An analysis of the optimal timing of peripheral blood stem cell harvesting following priming with cyclophosphamide and G-CSF.

Increasing demand on the apheresis service makes efficient harvesting of peripheral blood stem cells (PBSCs) essential. A total of 168 adult patients with haematological malignancy were primed using low-moderate dose cyclophosphamide (1.5-3 g/m(2)) with G-CSF 5-10 microg/kg per day. Harvesting was booked and peripheral blood (PB) counts first checked between 6 and 10 days post-priming. One hundred and thirty (77%) patients harvested successfully (total harvest yield > or =2 x 10(6) CD34(+)/kg) and the median PBSC collection per procedure was 2.18 x 10(6)/kg (range 0.1-14.5). Only more lines of prior chemotherapy predicted failure to harvest in multivariate analysis (P=0.003). The PB CD34(+) cell count correlated significantly with harvest yield (r=0.8448, P<0.0001). A PB CD34(+) count > or =10/microl predicted a collection of > or =2 x 10(6)/kg (positive-predictive value of 61%, negative-predictive-value 100%). Patients first attending day 9 required significantly fewer visits to achieve a successful harvest than those first attending days 6-8 without increasing the risk of failure. No significant difference in failure rates, number of days attending and total harvest yield was found between days 9 and 10 attendees. Collection from day 9 may however enable higher target yields to be achieved. PB CD34(+) count monitoring should commence and harvesting booked from day 9 to optimize both the harvest and the efficiency of the PBSC harvesting service.

Platelet production methods in the United Kingdom.

Platelets had traditionally been produced in the United Kingdom (U.K.) either from random donor blood by centrifugation of the platelet rich plasma or by plateletpheresis using various apheresis machines. The proportions of apheresis versus non-apheresis derived platelets varying from centre to centre depending on local policy. The production of platelets from random donor blood is labour intensive and in the late 1980s and early 1990s, biotechnology manufacturers developed newer automated techniques to derive platelets from buffy coats aiming to produce a more standard product and reduce the labour intensity of platelet production. At the same time, apheresis technology has continued to develop with the aim of maximising platelet yields from single donors by yielding 4-6 single unit equivalent of platelets per donor while eliminating the need for further laboratory processing. The trend in some European countries and in North America has been to move away from platelets recovered from whole blood either by buffy coat method or by centrifugation of platelet-rich plasma to plateletpheresis. Intense pressure is being put on blood centres to introduce newer technologies which are inevitably more expensive methods of platelet production. Since 1992, centres in the U.K. have gradually changed their method of platelet production and a survey was conducted to examine the status of platelet production within the U.K. This has shown that many centres are moving away from the production of random donor unit platelets derived by secondary centrifugation of platelet rich plasma (25%) towards buffy-coat derived platelets (45.3%) while plateletpheresis remains fairly static (29.7).