The invention provides antibodies which bind to the ADP-ribosyl cyclase 2. Nucleic acid molecules encoding the antibodies, expression vectors, host cells and methods for expressing the antibodies are also provided. The antibodies may be used for the treatment of human cancers, including acute myeloid leukemia (AML), B-cell chronic lymphocytic leukemia, breast cancer, colorectal cancer, kidney cancer, head and neck cancer, lung cancer, ovarian cancer and pancreatic cancer and human inflammatory diseases, including asthma, gout, crohns, lupus, multiple sclerosis, rheumatoid arthritis, psoriasis, diabetes and atherosclerotic.