CD34+ cell positive selection from mobilized peripheral blood by an indirect immunomagnetic method: effect of the type of mobilization and assessment of tumor depletion ability.

Mobilized peripheral blood has been shown to be a suitable source of hematopoietic progenitor cells for autologous transplantation in oncologic patients. However, tumor cell contamination can potentially occur, although to a lesser extent than in the bone marrow. CD34+ cell positive selection has been developed as a system for the ex vivo purging of remaining tumor cells when used in mobilized peripheral blood. This method has shown a lower purification potential than that obtained with bone marrow or cord blood. The reason for this is not clear, but different groups have tried to improve the purity and yield of the positive selection on mobilized peripheral blood by prede-pletion of nonlymphoid cell populations, since they can induce nonspecific binding. The present study was designed to test an indirect immunomagnetic CD34+ cell selection method to make it reproducible, feasible, and effective for purging mobilized peripheral blood. Twenty-nine samples from mobilized peripheral blood were tested. The me...