The ISHAGE guidelines for CD34+ cell determination by flow cytometry. International Society of Hematotherapy and Graft Engineering

Human Leukocyte Antigen and Red Blood Cells Impact Umbilical Cord Blood CD34+ Cell Viability after Thawing

Hematopoietic progenitor cell (HPC) transplantation is a treatment option for malignant and nonmalignant diseases. Umbilical cord blood (UCB) is an important HPC source, mainly for pediatric patients. It has been demonstrated that human leukocyte antigen (HLA) matching and cell dose are the most important features impacting clinical outcomes. However, UCB matching is performed using low resolution HLA typing and it has been demonstrated that the unnoticed mismatches negatively impact the transplant. Since we found differences in CD34+ viability after thawing of UCB units matched for two different patients (p = 0.05), we presumed a possible association between CD34+ cell viability and HLA. We performed a multivariate linear model (n = 67), comprising pre-cryopreservation variables and high resolution HLA genotypes separately. We found that pre-cryopreservation red blood cells (RBC), granulocytes, and viable CD34+ cell count significantly impacted CD34+ viability after thawing, along with HLA-B or -C (R2 = 0.95, p = 0.01; R2 = 0.56, p = 0.007, respectively). Although HLA-B*40:02 may have a negative impact on CD34+ cell viability, RBC depletion significantly improves it.

Flow cytometric enumeration of CD34+ hematopoietic stem cells: A comparison between single- versus dual-platform methodology using the International Society of Hematotherapy and Graft Engineering protocol

BACKGROUND

Flow cytometric enumeration of CD34+ hematopoietic stem cells (HSC) is the reference point for undertaking apheresis and evaluation of adequacy for peripheral blood stem cell (PBSC) engraftment.

AIMS

To determine whether single platform correlates with dual platform methods in CD34+ enumeration using ISHAGE protocol.

METHODS

Retrospective analysis of CD34 Enumeration assays on both peripheral blood and PBSC product samples using Beckman Coulter FC500 Flow Cytometer. The t test and correlation study was used to study the difference between single and dual platform methods in CD34+ enumeration.

RESULTS

We present our data on 152 samples comprising 41 peripheral blood samples collected before apheresis procedure and 111 samples collected from PBSC product. We observed strong positive correlation between single and dual platform methods for CD34+ counts in peripheral blood sample (r = 0.92; P < 0.001) and PBSC product sample (r = 0.85; P < 0.001).

CONCLUSION

In our study, both single versus dual platform had similar results in CD34+ cell counts. The single platform provides rapid results with ease of procedure. Errors with dual platforms are relatively common with respect to denominator. We recommend to use mean of total leukocyte count from two different hematology analyzer to minimize variation in dual platform.

From big flow cytometry datasets to smart diagnostic strategies: The EuroFlow approach

The rise in the analytical speed of mutiparameter flow cytometers made possible by the introduction of digital instruments, has brought up the possibility to manage progressively higher number of parameters simultaneously on significantly greater numbers of individual cells. This has led to an exponential increase in the complexity and volume of flow cytometry data generated about cells present in individual samples evaluated in a single measurement. This increase demands for new developments in flow cytometry data analysis, graphical representation, and visualization and interpretation tools to address the new big data challenges, i.e. processing data files of ≥10-25 parameters per cell in samples with >5-10 million cells (= up to 250 million data points per cell sample) obtained in a few minutes. Here, we present a comprehensive review of some of the tools developed by the EuroFlow consortium for processing flow cytometric big data files in diagnostic laboratories, particularly focused on automated EuroFlow approaches for: i) identification of all cell populations coexisting in a sample (automated gating); ii) smart classification of aberrant cell populations in routine diagnostics; iii) automated reporting; together with iv) new tools developed to visualize n-dimensional data in 2-dimensional plots to support expert-guided automated data analysis. The concept of using reference data bases implemented into software programs, in combination with multivariate statistical analysis pioneered by EuroFlow, provides an innovative, highly efficient and fast approach for diagnostic screening, classification and monitoring of patients with distinct hematological and immune disorders, as well as other diseases.

Maternal lipid profiles vs. fetal growth and cord blood hematopoietic cells: weak associations in healthy Korean newborn-mother pairs

BACKGROUND

We aimed to define the maternal lipid profiles that are associated with fetal growth and cord blood (CB) hematopoietic cells in healthy Korean full-term newborns.

METHODS

A total of 608 fetal-maternal pairs were enrolled; mothers voluntarily donated CB with informed consent. We analyzed birth weight (BW) as a marker of fetal growth, and we examined total nucleated cells (TNCs) and CD34⁺ cell concentrations of CB as markers of hematopoietic progenitor cell (HPC) contents. We also analyzed maternal lipid levels and investigated their associations with BW, TNCs and CD34⁺ cells.

RESULTS

Maternal triglycerides (TG) showed a significant positive association with BW and CD34⁺ cells, and low-density lipoprotein (LDL) showed a negative association with BW and CD34⁺ cells. Though not statistically significant, higher maternal TG showed a tendency toward higher levels of TNCs. Maternal TG was independently and positively correlated with BW, and maternal LDL was independently and negatively correlated with CD34⁺ cells, although the impacts were not as strong, as indicated by small beta coefficients (0.157 and -0.226, respectively).

CONCLUSIONS

We were able to investigate the association of maternal lipid profiles with BW and CB HPCs in healthy Korean newborn-mother pairs in this study. Both BW and the HPC contents showed independent associations with maternal TG and LDL, although the effect of maternal lipid levels on fetal growth and HPCs was not strong in the normal healthy population. Because maternal lipid levels were assessed once in the healthy fetal-maternal pairs, we could not investigate those associations across pregnancy.

Validation of a semi automatic device to standardize quantification of Colony-Forming Unit (CFU) on hematopoietic stem cell products

Accurate characterization of hematopoietic stem cells (HSC) products is needed to better anticipate the hematopoietic reconstitution and the outcome in patients. Although CD34+ viable cells enumeration is a key predictor of time to correction of aplasia, it does not fully inform about functionality of cells contained in the graft. CFU assay is the gold standard in vitro potency assay to assess clonogenicity of HSC and consists on the count and identification of colonies several days after culture in a semi solid media. Manual count of colonies with optic microscope is the most commonly used method but its important variability and subjectivity hinders the universal implementation of this potency assay. The aim of this study is to validate a standardized method using the STEMvision™ system, the first semi-automated instrument for imaging and scoring hematopoietic colonies, according to French and European recommendations. Results obtained highlight better performance criteria with STEMvision™ system than the manual method. This semi-automatic device tends to reduce the coefficients of variation of repeatability, inter-operator variability and intermediate precision. This newly available platform could represent an interesting option, significantly improving performances of CFU assays used for the characterization of hematopoietic progenitors.

