CD34+/CD90+ cells infused best predict late haematopoietic reconstitution following autologous peripheral blood stem cell transplantation

This study aimed to identify which graft product subset of cells might be the most predictive of late haematopoietic recovery (three to 12 months) following autologous peripheral blood stem cell transplantation (PBSCT). The relationships between the numbers of reinfused CD34+ cells and their immature subsets such as CD34+/CD90+, CD34+/AC133+, CD34+/CD38- and CD34+/HLA-DR- cells, and haemoglobin, white blood cell (WBC) and platelet counts at 3, 6, 9 and 12 months after PBSCT, were studied in 25 patients with haematological and solid malignancies. The total CD34+ cell number, as well as CD34+/CD90+ and CD34+/AC133+ cell numbers, correlated with platelet counts at 3, 6, 9 and 12 months after PBSCT, but the CD34+/CD90+ cells infused best predicted platelet recovery during the first 12 months after PBSCT (P < 0.0238 at any time-point). The CD34+/AC133+ cell dose also correlated with WBC counts at 3 months post PBSCT. In addition, all patients receiving more than 80 x 10(4) CD34+/CD90+ cells/kg showed platelet counts greater than 100 x 10(9)/l at all points after PBSCT, suggesting that this value of the CD34+/CD90+ cells infused was a threshold dose for durable haematopoietic engraftment after PBSCT.     

Subsets of CD34+ and early engraftment kinetics in allogeneic peripheral SCT for AML

This study aimed to identify which graft product subset of CD34+ cells might be the most predictive of early hematopoietic recovery following allogeneic peripheral SCT (allo-PBSCT). The relationship between the number of 'mature' subsets of CD34+ cells (CD34+/CD33+, CD34+/CD38+, CD34+/DR+ and CD34+/CD133-) and 'immature' subsets of CD34+ cells (CD34+/CD33-, CD34+/CD38-, CD34+/DR- and CD34+/CD133+) and early neutrophil and platelet engraftment were studied in a homogeneous series (for disease, pre transplant chemotherapy, conditioning regimen and GVHD prophylaxis) of 30 AML patients after allo-PBSCT from HLA-identical siblings. In our experience, the total CD34+/CD133+ cell number was inversely correlated with the days required for the recovery of 0.5 x 10(9)/l neutrophils (r=or-0.82, P=0.02) and platelets of 20 x 10(9)/l (r=or-0.60, P=0.06); this correlation was better than the total CD34+ cell dose and neutrophil (r=or-0.70, P=0.04) and platelet engraftment (r=or-0.56, P=0.07). We suggest that a high number of CD34+/CD133+ PBSC may be associated with faster neutrophil and platelet recovery; these findings may help to predict the repopulating capacity of PBSC in patients after allo-PBSCT, especially when a relatively low number of CD34+ cells is infused.     

Impact of CD34 subsets on engraftment kinetics in allogeneic peripheral blood stem cell transplantation

Our objective was to evaluate, probably for the first time, the impact of CD34 subsets on engraftment kinetics in allogeneic PBSC transplantation (PBSCT). PBSC graft components were analyzed in 62 cases for the absolute count/kg of total CD34+ and the following subsets: DR- and +, CD71+/-, CD38+/-, CD33+/- and CD61+/-. Time to ANC >0.5 and >1 x 10(9)/l and platelets >20 and >50 x 10(9)/l was reported. The median value for each parameter was used to discriminate rapid from slow engraftment. Four parameters showed significant predictive power of early neutrophil engraftment, namely CD34+ /DR- (P = 0.002), CD34+/38- (P = 0.02), CD34+/CD61- (P = 0.04) and total CD34+ cell dose (P = 0.04). Four parameters showed significant predictive power of early platelet engraftment, namely CD34+/CD61+ (P = 0.02), CD34+ /CD38- and total CD34+ cell dose (P = 0.04) and CD34+ /CD71- (P = 0.05). Comparing patients who received > to those who received < the threshold dose(s), only CD34+ /CD38- lost its significance for neutrophil engraftment; and only CD34+ /CD61+ retained its significance for platelet engraftment (P = 0.03); furthermore, the former group required significantly fewer platelet transfusions (P = 0.018). We concluded that in allogeneic PBSCT, the best predictor of early neutrophil engraftment is the absolute CD34+ /DR- and for early platelet engraftment is the absolute CD34+ /CD61+ cell dose.     

Subsets of CD34+ hematopoietic progenitors and platelet recovery after high dose chemotherapy and peripheral blood stem cell transplantation.

