Leukemia-associated changes identified by quantitative flow cytometry. III. B-cell gating in CD37/kappa/lambda clonality test.
Normal and malignant B-lymphoid cells were studied for CD37 antigen expression with three-color immunofluorescence (IF) in combination with kappa/lambda light chain staining, and by quantitative immunofluorescence utilizing the QIFI test. Peripheral B cells brightly expressed CD37 antigen (median 80-114 x 10(3) molecules/cell). Moderate to high levels (> 20 x 10(3)/cell) of CD37 expression were detected in 364 in 366 cases of peripheral B-cell disorders including all cases of B-ALL, B-cell lymphomas and B-CLL as well as eight of ten cases of PLL. By contrast, slg- B-cell precursors and other cell types in normal bone marrow (BM) were CD37-/CD37dull (< 10 x 10(3) molecules/cell). The negativity for CD37 or only CD37dull expression was confirmed in 180 of 182 cases of precursor B-ALL and 196 cases of non-B malignancies. Among the CD37 cluster, the RFB7 antibody of IgM class showed the weakest binding to non-B cells. In 64 normal samples of blood and BM the CD37+ gated cells showed normal kappa/lambda ratios as expected, while in 100 cases of B malignancy striking changes such as kappa/lambda monoclonality (79%) and aberrant slg- or sigdull expression (21%) were seen among the gated CD37+ B cells. The CD37/kappa/lambda test identified as few as 0.5% kappa+ or lambda- monoclonal B cells admixed to normal BM: circulating B-lymphoma cells were seen in nine patients with morphologically normal blood count. The discrimination of the Kolmogorov-Smirnov (KS) test for kappa/lambda excess was also improved by CD37+ B gating. Thus CD37+ B-cell gating and kappa/lambda analysis is a simple and sensitive routine test, e.g. when combined with autogating on a Cytoron-Absolute cytometer, for identifying malignant B cells in minimally involved BM and blood.
Department of Clinical Immunology, Royal Free Hospital School of Medicine, London, UK.
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Peters
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Janossy
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K
Ivory
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al-Ismail
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Mercolino
D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000032:analysis*; D000951:Antigens, Neoplasm; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D002999:Clone Cells; D005434:Flow Cytometry; D006023:Glycoproteins / Q000032:analysis*; D006801:Humans; D007145:Immunoglobulin kappa-Chains / Q000032:analysis*; D007146:Immunoglobulin lambda-Chains / Q000032:analysis*; D016130:Immunophenotyping; D015448:Leukemia, B-Cell / Q000276:immunology*; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000276:immunology*; D016393:Lymphoma, B-Cell / Q000276:immunology*; D059470:Tetraspanins
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000951:Antigens, Neoplasm; C059071:CD37 protein, human; D006023:Glycoproteins; D007145:Immunoglobulin kappa-Chains; D007146:Immunoglobulin lambda-Chains; D059470:Tetraspanins