The patient's symptoms indicate that he probably suffers from acute lung rejection. Acute rejection consists an immune reaction to the tissue introduced into the body and it could happen after a week of the transplant procedure. The patient should be administered corticosteroids, as they have been shown to have anti-inflammatory effects and they could reduce the fever. In addition, the patient should be administered prednisone, which is a synthetic corticosteroid drug very commonly used as a suppressor of the immune system.