Evaluation of neutrophils phagocytosis and killing in pulmonary cystic fibrosis patients

Abstract

Introduction: Cystic fibrosis (CF) is the most common monogenic disease that is eventually lethal. It is characterized by chronic bacterial infection of the lung and affecting additional organs including pancreas and liver. Neutrophils form the largest number of inflammatory cells in the airways of cystic fibrosis patients. Previous studies have shown that the killing function of neutrophils in CF patients is preserved, but maybe influenced by Pseudomonas aeruginosa (PA) colonization during the disease progression. Objective: To evaluate the phagocytosis and bacterial killing of Staphylococcus aureus (SA) and Pseudomonas aeruginosa (PA) by neutrophils in CF patients in comparison with cells of healthy controls. Materials and Methods: Our study was conducted in 10 CF patients (confirmed by clinical examination, sweat test and mutational analysis) in the Masih Daneshvari hospital (Tehran, Iran) and 10 age- and gender-matched healthy control subjects in 2017. Neutrophils were isolated from the peripheral blood of patients with CF patients and control subjects. The cells were incubated with SA and PA -labeled with GFP in a FLUOstar OPTIMA Microplate Fluorescent Reader. The fluorescence was measured over time as a measure of bacterial counts. Results: Neutrophils of CF patients were able to contain SA for long periods of time (72±5 h) that were significantly longer than by cells from healthy control (25±6 h) P≤0.05). Whereas, no differences in releasing of PA was observed. Our data support the hypothesis that neutrophils of CF patients exhibit a primed phenotype that enables them to contain SA longer than unprimed cells isolated from control individuals.