Effects of continuous high-dose G-CSF administration on hematopoietic stem cell mobilization and telomere length in patients with amyotrophic lateral sclerosis - a pilot study

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease of complex and still poorly understood etiology. Loss of upper and lower motoneurons results in death within few years after diagnosis. Recent studies have proposed neuroprotective and disease-slowing effects of granulocyte-colony stimulating factor (G-CSF) treatment in ALS mouse models as well as humans. In this study, six ALS patients were monitored up to 3.5 years during continuous high-dose G-CSF administration. Repetitive analyses were performed including blood count parameters, CD34⁺ hematopoietic stem and progenitor cell (HSPC) and colony forming cell (CFC) counts, serum cytokine levels and leukocyte telomere length. We demonstrate that continuous G-CSF therapy was well tolerated and safe resulting in only mild adverse events during the observation period. However, no mobilization of CD34⁺ HSPC was detected as compared to baseline values. CFC mobilization was equally low and even a decrease of myeloid precursors was observed in some patients. Assessment of telomere length within ALS patients' leukocytes revealed that G-CSF did not significantly shorten telomeres, while those of ALS patients were shorter compared to age-matched healthy controls, irrespective of G-CSF treatment. During G-CSF stimulation, TNF-alpha, CRP, IL-16, sVCAM-1, sICAM-1, Tie-2 and VEGF were significantly increased in serum whereas MCP-1 levels decreased. In conclusion, our data show that continuous G-CSF treatment fails to increase circulating CD34⁺ HSPC in ALS patients. Cytokine profiles revealed G-CSF-mediated immunomodulatory and proteolytic effects. Interestingly, despite intense G-CSF stimulation, telomere length was not significantly shortened.

CD34+ Hematopoietic Stem Cell Count Is Predictive of Vascular Event Occurrence in Children with Sickle Cell Disease

BACKGROUND/OBJECTIVES

Sickle cell disease (SCD) complications mostly result from vascular dysfunction, concerning systemic microvasculature and cerebral large vessels. The aim of this cohort study was to identify potential circulating biomarkers predictive for further vascular event occurrence in pediatric SCD.

METHODS

We consecutively enrolled 108 children with SCD at steady state, aged 3-18 years old (median 9.8 years). Hematology, coagulation, hemolysis, endothelial, platelet and vascular activation parameters were recorded at inclusion. Neurovascular and systemic vascular events were prospectively recorded during a mean follow-up period of 27 months.

RESULTS

Patients at steady state displayed significantly higher hemolysis and platelet activation markers, higher leukocyte, CD34+ hematopoietic stem cell and microvesicle counts, and a pro-coagulant profile compared to controls matched for age and ethnicity. Circulating endothelial cell or nucleosome level did not differ. During the follow-up period, 36 patients had at least one neurovascular (n = 12) or systemic vascular event (n = 25). In a multivariate model, high CD34+ cell count was the best predictor for the occurrence of a vascular event (OR 1.2 for 1000 cell/mL increase, 95% CI [1.049-1.4], p = 0.013, sensitivity 53%, specificity 84% for a threshold of 8675 cells/mL).

CONCLUSION

CD34+ cell count at steady state is a promising biomarker of further vascular event in children with SCD.

Effects of Extra Virgin Olive Oil and Apples Enriched-Dark Chocolate on Endothelial Progenitor Cells in Patients with Cardiovascular Risk Factors: A Randomized Cross-Over Trial

Background: Endothelial dysfunction has been associated to cardiovascular outcomes in patients with cardiovascular risk factors. Circulating endothelial progenitor cells (EPCs) play an important physiological role for their reparative potential of vascular integrity, but are numerically reduced and functionally impaired in patients with cardiovascular risks. This study assesses the effects of Extra Virgin Olive Oil (EVOO) and apple-enriched dark chocolate intake on the blood levels of EPCs. Methods: Thirty volunteers with cardiovascular risk factors, enrolled in a randomised, crossover, four-weeks trial, received a solid dark chocolate bar (40 g/day) containing 10% EVOO or 2.5% dry apples. Urine samples were analyzed for endogenous metabolites. Circulating EPCs levels, clinical data and anthropometric examinations were collected. Results: 26 volunteers (M/F:14/12, 51 ± 9 years of age) completed the study. Comparison of pre-post intervention revealed a significant increase in EPCs levels associated with EVOO-dark chocolate consumption. Most biochemical parameters were not significantly modified by both chocolates. Conclusions: This study shows that a daily consumption of a non fattening dose of dark chocolate enriched with EVOO improves blood levels of EPCs, a well known surrogate biologic marker for endothelial function.

Cardio-ankle vascular index and circulating CD34-positive cell levels as indicators of endothelial repair activity in older Japanese men

AIM

The cardio-ankle vascular index (CAVI) reflects functional arterial stiffness, which is related to endothelial dysfunction. CD34-positive cells carry out an important function in endothelial repair. However, there have been no reports assessing the association between CAVI and the number of circulating CD34-positive cells.

METHODS

We carried out a cross-sectional study of 249 Japanese men, aged 60-69 years, who underwent annual health checkups between 2013 and 2015. As individuals with high levels of circulating CD34-positive cells might indicate the influence of consumptive reduction of circulating CD34-positive cells as a result of aggressive endothelial repair, participants were stratified by circulating CD34-positive cell levels, using the median value in this population (0.95 cells/μL) as the cut-off.

RESULTS

For participants with low circulating CD34-positive cell levels, logarithmic values of circulating CD34-positive cells were inversely associated with CAVI (multivariable standardized parameter estimate [β] = -0.22, P = 0.014), but not for participants with high levels (β = -0.04, P = 0.638). In addition, even when no significant associations between CAVI and carotid intima-media thickness were detected for participants with low circulating CD34-positive cell levels (β = -0.02, P = 0.865), significant positive associations were identified for participants with high levels (β = 0.22, P = 0.028).

CONCLUSIONS

As circulating CD34-positive cell count might indicate endothelial repair activity, the present results show that CAVI is affected by insufficient endothelial repair in individuals with low circulating CD34-positive cell counts. Our results also show that a positive association between CAVI and carotid intima-media thickness exists only in individuals with aggressive endothelial repair, which indicates the presence of organic arterial disease, such as atherosclerosis. Geriatr Gerontol Int 2019; 19: 557-562.

Reduction of CFU-GM and circulating hematopoietic progenitors in a subgroup of children with chronic neutropenia associated with severe infections and delayed recovery

Myelopoiesis was evaluated in 66 pediatric patients with chronic neutropenia who were positive for anti-neutrophil antibodies (median age at diagnosis: 11 months, median neutrophil count at diagnosis: 419/μl). Other causes of neutropenia were excluded. Bone marrow morphology, clonogenic tests and/or the peripheral blood CD 34+ cell count, and apoptotic rate were evaluated in 61 patients with neutropenia lasting > 12 months or severe infections. The peripheral blood CD 34+ cell count and apoptotic rate were evaluated in five patients with shorter neutropenia. The median follow-up time was 29 months (range 7-180 months). Forty-seven patients (71.2%) had a spontaneous recovery after 7-180 months (median 29 months). The group of patients younger than 24 months at diagnosis (n = 50) had a higher probability of recovery (40/50 vs. 7/16 χ2 p<0.01) with a shorter period of neutropenia (median 26 versus 47 months, Kaplan-Meier analysis p = 0.001). The colony-forming units-granulocyte-macrophage (CFU-GM) were significantly decreased in 26/35 patients (74%) evaluated for clonogenic tests. All patients with normal CFU-GM recovered (9/9 patients); whereas, neutropenia persisted in 12/26 patients with reduced CFU-GM (46%, Pearson χ2 p = 0.02). In 36/55 (65%) patients evaluated by flow cytometry we observed reduced circulating CD34+ cells compared with controls of the same age. An increase in the circulating CD34+ cell apoptotic rate was observed in 28/55 patients (51%). Infections requiring hospitalization were observed in 9/18 (50%; Pearson χ2, p = 0.03) patients with both decreased circulating CD34+ cells and increased CD34+ apoptotic rates. In the group aged < 24 months, we observed a significant correlation between the persistence of neutropenia and decreased circulating CD34+ cells (Pearson χ2 p = 0.008). In conclusion, reduced CFU-GM and circulating hematopoietic progenitors were observed in a subgroup of children with chronic neutropenia who were positive for anti-neutrophil antibodies and had a higher incidence of severe infections and delayed spontaneous remission.

