Disaccharidase activities in small intestinal mucosa in patients with cystic fibrosis.

The disaccharidase activities in small intestinal biopsies were related to the morphology of the mucosa and the ages of 63 patients with cystic fibrosis and 177 healthy control subjects of Caucasian origin. In patients with CF and in the healthy control subjects under 5 years of age with normal intestinal mucosa, no low lactase activity was found. In those patients with CF who were over 5 years of age, one group had high and one group had low lactase activity, as occurs in healthy Caucasian control subjects of the same age. This finding supports the view that in patients with CF, lactase deficiency is not related to the disease entity. In patients with or without CF who had the same degree of mucosal atrophy, the decrease of disaccharidase activities followed the same pattern, indicating that enzyme activities are affected to the same extent by the damage of the mucosa. In patients with CF with pancreatic insufficiency, the disaccharidase activities were significantly (P less than 0.001) higher when compared to those in control subjects of the same age and ethnic group, although the increase was not uniform in all patients with cystic fibrosis.