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

Hepatic arterial infusion of autologous CD34+ cells for hepatitis C virus-related decompensated cirrhosis: A multicenter, open-label, exploratory randomized controlled trial

Introduction

In this multicenter clinical study, we aimed to investigate the efficacy and safety of the transhepatic arterial administration of granulocyte-colony stimulating factor (G-CSF)-mobilized autologous peripheral blood (PB)-CD34+ cells compared with standard therapy in patients with decompensated cirrhosis type C.

Methods

Patients were randomly assigned (2:1) to the CD34+ cell transplant (CD34+ cell) or standard-of-care (SOC) group and followed up for 52 weeks. The primary endpoints were the non-progression rate of Child-Pugh (CP) scores at 24 weeks post-enrollment and the safety of the protocol treatment.

Results

Fourteen patients (CD34+ cell group: 10; SOC group: 4) were enrolled. CP scores at 24 weeks had a non-progression rate of 90% in the CD34+ cell group and 100% in the SOC group, with no significant difference between groups. Importantly, 4 out of 10 patients in the CD34+ cell group exhibited an improvement from decompensated to compensated cirrhosis, whereas all patients in the SOC group remained in decompensated cirrhosis. With regard to secondary endpoints, a trend toward increased serum albumin levels in the CD34+ cell group was noted. Serious adverse events (SAEs) occurred in three patients in the CD34+ cell group and in one patient in the SOC group. No causal relationship was observed between all SAEs and G-CSF, leukapheresis, or cell transplantation in the CD34+ cell group. No patients died and no hepatocellular carcinoma occurred within the study period.

Conclusions

PB-CD34+ cell infusion therapy may have the potential to circumvent the decompensated stage of cirrhosis, thus avoiding the need for liver transplantation.

Nucleated red blood cell: a feasible quality parameter of cord blood units

INTRODUCTION

Umbilical cord blood is an alternative source of hematopoietic progenitor cells for bone marrow transplantation; however, it is associated with a higher graft failure rate. The presence of a high rate of nucleated red blood cells (NRBCs) seems to be related to a greater capacity for engraftment, although is also associated with fetal distress conditions. We analyzed the correlation of the NRBC with quality parameters and its association with the utilization score of a cord blood unit.

STUDY DESIGN AND METHOD

Data of 3346 units collected in a public cord blood bank from May 2010 to December 2017 were analyzed, retrospectively, to identify factors associated with an increased number of nucleated red blood cells and its correlation with the engraftment capacity measured through total nucleated cells (TNCs) and CD34 positive cells. We also evaluated the utilization score of these units and identified an NRBC cutoff associated with a higher score.

RESULTS

The median volume collected was 104 mL (42-255), the pre-processing TNC count was 144.77 × 107 (95.46-477.18), the post-processing TNC count was 119.44 × 107 (42.7-477.18), the CD34 count was 4.67 × 106 (0.31-48.01), the NRBC count was 5 (0-202) and the utilization score was 0.0228 (0.00143-0.9740). The NRBC showed a correlation with the collected volume, TNC and CD34 positive cells and a higher utilization score and the receiver operating characteristic (ROC) curve analysis identified the five NRBC/100 leukocytes cutoff that correlates better with the probability of use. No association with pathological conditions and the NRBC rate was observed.

CONCLUSIONS

The NRBC is a feasible parameter for the screening of the cord blood unit (CBU) and the minimum cutoff of five NRBC/100 leukocytes can be a strategy in conjunction with the TNC to identify better units for cord blood bank sustainability.

Comparison of peripheral blood automated hematopoietic progenitor cell count and flow cytometric CD34+ cell count

BACKGROUND

Stem cell apheresis in the context of autologous stem cell transplantation requires an accurate cluster of differentiantion 34 (CD34+) count determined by flow cytometry as the current gold standard. Since flow cytometry is a personnel and time-intensive diagnostic tool, automated stem cell enumeration may provide a promising alternative. Hence, this study aimed to compare automated hematopoietic progenitor enumeration carried out on a Sysmex XN-20 module compared with conventional flow cytometric measurements.

METHODS

One hundred forty-three blood samples from 41 patients were included in this study. Correlation between the two methods was calculated over all samples, depending on leukocyte count and diagnosis.

RESULTS

Overall, we found a high degree of correlation (r = 0.884). Furthermore, correlation was not impaired by elevated leukocyte counts (>10 000/μL, r = 0.860 vs <10 000/μL, r = 0.849; >20 000/μL, r = 0.843 vs <20 000/μL, r = 0.875). However, correlation was significantly impaired in patients with multiple myeloma (multiple myeloma r = 0.840 vs nonmyeloma r = 0.934).

SUMMARY

Stem cell measurement carried out on the Sysmex XN-20 module provides a significant correlation with flow cytometry and might be implemented in clinical practice. In clinical decision-making, there was discrepancy of under 15% of cases. In multiple myeloma patients, XN-20 should be used with caution.

Early recovery of natural killer cells post T-cell depleted allogeneic stem cell transplantation using alemtuzumab "in the bag"

BACKGROUND

Allogeneic stem cell transplantation (SCT) is a critical therapy for haematological malignancy but may lead to acute and chronic graft versus host disease (GvHD). T-cell depletion with alemtuzumab, either in vivo or ex vivo, reduces the incidence of GvHD but is a risk factor for disease relapse and poor immune reconstitution. Natural killer (NK) cells are the first lymphocytes to recover. Classical NK cells make up >90% of the normal circulating population and can directly kill neoplastic or virally infected cells while the regulatory subset makes up <10%, secretes cytokines and is not cytotoxic. The recovery and balance of these subsets post SCT remains controversial, with most studies analysing patients who received unmanipulated grafts and in vivo immunosuppression.

OBJECTIVE

The aim was to assess the early recovery of NK cells in 18 consecutive patients receiving ex vivo T-cell depleted SCT and to compare the results to 25 individuals receiving haploidentical non-T cell depleted grafts.

METHODS

All patients received myeloablative conditioning. After stem cell collection, the stem cells of the T cell depleted group were treated "in the bag" with alemtuzumab (CAMPATH 1H) at a concentration of 1mg/108 mononuclear cells and thereafter immediately infused. For those receiving non-T cell depleted grafts, GvHD prophylaxis was with post infusion therapeutic doses of cyclophosphamide. Blood samples were collected at days 21, 28 and 90. Complete blood counts were performed on an automated analyser while lymphocyte and NK subsets were examined using multiparameter flowcytometry. NK cells were defined as lymphocytes which were CD3-/CD56+. The classical subset was recognised as CD56dim/CD16+ while the regulatory population as CD56bright/CD16-. The results for both transplant types were compared at all time points using SPSS v8 statistical software.

RESULTS

The recovery of lymphocytes was slow in both groups. Those receiving non-T cell depleted grafts had significantly higher T cell counts at day 21 and 28 when compared to the T cell depleted group (P < 0.05). In contrast, NK cells in the ex vivo T-cell depleted patients recovered rapidly and by day 21 was no different to normal (p > 0.05), while the non-T cell depleted group had significantly decreased numbers (p < 0.001), only recovering at day 90. Both groups had abnormal NK cell subset ratios with significantly elevated percentages of regulatory cells (p < 0.05). However, significant differences were observed between the two groups with those receiving T cell depleted grafts having lower percentages of regulatory cells as well as higher numbers of classical NK cells at day 21 and 28 (p < 0.01).

CONCLUSION

This study of ex vivo T-cell depleted SCT's demonstrates that NK cells recover quicker when compared to those receiving unfractionated grafts. These results may have implications for GvHD and the GvL effect which warrants further study.

Local manufacturing processes contribute to variability in human mesenchymal stromal cell expansion while growth media supplements contribute to variability in gene expression and cell function: a Biomedical Excellence for Safer Transfusion (BEST) collaborative study

BACKGROUND AIMS

Culture-derived mesenchymal stromal cells (MSCs) exhibit variable characteristics when manufactured using different methods, source material and culture media. The purpose of this multicenter study was to assess the impact on MSC expansion, gene expression and other characteristics when different laboratories expanded MSCs from cultures initiated with bone marrow-MSC aliquots derived from the same donor source material yet with different growth media.

METHODS

Eight centers expanded MSCs using four human platelet lysate (HPL) and one fetal bovine serum (FBS) products as media supplements. The expanded cells were taken through two passages then assessed for cell count, viability, doubling time, immunophenotype, cell function, immunosuppression and gene expression. Results were analyzed by growth media and by center.

RESULTS

Center methodologies varied by their local seeding density, feeding regimen, inoculation density, base media and other growth media features (antibiotics, glutamine, serum). Doubling times were more dependent on center than on media supplements. Two centers had appropriate immunophenotyping showing all MSC cultures were positive for CD105, CD73, CD90 and negative for CD34, CD45, CD14, HLA-DR. MSCs cultured in media supplemented with FBS compared with HPL featured greater T-cell inhibition potential. Gene expression analysis showed greater impact of the type of media supplement (HPL versus FBS) than the manufacturing center. Specifically, nine genes were decreased in expression and six increased when combining the four HPL-grown MSCs versus FBS (false discovery rate [FDR] <0.01), however, without significant difference between different sources of HPL (FDR <0.01).

CONCLUSIONS

Local manufacturing process plays a critical role in MSC expansion while growth media may influence function and gene expression. All HPL and FBS products supported cell growth.