Enumeration of CD34-positive Stem Cells Using the ADAMII Image-based Fluorescence Cell Counter

Background

It is very important to accurately enumerate CD34-positive (CD34+) cells for successful hematopoietic stem cell transplantation (HSCT). We evaluated the ability of the newly developed image based-immunofluorescence cell counter ADAMII (NanoEntek, Seoul, Korea) to enumerate CD34+ cells, which was improved through simultaneous CD45 analysis.

Methods

We enumerated CD34+ cells with ADAMII using 19 peripheral blood (PB) and 91 leukapheresis samples from HSCT donors. Analytical performance, including precision and linearity, was analyzed, and sample stability during storage was evaluated. Viable CD34+ cell count (vCD34) and viable CD45+ cell count (vCD45) and the percentage of viable CD34+ cells among viable CD45+ cells (CD34/CD45) as measured by ADAMII were compared with the corresponding values from two flow cytometry assays, using regression analysis.

Results

ADAMII demonstrated acceptable precision, as CV values of vCD34 from six samples with different counts were all <10% (range: 3.49–9.51%). CV values of the vCD45 and CD34/45 ranged from 4.03% to 9.67% and from 2.48% to 10.07%, respectively. The linearity of vCD34 showed an excellent R² value (0.99) when analyzed using the intended count and flow cytometry data. The ADAMII and two flow cytometry-based assays generated very similar data for the PB and leukapheresis samples.

Conclusions

ADAMII demonstrated excellent performance for use as a routine clinical assay in terms of CD34+ cell enumeration from PB and leukapheresis samples. Moreover, it could be used as a point-of-care-test for determining mobilization time and predicting an adequate apheresis stem cell product.

Comparison of Volumetric and Bead-Based Counting of CD34 Cells by Single-Platform Flow Cytometry

Background

Over 2,000 people a year in the United Kingdom need a bone marrow or blood stem cell transplant. It is important to accurately quantify the hematopoietic stem cells to predict whether the transplant will be successful in replenishing the immune system. However, they are present at low frequency, which complicates accurate quantification. The current gold standard method is single‐platform flow cytometry using internal reference counting beads to determine the concentration of CD34 cells. However, volumetric flow cytometers have the ability to measure the acquisition volume, which removes the need for reference beads for calculation of cell concentrations.

Method

In this study, we compared both methods for calculating CD34 cell concentrations in volumetric cytometers, using either the volume reading or the number of reference beads for calculation. In addition, the uncertainty of measurement for each method was estimated.

Results

The results show that both methods have similar uncertainties of measurement. Regression analysis showed low to no statistical difference in CD34 cell concentrations obtained with each method.

Conclusions

Overall, this study suggests that the volumetric method is a valid approach but that the adoption of this technology may be hindered without some form of external calibration of volume readings to increase confidence in the measurement. © 2019 The Authors. Cytometry Part B: Clinical Cytometry published by Wiley Periodicals, Inc. on behalf of International Clinical Cytometry Society.

Association between chronic kidney disease and carotid intima-media thickness in relation to circulating CD34-positive cell count among community-dwelling elderly Japanese men

BACKGROUND AND AIMS

Endothelial injury is well-known as a process that can lead to chronic kidney disease (CKD) and atherosclerosis. Hematopoietic activity is known to be associated inversely with CKD and positively with atherosclerosis. Since bone-derived progenitor cells (CD34-positive cells) contribute to endothelial repair (including the progression of atherosclerosis), understanding the association between CKD and carotid intima-media thickness (CIMT), in relation to circulating CD34-positive cell count, may be an efficient means of clarifying the mechanisms underlying endothelial activity.

METHODS

We conducted a cross-sectional study of 570 elderly Japanese men aged 60-69 years, who underwent a general health check-up. Participants were stratified as per a median circulating CD34-positive cell count (1.01 cells/μL).

RESULTS

Independent of the known cardiovascular risk factors, CIMT was found to be positively associated with CKD in the participants with high circulating CD34-positive cell counts but not in participants with low counts. Odds ratios were 1.40 (1.04, 1.89) for participants with high and 1.01 (0.72, 1.43) for participants with low circulating CD34-positive cell counts after adjustment for known cardiovascular risk factors at 95% confidence intervals for CKD with one standard deviation increment of CIMT.

CONCLUSIONS

A positive association between CIMT and CKD was observed among participants with high circulating CD34-positive cell counts but not among participants with low counts. Endothelial repair activity might determine the association between CKD and CIMT.

Cryopreservation of Hematopoietic Stem Cells: Emerging Assays, Cryoprotectant Agents, and Technology to Improve Outcomes

Hematopoietic stem cell (HSC) therapy is widely used to treat a growing number of hematological and non-hematological diseases. Cryopreservation of HSCs allows for cells to be transported from the site of processing to the site of clinical use, creates a larger window of time in which cells can be administered to patients, and allows sufficient time for quality control and regulatory testing. Currently, HSCs and other cell therapies conform to the same cryopreservation techniques as cells used for research purposes: cells are cryopreserved in dimethyl sulfoxide (DMSO) at a slow cooling rate. As a result, HSC therapy can result in numerous adverse symptoms in patients due to the infusion of DMSO. Efforts are being made to improve the cryopreservation of HSCs for clinical use. This review discusses advances in the cryopreservation of HSCs from 2007 to the present. The preclinical development of new cryoprotectants and new technology to eliminate cryoprotectants after thawing are discussed in detail. Additional cryopreservation considerations are included, such as cooling rate, storage temperature, and cell concentration. Preclinical cell assessment and quality control are discussed, as well as clinical studies from the past decade that focus on new cryopreservation protocols to improve patient outcomes.

AIBP-mediated cholesterol efflux instructs hematopoietic stem and progenitor cell fate

Hypercholesterolemia, the driving force of atherosclerosis, accelerates the expansion and mobilization of hematopoietic stem and progenitor cells (HSPCs). The molecular determinants connecting hypercholesterolemia with hematopoiesis are unclear. Here, we report that a somite-derived prohematopoietic cue, AIBP, orchestrates HSPC emergence from the hemogenic endothelium, a type of specialized endothelium manifesting hematopoietic potential. Mechanistically, AIBP-mediated cholesterol efflux activates endothelial Srebp2, the master transcription factor for cholesterol biosynthesis, which in turn transactivates Notch and promotes HSPC emergence. Srebp2 inhibition impairs hypercholesterolemia-induced HSPC expansion. Srebp2 activation and Notch up-regulation are associated with HSPC expansion in hypercholesterolemic human subjects. Genome-wide chromatin immunoprecipitation followed by sequencing (ChIP-seq), RNA sequencing (RNA-seq), and assay for transposase-accessible chromatin using sequencing (ATAC-seq) indicate that Srebp2 transregulates Notch pathway genes required for hematopoiesis. Our studies outline an AIBP-regulated Srebp2-dependent paradigm for HSPC emergence in development and HPSC expansion in atherosclerotic cardiovascular disease.

Circulating angiogenic cell response to sprint interval and continuous exercise

INTRODUCTION

Although commonly understood as immune cells, certain T lymphocyte and monocyte subsets have angiogenic potential, contributing to blood vessel growth and repair. These cells are highly exercise responsive and may contribute to the cardiovascular benefits seen with exercise.

PURPOSE

To compare the effects of a single bout of continuous (CONTEX) and sprint interval exercise (SPRINT) on circulating angiogenic cells (CAC) in healthy recreationally active adults.

