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.
Estrogens alone do not appear to increase the risk of breast cancer when used for up to 7 years. Estrogen, when used with a progestin, can increase the risk of heart disease (such as heart attacks), stroke, serious blood clots in the lungs/legs, dementia, and cancer of the breast/ovaries. The risk for serious side effects may depend on the dose of estrogen and the length of time it is used. Therefore, this medication should be used at the lowest effective dose and for the shortest amount of time.