Utility of combining antigranulocyte with antileukocyte antibodies in differentiating Hodgkin's disease from non‐Hodgkin's lymphoma

The authors have reviewed their experience using the antigranulocyte marker, anti‐Leu‐M1, in combination with the antileukocyte marker, PD7/26, applied to paraffin sections of malignant lymphomas difficult to subclassify using morphologic criteria. The study group consisted of 73 lymphomas; 53 cases of Hodgkin's disease and 20 cases of non‐Hodgkin's lymphoma. Leu‐M1 was expressed by the Reed‐Sternberg and Hodgkin's cells in 33 (62%) of the cases of Hodgkin's disease. The Reed‐Sternberg and lymphocytic and histiocytic (L&H) cells in four cases of lymphocyte‐predominant Hodgkin's disease were Leu‐M1 negative. The Reed‐Sternberg cells and L&H cells expressed leukocyte common antigen, utilizing the monoclonal antibody PD7/26, in seven (13%) of the 53 cases including the four cases of lymphocyte‐predominant subtype (three nodular, one diffuse). The Reed‐Sternberg‐like cells in four (20%) of the cases of non‐Hodgkin's lymphoma were stained by anti‐Leu‐M1 whereas, in 12 cases (60%) these cells were stained by PD7/26. The combination of anti‐Leu‐M1 and PD7/26 provided more useful information than that provided by anti‐Leu‐M1 alone by providing immunologic support for the diagnosis of lymphocyte‐predominant Hodgkin's disease and by identifying cases which stained with neither antibody. The authors interpret the immunologic findings in the latter cases as equivocal. These studies were most helpful in cases with many atypical cells and provided unequivocal support for the diagnosis of Hodgkin's disease in six of 11 cases of the “syncytial variant,” a form of the nodular sclerosing type characterized by cohesive aggregates of Reed‐Sternberg cells and lacunar variants, not uncommonly misdiagnosed using only morphologic criteria.