Ikaros family transcription factors in chronic and acute leukemia

Ikaros, Aiolos, and Helios are transcription factors important in lymphocyte differentiation and development [1-6]. One of the most interesting aspects of the Ikaros family members is that they are expressed as multiple splice variants and proteins arising from alternatively spliced transcripts may act as dominant negatives. Although expression of these short isoforms has been linked to lymphoid and myeloid leukemia [7-11] the comparison of Ikaros members mRNA expression level has not been reported. Here we show, by means of real time qRT-PCR method, a quantitative distribution of Ikaros, Aiolos, and Helios mRNA in hemopoietic cells of patients with lymphocytic leukemia, represented by the most frequent B cell chronic lymphocytic leukemia (CLL) and acute lymphocytic leukemia (T cell ALL and common ALL), and compared with the acute leukemia of the myeloid lineage, acute myeloid leukemia (AML). We found that the relative quantity of Ikaros and Helios mRNA was similar in all subgroups. However, analysis of Aiolos showed a clear difference among groups because of its lower expression in all types of acute leukemia investigated. Our results associating a lower Aiolos expression with acute leukemia point to Aiolos's role in human lymphocyte development, as previously shown in mice.