Predictive factors for peripheral blood stem cell mobilization in multiple myeloma in the era of novel therapies: A single-center experience.

OBJECTIVE: Multiple myeloma (MM) is the leading indication of autologous hematopoietic stem cell transplantation. The aim of this study was to determine the incidence of mobilization failure and characterize the risk factors associated with poor mobilization (PM) of MM patients in novel therapies era. METHODS: We conducted a retrospective study of 211 MM patients who received their first peripheral blood stem cells (PBSC) mobilization at our single center. The following data were collected: age, gender, clinical stage, disease status, complete blood cell count, induction regimen, CD34+ cell count in peripheral blood (PB), and PBSC collections. RESULTS: In addition to conventional drugs, 22 (10.4%) patients received daratumumab containing induction, and 33 (15.6%) patients used plerixafor for poor mobilization (pre-apheresis PB CD34+ cells <20/µL). Failure of collection occurred in 24 (11.4%) patients and was correlated with low white blood cell (WBC), ≥3 cycles of lenalidomide treatment before mobilization, steady-state mobilization and nouse of plerixafor are associated with mobilization failure. Daratumumab-based induction treatment ≥2 courses, albumin >41 g/L before mobilization, and steady-state mobilization were risk factors for PM in subgroups of patients treated with lenalidomide for <3 courses. In addition, Hepatitis B virus infection at baseline, thalassemia and measurable residual disease positivity were recognized as predictive factors for PM in subset of chemo-mobilization patients. CONCLUSION: In addition to some well-recognized risk factors, baseline WBC count and daratumumab exposure ≥2 courses before mobilization were revealed as the predictive factors of mobilization failure, providing consultation for preemptive use of plerixafor.

Hematopoietic Progenitor Cell Counts of the Leukapheresis Product Determined Using Sysmex XN Analyzers Predict a Sufficient Number of CD34+ Stem Cells in a Peripheral Blood Stem Cell Harvest for Autologous Transplantation.

Objective Several institutions outsource CD34+ cell counting of leukapheresis products, limiting rapid measurements, as results are obtained the next day. This problem is compounded with plerixafor use, a stem cell-mobilizing drug that increases leukapheresis efficiency but requires administration the day before leukapheresis. Use of this drug for a second leukapheresis procedure before the first-day leukapheresis CD34+ count results are confirmed causes unnecessary leukapheresis and expensive plerixafor administration. We investigated whether or not measuring hematopoietic progenitor cells in leukapheresis products (AP-HPCs) using a Sysmex XN-series analyzer could resolve this problem. Methods We retrospectively compared the absolute AP-HPC value per body weight with the CD34+ (AP-CD34+) count in 96 first-day leukapheresis product samples obtained between September 2013 and January 2021. Comparisons were also conducted according to regimen: granulocyte colony-stimulating factor (G-CSF) monotherapy, chemotherapy plus G-CSF, or plerixafor mobilization. Results AP-CD34+ and AP-HPC counts correlated strongly (rs=0.846) overall and, in particular, under chemotherapy plus G-CSF (rs=0.92) but correlated mildly under G-CSF monotherapy (rs=0.655). AP-HPCs could not completely be dichotomized based on an AP-CD34+ threshold of 2×106/kg for any stimulation procedure. In most cases with AP-HPCs >6×106/kg, the AP-CD34+ count exceeded 2.0×106/kg, but in 5.7% of these cases, the AP-CD34+ count was <2.0×106/kg. A cut-off of AP-HPCs >4.843×106/kg yielded a sensitivity of 71% and specificity of 96% for predicting AP-CD34+≥2×106/kg. Conclusion AP-HPCs can identify cases in which sufficient stem cells have been collected.

[Comparison of Plerixafor or Cyclophosphamide Combined with G-CSF in Mobilization of Peripheral Blood Stem Cells in Multiple Myeloma].

