End-stage cystic fibrosis lung disease is characterised by a diverse inflammatory pattern: an immunohistochemical analysis

Elise J. Lammertyn, Elly Vandermeulen, Hannelore Bellon, Stephanie Everaerts, Stijn E. Verleden, Kathleen Van Den Eynde, Ken R. Bracke, Guy G. Brusselle, Pieter C. Goeminne, Erik K. Verbeken, Bart M. Vanaudenaerde, Lieven J. Dupont

Cystic fibrosis (CF) lung disease is characterised by vigorous airway inflammation eventually resulting in severe lung damage. This study aimed to describe the diversity of the inflammatory pattern in end-stage CF lungs by evaluating and quantifying which components of the innate and adaptive immunity are involved, and by assessing whether this is gender-specific. CF explant lung tissue (n = 20) collected at time of transplantation and control tissue (n = 22) was sectioned (9 μm) and stained for neutrophils, eosinophils, mast cells, dendritic cells, macrophages, CD4 T cells, cytotoxic T cells and B cells. Quantification with special attention for immune cell location was performed. Neutrophils, mast cells, dendritic cells, macrophages, CD4 T and cytotoxic T cells were significantly increased in CF compared to controls and there was a disproportionate increase of neutrophils around the airways in CF. Large amounts of lymphoid follicles were found in the CF lung and they had a skewed B cell/T cell composition. Upon subdividing the CF patients into a male and female population, eosinophils, mast cells and CD4 T cells were increased specifically in CF females. In this subpopulation, lymphoid follicles had less B cells and more CD8 T cells. These data demonstrate a diverse inflammatory response in the CF lung, reflected by an increase of both myeloid and lymphoid immune cells. Inflammation in the CF lung appeared to be gender-specific in our population, as the significant increase of eosinophils, mast cells and CD4 T cells was especially notable in the female subpopulation.