BALF cytokines in different phenotypes of chronic lung allograft dysfunction in lung transplant patients

The long‐term success of lung transplantation ( LT ) is limited by chronic lung allograft dysfunction ( CLAD ). Different phenotypes of CLAD have been described, such as bronchiolitis obliterans syndrome ( BOS ) and restrictive allograft syndrome ( RAS ). The purpose of this study was to investigate the levels of cytokines and chemokines in bronchoalveolar lavage fluid ( BALF ) as markers of these CLAD phenotypes. BALF was collected from 51 recipients who underwent (bilateral and unilateral) LT . The study population was divided into three groups: stable ( ST ), BOS , and RAS . Levels of interleukin ( IL )‐4, IL ‐5, IL ‐6, IL ‐10, IL ‐13, tumor necrosis factor alpha ( TNF ‐α), interferon‐gamma ( IFN ‐γ), and granulocyte‐macrophage colony‐stimulating factor ( GM ‐ CSF ) were measured using the multiplex technology. BALF neutrophilia medians were higher in BOS (38%) and RAS (30%) than in ST (8%) ( P =.008; P =.012). Regarding BALF cytokines, BOS and RAS patients showed higher levels of INF ‐ γ than ST ( P =.02; P =.008). Only IL ‐5 presented significant differences between BOS and RAS ( P =.001). BALF neutrophilia is as a marker for both CLAD phenotypes, BOS and RAS , and IL ‐5 seems to be a potential biomarker for the RAS phenotype.