title: [Analysis of usefulness of a whole blood interferon gamma assay (QuantiFERON TB-2G) for diagnosing active tuberculosis in immunocompromised patients].
abstract: OBJECTIVE
  Recently, there have been many reports that QuantiFERON TB-2G (QFT-2G) is useful for diagnosing active tuberculosis. However, it remains controversial whether QFT-2G is useful for diagnosing active tuberculosis in immunocompromised patients as well as immunocompetent ones. Therefore, we analyzed whether QFT-2G sensitivity is decreased in immunocompromised patients compared with that in immunocompetent patients and what factors affect the QFT-2G sensitivity.
  
  
  METHODS
  The subjects consisted of 159 patients (105 males, 54 females; age 64.0 years [14-91]) who were diagnosed with active tuberculosis and underwent the QFT-2G test in Nishi Kobe Medical Center between July, 2006 and December, 2008. We analyzed these patients with regard to age, sex, white blood cell count in peripheral blood (WBC), lymphocyte count in peripheral blood (Lym), serum total protein, serum albumin, and QFT-2G sensitivity, and compared the findings between immunocompetent and immunocompromised patients. Immunocompromised patients consisted of those with diabetes mellitus, malignant disease, chronic renal failure, systemic steroid administration and AIDS. To test significance of differences, we used Mann-Whitney test for categorical variables, and t test for continuous variables.
  
  
  RESULTS
  One hundred fifty one patients had pulmonary tuberculosis (including 8 with bronchial tuberculosis), 11 tuberculous pleurisy, 2 miliary tuberculosis, 2 intestinal tuberculosis, 1 tuberculous lymphadenitis, 1 tuberculosis of the hip joint, and 1 tuberculosis of the vertebra (there was some overlap among cases). In the entire patient group, positive QFT-2G results were detected in 125 (78.6%). In the immunocompetent and immunocompromised patients, positive results were seen in 82 (78.8%) and 43 (78.2%), respectively; these proportions were not significantly different (p = 1.00). In all patients, Lym was significantly lower in patients with intermediate, negative or indeterminate QFT-2G results than in QFT-2G-positive patients (p < 0.001).
  
  
  CONCLUSIONS
  In our analysis, QFT-2G sensitivity did not significantly differ between immunocompetent and immunocompromised patients. Therefore, it is considered that QFT-2G is useful for diagnosing active tuberculosis in immunocompromised as well as immunocompetent patients.
authors.affiliation: Department of Respiratory Medicine, Kurashiki Central Hospital, Okayama, Japan. ai12306@kchnet.or.jp
authors.forename: Iakihiro
authors.initials: I
authors.lastname: Ito
authors.forename: Kimihide
authors.initials: K
authors.lastname: Tada
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ootera
authors.forename: Toshiyasu
authors.initials: T
authors.lastname: Sakurai
authors.forename: Hironobu
authors.initials: H
authors.lastname: Iwasaki
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D016867:Immunocompromised Host; D007371:Interferon-gamma / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000097:blood*; D012680:Sensitivity and Specificity; D014376:Tuberculosis / Q000175:diagnosis*
chemical_list: D010446:Peptide Fragments; C069261:interferon gamma (1-39); D007371:Interferon-gamma