title: T-cell profiling and the immunodiagnosis of latent tuberculosis infection in patients with inflammatory bowel disease.
abstract: BACKGROUND
  Factors associated with performance of interferon-γ release assays (IGRA) and the tuberculin skin test (TST) in screening for latent tuberculosis infection in patients with inflammatory bowel diseases (IBD) are still poorly understood. The influence of peripheral T-cell subset counts on the results also remain unclear.
  
  
  METHODS
  Prospective single-center study in 205 patients with IBD. Latent tuberculosis infection screening included a chest radiograph, TST (retest if negative), and 2 IGRAs: QuantiFERON-TB Gold In-Tube (QFT-GIT) and TSPOT-TB (TSPOT). T-cell subpopulations were determined by flow cytometry.
  
  
  RESULTS
  Twenty-one (10.2%) patients had an abnormal chest radiograph, 55 (26.8%) had a positive TST, 16 (7.8%) had a positive QFT-GIT, and 25 (12.6%) had a positive TSPOT. TST positivity was lower in patients on ≥2 immunosuppressants compared with the controls (5-aminosalicylic acid treatment) (10.4% versus 38.2%, respectively) (P = 0.0057). No other drugs influenced TST or IGRA positivity. In patients on corticosteroid treatment, anti-TNF treatment, or ≥2 immunosuppressants, IGRAs detected 10 cases of latent tuberculosis infection not identified by TST. TSPOT and QFT-GIT increased yield by 56% and 22%, respectively. No significant differences in T-cell subpopulations were found between patients with positive or negative TST or TSPOT results. However, patients with positive QFT-GIT findings had more CD8 T cells (mean, 883 ± 576 versus 484 ± 385 cells per microliter in patients with negative results) (P = 0.022).
  
  
  CONCLUSIONS
  IGRAs can improve TST-based screening in patients with IBD on immunosuppressive therapy. A low CD8 count can affect QFT-GIT results. We suggest combining TSPOT and TST screening in patients with IBD on immunosuppressants.
authors.affiliation: *Department of Respiratory Medicine, Instituto Nacional de Silicosis, Hospital Universitario Central de Asturias, Oviedo, Spain; †Department of Digestive Diseases, Hospital Universitario Central de Asturias, Oviedo, Spain; ‡Department of Microbiology, Mycobacterial Reference Unit, Hospital Universitario Central de Asturias, Oviedo, Spain; §Department of Respiratory Medicine, Hospital Arnau de Villanova, Valencia, Spain; ‖Division of Pulmonary and Critical Care Medicine and Mayo Clinic Center for Tuberculosis, Mayo Clinic, Rochester, Minnesota; ¶Department of Radiology, Hospital Universitario Central de Asturias, Oviedo; and **Oficina de Investigación Biosanitaria, Hospital Universitario Central de Asturias, Oviedo, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Arias-Guillén
authors.forename: Sabino
authors.initials: S
authors.lastname: Riestra
authors.forename: Ruth
authors.initials: R
authors.lastname: de Francisco
authors.forename: Juan José
authors.initials: JJ
authors.lastname: Palacios
authors.forename: José
authors.initials: J
authors.lastname: Belda
authors.forename: Patricio
authors.initials: P
authors.lastname: Escalante
authors.forename: Isabel
authors.initials: I
authors.lastname: Pérez-Martínez
authors.forename: Luis M
authors.initials: LM
authors.lastname: Molinos
authors.forename: Marta
authors.initials: M
authors.lastname: Garcia-Clemente
authors.forename: Ana
authors.initials: A
authors.lastname: Pando-Sandoval
authors.forename: Luis
authors.initials: L
authors.lastname: Rodrigo
authors.forename: Amador
authors.initials: A
authors.lastname: Prieto
authors.forename: Pablo
authors.initials: P
authors.lastname: Martínez-Camblor
authors.forename: Ana
authors.initials: A
authors.lastname: Losada
authors.forename: Pere
authors.initials: P
authors.lastname: Casan
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007113:Immunity, Innate; D007159:Immunologic Tests / Q000379:methods; D015994:Incidence; D015212:Inflammatory Bowel Diseases / Q000150:complications / Q000453:epidemiology / Q000276:immunology*; D055985:Latent Tuberculosis / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology; D018655:Lymphocyte Count; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D016176:T-Lymphocyte Subsets / Q000276:immunology*