Extradigestive Manifestations of Helicobacter pylori Infection: What is Proven and Unproven in 2014?

It has long been known that chronic bacterial infections have an impact upon the overall organism. H. pylori infection is no exception to the rule. Indeed, the infection is acquired early in life and induces an intense/moderate local and systemic inflammatory status that lasts for the entire patients’ life. During this time, different organs and systems of infected individuals are exposed to injures exerted by the inflammation and immune responses to the infection, as well as to autoimmune reactions triggered by mechanisms of antigenic mimicry between human tissue cells and H. pylori. The CagA-positive bacterial genotype is mostly involved in extradigestive manifestations of such an infection, due to the increased inflammatory potential of this organism. The organs and systems that most of all may suffer from the detrimental consequences of H. pylori infection are the cardiovascular (ischaemic heart diseases), haematological (purpura, urticaria etc.), central nervous (Parkinson’s and Alzheimer’s diseases) and endocrine systems (autoimmune thyroid disorders). There is an increasing evidence, however, that no district of the human body is sheltered from the harmful effects of H. pylori infection. In conclusion, H. pylori infection may have deleterious consequences on organs and systems different from the gastroduodenal tract. To better understand the pathogenic mechanisms of extradigestive disorders associated with H. pylori infection, is essential to determine the CagA status of the infecting organisms