Daratumumab during Myeloma Induction Therapy Is Associated with Impaired Stem Cell Mobilization and Prolonged Post-Transplant Hematologic Recovery

Daratumumab is being increasingly integrated into first-line multiple myeloma (MM) induction regimens, leading to improved response depth and longer progression-free survival. Autologous stem cell transplantation (ASCT) is commonly performed as a consolidation strategy following first-line induction in fit MM patients. We investigated a cohort of 155 MM patients who received ASCT after first-line induction with or without daratumumab (RVd, n = 110; D-RVd, n = 45), analyzing differences in stem cell mobilization, apheresis, and engraftment. In the D-RVd group, fewer patients successfully completed mobilization at the planned apheresis date (44% vs. 71%, p = 0.0029), and more patients required the use of rescue plerixafor (38% vs. 28%, p = 0.3052). The median count of peripheral CD34+ cells at apheresis was lower (41.37 vs. 52.19 × 106/L, p = 0.0233), and the total number of collected CD34+ cells was inferior (8.27 vs. 10.22 × 106/kg BW, p = 0.0139). The time to recovery of neutrophils and platelets was prolonged (12 vs. 11 days, p = 0.0164; and 16 vs. 14 days, p = 0.0002, respectively), and a higher frequency of erythrocyte transfusions (74% vs. 51%, p = 0.0103) and a higher number of platelet concentrates/patients were required (4 vs. 2; p = 0.001). The use of daratumumab during MM induction might negatively impact stem cell mobilization and engraftment in the context of ASCT.

Effect of fetal distress on viability and yield of umbilical cord blood stem cells-a prospective comparative study

INTRODUCTION

Different factors affect the quality and viability of cord blood stem cells, and therefore the efficacy of umbilical cord stem cell transplantation. Fetal distress is one factor affecting the quantity of CD34+ cells in cord blood. This study was designed to compare the viability and yield of the umbilical cord blood stem cells of women who have undergone emergency lower segment caesarean section for fetal distress or for other causes.

MATERIALS AND METHODS

This cross-sectional analytical study was performed at a tertiary care hospital facility with a total sample size of 68: 34 participants had undergone emergency C-section for fetal distress, and 34 had undergone emergency C-section for other causes. Umbilical cord blood was collected ex-utero in a 350 mL bag with citrate-phosphate-dextrose solution with adenine. Three milliliter of blood were transferred to an ethylenediaminetetraacetic acid (EDTA) tube for cell counts and flow cytometry testing for CD34+. The chi-square test was used to compare the total mononuclear cell, CD34+, and viability between the groups.

RESULTS

The CD34+ count [mean 4.9 versus 1.1 (× 106 cells/unit)] and total nucleated cell count [mean 14.2 versus 7.5 (× 108/unit)] were significantly higher in cord blood units collected from women who delivered by C-section for fetal distress (p-value <0.05). However, the volume of umbilical cord stem cells and viability of stem cells did not vary significantly based on the presence or absence of fetal distress (p-value >0.05).

CONCLUSION

The current study shows that umbilical cord blood collected during fetal distress has a significantly higher content of stem cells and total nucleated cells than the non-fetal distress group.

Hyaluronan in mesenchymal stromal cell lineage differentiation from human pluripotent stem cells: application in serum free culture

BACKGROUND

Hyaluronan (HA) is an extracellular glycosaminoglycan polysaccharide with widespread roles throughout development and in healthy and neoplastic tissues. In pluripotent stem cell culture it can support both stem cell renewal and differentiation. However, responses to HA in culture are influenced by interaction with a range of cognate factors and receptors including components of blood serum supplements, which alter results. These may contribute to variation in cell batch production yield and phenotype as well as heighten the risks of adventitious pathogen transmission in the course of cell processing for therapeutic applications. MAIN: Here we characterise differentiation of a human embryo/pluripotent stem cell derived Mesenchymal Stromal Cell (hESC/PSC-MSC)-like cell population by culture on a planar surface coated with HA in serum-free media qualified for cell production for therapy. Resulting cells met minimum criteria of the International Society for Cellular Therapy for identification as MSC by expression of. CD90, CD73, CD105, and lack of expression for CD34, CD45, CD14 and HLA-II. They were positive for other MSC associated markers (i.e.CD166, CD56, CD44, HLA 1-A) whilst negative for others (e.g. CD271, CD71, CD146). In vitro co-culture assessment of MSC associated functionality confirmed support of growth of hematopoietic progenitors and inhibition of mitogen activated proliferation of lymphocytes from umbilical cord and adult peripheral blood mononuclear cells, respectively. Co-culture with immortalized THP-1 monocyte derived macrophages (Mɸ) concurrently stimulated with lipopolysaccharide as a pro-inflammatory stimulus, resulted in a dose dependent increase in pro-inflammatory IL6 but negligible effect on TNFα. To further investigate these functionalities, a bulk cell RNA sequence comparison with adult human bone marrow derived MSC and hESC substantiated a distinctive genetic signature more proximate to the former.

CONCLUSION

Cultivation of human pluripotent stem cells on a planar substrate of HA in serum-free culture media systems is sufficient to yield a distinctive developmental mesenchymal stromal cell lineage with potential to modify the function of haematopoietic lineages in therapeutic applications.

Impact of lower concentrations of dimethyl sulfoxide on cryopreservation of autologous hematopoietic stem cells: a systematic review and meta-analysis of controlled clinical studies

BACKGROUND AIMS

Cryopreservation of hematopoietic stem cells (HSCs) is crucial for autologous transplantation, cord blood banking and other special circumstances. Dimethyl sulfoxide (DMSO) is used most commonly for cryopreserving HSC products but can cause infusional toxicities and affect cell viability and engraftment after transplant. A systematic review of controlled studies using lower concentrations of DMSO to cryopreserve HSC products in clinical transplant studies is needed to determine the effect of reducing DMSO concentrations on post-thaw cell viability, initial engraftment and adverse effects on patient health.

METHODS

All studies identified in our systematic search (to July 11, 2023) examining the use of cryopreserved peripheral blood stem cells (PBSCs) for autologous stem cell transplantation (AHCT) were included. Meta-analysis was performed to determine how varying the concentration of DMSO during cryopreservation effects post-thaw cell viability, initial engraftment and adverse effects on patient health.

RESULTS

A total of 1547 studies were identified in our systematic search, with seven published articles meeting eligibility for inclusion in meta-analysis. All patients underwent AHCT using (PBSCs) to treat hematologic malignancies. The viability of CD34+ cells post thaw was greater when cryopreserved with 5% DMSO compared with 10% DMSO, with lower rates of adverse side effects in patients. DMSO concentration had minimal impact on rates of initial engraftment. Significant heterogeneity in outcome reporting was observed and the potential for bias was identified in all studies.

CONCLUSIONS

Reducing the concentration of DMSO from 10% to 5% during cryopreservation of autologous PBSCs may improve cell viability and reduce DMSO-associated adverse effects in patients undergoing AHCT. Data from more studies with similar patients and standard outcome reporting are needed to increase confidence in our initial observations.

PROTOCOL REGISTRATION

PROSPERO; registration number CRD42023476809 registered November 8, 2023.

A 3-step method for preparing cryopreserved samples of apheresis products for post-thaw analysis yields a higher percentage of viable cells

BACKGROUND

Standard flow cytometry protocols for CD34+ cell enumeration designed for fresh samples are not appropriate for cryopreserved products. Special protocols have been developed to remove the cryoprotectant by quickly washing a freshly thawed sample. Exposing cells to a large volume of hypotonic solution and subsequent washing process was hypothesized to cause lab-induced cell death. Moreover, standard gating strategies must be altered to avoid reporting falsely high viabilities.

STUDY DESIGN AND METHODS

We developed a novel method whereby thawed samples were diluted step-wise to 1:2 by 3 additions of 1/3 sample volume using 1% Human Albumin in Dextran 40 (10% Low Molecular Weight Dextran in 0.9% NaCl) separated by 5 min between each addition. An additional 1:10 dilution was required to obtain a desired cell concentration for flow cytometry testing resulting in a 1:20 dilution.

RESULTS

Twenty samples were tested simultaneously in a method comparison; the new method demonstrated significant increases in mean cell viabilities for white blood cells, hematopoietic progenitor cells, and T cells as well as reduced standard deviations for each parameter.

DISCUSSION

Slow, step-wise dilutions of freshly thawed samples of cryopreserved apheresis products to 1:20 yielded higher and more precise viability measurements compared to quickly washing samples to remove DMSO.

Insight into the mechanism of CD34+ cell mobilisation impairment in multiple myeloma patients treated with anti-CD38 therapy

Induction therapy followed by CD34+ cell mobilisation and autologous transplantation represents standard of care for multiple myeloma (MM). However, the anti-CD38 monoclonal antibodies daratumumab and isatuximab have been associated with mobilisation impairment, yet the mechanism remains unclear. In this study, we investigated the effect of three different regimens (dara-VCd, isa-KRd and VTd) on CD34+ cells using flow cytometry and transcriptomics. Decreased CD34+ cell peak concentration and yields, longer collection and delayed engraftment were reproduced after dara-VCd/isa-KRd versus VTd induction in 34 patients in total. Using flow cytometry, we detected major changes in the proportion of apheresis product and bone marrow CD34+ subsets in patients treated with regimens containing anti-CD38 therapy; however, without any decrease in CD38high B-lymphoid progenitors in both materials. RNA-seq of mobilised CD34+ cells from 21 patients showed that adhesion genes are overexpressed in CD34+ cells after dara-VCd/isa-KRd and JCAD, NRP2, MDK, ITGA3 and CLEC3B were identified as potential target genes. Finally, direct in vitro effect of isatuximab in upregulating JCAD and CLEC3B was confirmed by quantitative PCR. These findings suggest that upregulated adhesion-related interactions, rather than killing of CD34+ cells by effector mechanisms, could be leading causes of decreased mobilisation efficacy in MM patients treated with anti-CD38 therapy.

