Expression of CD20 in B Cell Precursor Acute Lymphoblastic Leukemia.

CD20 is a B cell differentiation antigen with variable expression in B cell precursor acute lymphoblastic leukemia (BCP-ALL). The significance of CD20 expression has been evaluated in BCP-ALL with conflicting results. There is paucity of data regarding CD 20 expression in BCP-ALL in Indian patients. We retrospectively analyzed 100 patients of BCP-ALL for CD20 expression. CD20 positivity was defined as expression of CD20 to be more than or equal to 20 % in the blast population. 62 % patients expressed CD20 while 38 % patients were negative for CD20. The positivity ranged from negative to dim (35.5 % patients), moderately bright (19.3 % patients) to bright (45.2 % patients). Additional prospective studies are needed to determine the optimal use of rituximab in treatment of CD20-positive BCP-ALL.