METHODS

Twelve participants (aged 29 ± 2 years, BMI 25.5 ± 0.9 kg m^- 2, [Formula: see text]peak 44.3 ± 1.8 ml kg^- 1 min^- 1; mean ± SEM) participated in the study. Participants completed a 45-min bout of CONTEX at 70% peak oxygen uptake and 6 × 20 s sprints on a cycle ergometer, in a counterbalanced design. Blood was sampled pre-, post-, 2 h and 24 h post-exercise for quantification of CAC subsets by whole blood flow cytometric analysis. Angiogenic T lymphocytes (T_ANG) and angiogenic Tie2-expressing monocytes (TEM) were identified by the expression of CD31 and Tie2, respectively.

RESULTS

Circulating (cells µL^- 1) CD3⁺CD31⁺ T_ANG increased immediately post-exercise in both trials (p < 0.05), with a significantly greater increase (p < 0.05) following SPRINT (+ 57%) compared to CONTEX (+ 14%). Exercise increased (p < 0.05) the expression of the chemokine receptor CXCR4 on T_ANG at 24 h. Tie2-expressing classical (CD14⁺⁺CD16^-), intermediate (CD14⁺⁺CD16⁺) and non-classical (CD14⁺CD16⁺⁺) monocytes and circulating CD34⁺CD45^dim progenitor cells were higher post-exercise in SPRINT, but unchanged in CONTEX. All post-exercise increases in SPRINT were back to pre-exercise levels at 2 h and 24 h.

CONCLUSION

Acute exercise transiently increases circulating T_ANG, TEM and progenitor cells with greater increases evident following very high intensity sprint exercise than following prolonged continuous paced endurance exercise.

Transfusion support for matched sibling allogeneic hematopoietic stem cell transplantation (1993-2010): factors that predict intensity and time to transfusion independence

BACKGROUND

Patients undergoing allogeneic hematopoietic stem cell transplant require variable, often extensive transfusion support. Identification of factors that predict urgent, intensive, or special needs should improve management of these patients.

STUDY DESIGN AND METHODS

This is a retrospective study of red blood cell (RBC) and platelet transfusion support provided for sequential matched sibling donor allogeneic transplants conducted at the Clinical Center, National Institutes of Health, from 1993 through 2010. Factors potentially important for predicting quantity of RBC and platelet transfusions, and time to transfusion independence through Day 200 following hematopoietic stem cell transplantation were evaluated.

RESULTS

Subjects (n = 800) received 10,591 RBC and 10,199 platelet transfusions. Multivariable analysis demonstrated that the need for RBC pretransplant, CD34+ dose, transplant year, diagnostic category, and ABO match were significantly independently associated with quantity of RBC transfusions during Days 0 through 30. Only pretransplant need for RBCs, CD34+ dose, and transplant year had significance during Days 0 through 100. Similar analyses for quantity of platelet transfusions demonstrated that for both Days 0 through 30 and 0 through 100 significant factors were need for platelet support before transplant, CD34+ dose, transplant year, and transplant regimen. Of note, long term, during Days 101 through 200, only CD34+ dose remained significant for quantity of RBC and platelet transfusions. Analysis of time to transfusion independence demonstrated that patients with ABO major mismatches required longer to achieve freedom from RBC transfusion support compared to identical matches or those with minor mismatches.

CONCLUSION

Patient-specific factors including CD34+ dose and ABO match of the graft should be given particular consideration by transfusion services when planning support of patients receiving allogeneic hematopoietic stem cell transplant.

Guidelines for Gating Flow Cytometry Data for Immunological Assays

"Gating" refers to the selection of successive subpopulations of cells for analysis in flow cytometry. It is usually performed manually, based on expert knowledge of cell characteristics. However, there can be considerable disagreement in how gates should be applied, even between individuals experienced in the field. While clinical software often automates gating, and some guidelines do exist (especially for clinical assays), there are no comprehensive guidelines across the various types of immunological assays performed using flow cytometry. Here we attempt to provide such guidelines, focused on the most general and pervasive types of gates, why they are important, and what recommendations can be made regarding their use. We do so through the display of example data, collected by academic, government, and industry representatives. These guidelines should be of value to both novice and experienced flow cytometrists analyzing a wide variety of immunological assays.

The value of the post-thaw CD34+ count with and without DMSO removal in the setting of autologous stem cell transplantation

BACKGROUND

CD34+ cell count correlates with engraftment potency after autologous stem cell transplantation. Assessment of CD34+ mainly occurs after apheresis and before cryopreservation with dimethyl sulfoxide (DMSO). The influence of postthaw CD34+ cell numbers over time to engraftment is not well studied, and determination of postthaw CD34+ cell counts is challenging for a variety of reasons. The aim of this retrospective study was to systematically assess the value of postthaw CD34+ cell counts in autologous grafts with and without DMSO removal.

STUDY DESIGN AND METHODS

Between January 2008 and December 2015, 236 adult patients underwent a total of 292 autologous stem cell transplantations. Median age at transplantation was 56 years, and the main indication was multiple myeloma (60%). DMSO removal was done in 96 grafts (33%), either by centrifugation or by Sepax method.

RESULTS

Patients receiving grafts containing DMSO showed a significantly faster platelet (p = 0.02) and RBC (p = 0.001) engraftment. DMSO removal was not associated with fewer infusion-related adverse events. We observed a good correlation between CD34+ cell count after apheresis and CD34+ cell count after thawing/washing (r = 0.931). Ninety grafts (31%) showed a significant loss of viable CD34+ cells, which translated into a delayed engraftment.

CONCLUSION

DMSO removal was associated with delayed platelet and RBC engraftment without preventing adverse events. CD34+ cell enumeration after thawing remains difficult to perform, but grafts showing higher cell loss during cryopreservation and thawing are associated with slower engraftment. Prospective studies on the role of DMSO removal and postthaw CD34+ enumeration using defined protocols are needed.

Nucleated red blood cells as a novel indicator of CD34+ cell content in umbilical cord blood

BACKGROUND

Umbilical cord blood (UCB) has become an important source of transplantable CD34⁺ hematopoietic progenitor cells. Cord blood banks (CBBs) can increase their efficiency by minimizing the processing of UCB units with low CD34⁺ content, which have a lower likelihood of transplant utilization. We sought to identify a readily available preprocessing metric that would correlate with CD34⁺ cell counts, without the cost of additional analysis.

STUDY DESIGN AND METHODS

Data were compiled for 131 UCB units processed at the regional CBB. Preprocessing hematologic metrics, including complete blood count and differential, were compared to postprocessing CD34⁺ cell quantities. The data were divided into six groups of varying preprocessing metrics, then compared for significant differences in postprocessing CD34⁺ cell quantities to develop a screening guidance.

RESULTS

UCB units with nucleated RBC (nRBC) content of 15% or greater were found to have a significant increase in CD34⁺ cell percentage (p < 0.00001) and total CD34⁺ cell content (p < 0.0001). Units with preprocessing total nucleated cell count (TNC) of ≥ 1.50 × 10⁹ with nRBC content of 15% or greater, and for TNC ≥ of 2.00 × 10⁹ with nRBC content less than15%, had a significant increase in CD34⁺ content (p < 0.05 and p < 0.001, respectively). Applied as a screening guideline, these units had an increase in mean CD34⁺ content from 6.24 × 10⁶ to 9.27 × 10⁶ . Units originally in the bottom and top quartiles of CD34⁺ content constitute 5% and 53% of processed units meeting these TNC/nRBC criteria, respectively.

CONCLUSION

These screening criteria utilizing nRBC provides a guideline that public CBBs may use to increase their efficiency by minimizing the processing of UCB units with lower CD34⁺ cell content.