OBJECTIVE: To compare the efficacy of plerixafor (PXF) combined with granulocyte colony-stimulating factor (G-CSF) (PXF+G-CSF) and cyclophosphamide (Cy) combined with G-CSF (Cy+G-CSF) in the mobilization of peripheral blood stem cells (PBSCs) in patients with multiple myeloma (MM). METHODS: The clinical data of 41 MM patients who underwent PBSC mobilization using PXF+G-CSF (18 cases) or Cy+G-CSF (23 cases) in Shanxi Bethune Hospital from January 2019 to December 2021 were retrospectively analyzed, including the count of collected CD34+ cells, acquisition success rate, failure rate, and optimal rate. The correlation of sex, age, disease type, DS staging, ISS staging, number of chemotherapy cycle, disease status before mobilization, and mobilization regimen with the collection results was analyzed, and the adverse reactions, length of hospital stay, and hospitalization costs were compared between the two mobilization regimens. RESULTS: The 41 patients underwent 97 mobilization collections, and the median number of CD34+ cells collected was 6.09 (0-34.07)×106/kg. The acquisition success rate, optimal rate, and failure rate was 90.2%, 56.1%, and 9.8%, respectively. Univariate analysis showed that sex, age, disease type, and disease stage had no significant correlation with the number of CD34+ cells collected and acquisition success rate (P >0.05), but the patients with better disease remission than partial remission before mobilization were more likely to obtain higher CD34+ cell count (P <0.05). The PXF+G-CSF group had a larger number of CD34+ cells and higher acquisition success rate in the first collection than Cy+G-CSF group (both P <0.05), and had lower infection risk and shorter length of hospital stay during mobilization (both P <0.05), but the economic burden increased (P <0.05). CONCLUSION: PXF+G-CSF used for PBSC mobilization in MM patients has high first acquisition success rate, large number of CD34+ cells, less number of collection times, and short length of hospital stay, but the economic cost is heavy.

The Effect of Iron Overload on the Mobilization of Peripheral Blood Hematopoietic Stem Cells in Pediatric Patients with Thalassemia Major.

INTRODUCTION: The purpose of this study was to examine the effect of iron overload on the mobilization of peripheral blood stem cells (PBSCs) in pediatric patients with ß-thalassemia major (TM). METHODS: We retrospectively reviewed the records of 226 patients with TM from whom PBSCs were collected. Iron overload was based on serum ferritin level, and liver and cardiac iron overload was measured by magnetic resonance imaging (MRI) T2*. RESULTS: The mean age of the TM patients was 7.35 ± 3.41 years. Of the patients, only 171 received MRI. Of the 171 patients, 35 had normal liver iron levels, 39 mild liver iron overload, 90 intermediate liver iron overload, and 7 severe liver iron overload. The intermediate + severe group was associated with significantly higher age and BMI and lower leukapheresis product white blood cell count and CD34+ cell levels (all, p < 0.05). CONCLUSION: Leukapheresis indices were similar between patients with different degrees of iron overload according to the ferritin level and cardiac iron overload, in which the later might be due to the small number of patients with cardiac overload. In patients with TM, the intermediate and severe liver iron overload was associated with poorer mobilization of PBSCs.

Short-Term Storage of Mobilized Peripheral Blood Stem Cells in a Closed System Changes the Microenvironment and May Affect the Quantity of CD34+ and CD34+CD38-CD45RA-CD90+ Cells.

Hypoxic conditions preserve the multipotency and self-renewing capacity of murine bone marrow and human cord blood stem cells. Blood samples stored in sealed blood gas tubes become hypoxic as leukocytes metabolize and consume oxygen. Taken together, these observations suggest that peripheral blood stem cell (PBSC) samples stored under airtight conditions become hypoxic, and that the stem cells contained may undergo qualitative or quantitative changes. This study aimed to determine the effect of storage for 8 hours in a sealed system on PBSC samples. Granulocyte colony-stimulating factor-mobilized PBSC samples were collected prospectively from 9 patients with myeloma or amyloidosis prior to apheresis, followed by measurement of CO2, O2, hydrogen ion (pH), lactate, and glucose concentrations in the blood and immunophenotyping of stem cell and multipotent progenitor cell populations before and after 8 hours of storage in sealed blood collection tubes. Blood concentrations of O2 and glucose and pH measurements were significantly decreased, whereas concentrations of CO2 and lactate were significantly increased after storage. Significantly higher concentrations of CD34+ cells (552 ± 84 cells/106 total nucleated cells [TNCs] versus 985 ± 143 cells/106 TNCs; P = .03), CD34+CD38- cells (98 ± 32 cells/106 TNCs versus 158 ± 52 cells/106 TNCs; P = .03), CD34+CD38+ cells (444 ± 92 cells/106 TNCs versus 789 ± 153 cells/106 TNCs; P = .03), and CD34+CD38-CD45RA-CD90+ cells (55 ± 17 cells/106 TNCs versus 89 ± 25 cells/106 TNCs; P = .02) were detected after 8 hours of storage. The changes in concentrations of CD34+CD38+ cells and CD34+ cells were inversely associated with the change in glucose concentration (P = .003 and P < .001, respectively) and positively associated with the change in lactate concentration (P = .01 and P <.001, respectively) after 8 hours of airtight storage. Storage of PBSC samples in a sealed, airtight environment is associated with microenvironmental changes consistent with hypoxia and increased concentrations of immunophenotypically defined stem cells. These results may have clinical implications with regard to the collection and processing of stem cell products and warrant confirmation with functional and mechanistic studies.

