Clara cell protein in nasal lavage fluid and nasalnitric oxide - biomarkers with anti-inflammatoryproperties in allergic rhinitis

摘要

Background Clara cell protein (CC16) is ascribed a protective and anti-inflammatory role in airway         inflammation. Lower levels have been observed in asthmatic subjects as well as in         subjects with intermittent allergic rhinitis than in healthy controls. Nasal nitric         oxide (nNO) is present in high concentrations in the upper airways, and considered         a biomarker with beneficial effects, due to inhibition of bacteria and viruses along         with stimulation of ciliary motility. The aim of this study was to evaluate the presumed         anti-inflammatory effects of nasal CC16 and nNO in subjects with allergic rhinitis.      Methods The levels of CC16 in nasal lavage fluids, achieved from subjects with persistent         allergic rhinitis (n = 13), intermittent allergic rhinitis in an allergen free interval         (n = 5) and healthy controls (n = 7), were analyzed by Western blot. The levels of         nNO were measured by the subtraction method using NIOX®. The occurrences of effector cells in allergic inflammation, i.e. metachromatic cells         (MC, mast cells and basophiles) and eosinophils (Eos) were analyzed by light microscopy         in samples achieved by nasal brushing.      Results The levels of CC16 correlated with nNO levels (r2 = 0.37; p = 0.02) in allergic subjects.      The levels of both biomarkers showed inverse relationships with MC occurrence, as         higher levels of CC16 (p = 0.03) and nNO (p = 0.05) were found in allergic subjects         with no demonstrable MC compared to the levels in subjects with demonstrable MC. Similar         relationships, but not reaching significance, were observed between the CC16 and nNO         levels and Eos occurrence. The levels of CC16 and nNO did not differ between the allergic         and the control groups.      Conclusions The correlation between nasal CC16 and nNO levels in patients with allergic rhinitis,         along with an inverse relationship between their levels and the occurrences of MC         in allergic inflammation, may indicate that both biomarkers have anti-inflammatory         effects by suppression of cell recruitment. The mechanisms behind these observations         warrant further analyses.