The Surface Phenotype of Lymphatic Leukemia, Cells: An Immunoscanning Electron Microscopy Study

Bone-marrow cells from 11 cases of T- and 18 cases of B-lymphatic leukemia, at different maturation stages, were examined by scanning electron microscope (SEMI. All cases were extensively studied for the expression of surface markers by immunofluorescence. In addition six cases of T- and 10 cases of B-cell leukemia were labeled with a panel of monoclon;tl antibodies (including CD3, CD5, CD7, CD10, CD4, CD8, CD19, CD20 and CD22) and, after incubation with a colloidal gold conjugate, observed with SEM in the back-scattered electron imaging mode. Early stages of leukemic lymphoid B- and T-cell differentiation are characterized by prevalently smooth cell surfaces. Short stub-like microvilli constantly appear on more mature T cells, while complex surface features like small ruffles and pleomorphic microvilli are present in well-differentiated B-cell proliferations. Surface microvilli can be interpreted als structural features of lymphoid cells, progressively expressed with maturation and differentiation of leukemic as well as normal cells.