Bronchiolitis and subsequent wheezing: role of neutrophils

<bold>Background:</bold> Risk factors for bronchiolitis and for recurrent wheezing remain unclear. Neutrophils assessment at the time of bronchiolitis hospitalization could play an important role. <bold>Aim:</bold> To study the correlation between blood netrophils’ level in patients with bronchiolitis and recurrent wheezing. <bold>Materials:</bold> 645 children hospitalized for bronchiolitis during 9 consecutive seasons were followed for 6 years. Clinical and laboratory information were obtained from clinical charts and a structured questionnaire was used to obtain demographic information. Parents were interviewed every year after hospitalization to check whether their children experienced recurrent wheezing. We considered patients who had more than two episodes of wheezing positive at follow-up. In accordance with the 75th percentile for number of neutrophils at the time of bronchiolitis hospitalization we divided the population into two groups <6000/μL (Group 1) and >6000/μL (Group 2). At 72 months after bronchiolitis 253 patients performed lung function tests (spirometry). <bold>Results:</bold> Patients in Group 2 had a higher wheezing probability at 12, 24 and 36 months after bronchiolitis (59.6% vs 49.6%, p=0.05; 49.2% vs 40.3%, p=0.08; 46.2% vs 33.1%, p=0.01). No difference was found at 48, 60 and 72 months after bronchiolitis (34.8% vs 27.1%, p=0.078; 22.8% vs 21.3%, p=0.42; 15.2% vs 14.9%, p=0.53). Spirometries performed at 6 years of age didn’t show significant differences in these two groups. <bold>Conclusions:</bold> Neutrophils inflammation can explain recurrent wheezing.