BACKGROUND AND OBJECTIVE: Randomized clinical trials have shown that peripheral blood stem cell transplantations (PBSCT) with appropriate doses of CD34+ cells are associated with rapid, complete and sustained recovery of marrow functions. Nevertheless, in a minority af patients delayed platelet recovery may occur and it remains to be established whether analysis of transplanted CD34+ cell subsets may demonstrate correlation with this phenomenon. We studied a series of 80 consecutive transplanted patients with the aim of evaluating the effect of CD34+ stem cell numbers and, in a subgroup of 32 patients, the effect of the lineage specific subset numbers on time to platelet engraftment (i.e. time to platelet counts higher than 20x10(9)/L for two consecutive days without the need for platelet transfusions). DESIGN AND METHODS: Different clinical and paraclinical factors were examined in a multivariate analysis for effect on platelet engraftment in 80 patients. RESULTS: The number of CD34+ cells/kg infused was the most important factor predicting the time to platelet engraftment. Patients receiving more than 10x10(6) CD34+ cells/kg had prompt platelet engraftment. The majority of the patients (78%) received fewer than 10x10(3) CD34+ cells/kg and 17/62 (27%) of these patients experienced delayed platelet engraftment. In 32 patients receiving fewer than 10x10(6) CD34+ cells/kg we focused on the content of different lineage specific CD34+ subsets in the PBSC products. The most significant correlation was recognized for CD34+/CD61+ megakaryocytic cell number and platelet engraftment. An inverse correlation between the CD34+/CD38Eth subset and platelet engraftment was found, indicating that a high number of CD34+/CD38Eth in the PBSC product might increase the risk for delayed engraftment. These results were further confirmed by the observation that patients who experienced platelet engraftment after day 20 had significantly more CD34+/CD38Eth cells/kg infused than patients with fast engraftment. INTERPRETATION AND CONCLUSIONS: The number of total CD34+ cells/kg infused was the most important factor predicting time to platelet engraftment. CD34+ subset analysis in a subgroup of patients suggests that a high number of uncommitted progenitors may be associated with slower platelet recovery than transplantation with a higher fraction of more committed peripheral blood stem cells.     

CD34~+ CD38~-细胞对异基因造血干细胞移植的影响研究

目的观察CD34+CD38-细胞对异基因造血干细胞移植术后造血重建和移植物抗宿主病(GVHD)的影响。方法分析2004年1月至2009年12月河南省人民医院血液科全相合异基因外周血干细胞造血干细胞移植78例,CD34+、CD34+CD38-细胞输入量与血缘全相合异基因外周血造血干细胞移植术后造血重建及GVHD发生率间的相关性。结果粒细胞、血小板恢复时间与CD34+CD38-细胞输入量呈负相关(r分别为-0.521、-0.448,P<0.01),与CD34+细胞输入量也呈负相关(r分别为-0.405、-0.371,P<0.05)。急性GVHD、慢性GVHD的发生与CD34+、CD34+CD38-、CD3+、CD4+、CD8+细胞输入量无相关性。结论输入高数量的CD34+CD38-细胞有利于移植术后的粒细胞、血小板快速恢复;对于预测术后造血恢复,CD34+CD38-细胞亚群输入量可能优于CD34+细胞总数。     

Influential Factors for the Collection of Peripheral Blood Stem Cells and Engraftment in Acute Myeloid Leukemia Patients in First Complete Remission

Although several studies have investigated factors influencing peripheral blood stem cell (PBSC) mobilization in patients with nonmyeloid malignancies in an effort to increase the efficiency of autologous PBSC transplantation (APBSCT), there are very few reports on the efficiency of PBSC mobilization in patients with leukemia. We analyzed the effects of influential variables on successful mobilization and the correlation between infused cell doses and engraftment in acute myeloid leukemia (AML) patients in first complete remission (CR1) who received APBSCT. Between May 1998 and May 2003, 34 patients with AML underwent APBSC collections at our institution. All patients were in CR1 at the time of transplantation. Except for 1 patient, all patients successfully achieved the target CD34(+) cell yield of > or = 2 x 10(6)/kg. Among progenitor cells, the CD34(+) cell dose and the colony-forming unit-granulocyte-macrophage count showed significant correlations with neutrophil and platelet engraftments. The time to neutrophil engraftment was inversely correlated to the number of infused CD34(+) cells (r = -0.67; P < .001), whereas the time to neutrophil engraftment was not significantly correlated with the number of monocytes (r = 0.20; P = .701) or the number of nucleated cells (r = 0.35; P = .062). The time to platelet engraftment was significantly correlated with the dose of infused CD34(+) cells (r = -0.47; P = .012). The univariate analysis showed that more CD34(+) cells per kilogram and more CD34(+) cells per kilogram per day were collected from patients who had a shorter interval (less than 2 months) between diagnosis and PBSC harvest (P = .0111). In conclusion, this study showed that the CD34(+) cell dose was most strongly correlated with a successful engraftment in AML CR1 patients who underwent APBSCT. The proper timing of PBSC collections should be explored to optimize the outcome of APBSCT in AML CR1 patients.     

