IL2 and sarcoidosis: Upon polyclonal TCR stimulation, a notable decrease is observed in the secretion of IL-2 and IFN-γ, as well as in the expression of crucial transcriptional mediators of IL-2, such as lymphocyte-specific tyrosine kinase (Lck), protein kinase C-theta (PKC-θ), and NF-κB [125]. Braun et al. discovered that CD4 T-cells from sarcoidosis patients, which express Programmed Death-1 (PD-1), exhibited reduced proliferative capacity upon PD-1 blockade by antibodies.