Successful Mobilization of Autologous Hematopoietic Peripheral Blood Stem Cells after Salvage Chemotherapy in Patients with Low CD34 Blood Cell Counts.

A major barrier for proceeding to autologous stem cell transplantation (ASCT) is an inability to mobilize and collect an adequate number of peripheral blood (PB) stem cells (PBSC) for the transplant graft. Plerixafor added to granulocyte colony stimulating factor (G-CSF) alone, without prior chemotherapy, significantly improves the mobilization of autologous PBSC in patients with non-Hodgkin lymphoma (NHL) and multiple myeloma (MM). However, the efficacy of plerixafor and the best timing to give the drug to poorly mobilizing patients with very low PB CD34+ cell counts after salvage chemotherapy and G-CSF are not well defined. We hypothesized that PBSC mobilization and collection might be improved in heavily treated patients who mobilized very poorly after salvage chemotherapy and G-CSF by alternating the days of plerixafor administration and leukapheresis. A day of rest between plerixafor doses, while continuing G-CSF, could allow time for some replenishment of the marrow stem/progenitor cell pool before the next mobilization. A retrospective review of collection results in poorly mobilizing patients at our center was undertaken. Three cohorts were identified: those who got every-other-day plerixafor and leukapheresis, those who got sequential plerixafor and leukapheresis and those who got risk adapted plerixafor. Overall, 69% of patients with NHL and MM with PB CD34+ cell counts <5/µL after salvage chemotherapy and G-CSF were ultimately able to collect adequate CD34+ cells to support ASCT using daily plerixafor and leukapheresis. On the alternating plerixafor and leukapheresis schedule, all 17 patients achieved the cumulative CD34+ cell product goals required for ASCT. This positive observation after salvage chemotherapy and G-CSF led to the incorporation at our center of an alternate-day schedule of plerixafor and leukapheresis into our real-time risk adapted strategy for poor mobilizers. © 2023 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

Autologous peripheral blood stem cell mobilization and collection in patients with lymphoma and multiple myeloma: A single-center experience using the plerixa for pre-emptive approach.

OBJECTIVES: To review and assess the efficiency of pre-emptive plerixafor administration for poor mobilization (PM) and to review and assess mobilization efficiency (≥2×106 CD34+ cells/kg) in patients who received autologous stem cell transplantation for lymphoma and multiple myeloma (MM) at the Department of Adult Hematology/Blood Marrow Transplant, Princess Noorah Oncology Center, King Abdulaziz Medical City, Jeddah, Saudi Arabia, over the past 7 years. METHODS: This retrospective study evaluated all patients with MM and lymphoma undergoing peripheral blood stem cell mobilization and collection at our institution between February 2014 and August 2021. Plerixafor was administered pre-emptively by a plateau of <10 peripheral blood CD34+/µl after chemotherapy-based mobilization or CD34+ of <8/µL on day 4 after mobilization with G-CSF alone. Between peak CD34+ levels of 10-15/µl, plerixafor will be used at the discretion of the treating physician. RESULTS: In total, 215 patients were enrolled. Among them, 80% had peak CD34+ level ≥20/µL, 11% had clear poor mobilization (peak CD34+ levels <10/µL), and 9% had borderline PM (CD34+ between 10-19/µL). Plerixafor was administered pre-emptively in 13% of the patients and 75% of patients with borderline PM were collected without plerixafor, suggesting that plerixafor is not needed if CD34+ >15/µL on the anticipated collection day. Mobilization failed in only one patient (<1%). CONCLUSION: Our data showed that with plerixafor pre-emptive administration, the primary endpoint was achieved for most patients identified with PM, preventing the need for a second mobilization attempt.