True volumetric counting of CD34+ cells using flow cytometry

While the single-platform flow cytometric CD34+ cell counting method is the preferred choice to predict the yield of mobilized peripheral blood stem cells, most flow cytometers lack the ability of hematology counter analyzers to perform volumetric counting. However, one of the problems using reference microbeads is the vanishing counting bead phenomenon. This phenomenon results in a drop in microbeads concentration and reduces the total and relative number of beads in calibration procedures. In the last years, flow cytometers including a volumetric system to quantify cells have been developed and may represent a promising alternative to enumerate CD34+ cells avoiding the use of beads. In this study we have used a direct true volumetric counting of CD34+ cells under continuous flow pump to overcome potential drawbacks with impact in rare cell analysis. To confirm this hypothesis, we have compared the results of CD34+ cell enumeration using non-volumetric vs. volumetric systems with FC500 (Beckman Coulter) and Attune NxT (ThermoFisher) flow cytometers, respectively, in mobilized peripheral blood samples. No statistically significant differences were observed between measurements of CD34+ cells using beads, when the FC500 and Attune NxT absolute counting values were compared, or when CD34+ counts were compared on the Attune NxT, either using or not using beads. Linear regressions to study the relationship between volumetric and non-volumetric CD34+ counts confirmed the accuracy of each method. Bland-Altman test showed agreement between both methods. Our data showed that CD34+ cell enumeration using a volumetric system is comparable with current counting systems. This method represents an alternative with the advantage of the simplification of sample preparation and the reduction of the analysis subjectivity.

Plasma THBS1 as a predictive biomarker for poor prognosis and brain metastasis in patients with HER2-enriched breast cancer

BACKGROUND

Thrombospondin-1 (THBS1) is a secretory adhesive glycoprotein involved in the progression of multiple malignancies, including breast cancer. However, the clinical significance and prognostic role of plasma THBS1 in breast cancer have yet to be clarified.

METHODS

Plasma THBS1 levels in 627 breast cancer patients were analyzed by enzyme-linked immunosorbent assay. Bone marrow blood was drawn from the anterior/posterior superior iliac spine to detect the presence of disseminated tumor cells (DTCs). The effects of plasma THBS1 on the clinicopathological characteristics and survival prediction of breast cancer patients were explored.

RESULTS

Plasma THBS1 did not correlate with overall survival, breast cancer-specific survival (BCSS), and distant disease-free survival (DDFS) in the entire breast cancer cohort. Notably, HER2-enriched patients with high-plasma THBS1 levels had significantly shorter BCSS (P = 0.027) and DDFS (P = 0.011) than those with low levels. Multivariate analyses revealed that plasma THBS1 was an independent prognostic marker of BCSS (P = 0.026) and DDFS (P = 0.007) in HER2-enriched patients. THBS1 levels were 24% higher in positive DTC patients than in negative DTC patients (P = 0.031), and high levels were significantly associated with poor BCSS in positive DTC patients (HR 2.08, 95% CI 1.17-3.71; P = 0.019). Moreover, high-plasma THBS1 levels were specifically associated with an increased occurrence of brain metastasis in HER2-enriched patients (P = 0.041).

CONCLUSION

These findings suggest that plasma THBS1 may be serving as an unfavorable prognosis predictor for HER2-enriched breast cancer and justifies the need for further research.

Collection efficiency and safety of large-volume leukapheresis for the manufacturing of tisagenlecleucel

BACKGROUND

In patients with relapsed or refractory B cell acute lymphoblastic leukemia or B cell non-Hodgkin lymphoma (r/r B-ALL/B-NHL) with low CD3+ cells in the peripheral blood (PB), sufficient CD3+ cell yield in a single day may not be obtained with normal-volume leukapheresis (NVL). Large-volume leukapheresis (LVL) refers to the processing of more than three times the total blood volume (TBV) in a single session for PB apheresis; however, the efficiency and safety of LVL for manufacturing of tisagenlecleucel (tisa-cel) remain unclear. This study aimed to investigate the tolerability of LVL.

STUDY DESIGN AND METHODS

We retrospectively collected data on LVL (≥3-fold TBV) and NVL (<3-fold TBV) performed for patients with r/r B-ALL/B-NHL in our institution during November 2019 and September 2023. All procedures were performed using a continuous mononuclear cell collection (cMNC) protocol with the Spectra Optia.

RESULTS

Although pre-apheresis CD3+ cells in the PB were significantly lower in LVL procedures (900 vs. 348/μL, p < .01), all patients could obtain sufficient CD3+ cell yield in a single day with a comparably successful rate of final products (including out-of-specification) between the two groups (97.2% vs. 100.0%, p = 1.00). The incidence and severity of citrate toxicity (no patients with grade ≥ 3) during procedures was not significantly different between the two groups (22.2% vs. 26.1%, p = .43) and no patient discontinued leukapheresis due to any complications.

CONCLUSION

LVL procedures using Spectra Optia cMNC protocol was well tolerated and did not affect the manufacturing of tisa-cel.

In vitro generation of epidermal keratinocytes from human CD34-positive hematopoietic stem cells

The epidermis is largely composed of keratinocytes (KCs), and the proliferation and differentiation of KCs from the stratum basale to the stratum corneum is the cellular hierarchy present in the epidermis. In this study, we explore the differentiation abilities of human hematopoietic stem cells (HSCs) into KCs. Cultured HSCs positive for CD34, CD45, and CD133 with prominent telomerase activity were induced with keratinocyte differentiation medium (KDM), which is composed of bovine pituitary extract (BPE), epidermal growth factor (EGF), insulin, hydrocortisone, epinephrine, transferrin, calcium chloride (CaCl2), bone morphogenetic protein 4 (BMP4), and retinoic acid (RA). Differentiation was monitored through the expression of cytokeratin markers K5 (keratin 5), K14 (keratin 14), K10 (keratin 10), K1 (keratin 1), transglutaminase 1 (TGM1), involucrin (IVL), and filaggrin (FLG) on day 0 (D0), day 6 (D6), day 11 (D11), day 18 (D18), day 24 (D24), and day 30 (D30) using immunocytochemistry, fluorescence microscopy, flow cytometry, qPCR, and Western blotting. The results revealed the expression of K5 and K14 genes in D6 cells (early keratinocytes), K10 and K1 genes in D11-D18 cells (mature keratinocytes) with active telomerase enzyme, and FLG, IVL, and TGM1 in D18-D24 cells (terminal keratinocytes), and by D30, the KCs were completely enucleated similar to cornified matrix. This method of differentiation of HSCs to KCs explains the cellular order exists in the normal epidermis and opens the possibility of exploring the use of human HSCs in the epidermal differentiation.

Evaluation of AQUIOS STEM, a novel method for automated CD34+ stem cell enumeration using flow cytometry

OBJECTIVES

Hematopoietic stem cell transplantation (HSCT) is a potentially curative treatment for various diseases. The measurement of CD34+ cells is crucial to schedule the peripheral blood stem cell collection and assess the engraftment potential of the apheresis product. The AQUIOS STEM system has been introduced as a novel application on the AQUIOS CL, a fully automated flow cytometer, for the enumeration of CD34+ hematopoietic progenitor cells (HPCs) in accordance with the The International Society for Hematotherapy and Graft Engineering guidelines. This study aimed to assess the potential of the novel AQUIOS STEM system versus currently used systems including the FACSCanto-II and the FACS Lyric flow cytometer in a multicenter study.

METHODS

A total of 91 samples were used for the validation of the AQUOIS STEM system, including an analytical performance evaluation by means of assessing precision, sample stability, intersample carryover, and linearity and a method comparison with the present FACS systems in use to assess analytical and clinical decision agreement.

RESULTS

Results showed excellent precision, with coefficient of variations <15% for dedicated quality control material and patient samples. There was no significant carry over. The fresh apheresis samples were stable when stored overnight at room temperature and at 4°C. Analytical comparison with the current systems demonstrated good correlation in peripheral blood, and minimal, clinically neglectable systematic and proportional bias in fresh apheresis products but a low correlation coefficient in cryopreserved products.

CONCLUSIONS

The STEM system on AQUIOS CL allows automated enumeration of CD34+ stem cells, demonstrating good analytical performance and promising overall outcomes in peripheral blood and fresh apheresis products.

Predicting the CD34 content of mobilized peripheral blood leukapheresis products: single institution experience over 20 years

BACKGROUND AIMS

Since the standardization of CD34 measurement by flow cytometry, predictors of leukapheresis CD34 yield have played a pivotal role in planning donor leukaphereses. We describe here a single institution's experience with a multivariate predictor that was used for 2,929 products without alteration for 20 years.

