Leu M-1 antigen: comparative expression in Hodgkin's disease and T cell lymphoma.

Expression of the granulocyte antigen Leu M-1 is characteristic of Reed-Sternberg cells and the related mononuclear cells of Hodgkin's Disease. Leu M-1 has been proposed as a specific immunological marker for Hodgkin's Disease which may be otherwise difficult to distinguish both morphologically and immunologically from non Hodgkin's lymphomas of peripheral T-cell type. In the present study the comparative expression of Leu M-1 in Hodgkin's Disease and peripheral T cell lymphoma was studied in a series of 43 cases including 25 cases of Hodgkin's Disease and 18 cases of immunologically documented peripheral T cell lymphoma. Leu M-1 staining by avidin-biotin-peroxidase complex technique in acetone fixed frozen sections was observed in 22 of 25 cases of Hodgkin's Diseases, (2 of 3 cases of lymphocyte predominant Hodgkin's Disease and 1 case of mixed cellularity were negative) and in 4 of 18 cases of peripheral T cell lymphoma. The pattern of staining in the peripheral T cell lymphomas was indistinguishable from that observed in Hodgkin's Disease in 2 of the cases. Leu M-1 staining appears to be of limited diagnostic value in the differential diagnosis of Hodgkin's Disease and T cell lymphoma. Absence of Leu M-1 staining in frozen tissue however, makes a diagnosis of Hodgkin's Disease (with the exception of the lymphocyte predominant form) unlikely.