Evaluation of proliferating cells in acute leukemia with antibodies to proliferating cell nuclear antigen and Ki-67 monoclonal antibodies. 
The percentage of proliferating leukemic cells was evaluated in 32 patients with acute leukemia; this percentage was measured by flow cytometry and immunostaining with antibodies to proliferating cell nuclear antigen and Ki-67 monoclonal antibodies.  In the peripheral blood samples, the mean proportion of cells that stained for proliferating cell nuclear antigen was 10%, the mean proportion of cells that stained for Ki-67 was 12%, and the mean proportion of cells in the S phase was 5.9%; in the bone marrow samples, these means were 15%, 15%, and 10.1%, respectively, all of which were higher than in the peripheral blood samples.  There was a correlation between the proportion of cells that stained for proliferating cell nuclear antigen and cells that stained for Ki-67, and there was no correlation between the proportion of cells that stained for proliferating cell nuclear antigen or Ki-67 and the proportion of cells in the S phase.