The value of immunohistochemical expression of SOX9 and CD34 in alopecia areata.

BACKGROUND: Alopecia areata (AA), an immune-mediated disorder, is marked by temporary, nonscarring hair loss. The bulge area is protected from immune attacks by immune privilege; however, recent studies demonstrated immune cells infiltrating the bulge area. OBJECTIVE: This study aims to investigate the immunohistochemical expression of the sex-determining region Y-box 9 (SOX9) and cluster of differentiation 34 (CD34) in AA patients as markers of hair follicle stem cells (HFSCs) and progenitor cells, respectively. METHODS: Immunohistochemical staining of SOX9 and CD34 was applied on skin samples of 20 AA patients and 20 healthy controls. RESULTS: SOX9 and CD34 were significantly lower in lesional samples of cases compared to perilesional and control skin biopsies. Furthermore, SOX9 level was negatively correlated with the severity of alopecia tool score (SALT score) among the studied AA patients. Moreover, lowered SOX9 expression was present in patients with recurrent attacks. CONCLUSIONS: The significant reduction of stem cell markers (SOX9 and CD34) in our studied AA cases signifies the pathological affection of HFSCs and their progeny in AA. This is thought to cause a loss of competence in generating new hair in some AA cases, which needs to be validated in further research. LIMITATIONS OF THE STUDY: This study has a small sample size.

CD34+ cell yield among healthy donors: Large-scale model development and validation.

BACKGROUND: Successful engraftment in hematopoietic stem cell transplantation necessitates the collection of an adequate dose of CD34+ cells. Thus, the precise estimation of CD34+ cells harvested via apheresis is critical. Current CD34+ cell yield prediction models have limited reproducibility. This study aims to develop a more reliable and universally applicable model by utilizing a large dataset, enhancing yield predictions, optimizing the collection process, and improving clinical outcomes. MATERIALS AND METHODS: A secondary analysis was conducted using the Center for International Blood and Marrow Transplant Research database, involving data from over 17 000 healthy donors who underwent filgrastim-mobilized hematopoietic progenitor cell apheresis. Linear regression, gradient boosting regressor, and logistic regression classification models were employed to predict CD34+ cell yield. RESULTS: Key predictors identified include pre-apheresis CD34+ cell count, weight, age, sex, and blood volume processed. The linear regression model achieved a coefficient of determination (R2) value of 0.66 and a correlation coefficient (r) of 0.81. The gradient boosting regressor model demonstrated marginally improved results with an R2 value of 0.67 and an r value of 0.82. The logistic regression classification model achieved a predictive accuracy of 96% at the 200 × 106 CD34+ cell count threshold. At thresholds of 400, 600, 800, and 1000 × 106 CD34+ cell count, the accuracies were 88%, 83%, 83%, and 88%, respectively. The model demonstrated a high area under the receiver operator curve scores ranging from 0.90 to 0.93. CONCLUSION: This study introduces advanced predictive models for estimating CD34+ cell yield, with the logistic regression classification model demonstrating remarkable accuracy and practical utility.

Personalized autologous stem cell harvesting improves patient collection outcomes.

OBJECTIVES: This study aims to demonstrate that utilizing a personalized approach to apheresis stem cell collection, can safely optimize the collection outcomes, especially in the context of poor mobilizers and high cell targets. BACKGROUND: The optimal mobilization and harvesting of peripheral blood stem cells is critical to the success of the stem cell transplant. The ideal strategy that promotes better cell yields, with sustainable use of resources and assuring patient safety, should be pursued. METHODS: PBSC collections for autologous stem cell transplant data according to a fixed-processed volume strategy (One Size Fits All) or individualized to patients CD34+ peripheral blood content and target approach (Custom-Tailored or CT) were retrospectively compared. RESULTS: A total of 263 collections from 142 patients were assessed. The majority of patients were male, had multiple myeloma and were mobilized with isolated G-CSF. The CT strategy promoted a significantly higher CD34+ cell yield when the pre-collection CD34 was lower than 20/µl (1.02 ± 0.16 versus 1.36 ± 0.23, p < 0.001) and also a decrease in the proportion of mobilization cycles that needed 3 apheresis (31% versus 14%, p = 0.02). There was no difference in apheresis-related adverse events between the groups. CONCLUSION: Tailoring the apheresis procedures to the patient-specific characteristics and objectives, can effectively promote better patient outcome.

MDS and AML show elevated fractions of CD34-positive blast cell populations with a high anti-apoptotic versus proliferation ratio.

