Midfacial T cell lymphoma: characterization by monoclonal antibodies.

Three cases of so-called lethal midline granuloma were studied immunologically, using monoclonal antibodies against T cell subsets, and electron microscopically. Immunofluorescence and immunoperoxidase studies of their surgical and autopsy specimens proved that the tumor cells showed positive stainings with anti-Leu 1 and anti-Leu 3a antibodies, and negative staining with anti-Leu 2a, anti-HLA-DR, and anti-immunoglobulin antibodies. These data might indicate that the tumor cells of the three cases had a similar surface antigen phenotype to that of peripheral helper-inducer T cells. The histopathological and ultrastructural examinations of the tumors showed general characteristics reported for T cell lymphomata derived from peripheral T cells.