Table 2.

Stages of Mycobacterium tuberculosis infection.

		Immunologic profile
Stage of infection	Patients, condition	IFN-γ	TNF-α
Initial infection	Skin test converters (before skin test conversion)	Low	High
Progressive primary tuberculosis	Children aged ≤5 y; diseased, PPD+	High	High
Protective immunity	Children aged ≤5 y; healthy, PPD+	High	Low
Latent tuberculosis	Adults aged ≥15 y; healthy, PPD+	High	Low
Reactivated tuberculosis	Adults aged ≥15 y; minimal tuberculosis	High	Low/high
Reactivated tuberculosis	Adults aged ≥15 y
	Moderate tuberculosis	Low	High
	Far-advanced tuberculosis	Lowest	Highest

NOTE. Table is based on unpublished data of Whalen et al.