and multiplex enzyme-linked immunosorbent assay, respectively.

Results: Among the 123 subjects, healthy controls constituted the largest group (81 participants; 65.9%), followed by the preserved ratio impaired spirometry group (21 patients; 17.1%) and the chronic obstructive pulmonary disease (COPD) group (21 patients; 17.1%). In COPD patients, PDGF-AA exhibited strong positive correlations with COPD assessment test (ρ = 0.5926, p = 0.0423) and SGRQ-C score (total, ρ = 0.6725, p = 0.0166; activity, ρ = 0.7176, p = 0.0086; and impacts, ρ = 0.6151, p = 0.0333). Granzyme B showed strong positive correlations with SGRQ-C score (symptoms, ρ = 0.6078, p = 0.0360 and impacts, ρ = 0.6007, p = 0.0389). IL-6 exhibited a strong positive correlation with SGRQ-C score (activity, ρ = 0.4671, p = 0.0378). The absolute serum eosinophil and basophil counts showed positive correlations with pro-collagen I alpha 1 (ρ = 0.6735, p = 0.0164 and ρ = 0.6295, p = 0.0283, respectively). In healthy subjects, FEV1/FVC demonstrated significant correlation with CCL3/MIP-1 alpha (ρ = 0.3897 and p = 0.0068). FEV1 exhibited significant correlation with CCL11/eotaxin (ρ = 0.4445 and p = 0.0017).

Conclusions: Inflammatory biomarkers in EBC might be useful to predict quality of life concerning respiratory symptoms and serologic markers. Further studies are needed.