Alemtuzumab, a humanized IgG1 directed against the CD52 protein, is primarily indicated in patients with chronic lymphocytic leukemia (CLL) or small cell lymphoma [125, 144-145]. It is also used in patients with immune-mediated, nonmalignant conditions, such as rheumatoid arthritis, solid organ transplants, multiple sclerosis, and as a conditioning agent for bone marrow transplantation [144]. Here, CD52 is linked to B-cell chronic lymphocytic leukemia.