METHODS

The ordinary least squares regression model variables included log peripheral CD34 count, collection duration (3- versus 4-hours), collection number, donor sex, and transplant type.

RESULTS

During the study period we changed flow cytometers twice and leukapheresis instruments once. During the Cobe Spectra era the predictor explained 90% of the variability in CD34 collection yield for autologous transplants (r2 = 0.90), and 70% for allogeneic transplants with an overall sensitivity to predict a CD34 yield of ≥ 1 × 106/kg of 97.7%, and specificity of 81.4%.

CONCLUSIONS

Implemented prospectively with real-time result reporting, the model allowed us to predict CD34 yield with both 3- and 4-hour collection scenarios. Given this guidance, 3-hour collections were selected by the clinical team 25% of the time, saving patient leukapheresis time and resources. When faced with a prediction of < 1 × 106 CD34/kg, the clinical team chose to defer collection 72% of the time. In instances where leukapheresis was performed despite a poor predicted outcome, 85% of patients collected on the Cobe Spectra, and 92% of patients collected on the Optia, failed to collect at least 1 × 106 CD34/kg. A revised model is tested retrospectively on Optia data, and suggestions for further improvements are discussed.

Review of flow cytometry as a tool for cell and gene therapy

Quality control testing and analytics are critical for the development and manufacture of cell and gene therapies, and flow cytometry is a key quality control and analytical assay that is used extensively. However, the technical scope of characterization assays and safety assays must keep apace as the breadth of cell therapy products continues to expand beyond hematopoietic stem cell products into producing novel adoptive immune therapies and gene therapy products.  Flow cytometry services are uniquely positioned to support the evolving needs of cell therapy facilities, as access to flow cytometers, new antibody clones and improved fluorochrome reagents becomes more egalitarian. This report will outline the features, logistics, limitations and the current state of flow cytometry within the context of cellular therapy.

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.

The Use of Umbilical Cord Blood Nucleated Cells in the Treatment of Regressive Autism: A Case Report

BACKGROUND

Interest in the issue of childhood autism has surged in the recent decades. At the same time, despite the significant progress achieved in understanding the etiological and pathogenetic aspects of the condition, effective ways to treat it have continued to elude us. Stem cell therapy appears to hold great promise in the treatment and rehabilitation of patients with both neurological diseases (cerebral palsy, hydrocephalus) and mental disorders (autism, schizophrenia).

METHODS

This article presents a case report describing the use of nucleated cord blood cells in a patient with regressive autism and resistance to standard therapies. The child's condition was assessed before treatment and 6 and 12 months after.

RESULTS

Clinical observation, psychometric, and instrumental diagnostic methods led to a significant improvement in the child's condition in the form of perception development, reduction of somatosensory disorders, normalization of emotional status, and a development of social and communication skills.

CONCLUSION

We assume that the result obtained may be associated with the normalization of the immunological status of our patient thanks to the cord blood cells therapy and consider it necessary to conduct further studies into the effectiveness of the method, taking the pathogenic mechanisms of autism into account.

Effect of different timings of umbilical cord clamping on the level of CD34+ cells in full-term neonates

Despite the fact that delayed cord clamping (DCC) is recommended by many international organizations, early cord clamping is still widely practiced worldwide. The overarching goal of the DCC practice is to maximize neonatal benefits as achieving higher hemoglobin levels and decreasing the incidence of anemia as well as avoiding the adverse consequences. The current study was conducted to identify the effect of of DCC on the number of CD34+ stem cells in cord blood of full term neonates after two different timings (30 and 60 s after birth). One hundred and three full-term (FT) newborn babies (gestational age 37-40 weeks) delivered by elective cesarean section were randomly assigned into 2 groups: Group 1: babies were subjected to DCC 30 s after birth (50 newborns). Group 2: babies were subjected to DCC 60 s after birth (53 newborns). Neonates in group 2 had significantly higher levels of hemoglobin, hematocrit, total nucleated cells and CD34+ cells compared to those in group 1. The practice of DCC 60 s after birth achieved better CD34+ stem cells transfer in FT neonates than clamping the cord after 30 s.

Prolonged infusion time of cyclophosphamide plus granulocyte colony-stimulating factor (G-CSF) as a mobilization regimen may improve mobilization efficiency in newly diagnosed multiple myeloma patients: a single center experience

OBJECTIVES

This study aimed to clarify the effectiveness and safety of two different infusion durations of cyclophosphamide (CTX) plus granulocyte colony-stimulating factor (G-CSF) for peripheral blood stem cell mobilization in patients with newly diagnosed multiple myeloma (NDMM).

METHODS

One hundred and fifty-six consecutive NDMM patients receiving CTX plus G-CSF mobilization and autologous stem cell transplantation during the period of September 2008 to May 2020 were selected for retrospective analysis. According to differences in prolonged infusion time of CTX, they were divided into a 24-h group (24-h continuous infusion) and a control group (4-6 h of infusion). Mobilization and safety of infusion were analyzed. Flow cytometry was used to detect the peripheral blood CD34+ cell count. Multivariate analysis was performed to determine the factors influencing the number of CD34+ cells.

RESULTS

The mean CD34+ cell counts collected in 24-h and control groups were 6.78 (interquartile range [IQR] 3.59-11.69) and 4.48 (IQR 2.39-6.30) ×106/kg, respectively (p < 0.001). Meanwhile, the target number of CD34+ cells/kg (defined as ≥4 × 106/kg) was collected from 51 (75%) of cases in 24-h group vs. 45 (51%) in the control group (p = 0.002). Multivariate analysis identified the independence of CTX infusion time as a factor influencing the target number of CD34+ cells/kg [odds ratio OR, 4.045; 95% CI: 1.630-10.038, p = 0.003]. The post-transplantation time to neutrophil engraftment was 10 (IQR 9-11) in 24-h group and 11 (IQR 10-12) in control group (p < 0.001). Finally, no statistical differences were identified between groups in terms of hematologic and non-hematologic toxicities.

CONCLUSIONS

For patients with NDMM, 24-h continuous infusion of CTX plus G-CSF contributes to improved mobilization efficiency and equivalent toxicity as a stem cell mobilization regimen.

Label-Free CD34+ Cell Identification Using Deep Learning and Lens-Free Shadow Imaging Technology

Accurate and efficient classification and quantification of CD34+ cells are essential for the diagnosis and monitoring of leukemia. Current methods, such as flow cytometry, are complex, time-consuming, and require specialized expertise and equipment. This study proposes a novel approach for the label-free identification of CD34+ cells using a deep learning model and lens-free shadow imaging technology (LSIT). LSIT is a portable and user-friendly technique that eliminates the need for cell staining, enhances accessibility to nonexperts, and reduces the risk of sample degradation. The study involved three phases: sample preparation, dataset generation, and data analysis. Bone marrow and peripheral blood samples were collected from leukemia patients, and mononuclear cells were isolated using Ficoll density gradient centrifugation. The samples were then injected into a cell chip and analyzed using a proprietary LSIT-based device (Cellytics). A robust dataset was generated, and a custom AlexNet deep learning model was meticulously trained to distinguish CD34+ from non-CD34+ cells using the dataset. The model achieved a high accuracy in identifying CD34+ cells from 1929 bone marrow cell images, with training and validation accuracies of 97.3% and 96.2%, respectively. The customized AlexNet model outperformed the Vgg16 and ResNet50 models. It also demonstrated a strong correlation with the standard fluorescence-activated cell sorting (FACS) technique for quantifying CD34+ cells across 13 patient samples, yielding a coefficient of determination of 0.81. Bland-Altman analysis confirmed the model's reliability, with a mean bias of -2.29 and 95% limits of agreement between 18.49 and -23.07. This deep-learning-powered LSIT offers a groundbreaking approach to detecting CD34+ cells without the need for cell staining, facilitating rapid CD34+ cell classification, even by individuals without prior expertise.

Comparison of Haemonetics Cell Saver 5+ and manual density separation for optimum depletion of red blood cells and preservation of CD34+ cells in major ABO-incompatible bone marrow grafts

BACKGROUND AIMS

The current approach for preventing hemolysis of red blood cells (RBCs) in major ABO-incompatible bone marrow (BM) grafts after infusion is to deplete RBCs from BM products before transplantation. Traditionally, manual density separation (MDS) using Ficoll-Hypaque (Cytiva Sweden AB, Uppsala, Sweden has been used to accomplish RBC depletion. This process yields good CD34+ cell recovery, but it requires open manipulation and is labor-intensive and time-consuming. We hypothesized that an alternative automated method using Haemonetics Cell Saver 5+ (Haemonetics Corporation, Boston, MA, USA) would offer equivalent RBC depletion and CD34+ cell recovery. Small marrow volumes from pediatric donors can be processed using Cell Saver (CS) without adding the third-party RBCs necessary for other automated methods.

METHODS

This retrospective analysis comprised data from 58 allogeneic BM grafts. RBC depletion and CD34+ cell recovery from BM using MDS (35 grafts) were compared with CS (14 grafts). Nine products underwent RBC depletion using CS with Ficoll (CS-F) when RBC volume was less than 125 mL.

RESULTS

Linear regression analysis of log transformation of CD34+ cell recovery adjusted for log transformation of both baseline CD34+ cell content and baseline total volume showed no significant difference between MDS and CS (estimated coefficient, -0.121, P = 0.096). All products contained an RBC volume of less than 0.25 mL/kg post-processing. CD34+ cell recovery with CS-F was comparable to MDS and CS and suitable for pediatric recipients of allogeneic hematopoietic cell transplantation.

