We have been privileged to start our academic careers at the begin ning of the decade in which the immunological roles and hypersensitivity diseases of the gastrointestinal tract and liver have been defined. In the early 1960s IgA was reported to be the main secretory immunoglobulin, immunoblasts were shown to home to the intestinal mucosa and certain serum autoantibodies were described in patients with chronic liver disease. Shortly thereafter IgE and Australia antigen were discovered. Parallel advances in clinical investigation, in particular closed biopsy techniques, facilitated...