oa A study on hemopoisis and differentiation of dendritic cells from primitive CD34 haematopoietic stem cells from CML patients

Haematopoietic stem cell transplantation (HSCT) is the treatment of choice for patients with refractory leukemia. However, HSCT is associated with lethal GVHD and/or disease relapse. The addition of alternative remedies such as adoptive immunotherapy may lead to eradication of minimal residual leukemia and prevention of relapse. Antigen-pulsed ex-vivo dendritic cells (DCs) have been utilized for the initiation of such immunotherapeutic modalities. DCs can successfully be generated from CD34+ haematopoietic stem cells (HPSCs) and DCs generated from patients with chronic myeloid leukemia (CML), displayed clonal heterogeneity with respect to the expression of the bcr/abl fusion gene. One reason could be that, DCs mixtures were originated from diverse sources of normal and leukemia either CD34+ or CD34- HPSC. CD34-HPSCs were reported to possess hematopoisis reconstitution capabilities. So far, the differentiation of DCs from CD34- HPSCs and their expression of bcr/abl have not been explored in CML patients. Consequently, we hypothesized that CD34-HPSCs could be a valuable source for the generation of an effective vaccine which could be stored and used latter to target residual leukemia if the patient encountered any relapses.

Our study showed that DCs generated from CD34-HPSCs were potent and efficient antigen presenting cells and comparable to their counterparts DCs from CD34+ HPSCs and hold promises in immunotherapy modality.

1A. Gaafar, 2H. M. Al-Omar, 1Z. Al-Mokhlafi, 1Manogaran PS, 1A. qniebi1, 1A Al-Mazrou, 2F.Al Mohareb, 1C. Adra, 1K. Al-hussein

1Stem Cells Therapy Program, 2 King Faisal Cancer Center, King Faisal Specialist Hospital & Research Centre.11211Riyadh, Saudi Arabia