Moreover, higher levels of CD69 expression (11.60%±11.93%, mean ± SD) on CD4+ T cells were observed in 78% of the PFCs from individuals with TBP than on the PBMCs of PTB or HD (1.48%±1.60% for healthy donors and 1.38%±1.68% for TB patients, mean ± SD). Here, CD4 is linked to tuberculosis.