PERIPHERAL-BLOOD CD34- METHOD OF PURIFICATION AND EX-VIVO EXPANSION( CELLS )

Peripheral blood stem cells (PBSC) are used increasingly for autotrans plantation in the treatment of acute leukemia, lymphoma, multiple myel oma, solid tumors such as ovarian and breast carcinoma. They are colle cted by leukaphereses during rapid hematopoietic recovery, following c ytotoxid chemotherapy with or without administration of hematopoietic growth factors. We studied the clonogenic and cytokine-mediated expans ion potential of CD34+ cells from mobilized PBSC. Low density mononucl ear cells were processed using the CEPRATE LC CD34 KIT (CellPro). CD34 + purified cells, were cultured in suspension with 6 combined hematopo ietic growth factors (IL1 beta, IL3, IL6 at 100 U/ml and G-CSF, GM-CSF and stem cell factor at 10 ng/ml of each) for up to four weeks. Every week, cells were counted and CFU-GM assay was performed in a methylce llulose based medium. We have analysed the percentage of cells bearing CD34, CD33, CD38, HLA-DR, CD45RA, CD45RO antigens. Our results showed , that CD34+ cells were obtained with a purity of 92 +/- 2.3% and a yi eld of 71 +/- 10.7%. The majority co-expressed CD33 (57.76 +/- 34.16%) and CD38 (62.2 +/- 34%) antigens. These culture conditions, are neces sary to obtain a fold increase of nucleated cells (377 fold at week 4) , of CFU-GM progenitors (41.2 fold at week 3) and of CD34+ cell absolu te number (10 fold at week 1) with an important differentiation of pro genitors in particular myeloid progenitors.