Quantitative distribution of immunoglobulin-producing cells in gastric mucosa: relation to chronic gastritis and glandular atrophy.

Immunoglobulin (Ig)-producing immunocytes were quantified by paired immunofluorescence staining in specimens of gastric antral (n = 52) and body (n = 117) mucosa obtained from 45 patients with various gastrointestinal disorders. Enumerations were carried out in a 500 micron wide zone from the muscularis mucosae to the lumen ('tissue unit'). The specimens were divided into three categories according to the degree of inflammation, and each specimen received a grade for atrophy (0-2). The total number of IgA-, IgM- and IgG-producing cells per tissue unit increased strikingly with increasing degree of inflammation, both in antral and body mucosa. IgA immunocytes predominated (61-91%) in all specimens, but the IgG isotype showed the largest relative increase (four to 17-fold), particularly in the basal part of the mucosa. In this layer of the gastric body the proportion of IgG cells was also significantly raised in association with atrophy, irrespective of degree of inflammation. Locally produced IgG may be of protective significance in terms of internal (or 'second line') defence but may at the same time maintain immunopathological mechanisms contributing to the chronicity of gastritis.