Factors predicting engraftment of autologous blood stem cells: CD34+ subsets inferior to the total CD34+ cell dose.

Data were analyzed on 178 consecutive patients (median age 43 years) who underwent autologous blood stem cell transplantation (ABSCT) at a single institution to determine if CD34+ subsets (CD34+38-, CD34+33-, CD34+33+, CD34+41+) or various clinical factors affect hematopoietic engraftment independent of the total CD34+ cell dose/kg. Using Cox proportional hazards models, the factors independently associated with rapid neutrophil engraftment were higher CD34+ dose/kg, use of G-CSF post-ABSCT, and conditioning regimen (single-agent melphalan +/- TBI slower). Factors independently associated with rapid platelet engraftment were higher CD34+ cell dose/kg, higher ratio of CD34+33-/total CD34+ cells infused, conditioning regimen (mitoxantrone, vinblastine, cyclophosphamide faster), and no CD34+ cell selection of the autograft. The CD34+ cell selection process seemed to deplete CD34+41+ cells to a greater extent than total CD34+ cells which may explain our observation that it resulted in slower platelet engraftment. In conclusion, the total CD34+ dose/kg was a better predictor of hematopoietic engraftment following ABSCT than the dose of any CD34+ subset. Platelet engraftment, however, was also influenced by the ratio of CD34+33-/total CD34+ cells for unmanipulated autografts, and possibly by the CD34+41+ dose for autografts manipulated by CD34+ selection. The use of CD34+ subsets requires further investigation in predicting engraftment of autografts which undergo ex vivo manipulation.     

CD34 cell subsets and long-term culture colony-forming cells evaluated on both autologous and normal bone marrow stroma predict long-term hematopoietic engraftment in patients undergoing autologous peripheral blood stem cell transplantation

OBJECTIVE: The aim of this study was to evaluate which CD34(+) cell subset contained in leukapheresis products could be regarded as the most predictive of long-term hematopoietic recovery after autologous peripheral blood stem cell transplantation (auto-PBSCT). MATERIALS AND METHODS: Based on data from 34 patients with hematologic malignancies, doses of CD34(+) cells and CD34(+) cell subsets, defined by the expression of HLA-DR, CD38, CD117 (c-kit/R), CD123 (alpha subunit of IL-3/R), CD133 (AC133), and CD90 (Thy-1) antigens, were correlated with the number of short-term (i.e., colony-forming cells [CFC]) and long-term culture CFC (LTC-CFC) (generated at week 5 of culture) and with the kinetics of hematopoietic engraftment following auto-PBSCT. The capacity of autologous stroma (AS), normal human bone marrow stroma, and M2-10B4 murine cell line to sustain CD34(+) cell growth was comparatively evaluated in the LTC assay. RESULTS: Our data demonstrated that some of the most primitive progenitor subsets (CD34(+)CD117(-)HLA-DR(-), and CD34(+)CD38(+)HLA-DR(-)) showed the strongest correlation with LTC-CFC numbers generated within the AS, whereas no significant correlation was noted using normal bone marrow stroma. Multivariate analysis showed that the only CD34 cell subset independently associated with long-term (3 to 6 months) platelet engraftment after auto-bone marrow transplantation was the CD34(+)CD117(-)HLA-DR(-) phenotype; long-term erythrocyte engraftment was correlated with CD34(+)CD38(+)HLA-DR(-) cell content. The latter further influenced platelet engraftment in the first 3 months after auto-PBSCT. The most predictive parameters for neutrophil engraftment were CD34(+)CD38(+)HLA-DR(-) cell subtype and the total LTC-CFC quantity infused. CONCLUSIONS: These data further support the hypothesis that the type of stromal feeders influences the frequency of LTC-CFC, possibly because they differ in their ability to interact with distinct subsets of hematopoietic stem cells. Furthermore, as the use of AS in LTC assay can mimic in vitro the human bone marrow microenvironment, it can be speculated that this culture system could be a useful means to study the kinetics of recovery of bone marrow stroma following chemotherapy and PBSCT. From these results, it can be concluded that some CD34(+) cell subsets appear to be more reliable predictors of long-term hematopoietic recovery rates than total CD34(+) cell quantity.     

