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.