title: Macrophages accumulate in the gut mucosa of untreated HIV-infected patients.
abstract: BACKGROUND
  Mucosal macrophages are involved in the maintenance of epithelial barrier integrity and the elimination of invading pathogens. Although an intestinal barrier defect and microbial translocation are hallmarks of human immunodeficiency virus (HIV) infection, recent data on gut mucosal macrophages in HIV infection are sparse.
  
  
  METHODS
  Treatment-naive and treated HIV-infected patients and healthy controls were studied for frequencies and functional parameters of blood monocytes and macrophages in duodenal mucosa.
  
  
  RESULTS
  We found mucosal enrichment of macrophages in untreated HIV infection associated with reduced monocyte counts in blood and increased monocyte expression of the gut-homing molecule integrin β7. Increased CCR2 density on integrin β7-expressing monocytes and mucosal secretion of CCL2 suggest that CCR2/CCL2-chemotaxis is involved in enhanced trafficking of blood monocytes to the gut. Secretion of macrophage-related proinflammatory molecules interleukin 1β, CCL5, CXCL9, and CXCL10 was increased in the gut mucosa of untreated patients. Moreover, mucosal macrophages of untreated patients showed reduced phagocytic activity.
  
  
  CONCLUSIONS
  These data suggest a role for gut mucosal macrophages in HIV immune pathogenesis: infiltrated macrophages in the intestinal mucosa may promote local inflammation and tissue injury, whereas their low phagocytic activity prevents the efficient elimination of luminal antigens that cross the damaged intestinal barrier.
authors.affiliation: Department of Gastroenterology, Infectious Diseases, and Rheumatology, Medical Clinic I, Campus Benjamin Franklin.
authors.forename: Kristina
authors.initials: K
authors.lastname: Allers
authors.forename: Mira
authors.initials: M
authors.lastname: Fehr
authors.forename: Kristina
authors.initials: K
authors.lastname: Conrad
authors.forename: Hans-Jörg
authors.initials: HJ
authors.lastname: Epple
authors.forename: Dirk
authors.initials: D
authors.lastname: Schürmann
authors.forename: Anika
authors.initials: A
authors.lastname: Geelhaar-Karsch
authors.forename: Katina
authors.initials: K
authors.lastname: Schinnerling
authors.forename: Verena
authors.initials: V
authors.lastname: Moos
authors.forename: Thomas
authors.initials: T
authors.lastname: Schneider
mesh_terms: D000328:Adult; D000368:Aged; D018932:Chemokine CCL2 / Q000276:immunology; D018946:Chemokine CCL5 / Q000276:immunology; D054357:Chemokine CXCL10 / Q000276:immunology; D054370:Chemokine CXCL9 / Q000276:immunology; D004386:Duodenum / Q000276:immunology / Q000821:virology; D005260:Female; D041981:Gastrointestinal Tract / Q000276:immunology* / Q000821:virology; D015658:HIV Infections / Q000276:immunology* / Q000821:virology; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D039641:Integrin beta Chains / Q000276:immunology; D053583:Interleukin-1beta / Q000276:immunology; D007413:Intestinal Mucosa / Q000276:immunology* / Q000821:virology; D008264:Macrophages / Q000276:immunology* / Q000821:virology; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology / Q000821:virology; D010587:Phagocytosis / Q000276:immunology; D054390:Receptors, CCR2 / Q000276:immunology; D055815:Young Adult
chemical_list: C111835:CCL2 protein, human; C483024:CCL5 protein, human; C515334:CCR2 protein, human; C114753:CXCL10 protein, human; C080810:CXCL9 protein, human; D018932:Chemokine CCL2; D018946:Chemokine CCL5; D054357:Chemokine CXCL10; D054370:Chemokine CXCL9; D039641:Integrin beta Chains; D053583:Interleukin-1beta; D054390:Receptors, CCR2; C091368:integrin beta7
keywords: HIV; HIV immune pathogenesis; gut mucosa; mucosal immune system; mucosal macrophages; phagocytosis