USEFULNESS OF IMMUNOCYTOCHEMISTRY FOR PHENOTYPICAL ANALYSIS OF ACUTE-LEUKEMIA - IMPROVED FIXATION PROCEDURE AND COMPARATIVE-STUDY WITH FLOW-CYTOMETRY

We investigated the phenotypes of blast cells of 53 patients with acut e leukemia by a modified streptavidin-biotin alkaline phosphatase (SAB -AP) labeling technique, using a panel of monoclonal-antibodies [MoAb; anti-CD11b, CD13, CD14, CD33, CD34, CD41, CD3, CD7, CD10, CD19, anti- HLA-DR, and anti-myeloperoxidase (MPO)]. The selection of an optimal f ixative solution for each antigen from five options of various combina tions of formalin, acetone, methanol, and/or ethanol, successfully con served cell morphology and improved specific reaction compared with th e conventional methods which used a single fixative for multiple antig ens. We compared the SAB-AP results with those obtained by flow cytome try (FCM) for surface markers in each case. High concordance rates for both positive and negative results were observed for each marker. How ever, positive reaction for some markers (anti-CD13, CD14, CD33, and C D34) were often noted only in the cytoplasm by the SAB-AP method, indi cating that combination of these two methods is essential for the prec ise immunophenotyping of poorly differentiated leukemia cells.