The objective of this study was to demonstrate the diagnostic usefulness of flow cytometric analysis of surface membrane
immunoglobulin light chain and
monoclonal antibody reactivities in B cell
non-Hodgkin's lymphoma. For this purpose, lymph node cell
suspensions from 80 patients (20 normal lymph nodes, 11 lymph nodes with benign lymphoid
hyperplasia, and 47 lymph nodes with B cell
non-Hodgkin's lymphoma) were studied to detect the expression of surface B and
T cell differentiation antigens recognized by a panel of
monoclonal antibodies (anti-Leu-1, anti-Leu-5, anti-HLA-DR, J-5, anti-BL-1, anti-BL-2, and anti-BL-7). The clonal excess calculation, percent kappa-positive minus percent lambda-positive/percent kappa-positive plus percent lambda-positive cells per discrete level of fluorescence intensity, was used to study the clonality of surface membrane
immunoglobulin light chain expression. Among the BL
surface antigens, BL-7 proved to be most consistently expressed in B cell
non-Hodgkin's lymphoma (79 percent). It was also present in 57 percent of lymph nodes with benign
hyperplasia. No significant relationships were detected between the patterns of reactivity with the anti-BL
monoclonal antibodies and histologic subtypes, although the small number of cases tested in each category precludes any definitive conclusions. Immunophenotypic heterogeneity within subgroups was also observed with expression of the other
antigens examined. Monoclonal expression of surface membrane
immunoglobulin light chain was seen in 43 of 47 (91 percent) of lymph nodes with
non-Hodgkin's lymphoma, three of 11 (27 percent) hyperplastic lymph nodes, and one of 22 (4 percent) normal lymph nodes. When the presence of BL-7 and clonal excess was examined as a panel, 83 percent of B cell non-Hodgkin's
lymphomas were positively identified, whereas one normal lymph node and no hyperplastic lymph nodes gave positive results. The simultaneous presence of clonal excess and BL-7 can be a useful diagnostic aid in the differentiation of lymphomatous from hyperplastic lymph nodes. Cytofluorimetry provides a rapid, objective, and reproducible technology to confirm the diagnosis of lymph node involvement in B cell
non-Hodgkin's lymphoma.