Subclass distribution of mucosal IgG-producing cells in gastritis.

IgG-mediated immune reactions are probably involved in the maintenance of gastritis and glandular atrophy; the mucosal IgG-subclass pattern may therefore influence the effect of local hypersensitivity mechanisms. In this study the proportions of IgG1-, IgG2-, IgG3-, and IgG4-producing immunocytes were determined by paired immunofluorescence staining in specimens from simple gastritis, gastritis after Billroth II (BII) resection, and gastritis associated with dermatitis herpetiformis (DH). The results were related to histopathological degree of inflammation and atrophy. Generally, IgG1 immunocytes predominated (48-60%) in all types of gastritis. With increasing severity of inflammation, the IgG2-cell proportion was significantly increased from 4-6% to 26-34% in simple and BII gastritis, whereas the ratio of IgG1 immunocytes was correspondingly decreased from 58-69% to 38-43%. In the same types of gastritis the proportion of IgG3 cells was increased in association with severe (35-38%) compared with mild (15-23%) atrophy, whereas the proportion of IgG1 cells was correspondingly decreased. In severe gastritis associated with DH, the proportion of IgG1 cells was relatively high (60%) and that of IgG2 cells relatively low (13%), and severe atrophy did not seem to influence significantly the subclass proportions.