Effects of cell concentration, time of fresh storage, and cryopreservation on peripheral blood stem cells: PBSC fresh storage and cryopreservation.

INTRODUCTION: Peripheral blood stem cells are widely used in autologous or allogeneic transplantation. The quality of the product directly impacts clinical outcomes, and the cell quality and/or functionality may be influenced by the storage conditions as time, temperature, total nucleated cells (TNC) concentration and cryopreservation requirement. OBJECTIVE: To verify the effects of time, cell concentration, and cryopreservation/thawing in the viability and functionality of stem cells for transplantation. METHODS: We evaluated TNC, CD45+ viable cells, CD34+ viable cells, and cell viability and functionality of 11 samples. Measurements were performed immediately and 24 h, 48 h, 72 h, and 96 h after sample collection at high and low TNC concentrations. The same parameters were also evaluated after cryopreservation and thawing of the samples. RESULT: Duration of storage and TNC concentration exhibited a negative effect on cell quality (CD45+ viable cells, CD34+ viable cells and functionality). Moreover, the association of these parameters increased the negative effect on graft quality. Cryopreservation and thawing also negatively affected the collected sample regarding viable CD34+ cells (recovery 66.2 %), viable CD45+ cells (recovery 56.8 %), and 7-AAD viability. No significant losses in viable CD45+/CD34+ cells and functionality were observed in the first 24 h in both TNC conditions. CONCLUSION: These results emphasize the importance to consider carefully the storage conditions until transplantation, measuring TNC/µL until 24 h after collection (diluting the product when TNC > 300 × 103/µL) and infusing fresh graft as soon as possible.

Long-Term Cryopreservation Does Not Affect Quality of Peripheral Blood Stem Cell Grafts: A Comparative Study of Native, Short-Term and Long-Term Cryopreserved Haematopoietic Stem Cells.

Cryopreserved haematopoietic progenitor cells are used to restore autologous haematopoiesis after high dose chemotherapy. Although the cells are routinely stored for a long period, concerns remain about the maximum storage time and the possible negative effect of storage on their potency. We evaluated the effect of cryopreservation on the quality of peripheral stem cell grafts stored for a short (3 months) and a long (10 years) period and we compared it to native products.The viability of CD34+ cells remained unaffected during storage, the apoptotic cells were represented up to 10% and did not differ between groups. The clonogenic activity measured by ATP production has decreased with the length of storage (ATP/cell 1.28 nM in native vs. 0.63 in long term stored products, P < 0.05). Only borderline changes without statistical significance were detected when examining mitochondrial and aldehyde dehydrogenase metabolic activity and intracellular pH, showing their good preservation during cell storage. Our experience demonstrates that cryostorage has no major negative effect on stem cell quality and potency, and therefore autologous stem cells can be stored safely for an extended period of at least 10 years. On the other hand, long term storage for 10 years and longer may lead to mild reduction of clonogenic capacity. When a sufficient dose of stem cells is infused, these changes will not have a clinical impact. However, in products stored beyond 10 years, especially when a low number of CD34+ cells is available, the quality of stem cell graft should be verified before infusion using the appropriate potency assays.

Addition of Anti-thymocyte Globulin in Allogeneic Stem Cell Transplantation With Peripheral Stem Cells From Matched Unrelated Donors Improves Graft-Versus-Host Disease and Relapse Free Survival.

