CHARACTERIZATION OF MYELOID OR LYMPHOID ACUTE-LEUKEMIA BY A CHEMILUMINESCENCE ASSAY - COMPARISON WITH IMMUNOCYTOCHEMISTRY USING AN ANTIMYELOPEROXIDASE ANTIBODY

A simple and sensitive chemiluminescence assay for the demonstration o f the activity of intracellular myeloperoxidase (MPO) is described, wh ich is useful for the distinction between myeloid and lymphoid commitm ent in blasts from acute leukemia patients. When the cut-off point was settled at 13 mV of chemiluminescence all cases of acute myeloid leuk emia (AML) were distinguished from those of acute lymphoid leukemia. I n addition, this technique was able to demonstrate MPO activity in AML poorly differentiated (FAB-MO) which usually does not stain for MPO i n classical cytochemistry preparations and could be negative also by i mmunocytochemistry with anti-MPO monoclonal antibody. Therefore the me thod here described presented a higher sensitivity than the immunocyto chemistry procedure with anti-MPO.