Sarcoidosis is characterized by an “immune paradox” [64]: a hypersensitivity reaction is present in areas of chronic inflammation, such as the mediastinal lymph nodes (MLNs) or the lungs, while sarcoidosis patients present peripheral anergy, and they are prone to other infections, mostly attributed to the lower concentration of CD4+ in peripheral blood compared with healthy controls. The gene discussed is CD4; the disease is sarcoidosis.