This study investigates the intertwined processes of (anti-)apoptosis and cell proliferation in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Utilizing antibodies to Bcl-2 and Ki-67, the CD34-positive blast cell compartments in bone marrow aspirates from 50 non-malignant cases, 25 MDS patients, and 25 AML patients were analyzed for their anti-apoptotic and proliferative cell fractions through ten-color flow cytometry. MDS patients exhibited a significantly increased anti-apoptotic (p=0.0014) and reduced proliferative cell fraction (p=0.0030) in their blast cell population as compared to non-malignant cases. AML patients showed an even more exacerbated trend than MDS patients. The resulting Bcl-2:Ki-67 cell fraction ratios in MDS and AML were significantly increased as compared to the non-malignant cases (p=0.0004 and p<0.0001, respectively). AML patients displayed, however, a high degree of variability in their anti-apoptotic and proliferation index, attributed to heterogeneity in maturation stage and severity of the disease at diagnosis. Using double-labeling for Bcl-2 and Ki-67 it could be shown that besides blast cells with a mutually exclusive Ki-67 and Bcl-2 expression, also blast cells concurrently exhibiting anti-apoptotic and proliferative marker expression were found. Integrating these two dynamic markers into MDS and AML diagnostic workups may enable informed conclusions about their biological behavior, facilitating individualized therapy decisions for patients.

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.

Donor Lymphocyte Infusion (DLI) post allogeneic stem cell transplant (allo-SCT) in Acute Myeloid Leukemia (AML) and High-Grade Myelodysplastic Syndrome (MDS). A longitudinal retrospective study using peripheral blood (PB) CD34+ and CD3+ donor chimerism (DC) monitoring.

INTRODUCTION: This longitudinal study was based on the outcomes of Donor Lymphocyte Infusion (DLI) for falling peripheral blood (PB) CD34+ and CD3+ donor chimerism (DC). METHODS: From 2012 to 2018, data was collected from the BMT database and electronic medical records (EMR). The primary objective was to compare the indication for DLI based on falling PB CD34+ or CD3+ DC in patients post allo-SCT for AML and MDS and their overall survival (OS). RESULTS: 18/70 patients met the inclusion criteria. Indications for DLI were i) falling PB CD34+ DC ≤ 80 % with morphological relapse, ii) falling PB CD34+ DC ≤ 80 % without morphological relapse and iii) falling PB CD3+ DC ≤ 80 % without falling PB CD34+ DC. Log rank analysis showed falling PB CD34+ DC and morphological relapse had significantly lower OS. Linear regression demonstrated better OS post DLI if there was PB CD34+ and CD3+ chimerism response at 30 days (p = 0.029), GVHD (p = 0.032) and tapering immunosuppression at the time of falling DC (p = 0.042). CONCLUSION: DLI for PB CD34+ DC values ≤ 80 % and morphological relapse had the lowest OS. In this study, full DC was achieved after DLI even with a PB CD3+DC value as low as 13 %, provided the PB CD34+ DC remained > 80 %. Further research is vital in CD34+ DC as a biomarker for disease relapse and loss of engraftment.

Nail Telocytes: Identification, Potential Physiological Function, and Role in Pathology: A Reappraisal of the So-Called Onychofibroblasts/Onychodermis.

ABSTRACT: Some authors have suggested that the fibroblasts of the nail mesenchyme (onychofibroblasts) can be distinguished from skin fibroblasts by their high expression of CD10. My 2015 study documented the presence of a relatively sparse CD34 + /CD10 + dendritic subpopulation in the dermis and hypodermis of the matrix. For some time now, my hypothesis has been that these interstitial dendritic mesenchymal cells of the matrix correspond to telocytes. Telocytes have been described as peculiar interstitial dendritic cells present in the mesenchymal tissue of numerous organs, including the skin, but their presence and characteristics in the nail unit have not been explored. This study was undertaken to more comprehensively investigate the existence and characteristics of nail telocytes. A series of 20 normal adult nail units were examined with a combination of morphological and immunohistochemical analyses. The matrix dermis contained a sparse subpopulation of CD34 + /CD10 + elongated telocytes with a higher density in the lunular region and, at this distal level, a change in their immunohistochemical profile, resulting in a progressive loss of CD34 expression. The matrix hypodermis showed CD34 + /CD10 + telocytes in their classical elongated aspect, which acquired, especially in the distal fibromyxoid area of the thumb, an oval to round morphology with multiple intracytoplasmic vacuoles. The characteristic dynamic immunophenotypic profile of the dermal telocytes with a progressive distal loss of the defining molecule CD34 was equally observed in the distal hypodermis. The nail bed dermis was thick with a dense fibrous connective tissue. A reticular network of CD34 - /CD10 + telocytes was present in the superficial dermis of the proximal nail bed. The mesenchymal cells of the deep part of the proximal nail bed dermis and the entire distal nail bed dermis were CD34 - /CD10 - . The adult nail mesenchyme is composed of 3 microanatomically distinct regions. Only the thumb has a distal hypodermis rich in mucinous material. The population of telocytes is relatively sparse compared with the fibroblastic population of the entire nail mesenchyme. The concept of onychodermis/onychofibroblasts is not valid. Nail telocytes have a dynamic immunohistochemical profile depending on whether they are located proximally or distally. The CD34 + /CD10 + profile correlates with the onychogenic epithelial region, while the CD34 - /CD10 + profile correlates with a spatial rearrangement of the nail epidermal bed.

