2. Confirmation of diagnosis of B cell malignancy and positivity for CD19 confirmed by the Laboratory of Pathology of the NCI. The choice of whether to use flow Cytometry or immunohistochemistry will be determined by what is the most easily available tissue sample in each patient. Immunohistochemistry will be used for lymph node biopsies, flow Cytometry will be used for peripheral blood, fine needle aspirates and bone marrow samples.