© American Society for Clinical Pathology Flow Cytometric Immunophenotypic Analysis of 306 Cases

Bone marrow aspirates from 306 patients with multiple myeloma were analyzed by flow cytometric immunophenotyping. The plasma cells (PCs) were identified by their characteristic light scatter distribution and reactivity patterns to CD138, CD38, and CD45. Monoclonality was confirmed by immunoglobulin light chain analysis. The immunophenotypic profile of the PCs was determined with a panel of antibodies. Moderate to bright expression of CD56, CD117, CD20, CD45, and CD52 was detected in 71.7%, 17.8%, 9.3%, 8.8%, and 5.2% of cases, respectively. These antigens were expressed by a distinct subpopulation of the PCs in 6.3%, 2.2%, 3.7%, 2.9%, and 2.6 % of additional cases. CD19 was negative in more than 99 % of cases. The combination o