Visualization of intradermal blood vessel structures by dual-wavelength photoacoustic microscopy and characterization of three-dimensional construction of livedo-racemosa in cutaneous polyarteritis nodosa.

BACKGROUND: Photoacoustic microscopy is expected to have clinical applications as a noninvasive and three-dimensional (3D) method of observing intradermal structures. OBJECTIVE: Investigate the applicability of a photoacoustic microscope equipped with two types of pulsed lasers that can simultaneously recognize hemoglobin and melanin. METHODS: 16 skin lesions including erythema, pigmented lesions, vitiligo and purpura, were analyzed to visualize 3D structure of melanin granule distribution and dermal blood vessels. 13 cases of livedo racemosa in cutaneous polyarteritis nodosa (cPN) were further analyzed to visualize the 3D structure of dermal blood vessels in detail. Vascular structure was also analyzed in the biopsy specimens obtained from tender indurated erythema of cPN by CD34 immunostaining. RESULTS: Hemoglobin-recognition signal clearly visualized the 3D structure of dermal blood vessels and melanin-recognition signal was consistently reduced in vitiligo. In livedo racemosa, the hemoglobin-recognition signal revealed a relatively thick and large reticular structure in the deeper layers that became denser and finer toward the upper layers. The numerical analysis revealed that the number of dermal blood vessels was 1.29-fold higher (p<0.05) in the deeper region of the lesion than that of normal skin. The CD34 immunohistochemical analysis in tender indurated erythema revealed an increased number of dermal vessels compared with normal skin in 88.9% (8/9) of the cases, suggesting that vascular network remodeling had occurred in cPN. CONCLUSION: The photoacoustic system has an advantage in noninvasively detecting dermal blood vessel structures that are difficult to recognize by two-dimensional histopathology specimen examination and is worth evaluating in various skin diseases.

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.

Solitary fibrous tumor occurring in the colon as submucosal mesenchymal lesion: report of two cases and review of the literature.

Solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm most often arising from the pleura and rarely in extra-pleural locations, including the gastrointestinal tract. We describe two cases of a SFT presenting as submucosal colonic lesion and review the literature on this lesion. One submucosal lesion was localized in the cecum and was 10 mm in size. The second lesion presented as a 17 mm submucosal rectal lesion. Both lesions presented as well-circumscribed submucosal lesions arranged in short fascicles, blending with abundant collagenous stroma. In both cases, the spindle cells were positive for CD34, STAT6 and CD99, and molecular studies showed NAB2:STAT6 fusion supporting the diagnosis of SFT. Both patients are alive and well 10 and 5 years post-excision, respectively. In conclusion, SFT can occur in the colon as a submucosal lesion and should be included in the differential diagnosis of colonic mesenchymal lesions.

Evaluation of the histologic and immunohistochemical (CD34, glutamine synthetase) findings in idiopathic non-cirrhotic portal hypertension (INCPH).

