Sensitivity of anti-Leu-M1 as a marker in Hodgkin's disease.

Seventy-eight cases of Hodgkin's disease (52 nodular sclerosis, 13 mixed cellularity, seven lymphocyte predominance, one lymphocyte depletion, one interfollicular, and four unclassified cases) were stained with anti-Leu-M1 using the immunoperoxidase technique on either formalin- or B-5-fixed, paraffin-embedded sections. The cytoplasmic pattern and extent of staining of Reed-Sternberg cells and mononuclear variants were recorded. Ninety-four percent of the cases had Leu-M1-positive cells. The staining intensity and number of positive cells were greatest in nodular sclerosis and least in lymphocyte predominance. There was variability, however, in the patterns and amounts of positivity for all subtypes. The neoplastic cells in 15 non-Hodgkin's lymphomas were uniformly negative for Leu-M1. For the individual case, lack of Leu-M1 positivity does not exclude Hodgkin's disease as a diagnostic possibility, but when adequate numbers of Reed-Sternberg-like cells are present, complete absence of staining suggests an alternative diagnosis.