ULTRASTRUCTURAL LESIONS IN THE SMALL-BOWEL OF PATIENTS WITH CYSTIC-FIBROSIS

In the small bowel of patients with cystic fibrosis, primary defects i nvolving both chloride transport and mucus secretion have been demonst rated, but there is no general consensus about the morphologic counter part of functional and biochemical abnormalities. We have studied the intestinal mucosa in a group of patients with cystic fibrosis and gast rointestinal symptoms with the aim of evaluating whether the intestina l mucosa is normal as previously described. The results showed that th e small bowel involvement is characterized by a typical pattern of les ions with preservation of the mucosal architecture and abundant mucus at the surface. In the villi, the absorbing cells were generally well preserved, but unusual features were found in the apical portion of th e goblet cells, which formed sacks containing mucus droplets. Similar sacks were also found detached from the goblet cells. Aspects of degen eration were present in the upper portion of the crypts where elements with an extensive vacuolization of the cytoplasm and swelling were de tectable. This study demonstrates that in patients with cystic fibrosi s the ultrastructure of the small bowel mucosa is not normal as previo usly described, but that an ultrastructurally detectable enteropathy e xists. This enteropathy seems to be localized mainly in sites where mo lecular biology studies described the highest expression of cystic fib rosis transmembrane conductance regulator.