CD34-VIVO EXPANSION, AND MALIGNANT-CELL DEPLETION FOLLOWING IMMUNOMAGNETIC SELECTION( CELL ENGRAFTMENT, EX)

This review describes the published preclinical and clinical data on t he use of a manual or semiautomated immunomagnetic selection device, t ermed the Isolex(R) system. Preclinical evaluation of hematopoietic pr ogenitor cells (CD34+ cells) selected from bone marrow, peripheral blo od leukapheresis products, and umbilical cord blood is reviewed with r espect to differentiation (CFU-GM, BFU-E, and CFU-GEMM formation) and proliferation, The purities and yields of CD34+ cell products from cli nical trials performed since 1994 are presented along with data on mal ignant cell depletion, On average, the Isolex(R) system resulted in a final product median purity of 67% and a final product median yield of 64%, Positive selection of CD34+ cells with this device decreased res idual tumor cell levels by 2-3 logs in autologous transplant products and reduced T cell levels by 3-4 logs in allogeneic grafts, To evaluat e the clinical effect of these immunomagnetically selected cells, data on the rate of engraftment were reviewed, Autologous CD34+ cell trans plantation resulted in recovery time from neutropenia (ANC > 500/mu l) of 9-14 days and recovery time from thrombocytopenia (platelet count >20,000/mu l) of 10-20 days, These data showed that the Isolex(R) syst em can positively select progenitor cells to reconstitute the hematopo ietic system following myeloablative therapy.