The phenotypic consequences of CT45A2 expression in the leukemia cells of this patient are currently unknown.
Alteration of ABH antigens in hematological malignancy was first reported by van Loghem et al [5] who described very weak A antigen expression on the RBCs of an acute myeloid leukemia (AML) patient, who had previously shown normal A antigen expression.
Importantly, CXCR4 is highly expressed on different types of human leukemia, including acute lymphoblastic leukemia and AML and high CXCR4 expression on leukemia blasts correlates with poor outcome.
Our experiments showed a synergistic effect of lenalidomide with rituximab in promoting ADCC against leukemia cells, and this effect is supported by the fact that lenalidomide upregulated CD20 expression on leukemia cells.
Alternatively, PR1 might derive from residual small fraction of leukemia cells that over-express P3 or NE, or it is possible that the level of PR1 expression on non-leukemia cells is sufficient to maintain a PR1-CTL population.
To characterize the underlying mechanism involved in the cooperative effect between lenalidomide and rituximab, we analyzed the effect of lenalidomide on CD20 expression on leukemia cells (CD5+/CD19+) after 2, 7, and 14 days of treatment.
Lenalidomide also upregulated CD20 expression on leukemia cells and, accordingly, it had a synergistic effect with rituximab on promoting antibody-dependent cell-mediated cytotoxicity against primary leukemia cells.
The U937 cell line is a monocytic leukemia with high ICAM-1 (CD-54 adhesion molecule) expression on the cell surface (Figure 3A, left & center).
CD99 is a 32-kD transmembrane protein with a high-level surface expression on pediatric leukemias and Ewing tumor (ET) cells.
Mi et al. [21] performed a genome-wide miRNA expression analysis on acute leukemia samples and demonstrated that the expression signatures from as few as two miRNAs could accurately discriminate ALL from AML, and raised the possibility of using such lineage-discriminatory miRNAs to develop a rapid and accurate diagnostic test of ALL versus AML in the future.
