title: Foxp3(+)CD4(+)CD25(+) regulatory T cells are increased in patients with Coxiella burnetii endocarditis.
abstract: Chronic Q fever, which principally manifests as endocarditis, is characterized by Coxiella burnetii persistence and an impaired cell-mediated immune response. The long-term persistence of pathogens has been associated with the expansion of regulatory T cells (Tregs), the CD4(+)  T-cell subset that is characterized by the expression of CD25 and Foxp3. We investigated the presence of Tregs in patients with acute Q fever (n = 17), known to exhibit an efficient immune response, patients with Q fever endocarditis (n = 54) and controls (n = 27) by flow cytometry. The proportion of CD3(+) , CD4(+)  and CD8(+)  T cells was similar in controls and patients with Q fever. The percentage of CD4(+)  T cells that expressed CD25 was similar in controls and patients with Q fever. The population of CD4(+)  T cells that expressed both CD25 and Foxp3 was significantly (P < 0.001) increased in patients with Q fever endocarditis compared with controls. Our data suggest that the expansion of Tregs may be critical for the chronic evolution of Q fever.
authors.affiliation: Unité de Recherche sur les Maladies Infectieuses Tropicales et Emergentes, Aix-Marseille Université, Marseille, France.
authors.forename: Corinne
authors.initials: C
authors.lastname: Layez
authors.forename: Corinne
authors.initials: C
authors.lastname: Brunet
authors.forename: Catherine
authors.initials: C
authors.lastname: Lépolard
authors.forename: Eric
authors.initials: E
authors.lastname: Ghigo
authors.forename: Christian
authors.initials: C
authors.lastname: Capo
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; D015496:CD4-Positive T-Lymphocytes / Q000737:chemistry / Q000276:immunology*; D016997:Coxiella burnetii / Q000276:immunology / Q000472:pathogenicity*; D004697:Endocarditis, Bacterial / Q000276:immunology* / Q000473:pathology; D005260:Female; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000032:analysis; D006801:Humans; D053645:Interleukin-2 Receptor alpha Subunit / Q000032:analysis; D008297:Male; D008875:Middle Aged; D011778:Q Fever / Q000276:immunology* / Q000473:pathology; D016176:T-Lymphocyte Subsets / Q000737:chemistry / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000737:chemistry / Q000276:immunology*
chemical_list: C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; C508017:IL2RA protein, human; D053645:Interleukin-2 Receptor alpha Subunit