Alemtuzumab (Campath) to Treat T-Large Granular Lymphocyte Leukemia

This study will examine the use of alemtuzumab (Campath) in patients with T cell large granular lymphocytic leukemia (T-LGL). Patients with T-LGL often have reduced white blood cells, red blood cells and platelets, and increased numbers of abnormal cells called large granular lymphocytes (LGLs). Patients may have recurrent infections, anemia, or abnormal bleeding. Campath destroys specific parts of the abnormal LGLs, which interfere with the production of normal blood cells. This study will determine whether Campath can increase blood counts and reduce the number of abnormal LGLs in patients and will examine the side effects of the drug. Patients 18 to 85 years of age with T-LGL leukemia may be eligible for this study. Participants undergo the following procedures: Before starting Campath treatment * Medical history and physical examination, blood tests, electrocardiogram (ECG). * Echocardiogram (heart ultrasound) and 24-hour Holter monitoring (continuous ECG recording). * Bone marrow biopsy: About a tablespoon of bone marrow is withdrawn through a needle inserted into the hipbone. The procedure is done using local anesthetic. * Placement of central line, if needed: An intravenous line (tube) is placed into a major vein in the chest. It can stay in the body and be used for the entire treatment period. The line is used to give chemotherapy or other medications, including antibiotics and blood transfusions, and to collect blood samples. The line is usually placed under local anesthesia in the radiology department or the operating room. * Apheresis: A catheter (plastic tube) is placed in a vein in each arm. Blood is drawn from one vein and run through a cell-separating machine, where the white blood cells are collected and saved. The remaining blood is transfused back to the patients through the vein in the other arm. During Campath treatment * Campath therapy: After a small test dose, patients receive10 daily infusions of Campath, each of which lasts about 2 hour