Anti-thymocyte globulin (ATG) is commonly used to prevent graft-versus-host disease (GvHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). To evaluate the impact of ATG as part of the GvHD prophylaxis in our institution, we report the outcome of 415 patients with matched unrelated donors (MUD) transplanted for hematological malignancies with or without ATG from 2005 to 2019 at Oslo University Hospital, Norway. The following groups were compared: (1) 154 patients transplanted with peripheral blood stem cells (PBSC) without ATG 2005-2014. (2) 137 patients transplanted with bone marrow stem cells (BMSC) 2005-2019. (3) 124 patients transplanted with PBSC and ATG (PBSC + ATG) 2014-2019. Three years survival was similar in the groups, 61% following allografting with PBSC, 54% with BMSC, and 59% with PBSC + ATG. Acute GvHD grade III-IV was 14%, 14%, and 7%; chronic GvHD was 81%, 32, and 26%; and extensive cGvHD 44%, 15%, and 6% in the corresponding groups. Both acute and chronic GvHD were significantly reduced in the PBSC + ATG-versus the PBSC group (p < 0.05 and p < 0.001 respectively).Transplant-related mortality (TRM) was 33%, 25%, and 17% (p = 0.18). Graft versus host disease and relapse free survival (GRFS) at 3 years was 43 %, 43%, and 64% in the groups. Adding ATG to the GvHD prophylaxis regimen of MUD allo-HSCT with PBSC resulted in a substantial reduction of both acute and chronic GvHD without compromising the disease control, reflected in a superior 3 years GRFS.

Effectiveness of supplemental oral calcium drink in preventing citrate-related adverse effects in peripheral blood progenitor cell collection.

Peripheral blood progenitor cells (PBPCs) are a predominant graft source in allogeneic hematopoietic cell transplantation. Citrate-induced hypocalcemia remains the most frequent side effect of PBPC apheresis. Although the method for preventing severe adverse events is established, more efficient prophylaxis is required so that volunteer donors can donate PBPCs without pain and anxiety. We studied 80 healthy donors who underwent PBPC harvest between February 2014 and June 2020. Of these, 23 donors who underwent apheresis between February 2014 and December 2015 received only the standard prophylaxis of intravenous calcium gluconate. Oral calcium drinks were provided to 57 donors who underwent apheresis from January 2016 to June 2020 to supplement intravenous calcium gluconate prophylaxis. The ionized calcium (ICa) levels at multiple time intervals and the hypocalcemic symptoms were evaluated. Oral supplementation with a calcium drink maintained significantly higher ICa levels. Analysis using the inverse probability weighted regression adjustment method suggested that calcium drinks reduced the frequency of citrate-related reactions by 39.2 %. Administering a prophylactic oral calcium drink before apheresis with intravenous administration of calcium gluconate is promising to further reduce citrate-induced hypocalcemia in volunteer donors.

Molecular Profiling and Gene Banking of Rabbit EPCs Derived from Two Biological Sources.

Endothelial progenitor cells (EPCs) have been broadly studied for several years due to their outstanding regenerative potential. Moreover, these cells might be a valuable source of genetic information for the preservation of endangered animal species. However, a controversy regarding their characterization still exists. The aim of this study was to isolate and compare the rabbit peripheral blood- and bone marrow-derived EPCs with human umbilical vein endothelial cells (HUVECs) in terms of their phenotype and morphology that could be affected by the passage number or cryopreservation as well as to assess their possible neuro-differentiation potential. Briefly, cells were isolated and cultured under standard endothelial conditions until passage 3. The morphological changes during the culture were monitored and each passage was analyzed for the typical phenotype using flow cytometry, quantitative real-time polymerase chain reaction (qPCR) and novel digital droplet PCR (ddPCR), and compared to HUVECs. The neurogenic differentiation was induced using a commercial kit. Rabbit cells were also cryopreserved for at least 3 months and then analyzed after thawing. According to the obtained results, both rabbit EPCs exhibit a spindle-shaped morphology and high proliferation rate. The both cell lines possess same stable phenotype: CD14-CD29+CD31-CD34-CD44+CD45-CD49f+CD73+CD90+CD105+CD133-CD146-CD166+VE-cadherin+VEGFR-2+SSEA-4+MSCA-1-vWF+eNOS+AcLDL+ALDH+vimentin+desmin+α-SMA+, slightly different from HUVECs. Moreover, both induced rabbit EPCs exhibit neuron-like morphological changes and expression of neuronal markers ENO2 and MAP2. In addition, cryopreserved rabbit cells maintained high viability (>85%) and endothelial phenotype after thawing. In conclusion, our findings suggest that cells expanded from the rabbit peripheral blood and bone marrow are of the endothelial origin with a stable marker expression and interesting proliferation and differentiation capacity.

