A sensitive method for immunophenotyping stored leukemia and lymphoma cells with preservation of morphological detail

We describe a method by which density-separated mononuclear preparations of blood and bone marrow may be stored and batch-processed for immunophenotyping by the indirect immunoperoxidase (IP) technique. The method gives excellent preservation of cellular detail thus permitting clear morphological categorization of IP-positive and IP-negative cells. We compared the immunofluorescence (IF) and IP techniques for estimation of the proportions of cells displaying a variety of antigens; with normal blood cells the results were closely similar but with chronic lymphocytic leukemia (CLL) cells, IP was superior to conventional IF. Using 910 D7, a new anti-la antibody, we were able to observe directly the presence of la-positive lymphocytes and monocytes in normal peripheral blood and la-positive granulocyte precursor cells from 2 cases of chronic granulocytic leukemia (CGL) in transformation. The method is useful for immunophenotyping of cases of lymphoproliferative disorder (LPD) and for morphological identification of specific antigen-positive cells.