title: Immune responses to ESAT-6 and CFP-10 by FASCIA and multiplex technology for diagnosis of M. tuberculosis infection; IP-10 is a promising marker.
abstract: BACKGROUND
  There is a need for reliable markers to diagnose active and latent tuberculosis (TB). The interferon gamma release assays (IGRAs) are compared to the tuberculin skin test (TST) more specific, but cannot discriminate between recent or remote TB infection. Here the Flow-cytometric Assay for Specific Cell-mediated Immune-response in Activated whole blood (FASCIA), which quantifies expanded T-lymphoblasts by flow-cytometric analysis after long-term antigen stimulation of whole blood, is combined with cytokine/chemokine analysis in the supernatant by multiplex technology for diagnosis of Mycobacterium tuberculosis (Mtb) infection.
  
  
  RESULTS
  Consecutive patients with suspected TB (n = 85), with microbiologically verified active pulmonary TB (n = 33), extra pulmonary TB (n = 21), clinical TB (n = 11), presumed latent TB infection (LTBI) (n = 23), patients negative for TB (n = 8) and 21 healthy controls were studied. Blood samples were analyzed with FASCIA and multiplex technology to determine and correlate proliferative responses and the value of 14 cytokines for diagnosis of Mtb infection: IFN- γ, IL-2, TNF-α, IP-10, IL-12, IL-6, IL-4, IL-5, IL-13, IL-17, MIP-1β, GM-CSF, IFN-α2 and IL-10. Cytokine levels for IFN-γ, IP-10, MIP-1β, IL-2, TNF-α, IL-6, IL-10, IL-13 and GM-CSF were significantly higher after stimulation with the Mtb specific antigens ESAT-6 and CFP-10 in patients with active TB compared to healthy controls (p<0.05) and correlated with proliferative responses. IP-10 was positive in all patients with verified TB, if using a combination of ESAT-6 and CFP-10 and was the only marker significantly more sensitive in detecting active TB then IFN-γ (p = 0.012). Cytokine responses in patients with active TB were more frequent and detected at higher levels than in patients with LTBI.
  
  
  CONCLUSIONS
  IP-10 seems to be an important marker for diagnosis of active and latent TB. Patients with active TB and LTBI responded with similar cytokine profiles against TB antigens but proliferative and cytokine responses were generally higher in patients with active TB.
authors.affiliation: Unit of Infectious Diseases, Institution of Medicine, Karolinska Institutet, Karolinska University Hospital, Solna, Stockholm, Sweden. emilie.wahren-borgstrom@karolinska.se
authors.forename: Emilie
authors.initials: E
authors.lastname: Borgström
authors.forename: Peter
authors.initials: P
authors.lastname: Andersen
authors.forename: Fredrik
authors.initials: F
authors.lastname: Atterfelt
authors.forename: Inger
authors.initials: I
authors.lastname: Julander
authors.forename: Gunilla
authors.initials: G
authors.lastname: Källenius
authors.forename: Markus
authors.initials: M
authors.lastname: Maeurer
authors.forename: Ida
authors.initials: I
authors.lastname: Rosenkrands
authors.forename: Maria
authors.initials: M
authors.lastname: Widfeldt
authors.forename: Judith
authors.initials: J
authors.lastname: Bruchfeld
authors.forename: Hans
authors.initials: H
authors.lastname: Gaines
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D054357:Chemokine CXCL10 / Q000097:blood / Q000276:immunology; D016207:Cytokines / Q000097:blood* / Q000276:immunology; D005260:Female; D006801:Humans; D008168:Lung / Q000276:immunology / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000276:immunology* / Q000302:isolation & purification; D014376:Tuberculosis / Q000097:blood* / Q000175:diagnosis / Q000276:immunology / Q000382:microbiology; D055815:Young Adult
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C117940:CFP-10 protein, Mycobacterium tuberculosis; D054357:Chemokine CXCL10; D016207:Cytokines; C093276:ESAT-6 protein, Mycobacterium tuberculosis