Immunoglobulin A secretion into pancreatic juice as a novel marker of local immune defense and exocrine pancreatic function

The importance of secretory immunoglobulin A (IgA) of local immune defense in the gastrointestinal tract has gained increasing acceptance. Bacterial c ontamination is a major factor related to mortality in acute pancreatitis. However, very little is known about IgA in pancreatic juice. Pure pancreati c juice was collected from 40 patients undergoing pancreatoduodenectomy. Th e patients were divided into three groups according to the degree of preope rative pancreatic duct obstruction, as follows: normal, narrowed, and obstr ucted. IgA concentration, amylase activity, and daily volume of pancreatic juice were measured. Daily IgA secretion into pancreatic juice was constant during the early period after the operation. The concentration of IgA in t he control group was 5 +/- 0.8 mug/ml, and IgA daily secretion was 1.2 +/- 0.2 mg/day. Pancreatic duct obstruction resulted in a marked decrease in bo th amylase and pancreatic juice secretion. The concentration of IgA, howeve r, was markedly increased in the narrowed group (11.1 +/- 2.4 mug/ml) and t he obstructed group (32.5 +/- 5.4 mug/ml). The concentration of amylase inc reased with the increase in pancreatic juice. Conversely, the concentration of IgA increased with the decrease in volume of pancreatic juice. Similarl y, the increased in IgA concentrations positively correlated with the decre ase in amylase activity. In conclusion, the mechanisms that modulate IgA se cretion in the human pancreas are essentially different from those that mod ulate digestive enzyme and fluid secretion. IgA in pancreatic juice may pla y an important role in pathological conditions such as pancreatic duct obst ruction. As such, the measurement of IgA in pancreatic juice may potentiall y be used as a new marker of local immune defense and exocrine pancreatic f unction.