Immunocytochemical staining of T and B lymphocytes in serous effusions.

Cell smears from serous effusions containing large numbers of lymphoid cells were stained by the alkaline phosphatase-anti-alkaline phosphatase technique with a panel of monoclonal antibodies, including anti-B and anti-T cell antibodies and anti-HLA-DR. Samples from 17 patients with lymphoproliferative disorders--such as chronic lymphocytic leukaemia and non-Hodgkin's lymphoma--and from 19 patients who had no evidence of lymphoid neoplasia--for example, cases of carcinoma, cardiac failure--were investigated. The majority of lymphoid cells in reactive effusions were T cells, which lacked HLA-DR and showed a marked excess of helper/inducer cells (mean helper to suppressor ratio of 3 X 5). In contrast, lymphoid cells in samples from nine cases of B cell neoplasia were positive for B cell antigen and HLA-DR. In a further four B cell neoplasms most lymphoid cells were reactive T cells. Two cases of T cell lymphoid leukaemia could also be characterised by immunocytochemical staining, both being classified as T helper cell neoplasms. Labelling was performed on routinely prepared, air dried cell smears, which could be stored in the unfixed state for long periods before staining. The technique may therefore be of use in many clinical cytology laboratories for the diagnosis of effusions containing numerous lymphoid cells.