Optimization of repeat plerixafor dosing for autologous peripheral blood stem-cell collection.

INTRODUCTION: Peripheral CD34+ cells may be mobilized using filgrastim alone or in combination with chemotherapy. The addition of plerixafor can be efficacious, though guidelines for repeat dosing are lacking. MATERIAL AND METHODS: This quality improvement project was initiated to generate guidelines for repeat plerixafor dosing after retrospective evaluation of data in adult patients undergoing autologous peripheral blood stem cell mobilization and collection. RESULTS: Analysis included 195 patients: 119 (61 %) with multiple myeloma and 76 (39 %) with lymphoma. Patients given at least one dose of plerixafor (n = 109) were further divided: Group 1) (A) goal of 3 × 10E6/kg and day 1 peripheral blood CD34+ count < 30 × 10E6/L, vs (B) ≥ 30 × 10 E6/L; Group 2) (A) goal of 6 × 10E6/kg and day 1 peripheral blood CD34+ count < 50 × 10E6/L or < 50 % of collection goal after day 1, vs (B) ≥ 50 % of collection goal after day 1. Ninety five percent of cases in Group 1B and 88 % of cases in Group 2B did not receive additional plerixafor doses and all of them achieved their collection goals. In contrast, those in Groups 1A and 2A required additional plerixafor dosing and some mobilizations/collections were futile. CONCLUSION: Based on these data, with consideration of collection goal, peripheral blood CD34+ count, and CD34+ cell bag count on collection day 1, we have generated institutional guidelines for collection initiation and repeat plerixafor dosing. Long term, we predict these guidelines will optimize pharmacy, apheresis, and stem cell processing resources while improving the patient experience.

First experience of the use of a generic of plerixafor in peripheral blood stem cell mobilization in multiple myeloma and lymphoma patients.

Mobilization failure in patients is a major therapeutic concern which makes subsequent ASCT impossible. A new growth factor called Plerixafor (Mozobil®) developed by the pharmaceutical industry (Sanofi-aventis, France), is a chemoreceptor antagonist, CXCR4 type, which disrupts the interaction of SDFI and CXCR4, thereby enhancing the effect of G-CSF mobilization and is especially indicated for mobilization failure. Currently, there is a generic of plerixafor developed by the pharmaceutical industry (Hetero Drugs Ltd, India). The brand name of this medicine is Mozifor®. The objective of this study was to evaluate if generic plerixafor has the same efficacy and safety as originator plerixafor when used with G-CSF in the mobilization of PBSCs for autologous ASCT in multiple myeloma (MM) and lymphoma failure patients. The 32 patients received plerixafor were divided in two groups. The first group concerns the 11 consecutive patients prospectively received generic plerixafor (Mozifor®) in the period between January to July 2020. These were compared with a retrospective control cohort (second group n = 21) who had been treated between 2009 and 2019 with originator plerixafor (Mozobil®). For the Mozifor® group, the mean CD34+ was 4.54x106/kg(1.56-6.79), the median time to achieve an absolute neutrophil count >0.5 G/L was 13 days (range: 8-21). The median time to self-sustained platelet count >20 G/L was 15 days (range: 8-24). For the Mozobil® group, the mean CD34+ was 3.1x106/kg (0.56-8.91) (p=0.86), the median time to achieve an absolute neutrophil count >0.5 G/L was 10 days (range 7-23). The median time to self-sustained platelet count >20 G/L was 13 days (range: 7-29). Our study showed that the generic of plerixafor was practically identical to that of the originator (Mozobil®) with no significant difference (p = 0.52). This study demonstrates the safety and feasibility of mobilization PBSC with generic plerixafor in ASCT in MM and lymphoma. Although these outcomes are encouraging, prospective comparison with other traditional auto-HCT regimens used for patients with MM and lymphoma is warranted.