Influence of the different CD34+ and CD34- cell subsets infused on clinical outcome after non-myeloablative allogeneic peripheral blood transplantation from human leucocyte antigen-identical sibling donors

Currently, no information is available regarding the influence of the different CD34+ cell subsets infused on the haematopoietic recovery, following non-myeloablative allogeneic peripheral blood stem cell transplantation (allo-PBSCT). We have explored, in a group of 13 patients receiving non-myeloablative allo-PBSCT from human leucocyte antigen-identical sibling donors, the influence of the total dose of CD34+ haematopoietic progenitor cells (HPC) infused, compared with that of the different CD34+ HPC and CD34- leucocyte subsets in the leukapheresis samples, on both engraftment and clinical outcome. The overall numbers of total CD34+ HPC (P = 0.002) and myelomonocytic-committed CD34+ HPC infused (P = 0.0002) were strongly associated with neutrophil recovery (> 1 x 109 neutrophils/l), the latter being the only independent parameter influencing neutrophil recovery. Regarding long-term engraftment, only the number of immature CD34+ HPC infused/kg correlated with the duration of hospitalization in the first 2 years after discharge (r = -0.75, P = 0.005). Both the overall amount of CD34+ HPC and the number of myelomonocytic CD34+ HPC infused showed a significant influence on the risk of graft-versus-host disease (GVHD). Thus, the overall probability of GVHD was 100%vs 25% for patients receiving >/= 5 x 106 CD34+ HPC or >/= 3.5 x 106 of myelomonocytic-committed CD34+ HPC vs lower doses (P = 0.013). None of the other CD34+ and CD34- cell subsets analysed correlated with development of GVHD. In summary, our results suggest that in non-myeloablative allo-PBSCT, high numbers of CD34+ HPC, especially the myelomonocytic-committed CD34+ progenitors, lead to rapid neutrophil engraftment. However, they also strongly impair clinical outcome by increasing the incidence of GVHD.     

An analysis of engraftment kinetics as a function of the CD34 content of peripheral blood progenitor cell collections in 692 patients after the administration of myeloablative chemotherapy

The CD34 antigen is expressed by committed and uncommitted hematopoietic progenitor cells and is increasingly used to assess stem cell content of peripheral blood progenitor cell (PBPC) collections. Quantitative CD34 expression in PBPC collections has been suggested to correlate with engraftment kinetics of PBPCs infused after myeloablative therapy. We analyzed the engraftment kinetics as a function of CD34 content in 692 patients treated with high-dose chemotherapy (HDC). Patients had PBPCs collected after cyclophosphamide based mobilization chemotherapy with or without recombinant human granulocyte colony-stimulating factor (rhG-CSF) until > or = 2.5 x 10(6) CD34+ cells/kg were harvested. Measurement of the CD34 content of PBPC collections was performed daily by a central reference laboratory using a single technique of CD34 analysis. Forty-five patients required a second mobilization procedure to achieve > or = 2.5 x 10(6) CD34+ cells/kg and 15 patients with less than 2.5 x 10(6) CD34+ cells/kg available for infusion received HDC. A median of 9.94 x 10(6) CD34+ cells/kg (range, 0.5 to 112.6 x 10(6) CD34+ cells/kg) contained in the PBPC collections was subsequently infused into patients after the administration of HDC. Engraftment was rapid with patients requiring a median of 9 days (range, 5 to 38 days) to achieve a neutrophil count of 0.5 x 10(9)/L and a median of 9 days (range, 4 to 53+ days) to achieve a platelet count of > or = 20 x 10(9)/L. A clear dose-response relationship was evident between the number of CD34+ cells per kilogram infused between the number of CD34+ cells per kilogram infused and neutrophil and platelet engraftment kinetics. Factors potentially influencing the engraftment kinetics of neutrophil and platelet recovery were examined using a Cox regression model. The single most powerful mediator of both platelet (P = .0001) and neutrophil (P = .0001) recovery was the CD34 content of the PBPC product. Administration of a post-PBPC infusion myeloid growth factor was also highly correlated with neutrophil recovery (P = .0001). Patients receiving high-dose cyclophosphamide, thiotepa, and carboplatin had more rapid platelet recovery than patients receiving other regimens (P = .006), and patients requiring 2 mobilization procedures versus 1 mobilization procedure to achieve > or = 2.5 x 10(6) CD34+ cells/kg experienced slower platelet recovery (P = .005). Although a minimal threshold CD34 dose could not be defined, > or = 5.0 x 10(6) CD34+ cells/kg appears to be optimal for ensuring rapid neutrophil and platelet recovery.     

