Evaluation of clinical scale CD34(+) cell purification: experience of 71 immunoaffinity column procedures

Seventy-one mobilised PBSC collections were subject to CD34(+) cell purification using the CEPRATE SC(R) stem cell concentration system, The overall median purity of CD34(+) cells was 69% (6-93%), CD34(+) cell, and GM-CFC recoveries were 52% (8-107%) and 36% (3-118%), Purity was logarithmically related to the input percentage of CD34(+) cells and starting requirements were established of 1% CD34 cell content for optimal purity and a minimum of 2 x 10(6)/kg CD34(+) cells to ensure recovery of our minimum engraftment threshold of 1 x 10(6)/kg CD34(+) cells, Reduction of the washing steps reduced non-specific cell losses and shortened the procedure but did not affect progenitor cell recovery, Purified CD34(+) cells were reinfused following high-dose therapy in 35 patients, The median time to neutrophil recovery of 0.5 x 10(9)/l was 12 (10-23) days and to the attainment of platelet independence was 13 (7-100) days, The risks of delayed platelet recovery were related to the CD34(+) cell dose infused and were identical to the risks when non-purified PBSC collections were used, In conclusion, purification of CD34(+) cells using the CEPRATE device is reliable and the purified product results in prompt engraftment, The cell losses that occur do however restrict its use in many patients.