TABLE 6.

Median CD8⁺ T-cell response^a

Categoryb	No. of TB1+ and TB2+	IFN-γ (TB2 − TB1) (median [IQR] IU/ml)	No. of TB1− and TB2−	IFN-γ (TB2 − TB1) (median [IQR] IU/ml)
Allc	102	0 (−0.12 to 0.33)	387	0 (−0.01 to 0.02)
Non-U.S. bornd	96	0 (−0.14 to 0.33)	323	0 (−0.01 to 0.03)
Class B1 immigrant	20	0.01 (−0.05 to 0.25)	25	0.01 (−0.01 to 0.03)
U.S. borne	6	0.10 (0.04 to 0.24)	63	0 (−0.01 to 0.02)
Close contact	4	−0.07 (−0.17 to 0.27)	44	0 (−0.01 to 0.02)

^aCD8⁺ T-cell response among groups positive (TB1⁺ or TB2⁺) or negative (TB1⁻ or TB2⁻) for both; 2 antigen tubes of QFT-Plus.

^bClass B1 immigrant, immigrant with abnormal chest radiograph but negative sputum smears and cultures in overseas examinations; close contact, ≥8 h/week exposure to TB case.

^cTwo indeterminate QFT plus results excluded.

^dIncludes class B1 immigrants and close contacts.

^eIncludes close contacts.