Hypotheses on the pathogenesis and natural history of Helicobacter pylori-induced inflammation.

Although Helicobacter pylori is now recognized as playing an etiologic role in chronic gastritis and peptic ulcer disease, information on the pathogenesis and natural history of infection is limited. A model is proposed in which luminal H. pylori secrete substances that mediate inflammation that is beneficial to the organism but ultimately deleterious for the host; in addition to tissue damage, inflammation also affects gastric secretory function. In this model, the host may attempt to suppress the inflammatory response, and the adequacy of this postulated down-regulation determines pathological and clinical outcome. The effects of the inflammatory process on gastrin-hydrochloric acid homeostasis may be of critical importance in the pathogenesis of peptic ulcer disease. Because the long-term consequences of H. pylori colonization reflect the continued presence of the organism in the host over years or decades, it may be useful to consider this as a "slow" bacterial infection.