CONCLUSIONS

We provide evidence that an automated method using Haemonetics Cell Saver 5+ achieves RBC depletion and CD34+ cell recovery comparable to MDS when adjusting for baseline factors.

Steady-state versus chemotherapy-based hematopoietic cell mobilization after anti-CD38-based induction therapy in newly diagnosed multiple myeloma

BACKGROUND

The incorporation of anti-CD38 monoclonal antibodies (mAb) in induction regimens of newly diagnosed transplant-eligible multiple myeloma (MM) patients has been established as a new standard. However, the optimal strategy of stem cell mobilization in this context is not yet clear.

STUDY DESIGN AND METHODS

From May 2020 till September 2022, we retrospectively reviewed patients receiving anti-CD38 mAb-based induction therapy followed by stem cell mobilization either in a steady-state protocol (SSM) using 10 μg/kg granulocyte colony-stimulating factor (G-CSF) for 5 days or in a chemotherapy-based protocol (CM) using 1-4 g/m2 cyclophosphamide and G-CSF.

RESULTS

Overall, 85 patients (median age 61 years) were included in the analysis. In total, 90 mobilization attempts were performed, 42 with SSM and 48 with CM. There was no significant difference in the median concentration of CD34+ cells in peripheral blood (PB) prior to apheresis between SSM and CM (61/μL vs. 55.4/μL; p = .60). Cumulative CD34+ yields did not differ between the groups with median of 6.68 and 6.75 × 106 /kg body weight, respectively (p = .35). The target yield (≥4 × 106 CD34+ cells/kg body weight) was reached in 88% (CM) and 86% (SSM), with a high proportion even after a single apheresis session (76% vs. 75%). Plerixafor was found to be more frequently used in SSM (52%) than in CM (23%; p < .01). A total of 83 patients underwent autologous transplantation and all were engrafted.

CONCLUSIONS

Stem cell collection in patients undergoing anti-CD38-based induction therapy is feasible with either CM or SSM, although SSM more frequently requires plerixafor.

Evaluating the efficiency and safety of large-volume leukapheresis using the Spectra Optia continuous mononuclear cell collection protocol for peripheral blood stem cell collection from healthy donors: A retrospective study

BACKGROUND

Large-volume leukapheresis (LVL) refers to processing of more than three volumes of blood in a single session for peripheral blood stem cell collection. Recently, continuous mononuclear cell collection (cMNC) protocol has been developed using the Spectra Optia system, which is a widely used apheresis device. LVL using the novel protocol has been investigated in patients. However, the efficiency and safety of LVL in healthy donors using this protocol has not been characterized. Therefore, this study aimed to evaluate the efficiency and tolerability of CD34+ collection of LVL with the cMNC protocol in healthy donors.

STUDY DESIGN AND METHODS

We retrospectively collected data on LVL (>3 total blood volume) and normal-volume leukapheresis (NVL) performed in healthy donors between October 2019 and December 2021. All procedures were performed using the cMNC protocol.

RESULTS

Although pre-apheresis CD34+ cell count was lesser in LVL (23.5 vs. 58.0/μL, p < .001), CD34+ collection efficiency was comparable between LVL and NVL (61.2% vs. 61.4%, p = .966). Platelet loss was significantly higher in LVL compared to NVL (38.0% vs. 29.4%, p < .001), with no correlation between attrition of platelet and processing blood volume. Moreover, the incidence of citrate toxicity during procedures was comparable between the two groups (31.6% vs. 21.4%, p = .322). All LVL procedures could be completed without any adverse events.

CONCLUSION

Allogeneic LVL procedure using Spectra Optia cMNC protocol was well tolerated by the donors and resulted in efficient collection of CD34+ cells, which was comparable to that of NVL.

Predicting Successful Hematopoietic Stem Cell Collection in Healthy Allogeneic Donors

Introduction

Collection of peripheral blood stem cells (PBSCs) from healthy donors is a well-established process. We aimed to identify factors predictive of successful CD34+ PBSC collection and established a formula capable of predicting CD34+ cell yield.

Methods

We retrospectively evaluated 588 healthy adult donors (median age 29 years, range 18-69 years) at our institution from 2017 to 2022. The predicted minimal number of CD34+ cells was calculated as follows: (peripheral CD34+ cells/µL × adjusted collection efficiency of 30%) × total liters processed. This formula was further modified according to donor and recipient body weight (BW).

Results

Median total collection was 8.0 × 106 CD34+ cells/kg BW (range 1.0-47.1 × 106 cells/kg BW) with 522 donors (89%) collecting ≥5.0 × 106 cells/kg of recipient BW. A second leukapheresis (LP) was performed in 49 donors. Need for two LPs was more common in female donors (OR 6.68, 95% CI, 2.62-17.05; p < 0.001), donors with higher age (OR for 10 years difference 1.53, 95% CI, 1.15-2.03, p = 0.003), donors with WBC count <30 × 109/L after 5 days of granulocyte-colony stimulating factor (G-CSF) stimulation (OR, 4.33; 95% CI, 1.59-11.83; p = 0.004), and a donor/recipient weight ratio <1 (OR 6.21, 95% CI, 2.69-14.34; p < 0.001). Predictive factors for optimal LP (i.e., ≥5.0 × 106 CD34+ cells/kg of recipient BW) were peripheral blood (PB) CD34+ cell count >50/µL (OR 12.82, range 6.34-25.92, p < 0.001), male donor (OR 2.77, range 1.06-7.23, p = 0.04), and a donor/recipient weight ratio >1 (OR 3.12, range 1.57-6.24, p = 0.001). WBC, platelets, hemoglobin, and age had no significant predictive value. Predicted versus observed number of CD34+ cells/kg BW collected demonstrated a very strong linear correlation (r = 0.925, 95% CI, 0.912-0.936, p < 0.0001).

Conclusions

Of the routinely monitored indicators in PBSC donors, CD34+ cell count in PB is the most important factor in predicting G-CSF-induced PBSC yields. Higher age, female sex, WBC <30 × 109/L, and a donor/recipient weight ratio <1 are useful indicators for identifying suboptimal mobilizers. The modified formula has shown successful and consistent performance in the prediction of key outcome measures including the minimum CD34+ cell collection, determination of the required length of apheresis, and whether a second day of PBSC collection was necessary to achieve the respective collection goal.

Flow Cytometric Characterization of Hematopoietic Stem and Progenitor Cell Subpopulations in Autologous Peripheral Blood Stem Cell Preparations after Cryopreservation

Introduction

Autologous stem cell transplantation is a successful routine procedure with only a small number of non-engraftment cases, although the time to hematopoietic recovery may vary considerably across patients. While CD34 has been the decisive marker for enumerating hematopoietic stem and progenitor cells (HSPCs) for more than 30 years, the impact of CD34-positive cellular subpopulations in autologous HSPC grafts on hematopoietic reconstitution remains unclear.

Methods

The two-color ISHAGE protocol represents the current gold standard for CD34+ cell enumeration but includes only the number of viable CD45+/CD34+ cells relative to the body weight of the recipient. We adapted a multicolor flow cytometry marker panel for advanced characterization of CD34 subpopulations in retained samples of autologous peripheral blood stem cell products (n = 49), which had been cryostored for a wide range from 4 to 15 years. The flow cytometric analysis included CD10, CD34, CD38, CD45, CD45RA, CD133, and viability staining with 7AAD. The findings were correlated with clinical engraftment data, including reconstitution of leukocytes, neutrophils, and platelets after transplantation (TPL).

Results

We demonstrated that the identification of autologous HSPC subpopulations by flow cytometry after cryopreservation is feasible. Regarding the distribution of HSPC subpopulations, a markedly different pattern was observed in comparison to previously published data obtained using fresh autologous material. Our data revealed the largest ratio of lympho-myeloid progenitors (LMPPs) after freezing and thawing, followed by multipotent progenitors and erythroid-myeloid progenitors. A high ratio of LMPPs, representing an immature stage of differentiation, correlated significantly with early neutrophilic granulocyte and leukocyte engraftment (p = 0.025 and p = 0.003). Conversely, a large ratio of differentiated cells correlated with late engraftment of neutrophilic granulocytes (p = 0.024). Overall, successful engraftment was documented for all patients.

Conclusion

We established an advanced flow cytometry panel to assess the differentiation ability of cryostored autologous peripheral blood stem cell grafts and correlated it with timely hematopoietic reconstitution. This approach represents a novel and comprehensive way to identify hematopoietic stem and progenitor subpopulations. It is a feasible way to indicate the engraftment capacity of stem cell products.

Flow Cytometric Enumeration of Peripheral Blood CD34+ Cells Predicts Bone Marrow Pathology in Patients with Less Than 1% Blasts by Manual Count

Background and Aims

Significance of absolute number of CD34+ cells in the peripheral blood of patients with less than 1% myeloblasts by manual differential count is unknown and our aim is to study its relevance in clinical practice.

Methods

We studied 138 peripheral bloods flow cytometric analyses in patients with less than 1% myeloblasts by manual differential, when CD34+ events were present in the gate that encompassed lymphocytes, monocytes, stem cells, and blasts.