Efficacy of Granulocyte Colony-Stimulating Factor and N-Acetylcysteine Therapies in Patients With Severe Alcoholic Hepatitis

BACKGROUND & AIMS

Patients with alcoholic hepatitis (AH) have high mortality, so new therapies are needed. Administration of granulocyte colony stimulating factor (G-CSF) increases survival times of patients with AH. It is not known whether addition of N-acetyl cysteine (NAC) to G-CSF could further increase survival time. We performed a randomized controlled pilot study to compare the efficacy of standard medical therapy with pentoxifylline to treatment with a combination of G-CSF and standard medical therapy as well as to the combination of NAC, G-CSF, and standard medical therapy in patients with severe AH.

METHODS

We performed an open-label, single-center study of 57 patients with severe AH admitted to a Liver Intensive Care unit in India from October 2014 through March 2017. Patients were randomly assigned to groups that received standard medical therapy (with pentoxifylline) plus G-CSF for 5 days (G-CSF group; n = 18), standard medical therapy plus G-CSF and intravenous NAC for 5 days (combination group; n = 19), or standard medical therapy alone (n = 20). Clinical data and blood samples were collected at baseline; on day 6; and 1, 2, and 3 months after the study began. CD34+ cells were measured in blood samples collected on days 0 and 6. The primary outcome was proportion of patients surviving for 90 days. Secondary outcomes were mobilization of CD34+ cells at day 6, as well as Child Turcotte Pugh, model for end-stage liver disease, and modified discriminant function scores until day 90.

RESULTS

Significantly higher proportions of patients in the G-CSF group (16/18) and the combination group (13/19) survived for 90 days than in the standard medical therapy group (6/20) (P = .0001 for G-CSF group and P = .037 and combination group). The GGSF and combination groups each had increased numbers of CD34+ cells from baseline until day 6, compared with the standard medical therapy group. The G-CSF group (but not the combination group) had significantly larger median reductions in modified discriminant function scores at study months 1 (reduction of 60.36%), 2 (reduction of 75.36%), and 3 (reduction of 88.73%) vs the standard medical therapy group (P = .02; P = .05; and P = .00, respectively). The G-CSF group had a significantly larger median reduction in model for end-stage liver disease score at 3 months (reduction of 55.77%; P = .01), but not in Child Turcotte Pugh score, compared with the standard medical therapy group. All groups had similar numbers of complications.

CONCLUSION

In a pilot randomized controlled trial, we found administration of G-CSF to improve liver function and increase survival times in patients with severe AH, compared with standard therapy. We found no evidence for benefit of adding NAC to G-CSF. These findings require confirmation in larger trials. ClincialTrials.gov, number: NCT02971306.

Outcomes after multiple courses of granulocyte colony-stimulating factor and growth hormone in decompensated cirrhosis: A randomized trial

Decompensated cirrhosis (DC) carries a high mortality. Liver transplantation (LT) is the treatment of choice; however, the limited availability of donor organs has resulted in high waitlist mortality. The present study investigated the impact of multiple courses of granulocyte-colony stimulating factor (G-CSF) with or without growth hormone (GH) in these patients. Sixty-five patients with DC were randomized to standard medical therapy (SMT) plus G-CSF 3 monthly plus GH daily (group A; n = 23) or SMT plus G-CSF (group B; n = 21) or SMT alone (group C; n = 21). The primary outcome was transplant-free survival (TFS) at 12 months. Secondary outcomes were mobilization of CD34⁺ cells at day 6 and improvement in clinical scores, liver stiffness, nutrition, episodes of infection, and quality of life (QOL) at 12 months. There was significantly better 12-month TFS in groups A and B than in group C (P = 0.001). At day 6 of therapy, CD34⁺ cells increased in groups A and B compared to baseline (P < 0.001). There was a significant decrease in clinical scores, improvement in nutrition, better control of ascites, reduction in liver stiffness, lesser infection episodes, and improvement in QOL scores in groups A and B at 12 months as compared to baseline (P < 0.05). The therapies were well tolerated.

CONCLUSION

Multiple courses of G-CSF improved 12-month TFS, mobilized hematopoietic stem cells, improved disease severity scores, nutrition, fibrosis, QOL scores, ascites control, reduced infections, and the need for LT in patients with DC. However, the use of GH was not found to have any additional benefit. (Hepatology 2017).

Deregulation of Notch1 pathway and circulating endothelial progenitor cell (EPC) number in patients with bicuspid aortic valve with and without ascending aorta aneurysm

Bicuspid aortic valve (BAV) is frequently associated with the development of ascending aortic aneurysm, even if the underlying mechanisms remain to be clarified. Here, we investigated if a deregulation of Notch1 signaling pathway and endothelial progenitor cells (EPCs) number is associated with BAV disease and an early ascending aortic aneurysm (AAA) onset. For this purpose, 70 subjects with BAV (M/F 50/20; mean age: 58.8 ± 14.8 years) and 70 subjects with tricuspid aortic valve (TAV) (M/F 35/35; mean age: 69.1 ± 12.8 years) and AAA complicated or not, were included. Interestingly, patients with AAA showed a significant increase in circulating Notch1 levels and EPC number than subjects without AAA. However, circulating Notch1 levels and EPC number were significantly lower in BAV subjects than TAV patients either in the presence or absence of AAA. Finally, Notch pathway was activated to a greater extent in aortic aneurysmatic portions with respect to healthy aortic fragments in both BAV and TAV patients. However, the expression of genes encoding components and ligands of Notch pathway in aortic tissues was significantly lower in BAV than TAV subjects. Our study demonstrates that BAV subjects are characterized by a significant decrease in both tissue and circulating levels of Notch pathway, and in blood EPC number than TAV patients, either in presence or absence of AAA disease.

Method comparison study of peripheral blood CD34+ count performed on an Abbott CELL-DYN Sapphire hematology analyzer versus flow cytometry reference procedure (modified ISHAGE)

Introduction

CD34+ cell enumeration is a critical parameter used to determine the timing of apheresis collections of hematopoietic progenitor cell products (HPC(A)). Automated hematology analyzers equipped with flow cytometry capabilities may be a solution to the problem of limited access to standard flow cytometry testing.

Methods

We compared CD34+ cell enumeration using a reference flow cytometry procedure employing modified International Society of Hematotherapy and Graft Engineering (ISHAGE) analysis with a hematology analyzer /flow cytometer hybrid (CELL DYN (CD)Sapphire) using a sequential gating analysis designed to emulate the ISHAGE gating strategy.

Results

CD34+ cell values obtained from the ISHAGE and CD Sapphire analysis were plotted and compared in a linear regression analysis which showed a high degree of correlation (R²=0.96). No statistically significant (p=0.53) differences in CD34+ cell enumeration values were observed between the flow cytometer and automated hematology analyzer using manual analysis schema.

Conclusions

We have demonstrated that an automated hematology analyzer equipped with a flow module can provide CD34+ cell enumeration results in the peripheral blood for clinical decision algorithms without the need for a dedicated flow cytometry laboratory.

