Potential value of serum total IgE for differentiation between autoimmune pancreatitis and pancreatic cancer

Autoimmune pancreatitis (AIP) is associated with a marked elevation of serum total IgG₄ . Although there is evidence of autoimmunity in AIP, there are also signs of an allergic nature of its pathogenesis. Therefore, we determined both IgE and IgG₄ in 13 patients with AIP, in 12 patients with pancreatic carcinoma and in 14 patients with atopic allergy and investigated the relationship between IgE and IgG₄ . Total IgG₄ was determined by automated nephelometry and total IgE by automated enzyme fluoroimmunoassay. Both total IgE and total IgG₄ levels in patients with AIP were significantly higher than those in patients with pancreatic carcinoma (P = 0.0004 and P = 0.015, respectively). There was a significant correlation between the total IgE and total IgG₄ levels in patients with AIP and patients with atopic allergy (r(s) =0.82, P=0.0006 and r(s) =0.88, P < 0.0001, respectively). The IgE/ IgG₄ ratio in sera from patients with atopic allergy was significantly different (P = 0.0012) from this ratio in sera from patients with AIP. These results suggest that analysis of total IgE in serum might be useful in the differentiation between autoimmune pancreatitis and pancreatic carcinoma.