title: Multiple cytokines are released when blood from patients with tuberculosis is stimulated with Mycobacterium tuberculosis antigens.
abstract: BACKGROUND
  Mycobacterium tuberculosis (Mtb) infection may cause overt disease or remain latent. Interferon gamma release assays (IGRAs) detect Mtb infection, both latent infection and infection manifesting as overt disease, by measuring whole-blood interferon gamma (IFN-γ) responses to Mtb antigens such as early secreted antigenic target-6 (ESAT-6), culture filtrate protein 10 (CFP-10), and TB7.7. Due to a lack of adequate diagnostic standards for confirming latent Mtb infection, IGRA sensitivity for detecting Mtb infection has been estimated using patients with culture-confirmed tuberculosis (CCTB) for whom recovery of Mtb confirms the infection. In this study, cytokines in addition to IFN-γ were assessed for potential to provide robust measures of Mtb infection.
  
  
  METHODS
  Cytokine responses to ESAT-6, CFP-10, TB7.7, or combinations of these Mtb antigens, for patients with CCTB were compared with responses for subjects at low risk for Mtb infection (controls). Three different multiplexed immunoassays were used to measure concentrations of 9 to 20 different cytokines. Responses were calculated by subtracting background cytokine concentrations from cytokine concentrations in plasma from blood stimulated with Mtb antigens.
  
  
  RESULTS
  Two assays demonstrated that ESAT-6, CFP-10, ESAT-6+CFP-10, and ESAT-6+CFP-10+TB7.7 stimulated the release of significantly greater amounts of IFN-γ, IL-2, IL-8, MCP-1 and MIP-1β for CCTB patients than for controls. Responses to combination antigens were, or tended to be, greater than responses to individual antigens. A third assay, using whole blood stimulation with ESAT-6+CFP-10+TB7.7, revealed significantly greater IFN-γ, IL-2, IL-6, IL-8, IP-10, MCP-1, MIP-1β, and TNF-α responses among patients compared with controls. One CCTB patient with a falsely negative IFN-γ response had elevated responses with other cytokines.
  
  
  CONCLUSIONS
  Multiple cytokines are released when whole blood from patients with CCTB is stimulated with Mtb antigens. Measurement of multiple cytokine responses may improve diagnostic sensitivity for Mtb infection compared with assessment of IFN-γ alone.
authors: Division of Scientific Resources, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors: Kathryn L
authors: KL
authors: Kellar
authors: Jennifer
authors: J
authors: Gehrke
authors: Stephen E
authors: SE
authors: Weis
authors: Aida
authors: A
authors: Mahmutovic-Mayhew
authors: Blachy
authors: B
authors: Davila
authors: Margan J
authors: MJ
authors: Zajdowicz
authors: Robin
authors: R
authors: Scarborough
authors: Philip A
authors: PA
authors: LoBue
authors: Alfred A
authors: AA
authors: Lardizabal
authors: Charles L
authors: CL
authors: Daley
authors: Randall R
authors: RR
authors: Reves
authors: John
authors: J
authors: Bernardo
authors: Brandon H
authors: BH
authors: Campbell
authors: William C
authors: WC
authors: Whitworth
authors: Gerald H
authors: GH
authors: Mazurek
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000942:Antigens, Bacterial / Q000276:immunology*; D016207:Cytokines / Q000097:blood*; D003710:Demography; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008863:Microspheres; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000276:immunology; D040081:Protein Array Analysis; D014376:Tuberculosis / Q000097:blood* / Q000276:immunology* / Q000382:microbiology; D055815:Young Adult
chemical_list: D000942:Antigens, Bacterial; D016207:Cytokines; C072681:Mycobacterium tuberculosis antigens