Results

The average absolute number of CD34+cells in the peripheral blood was 11 CD34+cells/µL ranging from less than 1 cell/µL to 147 cells/µL. The average absolute number of CD34+ cells in patients with an abnormal expansive process involving bone marrow (metastases, myelodysplasia, granulomas, marrow infections) or if bone marrow biopsy not performed, presumed expansive marrow process was 25 cells/µL, and in patients without an expansive marrow process (or presumed negative) was 4 cells/µL (P<0.00007). Cutoff 12 CD34+ cells/μL had 93% positive predictive value for bone marrow involvement by an expansive process and 78% negative predictive value.

Conclusion

Flow cytometric testing of the peripheral blood is extremely sensitive method for enumerating CD34+ cells and can detect fewer than one CD34+ cell/µL. The absolute number of CD34+ cells in the peripheral blood is a useful parameter in determining marrow involvement by an expansive process and may provide guidance with respect to the necessity for bone marrow biopsy.

Progression of Carotid Intima-Media Thickness Partly Indicates the Prevention of Hypertension among Older Individuals in the General Population

Structural atherosclerosis, as evaluated by carotid intima-media thickness (CIMT), is reported to be positively associated with hypertension. However, angiogenesis, which plays an important role in the progression of structural atherosclerosis, prevents hypertension by reducing peripheral vascular resistance. These associations evoke a contradiction: characteristics associated with the progression of structural atherosclerosis, which is related to hypertension, might prevent hypertension. To clarify novel mechanisms underlying the association between structural atherosclerosis and hypertension, multifaceted analyses are necessary. We performed several epidemiological studies based on this concept. This study summarizes those epidemiological studies and adds some discussion. Studies focusing on circulating CD34-positive cells, single-nucleotide polymorphisms (SNPs) of vascular endothelial growth factor (VEGF), SNPs in BRACA1-associated protein (BRAP), platelets, human T-cell leukemia virus type 1 (HTLV-1), and SNPs in aldehyde dehydrogenase 2 (ALDH2) have shown that active endothelial repair, which leads to the progression of structural atherosclerosis, helps prevent hypertension. These associations indicate that the progression of structural atherosclerosis could act as a marker of angiogenesis, which reduces peripheral vascular resistance. In general, a positive association between structural atherosclerosis and hypertension has been reported. However, the progression of structural atherosclerosis could act as a marker of activity that prevents hypertension via reductions in peripheral vascular resistance.

Correlation of various methods of hematopoietic progenitor cell estimation with standard flowcytometric CD34 enumeration

BACKGROUND AND OBJECTIVES

Enumeration of hematopoietic progenitor cell (HPC) is vital to decide the time to initiate harvest (TTIH) and adequacy of harvest dose (AOHD). Standard of care used for HPC enumeration is flowcytometric CD34+ enumeration, but it is expensive, time-consuming and requires skilled staff to perform the test. Alternatively, HPC-count by advanced automated cell analyzer is cheaper, quicker, and easy-to-perform test. Our objective was to find a correlation of HPC count with CD34+ enumeration in leukapheresis.

MATERIALS AND METHODS

An observational, prospective study was conducted in the year 2018-2019. A total of 126 samples were included in the study, the peripheral blood (PB) group comprised of 42samples and apheresis group of 84 samples. The samples were simultaneously tested for CD34+ expression and complete blood count which included the HPC count, white blood cells (WBC) count and multinational corporation (MNC) count and correlation analysis was performed with CD34+ flowcytometric count. The cut-off of PB HPC count for the target dose of 5 × 106 CD34+ cells/kg was established using Receiver Operator Curve.

RESULTS

The correlation coefficient (r) of HPC with CD34+ count was 0.617 and 0.699 for PB group and apheresis group sample respectively, which was statistically significant. The correlation with MNC and WBC count was not very significant. A cut-off value of PB HPC was established to be 66 HPC/μl with a positive predictive value of 94.12%. The cost of CD34 + flow cytometric enumeration was six times that of HPC enumeration by analyzer.

CONCLUSION

The HPC count is a cheaper, rapid and easy test and can be clinically applied to predict TTIH and AOHD but requires more studies to validate its efficacy in clinical use.

A retrospective study to assess the impact of ABO incompatibility on outcomes of allogeneic peripheral blood stem cell transplants at a tertiary care hospital in Western Maharashtra

BACKGROUND

Hematopoietic stem cell transplantation (HSCT) has emerged as a curative measure for life-threatening hematological disorders. It can be autologous or allogeneic depending on the disease characteristics. Providing transfusion support to the transplant patients can be challenging, especially in AB-mismatched allogeneic HSCT. In this study, we investigated the impact of ABO incompatibility in patients undergoing allogeneic HSCT.

MATERIALS AND METHODS

A retrospective review was conducted in 76 patients with hematological diseases who underwent allogeneic HSCT. Transfusion requirements, engraftment profile, incidence of graft versus host disease (GvHD), and mortality for a period of 1 year were analyzed.

RESULTS

ABO incompatibility between donor and the patient did not significantly affect the neutrophil and platelet (PLT) engraftment time (P = 0.389, 0.349, respectively), packed red blood cells transfusion requirement, and duration of initial hospital stay. However, patients of ABO-incompatible HSCT received more PLT transfusions posttransplant which was statistically significant. 29.1% of ABO compatible and 16.7% incompatible HSCT patients developed GVHD. Mortality rates in the two groups were 16.7% and 8.3%, respectively. However, differences in both the parameters were not statistically significant.

CONCLUSION

Our study showed that ABO incompatibility does not significantly affect the outcome and should not be a limiting factor for selection of donor. Donor availability and human leukocyte antigen (HLA) matching remain the critical selection criteria.

Common Yoga Protocol Increases Peripheral Blood CD34+ Cells: An Open-Label Single-Arm Exploratory Trial

Purpose

Physical inactivity can be a cause of various lifestyle disorders including atherosclerosis, diabetes, hypertension, and cardiovascular diseases (CVDs). Lifestyle modification by the inclusion of Yoga and similar activities has shown beneficial effects on disease prevention and psychological management. However, the molecular mechanism at the cellular level is unknown. This study aims to identify the molecular response at systemic level generated after three months of Common Yoga Protocol (CYP) practice.

Methods

A total of 25 healthy adult females were recruited for this study (25 to 55 years). After the drop out of 6 participants at baseline and 2 participants after 1 month; blood samples of 17 participants were assessed. Blood samples were assessed for lipid profile, CD34+ cell enumeration and angiogenesis markers (ie, VEGF, Angiogenin and BDNF) at baseline (before intervention), after one month and after three months of Common Yoga Protocol (CYP) practice. The psychological health of the participants was assessed at baseline and after three months of CYP practice. The psychological tests used were General Health Questionnaire (GHQ), State-Trait Anxiety Inventory (STAI), Trail Making Test A & B, Digit symbol test, Digit symbol substitution test.

Results

After 3 months of intervention, blood samples of 17 participants were collected and following results were reported (1) percentage of CD34+ cells increased significantly after 3 months of CYP practice (from 18.18±7.32 cells/μL to 42.48±18.83 cells/μL) (effect size: W, 0.40; 95% CI, p = 0.001) (2) neurogenesis marker, ie, BDNF showed a significant change with time after 3 months of CYP intervention (effect size: W, 0.431, 95% CI; p = 0.002), (3) HDL showed an increasing trend (non-significant) after three months of CYP practice (53.017±1.28 mg/dl to 63.94±5.66 mg/dl) (effect size: W, 0.122; 95% CI; p = 0.126) (4) General Health score (10.64 ± 3.53 to 6.52 ± 3.12) (effect size: d, 0.98; 95% CI; p = 0.001) along with visual and executive function improved (69.94±26.21 to 61.88±28.55 (time taken in seconds)) (effect size: d, 0.582; 95% CI; p = 0.036), also stress and anxiety showed reduction (effect size: d, 0.91; 95% CI; p = 0.002) (5) a significant positive correlation was found between: HDL with VEGF (r = 0.547, p = 0.023) and BDNF (r = 0.538, p = 0.039) after 3 months of intervention; also, a significant positive correlation was found between VEGF with BDNF (r = 0.818, p ≤ 0.001) and Angiogenin (r = 0.946, p ≤ 0.001), also, BDNF was also positively correlated with Angiogenin (r = 0.725, p = 0.002) at both 1 month and 3 months after intervention. Also, VEGF and BDNF showed a significantly negative correlation with stress and anxiety questionnaire after the intervention.

Conclusion

The current study provides insights into the molecular response to CYP practice at systemic level. The results suggest that CYP practice indeed increased CD34+ cells in peripheral blood and BDNF also showed a significant change after the intervention. An overall improvement in general health and psychology of the participants was also observed.

