Peripheral blood and BM CD34+ CD38- cells show better resistance to cryopreservation than CD34+ CD38+ cells in autologous stem cell transplantation.

Background: We and others have shown a critical role for CD34+ CD38- cells in hematopoietic recovery after autologous stem cell transplantation (ASCT), in particular for platelet reconstitution. Thus a routine assessment of CD34+ CD38- cells in freezing-thawing procedures for autografting could represent an important tool for predicting poor engraftment.

Methods: To compare the impact of cryopreservation on CD34+ CD38+ and CD34+ CD38- hematopoietic stem cell subsets, 193 autograft products collected in 84 patients with malignancies were assessed before controlled-rate cryopreservation in 10% DMSO and after thawing for autografting.

CD34+ cells and CD34+CD38- subset from mobilized blood show different patterns of adhesion molecules compared to those from steady-state blood, bone marrow, and cord blood.

As suggested previously, a down-regulation of some cellular adhesion molecules (CAMs) on CD34(+) hematopoietic progenitor cells (HPC) may contribute to their egress from bone marrow (BM) to peripheral blood (PB) by decreasing their adhesion to BM stromal cells. Besides counting the percentage of CAM-positive cells, we decided to define clearly the antigen density (AgD) of the CAM on mobilized- and steady-state CD34(+) HPC using QIFIKIT calibration beads. Five sources of cells were compared: PB and BM from normal donors (nPB, nBM) cord blood (CB), mobilized PB obtained from leukapheresis products (LKP), and mobilized BM (mBM) samples.