Protein content of gastroduodenal juice: concentration and significance.

IgG, IgA, IgM, C3 and albumin were measured in 572 samples of gastric juice and the bile fractions A, B and C obtained by a duodenal tube from 143 dermatological patients. The results were correlated to gastric acidity. The findings are consistent with the barrier function of gastric acid secretion, it having been found that, unless hypacidity or anacidity is present, the proteins in the gastric and duodenal fluid show neither high concentrations nor a wide variety. The finding that the fairly high IgA was nearly equal to the amount of IgG in the samples and that the concentration of albumin was much lower (IgG: albumin approximately equal to 2 : 1), seems to indicate that the immunoglobulins were produced by the local immune system.