Monoclonal antibodies marking B-cell non-Hodgkin's lymphoma in paraffin-embedded tissue

Traditional methods for the immunophenotypic analysis of the non-Hodgkin's lymphomas require fresh or snap-frozen tissue for flow cytometric or immunohistochemical studies. The monoclonal antibodies LN1, LN2, and L26 have been recently developed to recognize B-cell-specific antigens that survive routine tissue processing and paraffin embedding. In this study, the ability of these three antibodies to mark the neoplastic cells in 160 cases of paraffin-embedded non-Hodgkin's lymphoma relative to frozen section immunophenotype (42 T-cell, 118 B-cell), manner of fixation (B5 versus 10% buffered formalin), and histological subtype was examined. With B5-fixed tissue, the percentages of B-cell lymphoma marking with the antibodies were as follows: L26, 96.6%; LN1, 88.2%; LN2, 93.7%. With formalin-fixed tissue, the percentages of B-cell lymphoma reacting with the antibodies were: L26, 89.1%; LN1, 26.2%; LN2, 57.8%. Each of the antibodies marked a small percentage of paraffin-embedded T-cell lymphomas: L26, 4.7%; LN1, 4.7%; LN2, 7.1%. LN2, and to a lesser extent LN1, stained Reed-Sternberg cells, a feature not seen with L26. Nor did L26 mark nonlymphoid neoplasms, a feature previously reported with LN1 and LN2. Since a high percentage of B-cell lymphomas react with these antibodies and they are relatively specific for B-cells, they should prove highly useful for the evaluation of both diagnostic and experimental pathology specimens. L26 offers the distinct advantage of working well in both B5 and formalin-fixed tissues and seemingly not marking epithelial neoplasms.