The challenges of detecting neutrophil CFTR

Cystic fibrosis (CF) is a hereditary disorder caused by mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The major causes of morbidity and mortality in CF are related to lung disease, involving neutrophil-dominated lung inflammation. Whether the altered inflammatory response of neutrophils in patients with CF is an intrinsic defect due to a lack of CFTR expression, or alternatively, exacerbated by chronic exposure to infection and inflammation, is extensively debated. Fuelling this dispute are conflicting studies on CFTR protein expression by neutrophils, with opposing results described at both the gene and protein level. This is pertinent in the era of CFTR modulator therapies, with clinicians and scientists exploring the impact of different CFTR mutation classes and CFTR modulators on neutrophil function. To address this, the focus of this article is to uncover the cause for the described disparity of data on neutrophil CFTR expression, by investigating methods utilised for CFTR detection, and to draw consensus on the most optimal protocol for identifying CFTR protein in neutrophils.