The minimum CD34 threshold depends on prior chemotherapy in autologous peripheral blood stem cell recipients

Abstract

Summary:We analysed 57 patients with non-myeloid malignancies who received a non-purged autologous PBSCT. All had similar mobilisation and conditioning regimens. A high prior chemotherapy score and the number of chemotherapy lines used (P = 0.015 and P = 0.01, respectively) were adverse predictors of CD34 cell yields. Lower CD34 values (P = 0.002) were seen in patients treated with potent stem cell toxins (BCNU, melphalan, CCNU and mustine), designated toxicity factor 4 agents (TF4). All patients infused with grafts containing CD34 cell doses between 1.0 and 2.0 ؋ 10 6 /kg (range 1.25-1.90) engrafted by day 51. The only variable associated with slow platelet recovery was exposure to TF4 (P = 0.007). The majority of patients with CD34 Ͼ1.0 ؋ 10 6 /kg achieved rapid and sustained engraftment and the only predictive factor of delayed recovery is prior exposure to stem cell toxins. Potential PBSCT candidates should if possible avoid first line and salvage chemotherapy containing TF4 drugs. We therefore advocate a minimum CD34 threshold of Ͼ1.0 ؋ 10 6 /kg in patients without extensive prior chemoradiotherapy, and у2.0؋ 10 6 /kg in all other patients. Keywords: autologous stem cell transplant; CD34; transplantation; chemotherapy score Prior exposure to specific cytotoxic agents and the number of cycles of chemotherapy given, are associated with a reduced peripheral blood progenitor cell yield. 1,2 However the cumulative effects on long-term haematopoiesis of multiple cycles of combination chemotherapy are less well defined. Drake et al 3 have devised a chemotherapy scoring system (outlined in Table 1) in which each chemotherapy agent used was given a score based on its predicted stem cell toxicity (range 0-4). By multivariate analysis only exposure to stem cell toxicity factor 4 drugs (BCNU, melphalan, CCNU and mustine) prior to PBSC mobilisation was a significant predictor of lower CD34 counts. They did not analyse their data with respect to time to engraftment.In order to study the effect of prior chemoradiotherapy on CD34 levels and the rate of engraftment, we calculated the chemotherapy score 3 and the number of lines of chemo-

Significant and persistent loss of bone mineral density in the femoral neck after haematopoietic stem cell transplantation: long‐term follow‐up of a prospective study

“…Induction chemotherapy regimens used in the unit were as previously outlined (Gandhi et al, 1999a). Transplantation procedures were performed as per previously published protocols (Gandhi et al, 1999b(Gandhi et al, , 2001.…”

Improving stem cell mobilization strategies: future directions

“…34,56,57 The target dose of infused CD34 þ cells varies from a minimum of 2.0 Â 10 6 CD34 þ cells/kg 31,58,59 to an optimal level of 5.0 Â 10 6 CD34 þ cells/kg. 24,26,55 Within this range, higher doses of infused CD34 þ cells are more beneficial for patients with MM and NHL.…”

Blood stem cell collections in multiple myeloma: definition of a scoring system

“…A number ranging between 2.0 and 5.0 × 10 6 /kg seems adequate for a good engraftment, [12][13][14] with a threshold of Ͼ1.0 × 10 6 in patients without extensive prior chemoradiotherapy and у2 × 10 6 in all others. 15 Another crucial aspect is the identification of factors predictive of an adequate yield of CD34 + stem cells. These factors would be useful to define the optimal timing and the best combination of mobilizing agents.…”