title: Ia-like (HLA-DR) antigens in the diagnosis of lymphoma and undifferentiated tumors.
abstract: Several years of testing in clinical situations have shown that detection of Ia antigens by immunofluorescence is a highly reliable marker for human lymphomas, regardless of their histologic character and site. Ia antigens were found on malignant cells in patients with Hodgkin's disease (16/16), or with nodular (21/22) or diffuse (69/74) lymphomas. Four of the six Ia-negative lymphomas had T-cell markers. Expression of Ia antigens on lymphoma cells occurs in the absence of surface membrane immunoglobulin, IgG Fc, and complement receptors, which enables positive identification of aggressive "null"-cell lymphomas. Equally important, Ia antigens are absent in most solid tumors of epithelial (57/60) or connective tissue (11/11) origin, including "undifferentiated" tumors, thus facilitating their distinction from lymphoma.
mesh_terms: D002276:Carcinoid Tumor / Q000276:immunology; D002277:Carcinoma / Q000276:immunology; D003937:Diagnosis, Differential; D005455:Fluorescent Antibody Technique; D000949:Histocompatibility Antigens Class II / Q000032:analysis*; D006689:Hodgkin Disease / Q000276:immunology; D006801:Humans; D008223:Lymphoma / Q000175:diagnosis* / Q000276:immunology; D008479:Mediastinal Neoplasms / Q000276:immunology; D009101:Multiple Myeloma / Q000276:immunology; D009369:Neoplasms / Q000175:diagnosis; D009447:Neuroblastoma / Q000276:immunology; D012509:Sarcoma / Q000276:immunology
chemical_list: D000949:Histocompatibility Antigens Class II