Bacteriocin and flow cytometry in laboratory diagnosis of leukemic peripheral blood lymphocytes and bone marrow cells

The bacteriocin, colicin HSC10, produced by Escherichia coli HSC10, was studied as a laboratory tool for detection and differentiation of leukemic from normal lymphocytes in human peripheral blood. Flow cytometry studies detected DNA loss in bacteriocin-affected cells by computerized histograms. Differential analysis is given for the peripheral blood of 26 individuals using bacteriocin, cytochemistry and surface markers. Sensitivity to colicin was detected in 10 (83%) of the 12 patients with chronic lymphocytic leukemias and other leukemias with morphologically immature lymphocytes. Cells were lost from the G0/G1 phase and accumulated in the 'pre-G1' channels of the histogram, indicative of cells with reduced DNA content. The lymphocytes of 14 normals, however, were not or only slightly affected by the bacteriocin (P less than 0.001). Similarly, normal bone marrow cells exposed to bacteriocin remained unaffected (P greater than 0.2). Thus, immaturity per se was not recognized by bacteriocin. The bacteriocin effect was more discriminatory than other laboratory tests reported here and in most cases differentiated malignant from normal cells.