AIM: Idiopathic non-cirrhotic portal hypertension (INCPH) is a vascular disorder of uncertain origin. Diagnosis can be challenging on liver biopsy. Despite diverse histomorphologic findings documented in literature, studies on the frequency of these findings are lacking. This study aims to assess both the histomorphologic features and the immunoexpression patterns of CD34 and glutamine synthetase (GS) in liver biopsies and searched for their contribution to the pathologic diagnosis of INCPH. MATERIALS AND METHODS: Hematoxylin-eosin, CD34, and GS-stained liver needle biopsy sections of 16 patients clinically diagnosed with INCPH were retrospectively analyzed. Histologic findings such as portal vein narrowing, obliteration, or loss were grouped as major findings, while portal vein herniation, hypervascularized portal tracts, and periportal abnormal vessels were grouped as minor findings, and their frequency were evaluated. Periportal endothelial CD34 stained areas were measured via ocular micrometer. The distribution of GS immunoexpression was evaluated. Eighteen healthy liver donor biopsies were evaluated as controls. RESULTS: In INCPH cases, 58% of portal tracts showed major findings, compared to 15% in the control group (p < 0.001). Minor findings were observed in 16% of INCPH cases and 7% of controls (p = 0.014). The number of portal tracts with histologic findings is significantly higher in INCPH than in control liver biopsies. Abnormal portal tract distribution, like being close to each other, was seen in 75% of INCPH cases but not in controls (p < 0.001). Nodular regenerative hyperplasia (NRH) was present in 31% of cases. Periportal CD34 expression was higher in INCPH, and affected areas were larger than in controls (p < 0.001). Irregular GS staining, i.e. GS staining with patchy distribution in zone 3, and/or periportal and zone 2 hepatocytes, was found in 62% of INCPH cases, while controls showed the usual pattern (p < 0.001). CONCLUSION: In the biopsy diagnosis of INCPH, in addition to the presence of major histologic findings and the amount of portal tracts displaying these features, the expression of endothelial CD34 in periportal areas, and irregular hepatocellular GS expression can also be considered as supporting feature.

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.

A case of superficial CD34 positive fibroblastic tumor: Diagnostic challenges and pitfalls.

ABSTRACT: Superficial CD34 positive fibroblastic tumor (SCPFT) is a recently described soft tissue tumor of intermediate grade with predilection for subcutaneous and superficial fascial planes. Morphological diagnosis of these tumors can be challenging because of overlapping features with other benign and malignant soft tissue tumors of fibroblastic and myofibroblastic origin. A middle-aged man came with a subcutaneous mass in the left thigh. Microscopic examination showed features of an SCPFT comprised of a circumscribed spindle cell tumor with focal striking pleomorphism and bizarre hyperchromatic nuclei. Immunohistochemically (IHC), the tumor cells showed diffuse positivity for CD34 and focally for cytokeratin. Diagnosis of SCPFT on the basis of morphology alone can be challenging. A constellation of clinicoradiological profiles, IHC features, and sometimes molecular studies clinch the definitive diagnosis which can be helpful in avoiding overtreatment and chemotherapy. Here we highlight the diagnostic challenges and pitfalls in a case of SCPFT.

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.

Generation of human ILC3 from allogeneic and autologous CD34+ hematopoietic progenitors toward adoptive transfer.

Type 3 innate lymphoid cells (ILC3) are important in tissue homeostasis. In the gut, ILC3 repair damaged epithelium and suppress inflammation. In allogeneic hematopoietic cell transplantation (HCT), ILC3 protect against graft-versus-host disease (GvHD), most likely by restoring tissue damage and preventing inflammation. We hypothesize that supplementing HCT grafts with interleukin-22 (IL-22)-producing ILC3 may prevent acute GvHD. We therefore explored ex vivo generation of human IL-22-producing ILC3 from hematopoietic stem and progenitor cells (HSPC) obtained from adult, neonatal and fetal sources. We established a stroma-free system culturing human cord blood-derived CD34+ HSPC with successive cytokine mixes for 5 weeks. We analyzed the presence of phenotypically defined ILC, their viability, proliferation and IL-22 production (after stimulation) by flow cytometry and enzyme-linked immunosorbent assay (ELISA). We found that the addition of recombinant human IL-15 and the enhancer of zeste homolog 1/2 inhibitor UNC1999 promoted ILC3 generation. Similar results were demonstrated when UNC1999 was added to CD34+ HSPC derived from healthy adult granulocyte colony-stimulating factor mobilized peripheral blood and bone marrow, but not fetal liver. UNC1999 did not negatively impact IL-22 production in any of the HSPC sources. Finally, we observed that autologous HSPC mobilized from the blood of adults with hematological malignancies also developed into ILC3, albeit with a significantly lower capacity. Together, we developed a stroma-free protocol to generate large quantities of IL-22-producing ILC3 from healthy adult human HSPC that can be applied for adoptive transfer to prevent GvHD after allogeneic HCT.

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.

