Antioxidant-
oxidant imbalances in bronchoalveolar lavage fluid (BAL) are thought to contribute to oxidative stress in respiratory disease. However, normal reference ranges for BAL
antioxidants and oxidized
proteins in children are not available. In this study, we recruited 124 children attending for elective surgery for a noninflammatory condition; 83 were nonasthmatic, nonatopic (N) and 41 were nonasthmatic, atopic (NA). A nonbronchoscopic lavage was performed and ascorbate,
uric acid,
alpha-tocopherol, and
protein carbonyl (as a measure of oxidative damage) concentrations were determined in BAL fluid. The 95% reference range was 0.112-1.897 micromol/L for ascorbate, 0.149-2.163 micromol/L for
urate, 0.0029-0.066 micromol/L for
alpha-tocopherol, and 0.280-4.529 nmol/mg for
protein carbonyls in BAL fluid. Age, gender, and exposure to environmental tobacco
smoke did not affect the concentration of ascorbate,
urate,
alpha-tocopherol, or
protein carbonyls. However, in multiple linear regression analyses, the type of home heating (glass-fronted fires or oil-fired central heating) was found to influence ascorbate and
urate concentrations in the BAL fluid (ss-coefficient for ascorbate: 0.445, p = 0.031; for
urate: 0.114, p = 0.001). There was no significant difference between the N and NA group in BAL fluid concentrations of ascorbate,
urate, or
protein carbonyls. The
alpha-tocopherol concentration was significantly increased in the NA group (p = 0.037).
Uric acid and
alpha-tocopherol concentrations in BAL fluid and serum were not correlated. Intriguingly, serum and BAL ascorbate concentrations were significantly correlated (r = 0.297, p = 0.018, n = 63), which may offer an explanation for why supplementing the diet with
vitamin C can improve
asthma symptoms. Further studies will investigate the role of BAL
antioxidant concentrations in children with inflammatory
respiratory diseases.