Critical assessment of the efficiency of CD34 and CD133 antibodies for enrichment of rabbit hematopoietic stem cells

Rabbits have many hereditary diseases common to humans and are therefore a valuable model for regenerative disease and hematopoietic stem cell (HSC) therapies. Currently, there is no substantial data on the isolation and/or enrichment of rabbit HSCs. This study was initiated to evaluate the efficiency of the commercially available anti-CD34 and anti-CD133 antibodies for the detection and potential enrichment of rabbit HSCs from peripheral blood. PBMCs from rabbit and human blood were labelled with different clones of anti-human CD34 monoclonal antibodies (AC136, 581, and 8G12) and rabbit polyclonal CD34 antibody (pCD34) and anti-human CD133 monoclonal antibodies (AC133 and 293C3). Flow cytometry showed a higher percentage of rabbit CD34⁺ cells labelled by AC136 in comparison to the clone 581 and pCD34 (P < 0.01). A higher percentage of rabbit CD133⁺ cells were also detected by 293C3 compared to the AC133 clone (P < 0.01). Therefore, AC136 clone was used for the indirect immunomagnetic enrichment of rabbit CD34⁺ cells using magnetic-activated cell sorting (MACS). The enrichment of the rabbit CD34⁺ cells after sorting was low in comparison to human samples (2.4% vs. 39.6%). PCR analyses confirmed the efficient enrichment of human CD34⁺ cells and the low expression of CD34 mRNA in rabbit positive fraction. In conclusion, the tested antibodies might be suitable for detection, but not for sorting the rabbit CD34⁺ HSCs and new specific anti-rabbit CD34 antibodies are needed for efficient enrichment of rabbit HSCs. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 2018 © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:1278-1289, 2018.

The number of CD34+CD133+ hematopoietic stem cells residing in umbilical cord blood (UCB) units is not correlated with the numbers of total nucleated cells and CD34+ cells: a possible new indicator for quality evaluation of UCB units

Umbilical cord blood transplantation (UCBT) is often associated with delayed neutrophil and platelet recovery. Engraftment failure is another major obstacle. Several factors influence these serious complications, including the numbers of total nucleated cells (TNCs) and CD34⁺ cells which have been used as reliable factors for selecting UCB units for transplantation. However, whether both factors are reliable indices of the hematopoietic stem cell (HSC) activity of UCB units remains unknown. To evaluate the quality of UCB units, we quantified the actual number of transplantable CD34⁺CD133⁺ HSCs (tHSCs) residing in UCB units. The number of tHSCs was not correlated with the numbers of TNCs or CD34⁺ cells. These results strongly suggest that neither factor reflects the numbers of tHSCs residing in UCB units. To validate the significance of the number of tHSCs, further analysis is required to determine whether the number of tHSCs residing in UCB units is useful as a new indicator for the quality assessment of UCB units.

Membrane-Associated Proteinase 3 on Granulocytes and Acute Myeloid Leukemia Inhibits T Cell Proliferation

Proteinase 3 (P3), a serine protease expressed by myeloid cells, localized within azurophil granules, and also expressed on the cellular membrane of polymorphonuclear neutrophils (PMN), is the target of autoimmunity in granulomatosis with polyangiitis. PR1, an HLA-A2 restricted nonameric peptide derived from P3, has been targeted effectively in myeloid leukemia. We previously showed (Molldrem et al. 2003. JClinInvest 111: 639-647) that overexpression of P3 in chronic myeloid leukemia induces apoptosis of high-affinity PR1-specific T cells, leading to deletional tolerance and leukemia outgrowth. In this study, we investigated the effect of membrane P3 (mP3)-expressing PMN and acute myeloid leukemia (AML) blasts on the proliferation of CD4 and CD8 T cells in vitro. We demonstrate that mP3-expressing PMN significantly inhibits autologous healthy donor T cell proliferation but does not affect cytokine production in activated T cells and that this effect requires cell proximity and was abrogated by P3 blockade. This inhibition required P3 enzyme activity. However, suppression was not reversed by either the addition of catalase or the inhibition of arginase I. In addition to P3 blockade, anti-low density lipoprotein receptor-related protein 1 (LRP1) Ab also restored T cells' capacity to proliferate. Last, we show dose-dependent inhibition of T cell proliferation by mP3-expressing AML blasts. Together, our findings demonstrate a novel mechanism whereby PMN- and AML-associated mP3 inhibits T cell proliferation via direct LRP1 and mP3 interaction, and we identify P3 as a novel target to modulate immunity in myeloid leukemia and autoimmune disease.

Protocol for MicroRNA Transfer into Adult Bone Marrow-derived Hematopoietic Stem Cells to Enable Cell Engineering Combined with Magnetic Targeting

While CD133⁺ hematopoietic stem cells (SCs) have been proven to provide high potential in the field of regenerative medicine, their low retention rates after injection into injured tissues as well as the observed massive cell death rates lead to very restricted therapeutic effects. To overcome these limitations, we sought to establish a non-viral based protocol for suitable cell engineering prior to their administration. The modification of human CD133⁺ expressing SCs using microRNA (miR) loaded magnetic polyplexes was addressed with respect to uptake efficiency and safety as well as the targeting potential of the cells. Relying on our protocol, we can achieve high miR uptake rates of 80-90% while the CD133⁺ stem cell properties remain unaffected. Moreover, these modified cells offer the option of magnetic targeting. We describe here a safe and highly efficient procedure for the modification of CD133⁺ SCs. We expect this approach to provide a standard technology for optimization of therapeutic stem cell effects and for monitoring of the administered cell product via magnetic resonance imaging (MRI).

Repopulating hematopoietic stem cells from steady-state blood before and after ex vivo culture are enriched in the CD34+CD133+CXCR4low fraction

The feasibility of ex vivo expansion allows us to consider the steady-state peripheral blood as an alternative source of hematopoietic stem progenitor cells for transplantation when growth factor-induced cell mobilization is contraindicated or inapplicable. Ex vivo expansion dramatically enhances the in vivo reconstituting cell population from steady-state blood. In order to investigate phenotype and the expression of homing molecules, the expression of CD34, CD133, CD90, CD45RA, CD26 and CD9 was determined on sorted CD34⁺ cells according to CXCR4 (“neg”, “low” “bright”) and CD133 expression before and after ex vivo expansion. Hematopoietic stem cell activity was determined in vivo on the basis of hematopoietic repopulation of primary and secondary recipients - NSG immuno-deficient mice. In vivo reconstituting cells in the steady-state blood CD34⁺ cell fraction before expansion belong to the CD133⁺ population and are CXCR4^low or, to a lesser extent, CXCR4^neg, while after ex vivo expansion they are contained only in the CD133⁺CXCR4^low cells. The failure of the CXCR4^bright population to engraft is probably due to the exclusive expression of CD26 by these cells. The limiting-dilution analysis showed that both repopulating cell number and individual proliferative capacity were enhanced by ex vivo expansion. Thus, steady-state peripheral blood cells exhibit a different phenotype compared to mobilized and cord blood cells, as well as to those issued from the bone marrow. These data represent the first phenotypic characterization of steady-state blood cells exhibiting short- and long-term hematopoietic reconstituting potential, which can be expanded ex vivo, a sine qua non for their subsequent use for transplantation.

Prolonged hematopoietic and myeloid cellular response in patients after an acute coronary syndrome measured with 18F-DPA-714 PET/CT

Purpose

An acute coronary syndrome (ACS) is characterized by a multi-level inflammatory response, comprising activation of bone marrow and spleen accompanied by augmented release of leukocytes into the circulation. The duration of this response after an ACS remains unclear. Here, we assessed the effect of an ACS on the multi-level inflammatory response in patients both acutely and after 3 months.

Methods

We performed ¹⁸F-DPA-714 PET/CT acutely and 3 months post-ACS in eight patients and eight matched healthy controls. DPA-714, a PET tracer binding the TSPO receptor and highly expressed in myeloid cells, was used to assess hematopoietic activity. We also characterized circulating monocytes and hematopoietic stem and progenitor cells (HSPCs) by flow cytometry in 20 patients acutely and 3 months post-ACS and in 19 healthy controls.

