title: Persistent bacterial infections and primary immune disorders.
abstract: Mycobacteria, Salmonella and Helicobacter species have all evolved mechanisms to evade host defenses and cause persistent infection in humans. Host control of mycobacteria and Salmonella is largely achieved by the IFN-gamma/IL-12 pathway. Immune disorders affecting this pathway are characterized by disseminated infections with environmental or nontuberculous mycobacteria. Helicobacter is a predominantly extracellular bacterium that uses its remarkable genetic diversity (as well as other mechanisms) in order to evade host defenses. The importance of humoral immunity in containing Helicobacter infections to the mucosal surface is illustrated by the primary immune disorder, X-linked agammaglobulinemia in which patients are prone to chronic bacteremia and skin infections by Helicobacter and related species such as Flexispira and Campylobacter. Exploration of these particular infections in their specific immune defects sheds light on both host and bacterial mechanisms that have implications for pathogenesis and therapy.
authors.affiliation: National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-1684, USA.
authors.forename: Alexandra F
authors.initials: AF
authors.lastname: Freeman
authors.forename: Steven M
authors.initials: SM
authors.lastname: Holland
mesh_terms: D001424:Bacterial Infections / Q000235:genetics* / Q000276:immunology*; D020022:Genetic Predisposition to Disease; D016481:Helicobacter Infections / Q000235:genetics / Q000276:immunology; D006801:Humans; D007154:Immune System Diseases / Q000382:microbiology*; D009164:Mycobacterium Infections / Q000235:genetics / Q000276:immunology; D012480:Salmonella Infections / Q000235:genetics / Q000276:immunology