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.
How to use Prograf. Take this medication by mouth with or without food, usually every 12 hours or as directed by your doctor. If you have nausea or an upset stomach, you may take this drug with food, although this may cause your body to absorb less of the drug.