There was no major variation in serum IL-4 levels between TB subjects and the control group in the Caucasian (SMD = 0.224, [95% CI, −0.396 to 0.844], I2 = 91.8%, P = .479) and African populations (SMD = 0.185, [95% CI, −0.528 to 0.898], I2 = 90.8%, P = .61; see Table 3). Here, IL4 is linked to tuberculosis.