Gray, R D, Duncan, A, Noble, D, Imrie, M, O'Reilly, D S, Innes, J A, Porteous, D J, Greening, A P & Boyd, A C 2010, ' Sputum trace metals are biomarkers of inflammatory and suppurative lung disease ', Chest, vol. 137, no. 3, pp. 635-641 . https://doi.org/10.1378/chest.09-1047
Background: Induced sputum cytology and protein biomarkers can be used to assess airways infl ammation. Increases in sputum iron have been described in infl ammatory lung disease. We hypothesized that other sputum metals may be affected by airways infl ammation and investigated their potential value as biomarkers. Methods: Sputum was obtained from 20 healthy control subjects and from patients with infl ammatory pulmonary diseases (23 with cystic fi brosis [CF], 16 with bronchiectasis, 17 with asthma, and 23 with COPD), and iron, zinc, manganese, and copper were measured. Fourteen patients with CF were also studied through an exacerbation cycle. Results: Sputum zinc and iron were elevated in CF and non-CF bronchiectasis vs controls ( P , .001, zinc; P , .01 iron). Manganese was elevated in asthma ( P , .01) and bronchiectasis ( P , .05) vs controls. Copper was elevated in CF vs controls ( P , .05). Zinc decreased ( P , .01) following treatment of CF exacerbation. In subjects with CF zinc levels correlated with other biomarkers. Conclusions: These results suggest a relationship of high concentrations of total zinc and iron with airways infl ammation in CF and non-CF bronchiectasis, with longitudinal changes being observed in CF. Further work is required to elucidate potential infl ammatory mechanisms related to these observations. CHEST 2010; 137(3):635–641