Risk factors for CAR-T cell manufacturing failure among DLBCL patients: A nationwide survey in Japan

For successful chimeric antigen receptor T (CAR-T) cell therapy, CAR-T cells must be manufactured without failure caused by suboptimal expansion. In order to determine risk factors for CAR-T cell manufacturing failure, we performed a nationwide cohort study in Japan and analysed patients with diffuse large B-cell lymphoma (DLBCL) who underwent tisagenlecleucel production. We compared clinical factors between 30 cases that failed (7.4%) with those that succeeded (n = 378). Among the failures, the proportion of patients previously treated with bendamustine (43.3% vs. 14.8%; p < 0.001) was significantly higher, and their platelet counts (12.0 vs. 17.0 × 10⁴ /μL; p = 0.01) and CD4/CD8 T-cell ratio (0.30 vs. 0.56; p < 0.01) in peripheral blood at apheresis were significantly lower than in the successful group. Multivariate analysis revealed that repeated bendamustine use with short washout periods prior to apheresis (odds ratio [OR], 5.52; p = 0.013 for ≥6 cycles with washout period of 3-24 months; OR, 57.09; p = 0.005 for ≥3 cycles with washout period of <3 months), low platelet counts (OR, 0.495 per 10⁵ /μL; p = 0.022) or low CD4/CD8 ratios (<one third) (OR, 3.249; p = 0.011) in peripheral blood at apheresis increased the risk of manufacturing failure. Manufacturing failure remains an obstacle to CAR-T cell therapy for DLBCL patients. Avoiding risk factors, such as repeated bendamustine administration without sufficient washout, and risk-adapted strategies may help to optimize CAR-T cell therapy for DLBCL patients.

Early Stage Professionals Committee Proceedings from the International Society for Cell & Gene Therapy 2022 Annual Meeting

In this Committee Proceedings, representatives from the Early Stage Professional (ESP) committee highlight the innovative discoveries and key take-aways from oral presentations at the 2022 International Society for Cell and Gene Therapy (ISCT) Annual Meeting that cover the following subject categories: Immunotherapy, Exosomes and Extracellular Vesicles, HSC/Progenitor Cells and Engineering, Mesenchymal Stromal Cells, and ISCT Late-Breaking Abstracts.

Longitudinal profile of circulating endothelial cells in post-acute coronary syndrome patients

IntroductionPatients who have experienced an acute coronary syndrome (ACS) are at risk of a recurrent event, but their level of risk varies. Because of their close temporal relationship with vascular injury, longitudinal measurements of circulating endothelial cells (CECs) carry potential to improve individual risk assessment.MethodsWe conducted an explorative nested case-control study within our multicenter, prospective, observational biomarker study (BIOMArCS) of 844 ACS patients. Following an index ACS, high-frequency blood sampling was performed during 1-year follow-up. CECs were identified using flow cytometric analyses in 15 cases with recurrent event, and 30 matched controls.ResultsCases and controls had a median (25^th-75^thpercentile) age of 64.1 (58.1-75.1) years and 80% were men. During the months preceding the endpoint, the mean (95%CI) CEC concentration in cases was persistently higher than in controls (12.8 [8.2-20.0] versus 10.0 [7.0-14.4] cells/ml), although this difference was non-significant (P = 0.339). In controls, the mean cell concentration was significantly (P = 0.030) lower in post 30-day samples compared to samples collected within one day after index ACS: 10.1 (7.5-13.6) versus 17.0 (10.8-26.6) cells/ml. Similar results were observed for CEC subsets co-expressing CD133 and CD309 (VEGFR-2) or CD106 (VCAM-1).ConclusionDespite their close relation to vascular damage, no increase in cell concentrations were found prior to the occurrence of a secondary adverse cardiac event.

Artificial Intelligence-Derived Electrocardiogram Assessment of Cardiac Age and Molecular Markers of Senescence in Heart Failure

OBJECTIVE

To ascertain whether heart failure (HF) itself is a senescent phenomenon independent of age, and how this is reflected at a molecular level in the circulating progenitor cell niche, and at a substrate level using a novel electrocardiogram (ECG)-based artificial intelligence platform.

PATIENTS AND METHODS

Between October 14, 2016, and October 29, 2020, CD34⁺ progenitor cells were analyzed by flow cytometry and isolated by magnetic-activated cell sorting from patients of similar age with New York Heart Association functional classes IV (n = 17) and I-II (n = 10) heart failure with reduced ejection fraction and healthy controls (n = 10). CD34⁺ cellular senescence was quantitated by human telomerase reverse transcriptase expression and telomerase expression by quantitative polymerase chain reaction, and senescence-associated secretory phenotype (SASP) protein expression assayed in plasma. An ECG-based artificial intelligence (AI) algorithm was used to determine cardiac age and difference from chronological age (AI ECG age gap).

RESULTS

CD34⁺ counts and telomerase expression were significantly reduced and AI ECG age gap and SASP expression increased in all HF groups compared with healthy controls. Expression of SASP protein was closely associated with telomerase activity and severity of HF phenotype and inflammation. Telomerase activity was more closely associated with CD34⁺ cell counts and AI ECG age gap.

CONCLUSION

We conclude from this pilot study that HF may promote a senescent phenotype independent of chronological age. We show for the first time that the AI ECG in HF shows a phenotype of cardiac aging beyond chronological age, and appears to be associated with cellular and molecular evidence of senescence.

Characterization and Function of Cryopreserved Bone Marrow from Deceased Organ Donors: A Potential Viable Alternative Graft Source

Despite the readily available graft sources for allogeneic hematopoietic cell transplantation (alloHCT), a significant unmet need remains in the timely provision of suitable unrelated donor grafts. This shortage is related to the rarity of certain HLA alleles in the donor pool, nonclearance of donors owing to infectious disease or general health status, and prolonged graft procurement and processing times. An alternative hematopoietic progenitor cell (HPC) graft source obtained from the vertebral bodies (VBs) of deceased organ donors could alleviate many of the obstacles associated with using grafts from healthy living donors or umbilical cord blood (UCB). Deceased organ donor-derived bone marrow (BM) can be preemptively screened, cryogenically banked for on-demand use, and made available in adequate cell doses for HCT. We have developed a good manufacturing practice (GMP)-compliant process to recover and cryogenically bank VB-derived HPCs from deceased organ donor (OD) BM. Here we present results from an analysis of HPCs from BM obtained from 250 deceased donors to identify any substantial difference in composition or quality compared with HPCs from BM aspirated from the iliac crests of healthy living donors. BM from deceased donor VBs was processed in a central GMP facility and packaged for cryopreservation in 5% DMSO/2.5% human serum albumin. BM aspirated from living donor iliac crests was obtained and used for comparison. A portion of each specimen was analyzed before and after cryopreservation by flow cytometry and colony-forming unit potential. Bone marrow chimerism potential was assessed in irradiated immunocompromised NSG mice. Analysis of variance with Bonferroni correction for multiple comparisons was used to determine how cryopreservation affects BM cells and to evaluate indicators of successful engraftment of BM cells into irradiated murine models. The t test (with 95% confidence intervals [CIs]) was used to compare cells from deceased donors and living donors. A final dataset of complete clinical and matched laboratory data from 226 cryopreserved samples was used in linear regressions to predict outcomes of BM HPC processing. When compared before and after cryopreservation, OD-derived BM HPCs were found to be stable, with CD34+ cells maintaining high viability and function after thawing. The yield from a single donor is sufficient for transplantation of an average of 1.6 patients (range, 1.2 to 7.5). CD34+ cells from OD-derived HPCs from BM productively engrafted sublethally irradiated immunocompromised mouse BM (>44% and >67% chimerism at 8 and 16 weeks, respectively). Flow cytometry and secondary transplantation confirmed that OD HPCs from BM is composed of long-term engrafting CD34+CD38-CD45RA-CD90+CD49f+ HSCs. Linear regression identified no meaningful predictive associations between selected donor-related characteristics and OD BM HPC quality or yield. Collectively, these data demonstrate that cryopreserved BM HPCs from deceased organ donors is potent and functionally equivalent to living donor BM HPCs and is a viable on-demand graft source for clinical HCT. Prospective clinical trials will soon commence in collaboration with the Center for International Blood and Marrow Research to assess the feasibility, safety, and efficacy of Ossium HPCs from BM (ClinicalTrials.gov identifier NCT05068401).

Royal Jelly Increases Hematopoietic Stem Cells in Peripheral Blood: A Double-Blind, Placebo-Controlled, Randomized Trial in Healthy Subjects

Objectives

Royal jelly (RJ), produced by honeybees, influences stem cell functions, such as pluripotency maintenance of mouse embryonic stem cells and prevention of aging-related muscle stem cell functional deterioration. Thus, we hypothesized that RJ administration has various health-promoting effects based on stem cells. However, its effects are unknown in humans. In this study, we have attempted for the first time to clarify whether the administration of RJ in humans affects stem cells.

Materials and Methods

This randomized, double-blind, placebo-controlled study was performed on healthy subjects (n = 90) who received protease-treated RJ at a dose of 1200 mg/day or placebo daily for four weeks. Also, the participants with a low number of hematopoietic stem cells (HSCs) in peripheral blood were preferentially selected. HSC counts, endothelial progenitor cell (EPC) counts, blood cell counts in peripheral blood, cytokines in serum, and physical conditions were evaluated. Results and Conclusion. Eligible data from 86 subjects (placebo: 42, RJ: 44) who completed the study were analyzed. There were no significant differences between the two groups regarding the changes in peripheral HSC count (p=0.103), while diastolic blood pressure showed a significant improvement in the RJ group compared to that in the placebo group (p=0.032). The subgroup analysis excluded 14 subjects who complained of cold symptoms at baseline or within five days of the four-week study. The changes in the HSC populations were significantly higher in the RJ group than those in the placebo group (p=0.042). No adverse effects were observed in any of the groups. These results suggest that RJ administration affected the peripheral HSC count and may influence stem cell functions. Further research is needed to reveal the various health-promoting benefits of RJ based on stem cells.

