Pancreatic autoantibodies in Crohn's disease: A family study

Background-Pancreatic antibodies occur in about one third of patients with Crohn's disease. Aims-To evaluate the relevance of pancreatic antibodies as a genetic marker in patients with Crohn's disease and their first degree family members and spouses. To characterise further pancreatic antibodies by assessment of IgG subclasses. Methods-Six hundred and fifty serum samples were tested for pancreatic antibodies by immunofluorescence on sections of human pancreas. Incidence of pancreatic antibodies and their subtypes were studied on 212 serum samples from patients with Crohn's disease. In the familial study, 72 patients with Crohn's disease and 196 first degree family members and 26 patients with ulcerative colitis and 90 first degree family members were included. Ten healthy families sewed as controls. Results-Pancreatic antibodies were found in 58 (27%) of the patients with Crohn's disease and in none of the controls. Thirty patients had pancreatic antibodies of subtype I characterised by a drop-like fluorescence in the pancreatic acini, 28 patients had subtype II with a fine speckled staining in the acinar cells. Pancreatic antibodies of subtype I were both IgG1 and IgG2 antibodies by contrast with subtype II which were mainly of IgG1 subclass. Only five of 196 first degree relatives of patients with Crohn's disease had pancreatic antibodies. Four of these people had anamnestic data compatible with inflammatory bowel disease. Further investigations showed Crohn's disease in two of these people. In families with more than one member positive for pancreatic antibodies, pancreatic antibodies were of the same subtype in all cases. Conclusions-Pancreatic antibodies are a specific marker for Crohn's disease. Two subgroups of pancreatic antibodies can be distinguished by their pattern and immunoglobulin subclasses. Pancreatic antibodies rarely occur in family members of patients with Crohn's disease. These family members may also have Crohn's disease.