Pancreatic stone protein and lactoferrin in human pancreatic juice in chronic pancreatitis.

Lactoferrin and pancreatic stone protein (PSP) are thought to be closely related to pancreatic stone formation in chronic pancreatitis. However, the results reported so far have not been conclusive. To reevaluate the pathological importance of PSP in chronic pancreatitis, compared to lactoferrin, levels of PSP were determined by applying an immunoassay specific to PSP to pure pancreatic juice taken from a total of 52 patients. The patients consisted of 16 controls, 19 chronic pancreatitis patients (13 noncalcified and 6 calcified), and 17 probable cases of pancreatitis. The monoclonal antibody PSP antagonist used in the study recognizes both forms of the protein, PSP S1 and S2-5, with equal effectiveness. No significant reduction of PSP was observed in either calcified (mean +/- SEM, 111 +/- 30 micrograms/mg and 24 +/- 3 micrograms/mg protein) or noncalcified (305 +/- 133 and 97 +/- 47) chronic pancreatitis patients compared with controls (85 +/- 23 and 34 +/- 16). PSP levels did not decrease, at least not in the complete forms of the protein found in chronic pancreatitis. PSP antibody and assay results indicated that a reduction of PSP S2-5 alone could not be ruled out in chronic pancreatitis either.