Results

In the acute phase, patients displayed a 1.4-fold and 1.3-fold higher ¹⁸F-DPA-714 uptake in, respectively, bone marrow (p = 0.012) and spleen (p = 0.039) compared with healthy controls. This coincided with a 2.4-fold higher number of circulating HSPCs (p = 0.001). Three months post-ACS, ¹⁸F-DPA-714 uptake in bone marrow decreased significantly (p = 0.002), but no decrease was observed for ¹⁸F-DPA-714 uptake in the spleen (p = 0.67) nor for the number of circulating HSPCs (p = 0.75).

Conclusions

¹⁸F-DPA-714 PET/CT reveals an ACS- triggered hematopoietic organ activation as initiator of a prolonged cellular inflammatory response beyond 3 months, characterized by a higher number of circulating leukocytes and their precursors. This multi-level inflammatory response may provide an attractive target for novel treatment options aimed at reducing the high recurrence rate post-ACS.

Electronic supplementary material

The online version of this article (10.1007/s00259-018-4038-8) contains supplementary material, which is available to authorized users.

Hepatocyte growth factor and carotid intima-media thickness in relation to circulating CD34-positive cell levels

Background

Hepatocyte growth factor (HGF) may act as a possible biochemical index for vascular damage, although evidence for the association between HGF and carotid intima-media thickness (CIMT) is limited. Since both HGF and circulating CD34-positive cells play an important role in endothelial repair, circulating CD34-positive cell levels may influence the association between HGF and CIMT.

Methods

We conducted a cross-sectional study of 269 elderly Japanese men aged 60–69 years who had undertaken an annual medical checkup from 2014 to 2015.

Results

The median value for circulating CD34-positive cells was 0.93 cells/μL. Among the study population, 135 men showed low circulating CD34-positive cell levels (≤ 0.93 cells/μL). By multivariable linear regression analysis, HGF was found to be significantly positively associated with CIMT only to participants with low circulating CD34-positive cell levels, with a multi-adjusted β of 0.26 (p = 0.005) and 0.002 (0.986) for low and high circulating CD34-positive cell levels, respectively. In addition, a significant interaction was observed between HGF and circulating CD34-positive cell levels (low and high) on CIMT (multivariable p value of 0.049). A positive association exists between HGF and CIMT in elderly Japanese men, limited to participants with low circulating CD34-positive cell levels.

Conclusion

A positive association exists between HGF and CIMT in community-dwelling elderly Japanese men, which is limited to participants with low numbers of circulating CD34-positive cells. Our findings indicate that circulating CD34-positive cell levels could determine the influence of HGF on CIMT in elderly Japanese men.

Expression of adhesion molecules on CD34+ cells from steady-state bone marrow before and after mobilization and their association with the yield of CD34+ cells

Background

Cell adhesion molecules (CAMs) expressed on hematopoietic progenitor cells (HPCs), endothelial cells, and stromal cells play a pivotal role in the mobilization of CD34+ cells. Herein, we conducted a non-randomized peripheral blood stem cell (PBSC) mobilization study aimed to compare the potential differences in the expressions of several CAMs and chemokines on CD34+ cells obtained from bone marrow aspirate before and after HPC mobilization from patients with hematologic malignancies and healthy donors.

Methods

Three-color cytofluorometric analysis was used to compare the expressions of CAMs and chemokines in the bone marrow before and after mobilization.

Results

For all studied groups, CAM expression among those with good and poor yields of CD34+ cells was significantly correlated with VCAM-1 (P=0.007), CD44 (P=0.027), and VLA-4 (P=0.014) expressions. VCAM-1 (P=0.001), FLT-3 (P=0.001), CD44 (P=0.011), VLA-4 (P=0.001), and LFA-1 (P=0.001) expressions were higher before HPC mobilization than after HPC mobilization. By contrast, the expression of CXCR4 significantly varied before and after mobilization only among those with successful PBSC mobilization (P=0.002).

Conclusion

We attempted to identify particular aspects of CAMs involved in CD34+ cell mobilization, which is a highly complex mechanism that involves adhesion molecules and matrix metalloproteases. The mechanism by which CD34+ cell mobilization is activated through proteolytic enzymes is not fully understood. We believe that CXCR4, VLA-4, CD44, and VCAM-1 are the most important molecules implicated in HPC mobilization, particularly because they show a correlation with the yield of CD34+ cells collected via large volume leukapheresis.

The effects of lower CD34 yields after lowe dose G-CSF induction on long-term autologous stem cell transplantation outcome: A single center study

Peripheral blood stem cell transplantation (PBSCT) is an effective treatment for hematological malignancies. Mobilization of peripheral blood stem cells performs in different ways among transplantation centers. Since the Effects of lower CD34+ cells dose after low dose G-CSF induction on autologous stem cell transplantation outcomes are not studied much, so this study was performed for this purpose. 735 autologous stem cell transplanted patients with diagnoses of multiple myeloma (n = 330), Hodgkin lymphoma (n = 200), non-Hodgkin lymphoma (n = 129), acute myeloid leukemia (n = 54) and solid tumors (n = 22) were retrospectively evaluated. G-CSF was administered at the dose of 5 μg/kg/day during mobilization and all patients except acute myeloid leukemia received 10 μg/kg/day on the last day. Peripheral blood stem cells were harvested in one session for all patients. The amount of injected CD34+ cells/kg for patients were divided and studied in four groups: <0.5 × 10⁶ (n = 36), 0.5-1.0 × 10⁶, (n = 132), 1.0-2.0 × 10⁶ (n = 226) and >2.0 × 10⁶ (n = 305). The median time of follow up was 26.9 months. The amount of CD34+ cells dose were a significant predictor of platelet engraftment, but overall survival, relapse-free survival and also relapse rate was not associated with cells yield. More platelet transfusion (P = 0.003) and antibiotics prescription (P = 0.001) in transplanted patients with lower CD34 cells dose should be balanced with risks of higher G-CSF doses administration and also its side effects. Our results declare that lower CD34 yields after lowe dose G-CSF induction are probably not a troublesome issue affecting transplantation outcomes.

Quantification of peripheral blood CD34+ cells prior to stem cell harvesting by leukapheresis: a single center experience

Background

Due to laboratory logistic issues, our center has traditionally scheduled peripheral blood stem cell harvests based on timing from the start of mobilization. This has proved to be useful in some cases, but also resulted in many fruitless harvests due to poor mobilization. In order to improve the efficiency of collections and compare the effectiveness of peripheral blood CD34⁺ cells as a predictor with data from other reports, this study analyzed the implementation of this routine.

Methods

Peripheral blood and leukapheresis samples were quantified by flow cytometry and the association between these parameters was assessed.

Results

Sixty-six consecutive leukapheresis samples were collected from 34 patients after the collection of peripheral blood samples for CD34⁺ quantification. A moderate positive correlation was observed between peripheral blood CD34⁺ cell count and total CD34⁺ cell count/kg (r = 0.596; p-value < 0.001). A multivariable regression model also confirmed this association and allowed the estimation that for every increase in five CD34⁺ cells/μL in the peripheral blood, a mean increase of 0.38 × 10⁶ CD34⁺ cells/kg could be predicted. Demographic characteristics, baseline comorbidities and mobilization regimen did not influence final CD34⁺ cell count in this sample.

Conclusions

As observed in other centers, quantification of peripheral blood CD34⁺ progenitor cells is a strong predictor of effectiveness to guide stem cell harvesting. Due to the results of this study, a modification in the peripheral blood stem cell harvesting logistics was implemented at our center in order to incorporate this routine.

