PERIPHERAL-BLOOD STEM-CELL COLLECTION WITH REDUCED PLATELET LOSS TO THE PATIENT DONOR

Apheresis procedures that optimize peripheral blood stem cell (PBSC) h arvesting also result in a significant loss of platelets to the patien t/donor because of their similar densities. We compared the percent dr op in platelet count and hemoglobin concentration in the patients befo re and after PBSC collection using two different collection chambers w ith the CS-3000(TM). A modified plateletpheresis procedure was utilize d. Seven patients underwent 38 PBSC collections during steady state he matopoiesis using the standard A-35 collection chamber. At the end of the procedure, a second low-speed centrifugation of the PBSC concentra te was performed in the manual mode, with siphoning out and return of the PRP to the patient through a transfer pack. For 14 patients who un derwent 113 PBSC collections, a small volume collection chamber (SVCC) was substituted for the A-35 chamber and the second centrifugation st ep was omitted. These patients were also primed with 4 g/m(2) of cyclo phosphamide. The percent drop in platelet count in the patients after the collection procedures was significantly less in the SVCC group (20 .4 +/- 9.1 vs. 36.0 +/- 12.3, P = 0.000), even after correction for th e difference in the volume of blood processed between the two groups ( 3.2 +/- 1.4 vs. 3.9 +/- 1.3, P = 0.006). The percent drop in hemoglobi n concentration was also less with the SVCC both before (5.4 +/- 3.8 v s. 11.7 +/- 3.0, P = 0.000) and after (0.8 +/- 0.6 vs. 1.3 +/- 0.3, P = 0.000) correction for the difference in the volume of blood processe d. The cellular contents of the PBSC concentrates were similar in both groups although mononuclear cell (MNC) purity was slightly higher in the A-35 group (95.6 +/- 5.9% vs. 91.0 +/- 13.0%, P = 0.037). The MNC extraction efficiency was similar with both collection chambers (60.2 +/- 17.4% for the SV and 64.6 +/- 18.5% for the A-35). The advantages of the SVCC and the possible reasons for the observed differences are discussed. (C) 1995 Wiley-Liss, Inc.