Reinforcing the utility of chick embryo model to in vivo evaluate engraftment of human leukemic stem cells.

BACKGROUND AND OBJECTIVE: Development of appropriate translational in vivo models is a prerequisite for personalized management of leukemic patients. Indeed, several immunodeficient mice models were developed for leukemias with main limitations due to their high cost, demanding management, and elongated assessment intervals. In this report, we aimed at evaluating the engraftment of CD34+ cells, isolated from an acute myeloid leukemia (AML) patient, in naturally immunodeficient chick embryo model.

METHODS AND RESULTS: Mononuclear cells or immunomagnetic sorted CD34+ cells were injected into chick embryo chorioallantoic membrane (CAM) veins. Seven days post-injection, human CD34 transcript was detected by reverse transcription polymerase chain reaction (RT-PCR) in blood, bone marrow (BM), spleen and liver from embryos injected with human leukemic cells. Interestingly, an amplicon of the same length has been detected in both BM and spleen from PBS injected embryos, although analysis via bioinformatics tools revealed no matches in chicken; neither in transcriptome nor in genome databases. Importantly, splenomegaly and hepatic lesions were observed in some CD34+ cells injected embryos.

CONCLUSION: Collectively, our data confirm the engraftment of primary human CD34+ leukemic cells in chick embryo liver, but other experiments are required to verify engraftment in BM and spleen, and to confirm the identity of a putative CD34 orthologous transcript in these two organs.