Feasibility of cord blood bank in high altitude Abha: preclinical impacts

We explored the possibility of the cryo-storage of cord blood hematopoietic stem cells (CBHPSC) with respect to the quantity, quality and biologic efficacy of high altitude (HA) region Abha against sea level (SL) region. The results of the post-processed total nucleated cell count was 8.03 ± 0.31 × 10⁷ and 8.44 ± 0.23 × 10⁷ cells in the HA and SL regions respectively. The mean post processing viability of the nucleated cells was about 87.03 ± 1.39 (HA) and 88.33 ± 1.55% (SL) while post thaw cells were 85.61 ± 1.44 (HA) and 86.58 ± 1.61% (SL) after transient cryo-storage. The proliferation of CBHSCs after thawing were comparable between the HA and SL regions. The results of the colony forming unit (CFU) assays of CFU-E, CFU-GEMM, CFU-GM and BFU-E were comparable between HA and SL in both fresh and post thaw, while a declining trend with viability was significant. The differentiation capability of post thaw samples into adipocytes and osteocytes were comparable between HA and SL regions. Overall from the results, it can be evidenced that HA cord blood collection, processing or storage does not hinder the quality or biological efficacy of the CBHPSC.

Circulating CD34+ hematopoietic stem/progenitor cells paralleled with level of viremia in patients chronically infected with hepatitis B virus

Introduction: Liver regeneration is a heterogeneous process involving proliferation of different cell types in response to injury. Bone marrow derived stem cells may be involved in this process, by making contribution to parenchymal restoration and cellular replacement. We aimed to investigate the correlation between level of circulating mobilized CD34+ hematopoietic stem progenitor cells (HSPCs) and viremia level in patients chronically infected with hepatitis B virus (HBV).

Methods: Blood samples were prospectively collected for assessing percentage and absolute counts of circulating CD34+ HSPCs and viral load level using flow cytometry and RT-PCR respectively. Patients with chronic hepatitis B (CHB) (n = 30), Entecavir (ETV) treated subjects (n = 30) and 20 age and gender matched healthy controls were enrolled in this study. Results were expressed as mean ± SD.

Results and discussion: A significant increase in circulating CD34+ HSPCs level was observed in CHB patients (5 ± 3.1, 324 ± 195 × 10³/ml) as compared to ETV treated subjects (0.57 ± 0.27,1022 ± 325) and healthy controls (0.53 ± 0.37, 694 ± 254, P < 0.001) in regards to percentage and absolute counts respectively. Levels of CD34+ HSPCs strongly and positively correlated with HBV DNA viral load levels in CHB patients (r² = 0.8417, 0.649, P < 0.001).Thus, in chronic liver disorders (CHB), when reduced regenerative capacity of hepatocytes is reached, BMSCs mobilization occurs and their level increases in peripheral blood. The level of circulating CD34+ cells in peripheral blood of CHB patients paralleled with the hepatitis B viral load.

Platelets as an indicator of vascular repair in elderly Japanese men

Platelets and circulating CD34-positive cells have been reported to contribute to vascular repair (endothelial repair and developing atherosclerosis). And because hypertension is known to be a strong vascular impairment factors, it should also influence the respective numbers of these factors. To clarify the clinical importance of platelets on vascular repair, we conducted a cross-sectional study of 567 Japanese men aged 60-69 who underwent an annual health check-up between 2013 and 2015. Multiple linear regression analysis of non-hypertensive subjects adjusting for classical cardiovascular risk factors showed that although platelet count did not significantly correlate with carotid intima media thickness (β = −0.05, p = 0.356), it did positively correlate significantly with the natural log of the number of circulating CD34-positive cells (β = 0.26, p < 0.001). In hypertensive subjects, a significant positive correlation was seen between platelets and intima media thickness (β = 0.19, p = 0.008), whereas no significant correlation was seen between platelet count and the natural log of the number of circulating CD34-positive cells (β = 0.11, p = 0.119). Our results indicate that platelet count is an indicator of vascular repair activity (endothelial repair and developing atherosclerosis). Additionally, hypertension might mask the beneficial effects of circulating CD34-positive cells.

Orchestration of Chemomobilization and G-CSF Administration for Successful Hematopoietic Stem Cell Collection

Successful collection of peripheral blood stem cells (PBSCs) depends on the optimal orchestration of mobilization chemotherapy, granulocyte colony stimulating factor (G-CSF) application, and CD34⁺ cell number assessment in the peripheral blood (PB). However, determining the optimal timing in accordance to the applied chemomobilization regimen can be challenging. Although most centers apply their own local timing schedules, a reliable timetable including the currently most often used mobilization regimens is lacking. We present a comprehensive analysis of the timing modalities for 11 of the most commonly used chemomobilization regimens. A retrospective analysis was performed on the clinical and PBSC collection parameters (including duration of G-CSF application, time point of CD34⁺ assessment, PB CD34⁺ cell count, number of leukapheresis [LP] sessions, processed blood volume, and CD34⁺ collection results) of 91 representatively selected patients who had undergone stem cell mobilization at 2 collection centers. Six to 10 patients were analyzed per regimen with a variety of diagnoses, including multiple myeloma, malignant lymphoma, and sarcoma. No collection failures (<2 × 10⁶ CD34⁺ cells/kg body weight) were observed. All analyzed patients successfully reached their individual collection goal in adherence to the given schedule of chemotherapy, application of G-CSF, measurement of CD34⁺ cells, and subsequent LP. The presented data on the timing of chemomobilization, G-CSF application, and stem cell collection may be helpful in clinical decision making and contribute to a more transparent and predictable treatment process.

Pegylated Filgrastim Versus Filgrastim for Stem Cell Mobilization in Multiple Myeloma After Novel Agent Induction

BACKGROUND

The current standard of care for transplant-eligible myeloma patients is novel agent-based induction, followed by high-dose chemotherapy and autologous stem cell rescue. Chemo-mobilization of peripheral blood CD34⁺ stem cells (PBSCs) with pegylated filgrastim (pegfilgrastim), a sustained-duration formulation of filgrastim, has been used as an alternative to filgrastim in several studies involving heterogeneous cohorts of lymphoma and multiple myeloma (MM) patients and shown to be equivalent in PBSC yield and cost-effectiveness. The present study focused on the efficacy of pegfilgrastim in PBSC mobilization compared with filgrastim exclusively after novel agent-based induction in a homogeneous group of MM patients.

PATIENTS AND METHODS

We analyzed the data from 89 patients with MM treated at 2 transplant centers in Singapore who had received novel agent-based induction chemotherapy, PBSC mobilization with vinorelbine/cyclophosphamide, high-dose melphalan conditioning, and autologous stem cell rescue. Of the 89 patients, 61 were included in the pegfilgrastim group and 28 in the filgrastim group, with a similar median age and disease characteristics. PBSC harvesting was performed at a similar median time of 9.51 ± 0.84 days for both, and the peak peripheral blood CD34⁺ stem cell count was 19.90 × 10⁶/kg for pegfilgrastim and 32.50 × 10⁶/kg for filgrastim (95% confidence interval, -4.36 to 0.70 × 10⁶/kg).

RESULTS

No significant difference was found in the median PBSC collection between the 2 groups (pegfilgrastim, 7.90 × 10⁶/kg vs. filgrastim, 10.10 × 10⁶/kg; P = .16).

CONCLUSION

The present study has demonstrated that a single dose of pegfilgrastim is comparable to filgrastim in terms of the timing and efficacy of PBSC harvest and could potentially spare the patient 6 days of filgrastim injections. In addition, ours is the first study to compare these growth factors using vinorelbine/cyclophosphamide as mobilization chemotherapy.