Use of subgroup-specific hematopoietic stem cell collection efficiencies to improve truncation calculations for large-volume leukapheresis procedures.

PURPOSE: A critical component of optimizing peripheral blood (PB) hematopoietic stem cell (HSC) collections is accurately determining the processed blood volume required to collect the targeted number of HSCs. Fundamental to most truncation equations employed to determine this volume is the procedure's estimated collection efficiency (CE), which is typically applied uniformly across all HSC collections. Few studies have explored the utility of using different CEs in subpopulations of donors that have substantially different CEs than the institutional average. METHODS: Initial procedures from 343 autologous and 179 allogeneic HSC collections performed from 2018 to 2021 were retrospectively analyzed. Predictive equations were developed to determine theoretical truncation rates in various donor subgroups. RESULTS: Quantitative variables (pre-procedure cell counts) and qualitative variables (relatedness to recipient, gender, method of venous access, and mobilization strategy) were found to significantly impact CE. However, much of the variability in CE between donors could not be explained by the variables assessed. Analyses of procedures with high pre-collection PB cell counts identified lower CE values for these donors' truncation equations which still allow truncation but minimize risk of collecting less CD34+ cells than requested. CONCLUSIONS: Individualized CE does not substantially improve truncation volume calculations over use of a fixed CE and adds complexity to these calculations. The optimal fixed CE varies between autologous and allogeneic donors, and donors with high pre-collection PB cell counts in either of these groups. This model will be clinically validated and continuously refined through analysis of future HSC collections.

Stem cell mobilizating effect of heparin in patients undergoing autologous stem cell transplantation.

BACKGROUND: Adequate stem cell collection is essential for successful stem cell transplantation. Heparin enhances stem cell mobilization by competing with heparin sulfate proteoglycans. Heparin is also used as an anticoagulant before leukapheresis. Here, we evaluated the effects of heparin on stem cell mobilization in patients who underwent autologous stem cell transplantation (ASCT). METHODS: We evaluated patients who underwent ASCT. Patients were divided into two groups: those who received heparin plus citrate (heparinized patients) and those who received citrate only (nonheparinized patients) for anticoagulation. Univariate and multivariate analyses were also performed. The collection efficiency 2 (CE2) for CD34+ cells was calculated and compared between heparinized and nonheparinized patients. RESULTS: This study included 1017 patients. There were 478 (47%) heparinized and 539 (53%) nonheparinized patients. The number of collected CD34+ cells was significantly higher in heparinized patients (P < .00001). The multivariate analyses showed that using heparin was an independent positive factor for collected CD34+ cells (adj-R2 = 0.744; F = 369.331, P < .00001). CE2 was significantly higher in heparinized patients than in nonheparinized patients (66.8% vs 52.1%; P < .00001). The rate of collecting at least 2 × 106 /kg CD34+ cells was 3.3 times higher for heparinized patients in poor mobilizers (P < .00001). Heparinized patients had significantly higher total nucleated and mononuclear cell counts (P < .00001 and <.00001, respectively). CONCLUSION: Heparin enhances stem cell collection and increases CE2. The use of heparin may reduce the need for other strategies to increase stem cell mobilization.

Determination of the relationship between CD34+ stem cell amount and DMSO in hematopoetic stem cell transplantation.

It is important to calculate the CD34+ stem cell (SC) count at the right time in patients with hematological malignancies who will undergo Hematopoietic Stem Cell Transplantation (HSCT). The amount of SC infused into the patient affects the engraftment time and healing process of the patient. In this study, we aimed to compare which of the DMSO-not removed and DMSO-removed samples showed the CD34 + SC amount more accurately as the SC amount determination method after the SC was dissolved after cryopreservation in patients who will undergo HSCT. A total of 22 patients were included in the study. All 22 patients were transplanted from frozen samples using DMSO. After the SC products were dissolved in a 37 °C water bath, they were washed 2 times and the amount of CD34+ SC was studied from the samples taken by removing DMSO and without removing DMSO. In the findings, the amounts of CD34+ SC studied with both methods were compared. The increase in the number and percentage of CD34+ SC after DMSO-removed was found to be statistically significant both in terms of difference and proportionally, and the calculated effect sizes also showed that the increase was clinically significant (Cohen's d is between 0.43 and 0.677). After thawing the frozen SCs of the patients who will undergo HSCT, the analysis of CD34+ SCs from which DMSO is removed provides a more accurate calculation of the CD34+ SC amount in the AP.