[Preparation of leukocyte-depleted human platelet concentrates by centrifugation and filtration of a pool of sterilely connected buffy-coats].

We describe a new method for the preparation of standardised therapeutic doses of leukocyte depleted platelets. The first step is to remove the buffy-coat from whole blood units drawn on triple Siamese ACD/SAGM bags (Maco-Pharma) by means of a Compomat (NPBI). The second step is to connect (SCD Haemonetics) six buffy-coats and one plasma to a special kit (Maco-Pharma) including a PALL PL 100 filter; after centrifugation, the supernatant platelet concentrate is extracted, filtered and recovered in a 2 litre TOTM PVC bag. The volume, the number of platelets and leukocytes of these pools are measured. A comparison of these parameters is made with therapeutic doses prepared in the same way without filtration. Besides, pH measurements up to the 6th day of storage and bacteriological checks are carried out. The results show: no platelet loss related to filtration; a synergy between the preparation process out of buffy-coats and the filtration: so each dose contains less than 10(6) leukocytes; a good pH level allowing the storage for five days as it is associated to the bacteriological safety of the functionally closed system. This technique makes it possible to transfuse only leukocyte depleted platelet concentrates. In addition, it offers new prospects for standardisation and quality improvement.