A Quantitative Exploration of Surface Antigen Expression in Common B-Cell Malignancies Using Flow Cytometry

The use of flow cytometry to diagnose hematological malignancies has become routine due to its ability to often differentiate between morphologically similar diseases based on antigens expressed on the surface of malignant cells. In an attempt to expand on the utility of flow cytometry in the study of B-cell malignancies we have used the most reliable quantitative methodology, QIFI (quantitative indirect immunofluorescence assay), to study the expression of CD5, CD10, CD11c, CD19, CD20, CD22, CD23, and CD79b in 384 cases of several common B-lineage malignancies, including: B-ALL, CLL, SLL, hairy cell leukemia, diffuse large B-cell lymphoma, and follicular lymphoma. The impetus behind this extensive, single institution study of surface antigens was two-fold: evaluating similarities and differences of antigen expression between B-cell neoplasms and finding additional clinical utility for the quantitative flow cytometric data generated. Our results show that each distinct malignant histology has its own quantitative pattern of surface antigen expression. In most cases, these quantitative patterns do not increase the ability of flow cytometry to distinguish between them. However, a high expression of specific antigens on a given B-cell malignancy may potentially identify optimal therapeutic targets for current and/or future monoclonal antibody-based therapies.