Helicobacter pylori (H. pylori) is the main cause of chronic
gastritis and a major risk factor for
gastric cancer. This pathogen has also been considered a potential trigger of gastric autoimmunity, and in particular of autoimmune
gastritis. However, a considerable number of reports have attempted to link H. pylori
infection with the development of extra-gastrointestinal autoimmune disorders, affecting organs not immediately relevant to the stomach. This review discusses the current evidence in support or against the role of H. pylori as a potential trigger of autoimmune rheumatic and
skin diseases, as well as organ specific
autoimmune diseases. We discuss epidemiological, serological, immunological and experimental evidence associating this pathogen with
autoimmune diseases. Although over one hundred
autoimmune diseases have been investigated in relation to H. pylori, we discuss a select number of papers with a larger literature base, and include Sjögrens syndrome,
rheumatoid arthritis,
systemic lupus erythematosus,
vasculitides, autoimmune skin conditions,
idiopathic thrombocytopenic purpura, autoimmune
thyroid disease,
multiple sclerosis,
neuromyelitis optica and autoimmune
liver diseases. Specific mention is given to those studies reporting an association of anti-H. pylori
antibodies with the presence of
autoimmune disease-specific clinical parameters, as well as those failing to find such associations. We also provide helpful hints for future research.