Autoimmune-related pancreatitis is associated with autoantibodies and a Th1/Th2-type cellular immune response

Background & Aims: Although autoimmunity may be involved in some cases of p ancreatitis, the mechanism is still unknown. To clarify this, we studied se rum autoantibodies, subsets of lymphocytes, and the Th1/ Th2 balance of cel lular immune responses in patients with autoimmune-related pancreatitis (AI P), Methods: Seventeen patients with AIP (8 men and 9 women; age, 53.2 +/- 13.0 years) were studied. Autoantibodies including antilactoferrin (ALF) or carbonic anhydrase II antibody (ACA-II) were examined using the enzyme-lin ked immunosorbent assay (ELISA) or the indirect fluorescein antibody method . Intracellular cytokines (interferon gamma and interleukin 4) and subtypes of peripheral blood lymphocytes were examined by flow cytometry and ELISA, Results: More than one autoantibody was observed in all 17 patients. Serum antinuclear antibody was detected in 13 of 17 patients, ALF antibody in 13 , ACA-II antibody in 10, rheumatoid factor in 5; and anti-smooth muscle ant ibody in 3, but antimitochondrial antibody in none. The serum levels of ACA -II and LF antibody were not correlated. HLA-DR(+)CD8(+) and HL4-DR(+)CD4() cells were significantly increased in peripheral blood (P < 0.05). CD4(+) cells producing interferon gamma and the secreted levels were significantl y increased compared with those in controls (P < 0.05), but interleukin 4 w as not increased. Conclusions: An autoimmune mechanism against CA-II or LF, and Th1-type immune response, may be involved in AIP.