Immunology of ulcerative colitis.

Although much work has been done on the analysis of immunopathogenesis of UC, more mysteries remain to be solved in the future. One of the most interesting questions is (i) what initiates the immune response in the GALT of patients with UC. We are far from understanding whether inflammation starts from intrinsic or extrinsic factors. Valuable information has recently been assembled about (ii) antigen presentation and even more about (iii) regulation of immune response in the mucosa. Attractive models have been put forward concerning the integrity of GALT and in particular the role of Ig isotype and Ig subclasses. Further progress can be expected in particular from an analysis of homing of GALT-lymphocytes in disease. Thanks to improved methods, elucidation of regulation of immune response in patients with UC can be expected in the near future. This is less true for the effector functions of the immune response. In particular the action of mediators of acute and chronic inflammation, i.e. prostaglandins, leukotrienes and the broad spectrum of cytokines, represents a wide field of future research.