Breath markers of oxidative stress and airway inflammation in Seasonal Allergic Rhinitis

Oxidative stress (OS) is well documented in asthma, but so far little data has been reported in non-asthmatic patients with Seasonal Allergic Rhinitis (SAR). The aim of this study is to investigate the degree of OS and airway inflammation in patients with SAR, with and without concomitant Asthma (SAR +A), using breath markers in exhaled air and in Exhaled Breath Condensate (EBC). In addition, the effects of natural allergen exposure and intranasal steroid treatment on these markers were evaluated. Exhaled NO (eNO) and CO, combined with measurements of 8-Isoprostane (Iso-8), Leukotriene B₄ (LTB₄) and nitrate/nitrite in EBC, were performed in 23 patients, 11 with SAR and 12 with SAR+A, and 16 healthy subjects. Iso-8 and LTB₄ were significantly increased in both groups of patients (median values 43.6 pg/ml and 138.4 pg/ml in SAR group; 38.9 pg/ml, and 164.6 pg/ml in SAR+A group respectively; p>0.05) compared to healthy subjects (18.6 pg/ml and 7.8 pg/ml; p<0.05). Nitrate/ nitrite and eNO levels were elevated in both groups compared to controls, but were significantly higher in the SAR+A compared to SAR group (nitrate/nitrite 9 μM and 3.9 μM; p=0.025; and eNO 18.5 ppb and 12.5 ppb, respectively; p>0.05). Nasal steroids caused significant reduction in LTB₄ and 8-isoprostane levels in both groups of patients (p<0.05), while nitrate levels and eNO concentration were little affected by nasal treatment. OS markers were decreased at normal levels out of pollen season. Natural allergen exposure induces OS and airway inflammation, as assessed by measurements of markers in EBC and exhaled air, in patients with SAR who have no clinical signs of lower airway involvement. Besides, intranasal steroid treatment may have a regulatory role in the OS.