Immune Response to Mycobacterial Infection: Lessons from Flow Cytometry

Table 2

Flow cytometry: determined biomarkers for distinguishing active TB from nonactive states.

Reference	Population studied	Population validated	Biomarker	Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)
[30]	36	31	% PPD-reactive CD27^−IFN-𝛾^+ CD4^+ T-cells > 48	100	100	100	100
[19]	40	—	% ESAT-6/CFP-10-reactive IFN-γ ^+ CD4^+ T-cells > 0.01	94.1	36.4
[4]	52	50	% PPD-reactive IFN-𝛾^+IL-2^+ CD4^+ T-cells < 56	70	100
[31]	42	—	% PPD-specific IFN-𝛾^+ CD4^+ T-cells ≥ 0.5	89	80
[21]	48	101	% ESAT-6/CFP-10-reactive single-positive TNF-𝛼 CD4^+ T-cells > 37.4	67	92	80	92.4
[16]	31	—	% ESAT-6-reactive CD69^+ CD4^+ T-cells producing at least one of the following cytokines: IL-2/IL-4/IL-10/IFN-𝛾 and/or CD40L^+ ≥ 0.01	100	88

PPV: positive predictive value; NPV: negative predictive value.