The comparison of expression patterns of CD19 and CD20 on 321 cases of acute leukemia

objective To investigate the expression and distribution of CD19 and CD20 on acute leukemia (AL) cells, and to provide evidences for selecting immunotoxin. Methods Samples from 321 AL patients were analyzed by CD45/SSC double parameters and multi-color flow cytometry using a panel of 27 fluorescein- labeled monoclonal antibodies, to determine the expression of CD19, CD20 and other leukocyte differentiation antigens. Results Among 116 cases of B lineage ALL, CD19 is continuously and stably expressed. The positive rate (99.1%) of CD19 on B lineage ALL was higher than that of CD20 (28.4%,P = 0.001). The positive rates of CD19 in all 17 cases of B-lineage hybrid acute leukemia (HAL) including B/myeloid (My) and B/T lineage (HAL) were also significantly higher than that of CD20 (P 0.001), while CD19 and CD20 were not expressed in the 29 cases of T lineage leukemia and 7 cases of T/My HAL. Among 152 cases of acute myeloid leukemia (AML),the positive rates of CD19 and CD20 were only 7.2% and 2.0%, respectively.Conclusion CD19 is continuously and stably expressed on all stages of B lineage differentiation, so that this antigen might be an ideal target for antibody-targeting treatment of B lineage ALL.