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Table 4 Median (IQR)b IFN-γb Responses to M. tuberculosis Culture Filtrate Protein in pg/ml By Clinical and Epidemiologic Characteristics and Outcome Group

From: Predictive value of TNF-α, IFN-γ, and IL-10 for tuberculosis among recently exposed contacts in the United States and Canada

Characteristicc

Contact Outcome Group

P-value

P-value

Co-prevalent TBd

(n = 41)

Incident TBd

(n = 19)

Not TBd

(n = 1212)

Co-prevalent TB

vs. Not TB

Incident TB

vs. Not TB

All

231 (68–549)

88 (0–445)

27(0–349)

< 0.001

0.15

Age (yr)

 0–14

313 (101–857)

4994 (4994–4994)

0 (0–294)

0.08

0.29

 15–24

336 (90–597)

474 (153–593)f

32(0–564)f

0.01

0.01

 25–44

231 (34–410)

0 (0–42)

31(0–341)e

0.08

0.41

 45–64

125 (6–549)

51 (0–66)

23(0–309)f

0.12

0.65

  > = 65

NAa

NAa

77(0–275)f

NAa

NAa

Sex

 Male

410 (101–562)

109 (0–593)

28 (0–372)

0.001

0.07

 Female

231 (69–336)

0 (0–154)

27 (0–320)

0.049

0.57

Race/Ethnicity

 Black

175 (45–644)

50 (0–154)

14 (0–262)

0.15

0.31

 Non-black

336 (69–549)

356 (0–593)f

41 (0–484)e

< 0.001

0.31

Birthplace

 US/Canada

90 (0–430)

46 (0–171)

15 (0–282)

0.79

0.56

 Other

373 (178–573)e

474 (109–593)f

65 (0–692)e

< 0.001

0.10

 BCG+

125 (125–3105)

445 (0–593)

51 (0–594)

0.01

0.25

 BCG-

303 (6–549)

50 (0–154)f

17 (0–285)e

0.03

0.36

HIV statusb

 HIV negative

336 (101–549)

80 (0–401)

15 (0–309)

< 0.001

0.31

 HIV unknown

132 (0–644)

2530 (66–4994)

32 (0–372)

0.47

0.16

Diabetes mellitus

 Yes

NAa

0 (0–445)

49 (0–259)

0.5584

0.56

 No

283 (90–549)

109 (0–593)

24 (0–349)

<  0.001

0.07

Steroidsb

 Yes

34 (0–69)

NA

1 (0–252)

1.000

NA

 No

336 (113–556)f

88 (0–445)

25 (0–347)

< 0.001

0.15

Smoking past 6 months

 Yes

358 (6–598)

127 (0–593)

29 (0–316)

0.56

0.10

 No

231 (101–410)

55 (0–131)

23 (0–362)

<  0.001

1.0

Heavy alcoholb

 Yes

0 (0–562)

33 (0–211)

35 (0–368)

0.57

1.0

 No

336 (101–549)

132 (0–593)

23 (0–341)

< 0.001

0.11

IV drugsb

 Yes

68 (68–68)

0 (0–0)

15 (0–181)

0.32

0.32

 No

336 (101–549)

109 (0–445)

26 (0–348)

< 0.001

0.09

Street drugsb

 Yes

35 (68–562)

0 (0–51)

30 (0–290)

0.15

0.56

 No

283 (95–549)

154 (0–593)f

24 (0–362)

< 0.001

0.07

  1. aNA (not applicable) in place of a cytokine response designates that there were no specimens for testing; NA in place of a p-value designates that a comparison could not be made
  2. bCo-prevalent TB defined as TB diagnosis before or < 30 days after blood draw; Incident TB defined as TB diagnosis > 30 days after blood draw; IFN-γ = Interferon gamma; Steroids = current steroid use; IV drug = current intravenous drug use; HIV=Human Immunodeficiency Virus; Heavy alcohol = current consumption of > 12 beers or > 1 bottle of wine or > 1 pint of hard liquor per week; Street drugs = current use of drugs other than intravenous acquired without a prescription; IQR = interquartile range, with 25 and 75% values displayed; TST = tuberculin skin test; TB = tuberculosis
  3. cAll risk variables were self-reported
  4. dThe number of contacts included varies slightly from the numbers presented in the heading for some characteristics because 14 contacts were missing TNF results, 38 contacts were missing IFN results, and 23 contacts were missing IL10 results
  5. eP < 0.05 compared with the referent (first) group within each variable; fP = 0.05–0.20 compared with the referent (first) group