SERUM BETA-2-MICROGLOBULIN IN CHRONIC DISEASES OF THE PANCREAS

Elevated serum concentrations of beta 2-Microglobulin (beta 2-MG) has been reported in a variety of chronic diseases and solid tumors. We determined serum beta 2-MG concentrations in 140 subjects divided into five groups: group 1, 34 patients with proven chronic pancreatitis, 8 of whom were studied during a painful relapse; group 2, 40 patients with pancreatic cancer staged according to the Cubilla-Fitzgerald classification; group 3, 40 healthy subjects; group 4, 10 patients with digestive nonpancreatic carcinomas; group 5, 16 patients with benign digestive nonpancreatic diseases. Serum soluble interleukin-2 receptor (sIL-2R) was also determined in all patients with pancreatic diseases as an index of immune system activation. In addition, serum CA 19-9 was assayed in patients of groups 2 and 4, and C-reactive protein (CRP) of groups 1 and 5. Renal function, evaluated by serum creatinine determination, was normal in all subjects studied. Patients with pancreatic cancer and those with chronic pancreatitis had serum concentrations of beta 2-MG significantly higher than those of healthy subjects (p < 0.001 and p < 0.005, respectively). Patients with stage I and stage III pancreatic cancer had similar serum levels of beta 2-MG, and these concentrations were significantly lower than those of patients with stage II tumors (p < 0.002 and p < 0.05, respectively). In chronic pancreatitis patients, those studied during painful relapse of the disease had serum concentrations of beta 2-MG similar to those studied during clinical remission. A good correlation was found between serum concentrations of these two proteins (r = 0.73, p < 0.001). In patients with pancreatic cancer, serum beta 2-MG and serum CA 19-9 were abnormally high in 85 and 75%, respectively; in those with digestive nonpancreatic carcinomas, beta 2-MG was abnormally high in all patients, whereas CA 19-9 was so in 70%. Elevated serum levels of beta 2-MG in patients with pancreatic cancer may be the result of increased tumor cell turnover or to activation of the immune response by malignancy; the concomitant serum elevation of beta 2-MG and sIL-2R in these patients supports the latter hypothesis. The simultaneous increase in serum levels of sIL-2R, beta 2-MG, and CRP in patients with chronic pancreatitis probably reflects a persistent activation of the immune response during clinical remission of the disease as well.