More recently, there have been case reports of treatments with thecombination of the anti-CD20 monoclonal antibody, rituximab, and chemotherapy, whichhave produced excellent responses.2 There are, however, no known reports of the more novel humanized type IIanti-CD20 monoclonal antibody obinutuzumab in the treatment of B-PLL. Here, MS4A1 is linked to B-cell prolymphocytic leukemia.