Histochemical observations on the pulmonary macrophages in cystic fibrosis.

The pulmonary macrophages collected with bronchial mucus from patients with cystic fibrosis 
and other chronic lung diseases were investigated histochemically for acid phosphatase, 
beta-glucuronidase and beta-glucosaminidase activity, and also for mucopolysaccharide content. In macrophages 
from patients with cystic fibrosis decreased beta-glucuronidase activity was observed, together 
with large cytoplasmic vacuoles suggesting storage of partially digested material. It 
thus seems very likely that apart from the increased synthesis of 
mucopolysaccharides described in cystic fibrosis by several authors, the degradation of 
mucosubstances produced can be impaired. 