B-CELL CHRONIC LYMPHOCYTIC-LEUKEMIA STAGE-0 - AN IMMUNOPHENOTYPIC STUDY OF 66 CASES AND COMPARISON WITH B-SMALL-CELL LYMPHOMAS

The cells of 66 B-CLL stage 0 patients were analyzed using a large pan el of monoclonal antibodies in order to better define the immunophenot ype of B-CLL. The data were compared with the immunophenotypes of lymp h node cells from 51 patients with diffuse B small cell lymphoma or le ukaemia with lymph node enlargement. The most frequent immunophenotype of B-CLL stage 0 was SIgM(D)+ EmR(+) CD5(+) CD9(+) CD21(+) CD23(+) CD 35(-) CD38(-). Among the lymphomas, EmR-positive and EmR-negative case s were identified. The vast majority of the EmR-positive cases usually showed the leukaemic pattern, immunophenotype and lymph node histolog y of B-CLL. The EmR-negative cases usually had immunophenotypes quite different from those of B-CLL and the histology of indented cell lymph oma (centrocytic or intermediate) or features of lymphoplasmacytoid/cy tic lymphoma. More than 20% of EmR-positive cells proved to be the mos t important marker to distinguish B-CLL from other lymphocytic lymphom as. Indeed this was a sign of better prognosis. Lymphoplasmacytoid/cyt ic lymphomas were EmR-positive with the immunophenotype of B-CLL or Em R-negative with a definitely different immunological profile. This sug gests two morphologically similar but biologically different subgroups of these diseases.