Changes in endogenous TPO levels during mobilization chemotherapy are predictive of CD34+ megakaryocyte progenitor yield and identify patients at risk of delayed platelet engraftment post-PBPC transplant

Patients with delayed platelet recovery post-PBPC transplant (PBPCT) are a high-risk group for thrombocytopenic bleeding and platelet transfusion dependence. Total CD34+ cell dosage has been proposed as the most important factor influencing the rate of platelet recovery. To achieve the shortest time to platelet engraftment, a minimum leukapheresis target of 10x10(6) CD34+ cells/kg was established for 30 patients. Of the 29 evaluable patients, 62% had rapid (group I: time to platelets >20x10(9)/l < or =10 days and 50x10(9)/l < or =14 days) platelet recoveries while 38% had delayed (group II: 20x10(9)/l >10 days and 50x10(9)/l >14 days) recoveries. Groups I and II were compared for: (1) pretreatment variables; (2) mobilizing capability of CD34+ cells and subsets including megakaryocyte (Mk) progenitors; (3) infused dose of these cells at transplant; (4) changes in endogenous levels of Mpl ligand (or TPO) during mobilization and myeloablative chemotherapy. Group II patients received significantly more platelet transfusions (6 vs. 2.1, P = 0.002) post-PBPCT, had a higher proportion of patients with a prior history of BM disease (64% vs. 6%, P = 0.001), and showed a reduced ability to mobilize differentiated (CD34+/38+, CD34+/DR+) and Mk progenitors (CD34+/42a+, CD34+/61+). Only the number of Mk progenitors reinfused at transplant was significantly different between the groups (group II vs. group I: CD34+/42a+ = 1.02 vs. 2.56x10(6)/kg, P = 0.013; CD34+/61+ = 1.12 vs. 2.70x10(6)/kg, P = 0.015). The ability to mobilize Mk progenitors correlated with percentage changes in endogenous levels of TPO from baseline to platelet nadir during mobilization chemotherapy (CD34+/42a+: r = 0.684, P = 0.007; CD34+/61+: r = 0.684, P = 0.007), with group II patients experiencing lower percentage changes. An inverse trend but no correlation was observed between serial TPO levels and platelet counts. TPO levels remained elevated in group II patients throughout a prolonged period of thrombocytopenia (median days to 50x10(9)/l = 25 vs. 11 for group I), indicating that delayed engraftment was not due to a deficiency of TPO but to a lack of Mk progenitor target cells. Our results show that the number of reinfused Mk progenitors is a better predictor of platelet engraftment than total CD34+ cell dosage. Small changes in endogenous TPO levels during mobilization predict for low Mk progenitor yields.     

Long-Term Engraftment Stability of Peripheral Blood Stem Cells Cryopreserved Using the Dump-Freezing Method in a −80°C Mechanical Freezer with 10% Dimethyl Sulfoxide

In this study, we summarize our long-term follow-up data of 24 patients who underwent autologous peripheral blood stem cell transplantation (PBSCT) using the dump-freezing method in a -80 degrees C freezer. Collected peripheral blood mononuclear cells were mixed with a cryoprotectant solution consisting of autologous plasma and 20% dimethyl sulfoxide, then placed in a -80 degrees C freezer. The recovery rate of mononuclear cells (MNCs), colony-forming unit-granulocyte/macrophage (CFU-GM) colonies, and CD34+ cells were calculated. Engraftment time (with neutrophil count > 0.5 x 10(9)/L, platelet count > 50 x 10(9)/L) and normal hemopoiesis (neutrophil count > 2 x 10(9)/L, platelet count > 100 x 10(9)/L) were evaluated. Median duration of cryopreservation was 76 days. The mean recovery rates of MNCs, CFU-GM colonies, and CD34+ cells were 93.4%, 78.4%, and 95.3%, respectively. The median engraftment times of neutrophils and platelets were 8 and 27 days, respectively. The median normal hemopoiesis times of neutrophil and platelet were 31 and 45 days, respectively. Nine patients are alive and in complete remission (CR). Seven patients in first CR sustained normal hemopoiesis with a median duration of 35 months. Two patients, who achieved second CR after salvage chemotherapy due to a leukemia relapse after PBSCT, maintained engraftment status for 24 and 28 months, and 1 reached normal hemopoiesis. These results demonstrate that PBSCT using the dump-freezing method in a -80 degrees C freezer leads to acceptable long-term engraftment stability.     

