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.
Prograf (tacrolimus) is an immunosuppressant used together with other medicines to prevent your body from rejecting a heart, liver, or kidney transplant. Some forms of Prograf are available in generic form.Common side effects of Prograf include shaking, headache, diarrhea, constipation, nausea, vomiting, upset stomach, stomach pain, loss of appetite, trouble sleeping (insomnia), or tingling or swelling of the hands or feet.ome forms of Prograf are available in generic form. Common side effects of Prograf include shaking, headache, diarrhea, constipation, nausea, vomiting, upset stomach, stomach pain, loss of appetite, trouble sleeping (insomnia), or tingling or swelling of the hands or feet.