The clinical utility of reticular basement membrane thickness measurements in asthmatic children

Abstract Objective: Reticular basement membrane (RBM) thickness is one of the pathological features of asthma and can be measured in endobronchial biopsies. We assessed the feasibility of endobronchial biopsies in a routine clinical setting and investigated the clinical value of RBM thickness measurements for asthma diagnosis in children. Methods: We included all children who underwent bronchoscopy with endobronchial mucosal biopsies for clinical reasons and divided them into three subgroups: (1) no asthma, (2) mild–moderate asthma, and (3) problematic severe asthma. Results: In 152/214 (71%) patients, mean age 9.5 years (SD 4.6; range 0.1–18.7) adequate biopsies were retrieved in which RBM thickness could be measured. Mean (SD) RBM thickness differed significantly among children without asthma, with mild–moderate asthma, and with problematic severe asthma (p = 0.04), 4.68 (1.24) µm, 4.56 (0.89) µm, and 5.21 (1.10) µm respectively. This difference disappeared after adding exhaled nitric oxide to the multivariate model. Conclusions: This study confirms the difference in RBM thickness between children with and without asthma and between asthma severities in a routine clinical care setting. However, quantifying the RBM thickness appeared to have no added clinical diagnostic value for asthma in children.