Mechanism underlying vascular remodeling in relation to circulating CD34-positive cells among older Japanese men

Development of structural atherosclerosis, an established cardiovascular risk factor, requires hematopoietic stem cells known as CD34-positive cells. However, an inverse association between circulating CD34-positive cell count and cardiovascular disease has been reported. These studies evoke a contradiction: characteristics associated with a low risk of developing structural atherosclerosis are also associated with a high risk of cardiovascular disease. To clarify the mechanisms underlying vascular remodeling, we conducted several epidemiological studies of Japanese men aged 60 to 69 years who participated in annual health check-ups. The present study summarizes those epidemiological studies and adds some discussion. From the perspective of endothelial repair activity, there are significant differences between functional versus structural atherosclerosis. Aggressive endothelial repair increases both functional and structural atherosclerosis. Deficient endothelial repair related to a shortage of CD34-positive cells due to consumption furthers functional atherosclerosis but not structural atherosclerosis. Therefore, the lack of structural atherosclerosis does not always reflect a favorable condition for the endothelium. Although further investigation is necessary, the present study suggests that higher endothelial repair activity that leads to structural atherosclerosis might have a beneficial effect on vascular health among older men.

Antithymocyte Globulin Plus Post-Transplant Cyclophosphamide Combination as an Effective Strategy for Graft-versus-Host Disease Prevention in Haploidentical Peripheral Blood Stem Cell Transplantation for Children with High-Risk Malignancies

Haploidentical hematopoietic stem cell transplantation using post-transplant cyclophosphamide (PTCy) for graft-versus-host disease (GVHD) prophylaxis has emerged as a valid alternative transplant strategy for patients lacking a suitable HLA-matched related donor. The high risk of severe GVHD remains the major clinical challenge in this setting. The addition of antithymocyte globulin (ATG) in PTCy-based regimens for GVHD reduction in haploidentical hematopoietic stem cell transplantation is rational and was reported in adult series. However, its feasibility is unknown in pediatric patients. Here, we firstly describe our experience of 15 consecutive children with high-risk malignancies receiving haploidentical peripheral blood stem cell transplantation using ATG plus PTCy for GVHD prophylaxis. Only three patients developed grade 1-2 acute GVHD, limited to skin. No grade 3-4 acute GVHD and chronic GVHD were observed. Viral reactivations were frequently seen but manageable. Six patients relapsed, as the main cause of death in our series. None died from events related to GVHD. Our data suggest that ATG plus PTCy is an effective strategy for GVHD prevention in haploidentical peripheral blood stem cell transplantation and is feasible in children with high-risk malignancies.

Widely applicable, extended flow cytometric stem cell enumeration panel for quality control of advanced cellular products

The most widely used quality control assay for CD34 + hematopoietic stem cell product characterization is the protocol established by the International Society of Hematotherapy and Graft Engineering (ISHAGE). While this protocol is still the gold standard for stem cell enumeration and viability assessment, it does not include T cell enumeration, which is nowadays mandatory for assaying standard allogeneic grafts and various advanced therapy medicinal products (ATMPs). In accordance, we have developed and extensively validated a new approach for a more comprehensive characterization of hematopoietic cellular products using a pre-formulated dried antibody format panel. In addition to the counting beads, the typical markers CD45 fluorescein isothiocyanate (FITC) and CD34 phycoerythrin (PE), as well as the viability dye 7-amino actinomycin D (7-AAD), our novel pre-formulated panel also contains CD3 Pacific Blue (PB) and CD19 allophycocyanin (APC) in the same tube, thereby allowing a combined calculation of leucocytes, stem cells, T and B cells. Showing high linearity, sensitivity and accuracy, our approach is easy to implement and enables a more in-depth characterization of the cellular product under release testing conditions. In addition, the dried pre-formulated antibody approach increases assay reliability compared to the standard antibody panel.

Peptide ILE-GLU-TRP (Stemokin) Potential Adjuvant Stimulating a Balanced Immune Response

Vaccines are widely used worldwide to prevent and protect from various infections. A variety of modern approaches to developing prophylactic and therapeutic vaccines is growing. In almost all cases, adjuvants are necessary to obtain an effective immune response.This work investigated the possibility of using the pharmaceutical peptide drug Stemokin as an adjuvant stimulating a balanced Th1/Th2 response.A study was conducted to compare the activity of Stemokin versus the approved adjuvant Alhydrogel in a murine vaccination model with the approved VAXIGRIP® vaccine.The first proof-of-concept experimental study shows that the peptide Ile-Glu-Trp has the adjuvant vaccine properties and anti-HA IgG2a enhancing response, revealing a Th1- favoring balanced Th1/Th2 immunomodulation.

Characterisation of canine CD34+/CD45 diminished cells by colony-forming unit assay and transcriptome analysis

Haematopoietic stem and progenitor cells (HSPCs) are used for transplantation to reconstruct the haematopoietic pathways in humans receiving severe chemotherapy. However, the characteristics of canine HSPCs, such as specific surface antigens and gene expression profiles, are still unclear. This study aimed to characterise the haematopoietic ability and gene expression profiles of canine bone marrow HSPCs in healthy dogs. In this study, the CD34 positive (CD34+) cells were defined as classical HSPCs, CD34+/CD45 diminished (CD45^dim) cells as more enriched HSPCs, and whole viable cells as controls. Haematopoietic abilities and gene expression profiles were evaluated using a colony-forming unit assay and RNA-sequencing analysis. Canine CD34+/CD45^dim cells exhibited a significantly higher haematopoietic colony formation ability and expressed more similarity in the gene expression profiles to human and mouse HSPCs than those of the other cell fractions. Furthermore, the canine CD34+/CD45^dim cells expressed candidate cell surface antigens necessary to define the canine haematopoietic hierarchy roadmap. These results indicate that the canine CD34+/CD45^dim cells express the HSPC characteristics more than the other cell fractions, thereby suggesting that these cells have the potential to be used for studying haematopoietic stem cells in dogs.

Functional Impairment of Endothelial Colony Forming Cells (ECFC) in Patients with Severe Atherosclerotic Cardiovascular Disease (ASCVD)

Endothelial dysfunction is a key factor in atherosclerosis. However, the link between endothelial repair and severity of atherosclerotic cardiovascular disease (ASCVD) is unclear. This study investigates the relationship between ASCVD, markers of inflammation, and circulating endothelial progenitor cells, namely hematopoietic cells with paracrine angiogenic activity and endothelial colony forming cells (ECFC). Two hundred and forty-three subjects from the TELARTA study were classified according to the presence of clinical atherosclerotic disease. ASCVD severity was assessed by the number of involved vascular territories. Flow cytometry was used to numerate circulating progenitor cells (PC) expressing CD34 and those co-expressing CD45, CD34, and KDR. Peripheral blood mononuclear cells ex vivo culture methods were used to determine ECFC and Colony Forming Unit- endothelial cells (CFU-EC). The ECFC subpopulation was analyzed for proliferation, senescence, and vasculogenic properties. Plasma levels of IL-6 and VEGF-A were measured using Cytokine Array. Despite an increased number of circulating precursors in ASCVD patients, ASCVD impaired the colony forming capacity and the angiogenic properties of ECFC in a severity-dependent manner. Alteration of ECFC was associated with increased senescent phenotype and IL-6 levels. Our study demonstrates a decrease in ECFC repair capacity according to ASCVD severity in an inflammatory and senescence-associated secretory phenotype context.

Multicenter evaluation of the IL-3-pSTAT5 assay to assess the potency of cryopreserved stem cells from cord blood units: The BEST Collaborative study

BACKGROUND

The IL-3-pSTAT5 assay, a new, rapid, and standardized flow-cytometry-based assay may compensate for several limitations of the colony-forming unit (CFU) assay typically used for stem cell potency assessments of cord blood units (CBU). We performed an inter-laboratory evaluation of the performance of this new assay.

STUDY DESIGN AND METHODS

This Biomedical Excellence for Safer Transfusion (BEST) Collaborative multicenter, international study included 15 participants from public cord blood banks (CBBs), CBB-supporting research laboratories, and stem cell laboratories. To perform the IL-3-pSTAT5 assay, participating centers received reagents, instructions, and 10 blind CBU samples, including eight normal samples and two samples exposed to a transient warming event. We measured inter-laboratory agreement qualitatively (proportion of correctly classified samples) and quantitatively (coefficient of variation [CV], correlation coefficients, receiver operating characteristics (ROC) curve, and intraclass correlation coefficient [ICC]).

RESULTS

The qualitative agreement was 97.3% (i.e., 107/110; Fleiss' kappa = 0.835). The average CV on a per-sample basis was 11.57% among all samples, 8.99% among normal samples, and on a per-center basis was 9.42% among normal samples. In a correlation matrix that compared results across centers, the mean Pearson's correlation coefficient was 0.88 (standard deviation = 0.04). The ICC was 0.83 (95% confidence interval = 0.68-0.95). The area under the curve (AUC) from the ROC curve was 0.9974.

DISCUSSION

Excellent qualitative and quantitative agreement was exhibited across laboratories. The IL-3-pSTAT5 assay may therefore be implemented in flow cytometry laboratories to rapidly and reliably provide standardized measures of stem cell potency in CBUs.