Analysis of CD34+ cell subsets in stem cell harvests can more reliably predict rapidity and durability of engraftment than total CD34+ cell dose, but steady state levels do not correlate with bone marrow reserve

In peripheral blood stem cell transplantation (PBSCT), the number of CD34+ cells transplanted has been shown to correlate well with both rapidity and durability of engraftment. However, it is clear that engraftment does not necessarily correlate with total CD34+ cell numbers in some patients. Consequently, there is increasing interest in evaluating the role of CD34+ subsets in haemopoietic recovery as a more accurate marker of harvest quality. We analysed the numbers of CD34+ cell subsets, namely Thy-1+, L-Selectin+ and CD38-, and correlated this with engraftment in 86 patients undergoing PBSCT. Adequate engraftment was defined as being a platelet count greater than 50 x 10(9)/l and a neutrophil count greater than 1.0 x 10(9)/l. CD34+L-Selectin+ provided the best prediction of engraftment rapidity, although the improvement over total CD34+ cell dose was minor. Only the dose of CD34+Thy-1+ cells transplanted correlated with durable engraftment. The probability of adequate 3-month engraftment increased with the dose of CD34+ cells transplanted, but 10% of patients receiving > 5 x 10(6)/kg still showed poor engraftment at 3 months. However, all patients receiving > 2.5 x 10(5)/kg CD34+Thy-1+ showed adequate engraftment at this time point. We also demonstrated that CD34+Thy-1+ progenitors were restricted to the bone marrow under normal conditions and, during stem cell mobilization, their kinetics generally paralleled total CD34+ numbers.     

The CD34+90+ cell dose does not predict early engraftment of autologous blood stem cells as well as the total CD34+ cell dose

CD90 or Thy-1 is an antigen co-expressed with CD34+ on putative immature hematopoietic stem cells. Peak mobilization of CD34+90+ cells into the blood occurs a few days earlier than peak mobilization of total CD34+ cells. Because it is not known which cell type best correlates with engraftment, the optimal timing of apheresis remains unclear. The purpose of the study was to determine if the CD34+90+ cell dose predicts engraftment of autologous blood stem cells independent of the total CD34+ cell dose/kg, the dose of other CD34+ cell subsets (CD34+33-, CD34+38-, CD34+41+), or various clinical factors. Data were analyzed on 125 consecutive patients ranging in age from 19 to 66 years (median 46) who underwent autologous blood stem cell transplantation (ABSCT) for breast cancer (54), lymphoma (59), or other malignancies (12). By univariate analysis, neutrophil (> or = 0.5 x 10(9)/l) and platelet (> or = 20 x 10(9)/l or > or = 100 x 10(9)/l) engraftment correlated better with the total CD34+ cell dose than with the CD34+90+ cell subset. Using Cox proportional hazards models, factors independently associated with both neutrophil engraftment (> or = 0.5 x 10(9)/l) and platelet engraftment (> or = 20 x 10(9)/l and > or = 100 x 10(9)/l) were higher total CD34+ dose/kg and high-dose regimen (melphalan-containing slower than other regimens). In conclusion, the total CD34+ dose/kg was a better predictor of hematopoietic engraftment following ABSCT than the dose of any CD34+ subset, including CD34+90+ cells. Apheresis should continue to be timed according to peak CD34+ levels.     

Autologous transplantation in acute myeloid leukemia: peripheral blood stem cell harvest after mobilization in steady state by granulocyte colony-stimulating factor alone

In order to determine whether granulocyte colony-stimulating factor (G-CSF) alone initiated during steady state was able to mobilize peripheral blood stem cells (PBSC) in acute myeloid leukemia (AML) and to assess predictive factors for engraftment after autologous PBSC transplantation, we studied 49 successive adult AML patients for whom autologous transplantation was planned between July 1994 and November 1998. G-CSF was used as priming agent and was initiated at least 4 weeks after the last day of chemotherapy, while neutrophil count was >0.5 x 10(9)/l and platelet count was >30 x 10(9)/l. A median of three aphereses was performed resulting in a median collection of 14.8 x 10(8) nucleated cells/kg containing 7.7 x 10(8) mononuclear cells/kg, 47.1 x 10(4) CFU-GM/kg, and 3.8 x 10(6) CD34+ cells/kg. A significant correlation was observed between nucleated cell, mononuclear cell, and CFU-GM yields, while no correlation was found with CD34+ cell yield. Recruitment was not significantly different in patients with CD34+ leukemic cells at the time of initial diagnosis when compared to that of those presenting with CD34- blastic cells. Thirty-three patients actually underwent transplantation. Reasons for not autografting were inadequate stem cell harvest (ten patients), early relapse (two patients), prolonged neutropenia (one patient), organ failure (two patients), or patient refusal (one patient). Median time to achieve a neutrophil count greater than 0.5 x 10(9)/l and platelet count >50 x 10(9)/l untransfused was 13 and 36 days, respectively. A predictive factor for a shorter period neutropenia and a shorter thrombopenia was a higher count of harvested nucleated cells (p < 0.01 and p = 0.02, respectively). A higher count of harvested cells was also a predictive factor for less red cell and platelet transfusions (p=0.03 and p=0.02, respectively). The number of CD34+ harvested PBSC was not predictive for engraftment. We conclude that PBSC mobilization with G-CSF alone initiated in steady state is a feasible, safe, and suitable procedure for harvesting cells in sight of autologous transplantation in adult acute myeloid leukemia.     