The effect of serum lipid levels on peripheral blood hematopoietic stem cell levels.

INTRODUCTION: There are limited numbers of available retrospective studies on various hematological diseases treated with stem cell mobilization therapy. In the present study, we aimed to demonstrate the effects of serum lipid levels on peripheral blood CD34+ (PBCD34+) cell counts as well as the changes in serum lipid levels during stem cell mobilization process. METHOD: PBCD34+ cell counts were compared between hypercholesterolemic patients and healthy individuals. Additionally, total cholesterol (TChol), LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C), and triglyceride (TG) levels were measured from healthy donors who underwent stem cell mobilization, at different time points (prior to filgrastim [phase 1], prior to apheresis [phase II], and the first week following apheresis [phase III]. RESULTS: In the hypercholesterolemia group, the PBCD34+ cell count was found to be higher among patients with elevated LDL-C (2.6 ± 0.35/µL vs. 1.7 ± 0.17/µL, p = 0.003) and TChol (2.6 ± 0.34/µL vs. 1.7 ± 0.14/µL, p = 0.006) in comparison to the healthy controls. In the mobilization group, phase II HDL-C levels (35.3 ± 2.8 mg/dL) were found to be lower than both phase I (45.6 ± 2.1 mg/dL) and phase III (44.5 ± 2.6 mg/dL) (p = 0.007). Phase II TChol levels (183.5 ± 10.0 mg/dL) were lower than both phase I (216.8 ± 8.5 mg/dL) and phase III (212.2 ± 8.4 mg/dL) (p = 0.02). At phase II, there was an inverse correlation between PBCD34+ cell count and HDL-C (r = - 0.57, p = 0.003). DISCUSSION: Our results indicate that, while increased LDL-C level is the determinant of baseline PBCD34+ cell count, reduced HDL-C is the determinant of PBCD34+ cell count during mobilization process.

Peripheral blood stem cell grafts in allogeneic hematopoietic cell transplantation: It is not all about the CD34+ cell dose.

Allogeneic Hematopoietic Cell Transplantation is a curative approach in various malignant and non-malignant disorders. The majority of adult transplants in the current era are performed using mobilized stem cells, harvested from the peripheral blood by leukapheresis. Peripheral blood stem cell (PBSC) collections are designed to target a dose of stem cells that will result in safe engraftment and hematopoietic recovery; however, 99 % of the cells contained in a PBSC graft are not stem cells and a growing number of studies attempt to characterize the associations between graft composition and transplant outcomes. A better understanding of the impact of the quantity and quality of various cell types in PBSC grafts may lead to development of novel collection strategies or improved donor selection algorithms. Here we review relevant findings from recent studies in this area.

A multicenter report on the safety and efficacy of plerixafor based stem cell mobilization in children with malignant disorders.

BACKGROUND: Pleraxifor for peripheral blood stem cell (PBSC) mobilization in children with malignancies is often given following failure of standard mobilization (SM) rather than as a primary mobilizing agent. STUDY DESIGN AND METHODS: In this retrospective multicenter study, we report the safety of plerixafor-based PBSC mobilization in children with malignancies and compare outcomes between patients who received plerixafor upfront with SM (Group A) with those who received plerixafor following failure of SM (Group B). In the latter pleraxifor was given either following a low peripheral blood (PB) CD34 (<20 cells/cu.mm) (Group B1) or as a second collection process due to an unsuccessful yield (CD34 + < 2 × 106 /kg) (Group B2) following failed SM and first apheresis attempts. RESULTS: The study cohort (n = 47) with a median age of 8 (range 0.6-21) year, comprised 19 (40%) Group A and 28 (60%) Group B patients (B1 = 12 and B2 = 16). Pleraxifor mobilization was successful in 87.2% of patients, similar between Groups A and B (84.2% vs 89.2%) and resulted in a median 4-fold increase in PB CD34. Median number of apheresis attempts was 2 in Groups A and B1 but 4 in Group B2. In Group B2, median total CD34+ yield post-plerixafor was 9-fold higher than after SM (P = .0013). Mild to moderate transient adverse events affected 8.5% of patients. Among patients who proceeded to autologous transplant (n = 39), all but one engrafted. CONCLUSION: Plerixafor-based PBSC collection was safe and effective in our cohort and supports consideration as a primary mobilizing agent in children with malignancies.

