Gastric IgA in cystic fibrosis in relation to the migrating motor complex

Background: Gastrointestinal symptoms in cystic fibrosis are frequent, but little is known about the underlying pathophysiology. Mucosal secretion of IgA is important for the immunologic function in the human gastrointestinal tract but has not been studied in cystic fibrosis. The aim of this: study was to quantify the release of IgA by the gastric mucosa in relation to int erdigestive motor activity in patients with cystic fibrosis with different genotypes. Methods: The study included 7 healthy adult volunteers and 10 ad ult patients with cystic fibrosis, all Helicobacter pylori-negative. All pa tients had pathological sweat tests and clinical symptoms and signs of cyst ic fibrosis. All but one were colonized with Pseudonomas aeruginosa. Three patients were pancreatic sufficient. The investigation was performed using intragastric perfusion and gastroduodenal manometry. Results: During the in vestigation, 8 of 10 patients with cystic fibrosis showed the characteristi c pattern of interdigestive motility. The patients had significantly lower levels of gastric IgA compared to healthy subjects during phases II and III of migrating motor complex, median (range) 120 (67-442) and 36 (6-299) mug /5 min, 382 (40-1176) and 56 (4-398) (P = 0.03 and P = 0.04), respectively. Only one patient with genotype R668C/unknown showed IgA levels within the normal range. There was no correlation to gastric presence of duodenogastri c reflux markers. Conclusion: The interdigestive motility pattern was norma l in most patients with cystic fibrosis. The low levels of IgA released fro m the gastric mucosa in the patients might indicate a defective gastric tra nsmucosal IgA transport in cystic fibrosis.