Long-term hematopoietic engraftment after autologous peripheral blood progenitor cell transplantation in pediatric patients: effect of the CD34+ cell dose

BACKGROUND AND OBJECTIVES: We analyzed the relationship between long-term hematopoietic recovery and the number of CD34+ cells infused in order to determine the optimal dose of CD34+ cells for rapid and stable engraftment. PATIENTS AND METHODS: Between November 1993 and December 1998, 96 consecutive autologous transplantations were performed in 92 pediatric patients with different malignancies. Peripheral blood progenitor cells (PBPC) were mobilized by G-CSF alone (12 microg/kg/day s.c., Neupogen((R)); Amgen, Thousand Oaks, Calif., USA) and collected using a Cobe Spectra blood cell separator (Cobe, Denver, Colo., USA) through a central venous catheter with double lumen. The CD34+ cell contents of apheresis products were assessed by means of flow-cytometric analysis using an Epics Elite flow cytometer (Coulter, USA). RESULTS: The median number of CD34+ cells infused was 3.2 x 10(6)/kg (range 0.17-44.4). The median times for short-term engraftment (neutrophil count >0.5 x 10(9)/l and platelet count >20 x 10(9)/l) was 9 (range: 7-16) and 13 days (range: 7-91), respectively. The median times for long-term engraftment (platelet count >50 x 10(9)/l and >100 x 10(9)/l) was 21 (range: 10-249) and 45 days (range: 12-288). When the infused CD34+ cell dose was >/=5 x 10(6)/kg (median 7.99, range 5.01-44.4), there was a statistically significant increase in the rate of short- and long-term hematopoietic recovery compared to patients transplanted with a lower number of CD34+ cells (p < 0.0001). The earlier recovery in the high CD34+ cell group resulted in less transfusional support, fewer days on intravenous antibiotics and shorter hospitalization. CONCLUSIONS: This study confirms that G-CSF-mobilized PBPC provide rapid short- and long-term hematopoietic engraftment in pediatric patients undergoing autologous transplantation if a CD34+ cell dose >/=5.0 x 10(6)/kg is infused. As this PBPC dose seems to have clinical and potentially economic implications, it should be considered the optimal dose for apheresis.     

Primordial role of CD34+38− cells in early and late trilineage haemopoietic engraftment after autologous blood cell transplantation

In order to better define which cell subset contained in graft products might be the most predictive of haemopoietic recovery following autologous blood cell transplantation (ABCT), the relationships between the amounts of reinfused mononuclear cells (MNC), CFU-GM, total CD34⁺ cells and their CD33 and CD38 subsets, and the successive stages of trilineage engraftment kinetics, were studied in 45 cancer patients, using the Spearman correlation test, a linear regression model and a log-inverse model. No relationship was found between the infused numbers of MNC, CD33⁺ and CD33^? subsets observed and the numbers of days to reach predetermined absolute neutrophil (ANC), platelet and reticulocyte counts. The infused numbers of CFU-GM, CD34⁺ and CD34⁺38⁺ cells correlated inconstantly with haemopoietic recovery parameters. The strongest and the most constant correlations were significantly observed between the infused numbers of CD34⁺38^? cells and each trilineage engraftment parameter. The log-inverse model determined a threshold dose of 0.05 × 10⁶ (= 5 × 10⁴) CD34⁺38^? cells/kg, below which the trilineage engraftment kinetics were significantly slower and unpredictable. Post-transplant TBI-conditioning regimens increased the low cell dose-related delay of engraftment kinetics whereas post-transplant administration of haemopoietic growth factors (HGF) seemed to abrogate this delay. This would justify clinical use of HGF only in patients transplanted with CD34⁺38^? cell amounts lower than the proposed threshold value. This study suggests that the CD34⁺38^? subpopulation, although essentially participating in late complete haemopoietic recovery, is also composed of committed progenitor cells involved in early trilineage engraftment.     

