Lymphoid tissue: T-lymphocytes and the Thymus The thymus is a primary lymphoid organ found within the superior mediatinum, behind the upper part of the sternum. This organ is active in children, but at the start of puberty, until old age, it starts to atrophy, producing fewer T-cells.
2. Increased risk of infection. PROGRAF is a medicine that affects your immune system. Prograf can lower the ability of your immune system to fight infections. Serious infections can happen in people receiving Prograf that can cause death. Call your doctor right away if you have symptoms of an infection such as: 1  fever.2  sweats or chills.3  cough or flu-like symptoms. 4  muscle aches. 5  warm, red, or painful areas on your skin.erious infections can happen in people receiving Prograf that can cause death. Call your doctor right away if you have symptoms of an infection such as: 1  fever. 2  sweats or chills. 3  cough or flu-like symptoms. 4  muscle aches. 5  warm, red, or painful areas on your skin.
Liu J, Yang HI, Lee MH, et al. Serum Levels of Hepatitis B Surface Antigen and DNA Can Predict Inactive Carriers With Low Risk of Disease Progression. Hepatology. 2016;64:381-389. Tseng TC, Liu CJ, Yang HC, et al. High levels of hepatitis B surface antigen increase risk of hepatocellular carcinoma in patients with low HBV load.