Bronchial Epithelium of Children With Post-infectious Bronchiolitis Obliterans

Bronchiolitis obliterans (BO) is an irreversible chronic obstructive pulmonary pathology leading to obstruction and/or obliteration of the small airways. In children, the most common form of BO occurs following a serious lower respiratory tract infection. This is a rare complication; the incidence is unknown. The diagnosis, often late, is made on clinical, spirometric and radiological arguments. The pathophysiology would be linked to damage to the airway epithelium. PIBO is most commonly associated with adenovirus (ADV) infection (serotypes 3, 7, 11 and 21) but also other viruses such as rhinovirus (RV). The treatment of PIBO is not clearly established, it remains empirical. The research hypothesis is that the morphology of the nasal epithelium of children with ADV or RV infection is different for those progressing to PIBO. The main objective of the proposed observational study is to characterize damage to the respiratory epithelium in these children. This is a single-center prospective longitudinal study (AP-HM), in children aged 1 month to 6 years, comparing children hospitalized for lower respiratory infection by ADV or RV progressing or not to PIBO. All children included will have a nasal swab and brushing on D0. Children developing PIBO will have nasal brushing with bronchial endoscopy with bronchial biopsies and bronchoalveolar washing at the time of PIBO diagnosis and again at M6 in case of partial response to treatment. This is therefore a pilot study aimed at defining damage to the respiratory epithelium in children with PIBO following an ADV or RV infection and the role of respiratory epithelial cells in PIBO.