DISCORDANT IMMUNOPHENOTYPE OF CHRONIC B-CELL LYMPHOPROLIFERATIVE DISORDERS IN SIMULTANEOUS SPECIMENS FROM BONE-MARROW AND PERIPHERAL SITES

This study consisted of 10 cases of chronic B-cell lymphoproliferative disorders that had simultaneous specimens obtained from both bone mar row and peripheral sites for flow cytometric immunophenotyping. The im munophenotyping results of peripheral sites from all 10 cases showed a monoclonal B-cell proliferation expressing monoclonal surface immunog lobulin, CD19, CD20, HLA-DR, and CD5 (except 1 case). Eight (80%) of t he 10 cases, however, demonstrated discordant immunophenotypes with my eloid-associated marker expression (CD13, CD11b, and/or CD15) found on ly in the bone marrow. Patients with CD13 or CD11b marker expression i n the bone marrow followed an aggressive clinical course with advanced Rai's stage and a diffuse or mixed bone marrow infiltration pattern o r disease transformation. These results indicate that discordant immun ophenotypes of malignant cells from different body sites occur in chro nic B-cell lymphoproliferative disorders and are not uncommon. Additio nally, myeloid-associated markers, which some investigators have descr ibed as being associated with an unfavorable clinical course, may be e xpressed only in bone marrow specimens in these disorders. Thus, bone marrow specimens may be preferential in determining myeloid-associated marker expression in chronic B-cell lymphoproliferative disorders.