Diminished cellular immune response to carbonic anhydrase II in patients with Sjögren's syndrome and idiopathic chronic pancreatitis.

CONTEXT A serum antibody to carbonic anhydrase II has been reported in patients with Sjögren's syndrome and idiopathic chronic pancreatitis. OBJECTIVE To evaluate cellular immune response to carbonic anhydrase II in patients with Sjögren's syndrome and idiopathic chronic pancreatitis. PATIENTS Idiopathic chronic pancreatitis (n=23), Sjögren's syndrome (n=12), alcoholic chronic pancreatitis (n=3) and normal controls (n=13). MAIN OUTCOME MEASURES Proliferation assay of peripheral blood mononuclear cells. RESULTS Notable increased proliferation of the mononuclear cells upon stimulation with carbonic anhydrase II was observed in 2 patients with idiopathic chronic pancreatitis (9%) and 2 patients with Sjögren's syndrome (17%) but not in patients with alcoholic chronic pancreatitis nor in normal controls. Among the four study groups, there was no significant difference in the prevalence rate of the positive proliferative responses (P=0.444). CONCLUSION Carbonic anhydrase II may not be a major target antigen for the immunological process in the pathogenesis of Sjögren's syndrome and idiopathic chronic pancreatitis. Serum antibody to carbonic anhydrase II may be detected in these patients as a consequence of the immune reaction against other antigens which mimic carbonic anhydrase II.