Secretory immunoglobulin A in pancreatic juice and pancreatictissue of patients with chronic pancreatitis

Background—The predominace of secretory IgA(S-IgA) in intestinal secretions compared with blood is wellestablished, but concentrations of this protein in pancreatic juice andits origin, especially in chronic pancreatitis, are unknown.
Aims—To investigate the role of S-IgA in chronic pancreatitis.
Patients—Twenty one patients with chronicpancreatitis (group I), three patients with proven malignancies (groupII), and 12 patients without pancreatic disease (group III).
Methods—Pure human pancreatic juice was collectedendoscopically in four fractions after consecutive stimulation withsecretin and cholecystokinin (CCK). Samples were analysed for S-IgA,protein, trypsinogen, and proteolytic activity.
Results—The S-IgA level was significant increasedin fraction 1 of pancreatic juice of group I (1210 (1411) ng/ml)compared with controls (33 (70) ng/ml). Protein concentrations andtrypsinogen content were lower in group I than in the other groups.Proteolytic activity could be observed in 53% of all 133 pancreaticjuice samples, but in 87% of fraction 1. In pancreatic tissue of three patients with chronic pancreatitis both IgA and secretory component were detected by immunohistology. Expression of the secretory componentby human pancreatic epithelial cells was increased in patients withchronic pancreatitis compared with normal controls. The concentrationof S-IgA in pancreatic juice did not correlate with the serum S-IgAlevel. In contrast, serum levels of S-IgA were decreased in patientswith chronic pancreatitis.
Conclusion—There are high levels of S-IgA inhuman pancreatic juice following chronic inflammation and a protectiverole is suggested for this immunoglobulin.

Keywords:chronic pancreatitis; pancreatic juice; proteaseactivity; protease inhibitors; secretory IgA; immunohistochemistry