title: Bartonella quintana bacteremia and overproduction of interleukin-10: model of bacterial persistence in homeless people.
abstract: Chronic asymptomatic bacteremia caused by Bartonella quintana occurs in homeless people, but its pathophysiology is unknown. We investigated homeless people with bacteremia to determine whether the persistence of B. quintana is associated with a specific immune profile. Homeless people without B. quintana infection exhibited an inflammatory profile--levels of circulating markers of leukocyte activation (soluble interleukin [IL]-2 receptor and neopterin) and cytokines released by mononuclear cells (tumor necrosis factor, IL-1beta, IL-6, and IL-10) were significantly higher than levels in healthy control subjects. In contrast, homeless people with B. quintana bacteremia exhibited specific increases in IL-10 secretion by mononuclear cells. This overproduction of IL-10 was associated with an attenuated inflammatory profile. The depressed inflammatory response was specific of bacteremia, because patients with specific antibodies and without bacteremia had responses similar to those of homeless people. The overproduction of IL-10 and attenuated inflammatory response may account for the persistence of B. quintana in homeless people.
authors.affiliation: Unité des Rickettsies, Faculté de Medecine, Hôpital Nord, Université de la Méditerranée, 27 boulevard Jean Moulin, 13385 Marseille, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Capo
authors.forename: Nathalie
authors.initials: N
authors.lastname: Amirayan-Chevillard
authors.forename: Philippe
authors.initials: P
authors.lastname: Brouqui
authors.forename: Didier
authors.initials: D
authors.lastname: Raoult
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Mege
mesh_terms: D000328:Adult; D000368:Aged; D016470:Bacteremia / Q000276:immunology* / Q000382:microbiology / Q000503:physiopathology; D018413:Bartonella quintana / Q000502:physiology*; D002908:Chronic Disease; D016207:Cytokines / Q000096:biosynthesis; D005260:Female; D006703:Ill-Housed Persons; D006801:Humans; D016753:Interleukin-10 / Q000096:biosynthesis*; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D014205:Trench Fever / Q000276:immunology* / Q000382:microbiology / Q000503:physiopathology
chemical_list: D016207:Cytokines; D016753:Interleukin-10