Evaluation of the Immune Response of Individuals Infected with Mycobacterium tuberculosis and Patients with Active Tuberculosis

Table 1

Comparison of the results of the immunological tests by group.

Immunological tests	Group A	Group B	Group C	𝑃 value
IgG
≤214 (cut off)	11 (64.7%)	25 (69.4%)	11 (18.0%)	<0.001*
>214	6 (35.3%)	11 (30.6%)	50 (82.0%)
Median	146	147	685.1
LPA (SI)
≤3 (cut off)	9 (45.0%)	19 (51.4%)	7 (18.9%)	0.011*
>3	11 (55.0%)	18 (48.6%)	30 (81.1%)
Median	3.1	2.8	6.5
IFN-γ
≤378 (cut off)	3 (75.0%)	10 (76.9%)	22 (52.4%)	0.268*
>378	1 (25.0%)	3 (23.1%)	20 (47.6%)
Median	174.8	141	2045
IL-10
≤126.2 (cut off)	4 (100.0%)	4 (50.0%)	16 (34.0%)	0.030**
>126.2	0 (0.0%)	4 (50.0%)	31 (66.0%)
Median	0	123	250
TNF-α
≤36.3 (cut off)	3 (42.9%)	2 (20.0%)	0 (0.0%)	0.006**
>36.3	4 (57.1%)	8 (80.0%)	24 (100.0%)
Median	370	1168	1038.5

*Chi-squared test, **Fisher’s test.
IgG levels determined by ELISA in the plasma of healthy TST⁻ individuals (Group A), of LTBI (Group B), and patients with active tuberculosis (Group C). Calculation of the stimulation index (SI) obtained after testing the lymph proliferative assay (LPA) after PBMC stimulation with BCG for 72 hours. Measurement of the cytokine levels (IFN-γ, TNF-α, and IL-10) obtained from the supernatant of a PBMC culture from individuals from Groups A, B, and C after stimulation for 72 hours with BCG. The median represents the absorbance obtained by the ELISA reaction for IgG levels in plasma and cytokines in supernatants of PBMC cultures stimulated with BCG. However, in the LPA, the median signifies the SI.