[An attempt at differentiating between medullary and extramedullary derived B-cell chronic lymphocytic leukemia]

A comparative research on lymphocyte immunological phenotypes in peripheral blood and bone marrow was carried out on 14 patients with B-cell chronic lymphocytic leukaemia. Three types of B cell markers were estimated: 1-light chains (lambda or kappa) on the surface of cells, 2-CD5 antigen, 3-capability of forming mouse erythrocyte rosettes (MER); the last two markers are mostly characteristic of leukaemic cells. The patients were divided into 3 groups according to the localisation of the main mass of tumorous cells: group I-the patients, whose clinical picture was dominated by the infiltration of lymphoid structures of the abdominal cavity and/or with massive infiltration of peripheral lymph nodes; group II-the patients, whose clinical picture was dominated by the infiltration of bone marrow; group III-the intermediate-patients with large mass of tumor in lymphoid structures and with bone marrow insufficiency symptoms. In most of the patients of group I, the percentage of CD5+ cells in peripheral blood was higher than the one in bone marrow (arithmetic means were 38.5% for blood and 26.7% for marrow). It was the reverse in group II (the means were 44.8% for blood and 64.3% for marrow, P < 0.01). The percentage in group III was similar to that of group I (the means-48% for blood and 29.25% for marrow). No correlation between the percentage of CD5+ and MER+ cells was found in respective groups of the patients although the last marker behaved similarly to CD5. The results obtained suggest that while estimating percentages of CD5+ cells in peripheral blood and bone marrow, one can differentiate between chronic lymphocytic leukaemia (with domination of CD5+ cells in bone marrow) and leukaemic phase of small lymphocyte lymphoma (with domination of CD5+ cells in peripheral blood).