Threshold for optimal administration of plerixafor in autologous peripheral blood stem cell collections through CD34+ cell monitoring based on the experience from two Japanese university hospitals.

Plerixafor was introduced to Japan in 2017 as a stem cell mobilization enhancement reagent, but the threshold for its use remains unclear. In this study, we assessed 57 patients treated with plerixafor (33 patients with multiple myeloma (MM) and 24 with malignant lymphoma (ML) and 152 patients without plerixafor administration. When CD34+ cell pre-counts were between 5.5 and 20 cells/µL in MM or 6 and 21 cells/µL in ML, the CD34+ cell count increased significantly, attaining the highest yield in response to plerixafor (achievement rate by one leukapheresis is 93.3% and 91.7% in MM and ML, at P < .001 and P = .012, respectively). In case the CD34+ cell pre-count was less than 5.5 cells/µL, an increase of at least 7 cells/µL from baseline by plerixafor was the necessary condition to achieve successful collection through a two-time leukapheresis. Monitoring CD34+ cell numbers might improve the collection efficiency and reduce the cost.

Optimizing pediatric peripheral blood stem cell collection.

INTRODUCTION: Pediatric PBSC harvests pose specific challenges during apheresis and a knowledge of the same and variables affecting PBSC collection are very important in planning these procedures. In the present study safety profile of pediatric PBSC procedures and variables influencing the successful collection were analyzed. METHOD: Pediatric PBSC harvest data for 3 years was reviewed for donor, procedural and product parameters and any specific challenges faced during the procedures. Successful PBSC collection was defined when CD34 dose obtained was ≥2 × 106 cells/Kg of recipients' body weight. RESULTS: 85 PBSC collections performed on 46 children (age range 1.5-15 years) were included. Sixty-two procedures were on autologous donors and 23 on allogenic donors. The median CD34+ cell dose in the PBSC product per procedure was 2.12 × 106 cells/Kg for autologous procedures and 4.6 × 106 cells/Kg for allogenic procedures. Systemic adverse reaction was observed during only one procedure (0.01 %) and was managed conservatively. Successful dose was collected in 52 procedures (61.17 %) and was significantly associated with CD34+ count of more than 19.7/µL, monocyte count of more than 1.65 × 106/µL, allogenic collection and female gender (p = 0.00001, p = 0.011, p = 0.00052, and p = 0.0001, respectively). CONCLUSION: PBSC collection is safe in pediatric age groups and pre-procedure CD34 count of ≥20/µL on the day of collection may result in successful collection of stem cell dose. It is important to identify factors associated with failed collection for appropriate counselling and justifying pre-emptive use of stem cell mobilizing agents.

Safety of peripheral blood stem cell harvest in children under anaesthesia in the day care setting - A single centre experience.

The use of cytokine mobilized peripheral blood stem cells (PBSC) for stem cell transplantation offers early engraftment, and less early transplant related mortality and morbidity. This can be done easily in the out-patient setting in an adult donor, but is difficult in children. The safety and efficacy of general anaesthesia outside the controlled operation room setting is quite challenging and demanding. We present our experience with paediatric PBSC harvest done under anaesthesia in the out-patient setting between January 2009 to June 2017. A total of 158 children underwent 164 PBSC harvests during the study period. Donors were predominantly females with a median age of 5 years (1-12) and a median weight of 17.5 kg (9.4-51). In 50% of the cases, induction of anaesthesia was by sevoflurane followed by total intravenous anaesthesia (TIVA) while in 32% it was sevoflurane induction followed by sedation. Hudson mask (48.5%) and laryngeal mask airway (50%) were the most common modes of airway and all patients were ventilated in the spontaneous mode. Propofol was the most commonly used maintenance agent (67%). There were no major complications except for acute pulmonary edema secondary to infusion of blood products requiring a short stay in ICU for one donor. All donors were discharged on the next day of harvest. No long term complications have been reported in any of these donors. Paediatric PBSC harvest can be safely done under anaesthesia with due precautions in the day care setting.