Malignant lymphoma in pleural effusions an immunocytochemical cell surface analysis

Nine malignant pleural effusions due to lymphoma were imrnunocytochemically analyzed with the peroxidase-antiperoxidase adhesive slide assay for detection of cell surface antigens using a broad panel of monoclonal antibodies. The study population included one case of hairy-cell leukemia; four cases of B cell nonHodgkin's lymphoma (B-NHL), low malignant grade; two cases of B-NHL, high malignant grade; one case of Hodgkin's disease; and one case of plasmacytoma. In the cases of B cell lymphoma, high percentages of B cells with monoclonal staining for kappa were found. In hairy-cell leukemia, the hairy cells reacted with the monoclonal antibodies CD20, CD25, HLA-DR, CD4.5, and HLA-1. In Hodgkin 's disease, the Hodgkin cells reacted with CD1.5, CD20, CD2.5, CD30, Tii9, and OKT9. Theplasmacytoma case showed tumor cells negative for CD20, HLA-DR, and CD4.5; partially positive for CD38; positive for HLA-I; rnonoclonallypositive for lambda; and negative for heavy-chain immunoglobulins. The analysis of nonmalignant lymphocyte subpopulations revealed CD4/CD8 ratios similar to those in effusions of other etiologies. The percentages of natural killer cells (Leu- 7-positive and CDl6-positive) were small and also similar topercentages in effusions of other etiologies. We conclude that immunocytochemical analysis of pleural effusions allows a clear recognition of B lymphoma cells and also of Hodgkin and hairy cells and that the distribution of nonmalignant lymphocyte subsets is indistinguishable from those found in other malignant and nonmalignant effusions. Diagn Cytopathol 1991;7:113-118.