Combined bone marrow and peripheral blood progenitor cell autografts for patients with poor mobilization

Mobilization strategies in hard-to-mobilize patients with lymphoid malignancies

Depending on definitions and patient characteristics, 5-40% of patients with lymphoid malignancies are hard-to-mobilize. Several premobilization factors such as previous chemotherapy (CT), disease, marrow infiltration and platelet count at the time of mobilization influence the efficacy of CD34(+) cell mobilization. In general, however, prediction of hard-to-mobilize patient is difficult. Postmobilization factors especially low blood CD34(+) counts are important in clinical practice as we have now ways to enhance mobilization at this point. Plerixafor combined with granulocyte-colony stimulating factor (G-CSF) has significantly increased efficacy of remobilization in patients who have failed a previous mobilization attempt with a success rate of about 70%. Addition of plerixafor to G-CSF or more recently to a mobilization regimen consisting of CT + G-CSF is promising as blood CD34(+) counts can be increased three to fivefold to facilitate effective collection with less aphaeresis sessions. As plerixafor is expensive, development of practical algorithms for its use is important to make blood stem cell mobilization and collection more efficient in a cost-effective way. This review attempts to summarize current treatment strategies in hard-to-mobilize patients with lymphoid malignancies.

The effect of CD34 count and clonogenic potential of hematopoietic stem cells on engraftment

In this study we have determined that the number of the CD34 (+) cells in the grafts that were infused to 48 patients who underwent autologous and allogeneic hematopoietic cell transplantation and evaluated the number of colony forming units in vitro. Our aim was to determine whether there is a relation between these cell counts and post transplantation engraftment kinetics. A negative correlation was detected (p<0.05) between the CD34 (+) cell count and all colony forming units. A correlation between the CD34 (+) cell count and the kinetics of engraftment could not be demonstrated. In the autologous group, only a weak negative correlation between the CFU-GEMM and neutrophil engraftment was detected. In the allogeneic group, colony forming units did not determine the engraftment.