CD4 and tuberculosis: Specifically, we demonstrated that the proportion of purified protein derivative–specific CD4+ T cells secreting tumor necrosis factor α (TNF-α) but not interferon γ (IFN-γ) or interleukin 2 (IL-2) which had a differentiated effector memory (CD45RA−CCR7−CD127−) phenotype (TNF-α–only TEFF) was able to distinguish tuberculosis from LTBI [8].