Reticular basement membrane thickness for prediction of subsequent lung function in children with primary ciliary dyskinesia: follow up study.

Abstract

<b>Background:</b> In primary ciliary dyskinesia (PCD), the thickening of bronchial reticular basement membrane (RBM) has been described. Its impact on later lung function development remains unknown. <b>Objectives:</b> To investigate the relationship between RBM thickness and subsequent development of spirometry (SP) in PCD children. <b>Methods:</b> Bronchoscopy with bronchoalveolar lavage fluid (BALF) analysis and endobronchial biopsy (EBB) was performed in patients with PCD and in non-inflammatory controls. EBB samples were evaluated for RBM thickness using haematoxylin-eosin staining, percentage of neutrophils in BALF was assessed using cytospin method. SP was done prior to bronchoscopy and then at least every 6 months. Trends in z-scores of forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC) and FEV1/FVC were evaluated and related to RBM thickness, BALF neutrophil count and baseline SP. <b>Results:</b> EBB, BALF and spirometry data were available in 17 PCD patients and 15 controls. Mean follow up time was 5.7 and 2.1 years respectively (p &lt; 0.001). In PCD, RBM was thicker (6.05 vs. 3.35 μm, p &lt; 0.001) and BALF neutrophils increased (50.4 vs. 7.9 %, p &lt; 0.001) compared to controls. In PCD FEV1/FVC z-score significantly decreased during follow up (-0.16/year, p = 0.005), while in controls it remained stable (0.04/year, p = 0.452). In PCD, RBM was negatively correlated with FEV1 (r = -0.769, p = 0.002) and FEV1/FVC z-score decline (r = -0.739, p = 0.004). There was no such correlation for BALF neutrophils or any of the baseline SP parameters. <b>Conclusion:</b> RBM thickness is increased in PCD children and may predict subsequent decline in their SP.