Immunophenotypes of Reed-Sternberg cells: a study of 19 cases of Hodgkin's disease in plastic-embedded sections

The immunophenotype of Reed-Sternberg (RS) cells in Hodgkin's disease (HD) has not been clearly defined, partly owing to difficulties in studying RS cells in cell suspensions or identifying them with certainty in frozen sections. We studied the immunophenotype of RS cells with a recently developed plastic section immunohistochemical technique on acetone-fixed tissues that affords superior morphological detail while preserving a wide variety of lymphoid differentiation antigens. Nineteen cases of HD [16 nodular sclerosing (NS), 2 mixed cellularity (MC), and 1 lymphocyte depleted (LD)] were embedded in plastic and stained for pan-B, pan-T, and various T-subset markers, as well as leukocyte common antigen (CD45), interleukin-2 (IL-2) receptor (CD25), and RS cell markers CD15 and CD30. RS cells were positive for CD45, CD15, CD30, and CD25, except for 3 cases (2 NS, 1 MC) that were CD15 negative and 2 cases (NS) that were CD45 negative. In 10 cases (NS), RS cells were positive for at least two pan-T-cell markers and CD4; pan-B cell markers were uniformly negative. RS cells in 6 cases (3 NS, 2 MC, 1 LD) were positive for at least one T-cell marker (CD2) and one B-cell marker (CD22). Two cases of NSHD showed no T- or B-cell marking. These data provide further evidence that RS cells in some cases of NSHD have T-cell phenotypes and that RS cells are not homogeneous in their immunoreactivity.