[Gastritis C, non-A non-B and the Sydney system: European unification or tower of Babel?]

The isolation of Helicobacter pylori from the human stomach has changed the insights into the mechanisms of chronic gastritis. The altered concepts are reflected in newly developed classification systems. In 1989 distinction of the types A, B and C of chronic gastritis was proposed as a working formulation. In this classification type A gastritis is an autoimmune disease with antibodies against parietal cells and intrinsic factor. It is limited to the body of the stomach and may be complicated by pernicious anaemia. Type B gastritis is related to bacterial infection by Helicobacter pylori and predominantly affects the antrum. It is associated with peptic ulcer disease. Type C gastritis is caused by chemical injury due to bile reflux and drugs. Especially NSAIDs are implicated. Each of these forms of gastritis has its histological counterpart. In 1990 the A, B, C terminology was overruled by the Sydney system, which recognises three forms of gastritis: acute, chronic and special forms and is otherwise mainly descriptive. The different classification systems are briefly discussed. It is concluded that uniformity in classification is most important since it will facilitate epidemiologic research of the natural history and long-term outcome of these diseases.