Small bowel mucosal dysfunction in patients with cystic fibrosis.

Jejunal biopsies were obtained from 37 children with cystic fibrosis, 16 with 
gluten-induced enteropathy, and 18 control subjects for the following studies: (1) 
disaccharidase activity, (2) L-ALA-L-Phe hydrolase activity, and (3) intestinal uptake of 
three 14C-labeled amino acids. Values were significantly reduced in the three 
determinations in patients with gluten-induced enteropathy as compared to control subjects. 
Lactase and L-ALA-L-Phe hydrolase activities were significantly reduced (p less than 
0.01) in CF patients as compared to control subjects. Definite hypolactasia 
was also observed in 23% of the children with CF. Uptake 
of lysine was normal in CF patients whereas that of phenylalanine 
and cycloleucine was reduced as compared to control subjects. This study 
suggests an intestinal component to the malabsorption of patients with CF. 
