Comparison of processing four and five times the patients' blood volume during peripheral blood stem cell collection and analysis of CD34+38--and CD34+49d+ subsets during apheresis.

Abstract

We investigated whether increasing the patients' processed blood volume (BV) during peripheral blood stem cell collection (PBSCC) from four to five times leads to a greater yield of CD34+ cells. We also studied the kinetics of CD34+38- and CD34+49d+ subsets and compared the amount of transfused cells with engraftment. All patients ( n=20) received chemotherapy followed by G-CSF for PBSC mobilization. Samples from the patients' peripheral blood and the PBSC harvests were taken after processing 1-, 4-, and 5 times the patients' calculated BV. The mean total yields of CD34+, CD34+38-, and CD34+49d+ cells were 15.69-, 1.13- and 4.17 x 10(6)/kg body weight, respectively. The mean increase for these subsets between 4- and 5 BV was 10%, 8%, and 21%, respectively. Based on the mean number of 2.25 (range 2-3) planned courses of high-dose chemotherapy (HDC) per patient, the mean yield of CD34+ cells per kg body weight and intended course of HDC after 4- and 5 BV was 6.31- and 6.97 x 10(6) ( P=0.014). Twenty HDC were evaluable for engraftment. There was some correlation between the number of transfused CD34+ and CD34+38- cells and WBC engraftment ( r = -0.66 and --0.69; P<0.01) and CD34+ cells and platelet engraftment ( r = -0.56; P= 0.013). No toxicity occurred during PBSCC, although the mean platelet count dropped by 50% which must be kept in mind regarding the additional application of anti-coagulants and the fact that most patients had large indwelling catheters. Processing 4 BV is sufficient to collect >5 x 10(6) CD34+ cells/kg body weight and intended course of HDC in most patients, although extension to 5 BV further increases the total yield of CD34+ cells.