Monoclonal Antibody Phenotyping of B-cell Non-Hodgkin's Lymphomas. The Southeastern Cancer Study Group Experience

This report describes the experience of the Southeastern Cancer Study Group (SECSG) with the frozen-section immunoperoxidase phenotyping of 162 cases of B-lineage non-Hodgkin's lymphomas. The authors used a panel of 13 different markers with varying degrees of specificity for B lymphocytes and B-cell neoplasms. All lymphomas were classified according to the International Working Formulation. Several antibodies, including anti-immunoglobulin, B1, Leu 12, and Leu 14 were B-cell-specific markers that were generally pan-reactive. Several other monoclonal antibodies, however, were selectively reactive with subpopulations of B-cell lymphomas. Three "selective-B" antigens (BA1, p24, CALLA) were found on about half of the B-cell lymphomas tested, while another three (HB31, transferrin receptor, C3d receptor) were found on about two-thirds of the lymphomas tested. Leu 1 reacted with 18% of the B-cell lymphomas, particularly the small lymphocytic lymphomas. When the reactivity of the monoclonal antibodies was compared with the histologic classification, two important points became apparent. First, with the large panel of antibodies, there was tremendous phenotypic diversity even among histologically similar tumors. Second, however, not all possible combinations of antibody phenotypes were encountered. That is, clusters of antigenic phenotypes were seen, and these phenotypes correlated to some degree with the histologic diagnosis of the tumor. Small lymphocytic and follicular lymphomas tended to be phenotypically distinct, although there was some overlap. Intermediate- and high-grade lymphomas were phenotypically more diverse. The more common phenotypes of lymphomas encountered could not be reconciled with any simple linear scheme of neoplastic B-cell differentiation.