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Follicle-associated epithelium of Peyer's patches can be differentiated from nearby villous epithelium by the presence of M cells which are antigen-sampling epithelial cells, and by an increase in intraepithelial lymphocytes that are in close contact with M cells. The phenotype of the immune cells close to the M cells of the follicle-associated epithelium of rat Peyer's patches was determined by immunohistochemistry and compared with that of the intra-epithelial lymphocytes of the villous epithelium. Lymphoid T cells, predominantly of the cytotoxic/suppressor phenotype, were observed both in follicle-associated epithelium and in villous epithelium. Lymphoid B cells, mainly immunoblasts and plasma cells containing intracytoplasmic IgM, were present only in the follicle-associated epithelium, near M cells. Macrophages were also present, in contact with M cells, in follicle-associated epithelium, but not in villous epithelium. In addition, M cells bore Ia molecules on their apical membranes. These findings reinforce the concept of immune specialization of the follicle-associated epithelium, by demonstrating that this epithelium contains all the effector cells of immune responses.

The authors report the case of a 30 year-old man with previous history of sarcoidosis, who presented with a painful infiltration of the pancreas. A review of the literature showed that symptomatic pancreatic sarcoidosis was uncommon, since only 8 other cases have been reported. Pancreatic involvement is frequently associated with hepatic infiltration (5/6 cases). Exocrine or endocrine dysfunction are possible. Diagnosis is made only at exploratory laparotomy. Prognosis is good. Steroid therapy is indicated in this peculiar type of pancreatitis, because of its long-range effectiveness on the outcome of the disease.

A randomized prospective trial was designed to evaluate the preventive treatment of esophagitis in 31 intensive care patients who had a nasogastric feeding tube for at least 10 days. Fourteen patients (group B) received no preventive treatment while 17 patients (group A) received 300 mg of cimetidine every 6 h intravenously and 11 g of colloidal aluminium phosphate every 4 h per os. All patients were fed a standard diet through their nasogastric tube at a constant rate of 30 Kcal/kg/day. Endoscopic controls at day 1 and 10 showed that the number of initial and final esophagitis was not different in groups B and A: 7 and 8 at day 1, 11 and 10 at day 10, respectively. The inefficiency of this preventive treatment suggested that acid gastroesophageal reflux is not a major factor in the occurrence of nasogastric feeding tube-induced esophagitis. However as esophagitis is associated with a more severe Knaus index and a greater number of gastric stress ulcer risk factors, it is suggested that decreased defense of the mucosa may be a key factor in the occurrence of this type of esophagitis.