Predictive factors for rapid neutrophil and platelet engraftment after allogenic peripheral blood stem cell transplantation in patients with acute leukemia

The aim of this study was to investigate predictive factors for rapid engraftment after allogeneic peripheral blood stem cell transplantation (alloPBSCT) in patients with acute leukemia. Two hundred sixty-two patients receiving alloPBSCT were analyzed. Subset analyses of donor stem cells were conducted using a flow cytometric method. The correlation between rapid engraftment of neutrophils, platelets, and donor stem cells doses, as well as other recipient and donor clinical factors, was analyzed. In univariate analysis, factors correlated with neutrophil engraftment (≥0.5?×?10⁹/L) by day 12 were achievement of complete remission (CR) after induction chemotherapy (CR1) before hematopoietic cell transplantation (HCT) and high numbers of CD34+ cells, CD3+ T cells, and CD3+/CD4+ T cells. Factors correlated with platelet engraftment (≥20?×?10⁹/L) by day 12 were achievement of CR1 before HCT, donor and recipient sex mismatch, and high numbers of mononuclear cells, CD34+ cells, CD3+ T cells, CD3+/CD4+ T cells, CD3+/CD8+ T cells, and CD56+ NK cells. In multivariate analysis, independent predictive factors for rapid neutrophil and platelet engraftment were CR1 before HCT (p?<?0.001 and p?=?0.002, respectively), high number of donor CD34+ cells (p?=?0.005 and p?<?0.001, respectively), and high number of CD3+ T cells (p?=?0.005 and p?=?0.001, respectively). In conclusion, achieving CR1 before HCT, as well as larger quantities of donor CD34+ and CD3+ T cells, may predict rapid neutrophil and platelet engraftment after PBSCT.     

Factors influencing hematopoietic recovery after autologous blood stem cell transplantation in patients with acute myeloblastic leukemia and with non-myeloid malignancies

Factors influencing hematopoietic recovery (HR) after autologous blood stem cell transplantation (ABSCT) were analyzed in 73 patients with various non-myeloid malignancies (NMM), and in 58 patients with acute myeloblastic leukemia (AML). Peripheral blood stem cells were collected following mobilization with chemotherapy, granulocyte colony-stimulating factor (G-CSF), or chemotherapy plus G-CSF. The conditioning regimen used consisted of either chemotherapy alone (112 cases) or chemotherapy plus total body irradiation (19 cases). The median number of colony-forming units granulocyte-macrophage (CFU-GM) was similar in both groups of patients, with the median number of CD34(+) cells infused being higher in the AML group (5.4 vs 4 x 10(6)/kg; P = 0.03). Median time neutrophils >0.5 x 10(9)/l was 13 days in both groups, and median time to a platelet count >20 x 10(9)/l was longer in AML patients (14 vs 12 days; P = 0.01). In multivariate analysis, the only factors affecting neutrophil recovery in the NMM group were the CD34+ cell number (continuous model) and the CFU-GM dose (categorized model) infused, whereas for platelet recovery, previous chemotherapy also remained significant. In the AML group, the only factors significantly affecting the speed of neutrophil recovery were dose of CD34+ cells administered and the patient's age. As for platelet recovery, only the progenitor dose administered remained significant. In the NMM group, the most discriminating cut-off values for a rapid neutrophil and platelet recovery were 1.5 x 10(6) and 2.5 x 10(6) CD34+ cells/kg, respectively, and for AML patients these figures were 1.5 x 10(6) and 4 x 10(6) CD34+ cells/kg, respectively. Our results confirm the slower HR after ABSCT in AML, and highlight the importance of progenitor cell dose in accelerating HR after ABSCT.     

Analysis of platelet recovery after autologous transplantation with G-CSF mobilized CD34+ cells purified from leukapheresis products

Abstract. We studied platelet recovery in relation to graft content in CFUs and CD34+ cells in 31 patients with multiple myeloma (21) or non-Hodgkin lymphoma (10) receiving marrow-ablative therapy followed by autologous transplantation with G-CSF mobilized CD34+ cells purified from leukapheresis products. Twelve patients had prolonged post-transplantation thrombopenia (? 14 days): their graft contents in CD34+ cells, CFU-GM and BFU-E were significantly inferior to those of patients with rapid platelet recovery. Although numbers of infused CD34+ cells and CFU-GM or BFU-E were well correlated, the graft content in CD34+ cells was the only parameter predictive of platelet recovery (r = ?0.38, p = 0.04), with a threshold of 2.5 × 106 CD34+ cells/kg. However, because rapid platelet reconstitution was obtained for 4 of 16 patients re-infused with < 2.5 × 106 CD34+ cells/kg, we investigated whether the graft CFU-MK content might be a better predictor of platelet reconstitution than the CD34+ cell content. Eighteen CD34 grafts were studied for CFU-MK content: CD34 and CFU-MK contents were weakly correlated (r = 0.52, p = 0.03), but there was no correlation between numbers of infused CFU-MK and time to platelet recovery. We conclude that, for autologous CD34 grafts, CFU-MK assays, like CFU-GM or BFU-E assays, cannot be used to predict platelet recovery. A CD34+ cell content >= 2.5 × 106/kg remains the only reliable indicator of the platelet reconstitution capacity of a CD34 graft.