CD34+ cell content for selecting umbilical cord blood units for cryopreservation

Total nucleated cell counts are driving clinician's choice rather than cryopreservation period: Lesson for cord blood banks

According to the increase in both the number of cryopreserved cord blood (CB) units and the cryopreservation period for each CB unit in the largest public CB bank in Korea, we are pursuing greater efficiency in CB bank management. Thus, we analyzed whether the cryopreservation period has a negative impact on the selection of CB units for CB transplantation (CBT). Until December 2019, 468 CB units were used for transplantation. The cryopreservation period, total nucleated cell (TNC), and CD34+ cell counts were analyzed among the CB units according to the CBT-year and the donation year. The results showed that the cryopreservation period was increased in recent CBT-year groups. The transplanted CB units showed similar TNC counts irrespective of the donation year, and the mean TNC count was 13.9 × 108/unit. CB units cryopreserved for a relatively long period were transplanted consistently. The mean TNC count of CB units cryopreserved for over 10 years was 16.4 × 108/unit. The mean CD34+ cell counts were not significantly different among the CB units transplanted after CBT-2013 and among the CB units donated after CBT-2011. Through an analysis of the CB units selected by clinicians for CBT, this study revealed that clinicians placed more weight on the TNC counts than on the cryopreservation period of cryopreserved CB units. Therefore, the minimum TNC count of CB units suitable for cryopreservation should be increased up to 13.0 × 108/unit to balance the satisfaction of clinicians' needs with the efficiency of the CB bank.

Current Advances in Red Blood Cell Generation Using Stem Cells from Diverse Sources

Blood transfusions hold an indispensable part in the modern healthcare system. Up to date, the blood supply is largely dependent on donations. Unfortunately, collecting the clinical-grade blood products has become a challenging mission due to accelerated population aging, which not only increases the need for blood transfusions but also decreases the number of healthy donors. Moreover, individuals with severe hematological abnormalities or rare blood phenotypes need alternative therapeutic approaches instead of conventional blood transfusion. In these aspects, the concept of in vitro/ex vivo production of blood cells has been emerging and many attempts have been focused on manufacturing mature erythrocytes, so-called red blood cells (RBCs), the most common and important component among the blood derivatives. In this review, we provide a general overview regarding the current strategies for generating RBCs from various stem cell sources including pluripotent stem cells (PSCs) as well as circulating blood stem cells and the remaining challenges that must be overcome prior to their practical application.

Concise review: stem cell-based approaches to red blood cell production for transfusion

Blood transfusion is a common procedure in modern medicine, and it is practiced throughout the world; however, many countries report a less than sufficient blood supply. Even in developed countries where the supply is currently adequate, projected demographics predict an insufficient supply as early as 2050. The blood supply is also strained during occasional widespread disasters and crises. Transfusion of blood components such as red blood cells (RBCs), platelets, or neutrophils is increasingly used from the same blood unit for multiple purposes and to reduce alloimmune responses. Even for RBCs and platelets lacking nuclei and many antigenic cell-surface molecules, alloimmunity could occur, especially in patients with chronic transfusion requirements. Once alloimmunization occurs, such patients require RBCs from donors with a different blood group antigen combination, making it a challenge to find donors after every successive episode of alloimmunization. Alternative blood substitutes such as synthetic oxygen carriers have so far proven unsuccessful. In this review, we focus on current research and technologies that permit RBC production ex vivo from hematopoietic stem cells, pluripotent stem cells, and immortalized erythroid precursors.

Toward personalized cell therapies by using stem cells: seven relevant topics for safety and success in stem cell therapy

Stem cells, both embryonic and adult, due to the potential for application in tissue regeneration have been the target of interest to the world scientific community. In fact, stem cells can be considered revolutionary in the field of medicine, especially in the treatment of a wide range of human diseases. However, caution is needed in the clinical application of such cells and this is an issue that demands more studies. This paper will discuss some controversial issues of importance for achieving cell therapy safety and success. Particularly, the following aspects of stem cell biology will be presented: methods for stem cells culture, teratogenic or tumorigenic potential, cellular dose, proliferation, senescence, karyotyping, and immunosuppressive activity.

Acute maternal cytomegalovirus infection is associated with significantly decreased numbers of CD34+ cells in umbilical cord blood

OBJECTIVE AND BACKGROUND

There is little information regarding the serologic status of umbilical cord blood (UCB) donors. Cytomegalovirus (CMV) is the most frequent agent transmitted by blood products and studies have reported that CMV can inhibit myelopoiesis, however, its effects on the cellular content of UCB have not been documented.

STUDY DESIGN AND METHODS

We investigated, retrospectively, the prevalence of serological evidence of infection in 857 women donating their UCB at a public university hospital and studied the influence of acute CMV exposure on UCB content of CD34+ cells. The biological characteristics of UCB from serology positive-donors were compared with those of women with negative tests.

RESULTS

We found that 51 of 857 (6%) UCB units were positive for infectious disease markers; anti-CMV IgM was the most prevalent marker, 43 of 51 (86%) of cases with infectious markers. UCB collected from anti-CMV IgM-positive donors more frequently met rejection criteria for use as a transplanation product. The CD34+ cell count was the most often affected, 2.48×10(6) in anti-CMV IgM-positive donors compared to 1.48×10(6) in unaffecetd donors( p=0.006). The probability of a UCB meeting a CD34+ cell content≥2×10(6) was significantly lower in units from IgM anti-CMV+ women compared to unaffecetd donors [Odds ratio (OR)=0.428 (95% CI 0.182-0.632; p=0.015]; the total nucleated cell count (TNC) was lower but not statistically significant [p=0.068].

CONCLUSION

UCB donated by anti-CMV IgM-positive women has a high probability of not meeting the criteria required for cryopreservation for future use as a transplantation product, because of the low number of CD34+ cells.

Evaluation of volume and total nucleated cell count as cord blood selection parameters: a receiver operating characteristic curve modeling approach

The objective of the study was to evaluate the current standard practice of using volume and total nucleated cell (TNC) count for the selection of cord blood (CB) units for cryopreservation and further transplantation. Data on 794 CB units whose CD34+ cell content was determined by flow cytometry were analyzed by using a receiver operating characteristic (ROC) curve model to validate the performance of volume and TNC count for the selection of CB units with grafting purposes. The TNC count was the best parameter to identify CB units having 2 × 10(6) or more CD34+ cells, with an area under the ROC curve of 0.828 (95% confidence interval, 0.800-0.856; P < .01) and an efficiency of 75.4%. Combination of parameters (TNC/mononuclear cells [MNCs], efficiency 74.7%; TNC/volume, efficiency 68.9%; and volume/MNCs, efficiency 68.3%) did not lead to improvement in CB selection. All CB units having a TNC count of 8 × 10(8) or more had the required CD34+ cell dose for patients weighing 10 kg or less.

Evaluation of Quality Parameters for Cord Blood Donations

SUMMARY: BACKGROUND: Umbilical cord blood (CB) is widely used for hematopoietic stem cell transplantation and holds promise for the development of innovative medicinal products. In order to find out whether the conditions for collection and storage before processing might have an impact on the quality of CB preparations, viability and the clonogenic potential were assessed. METHODS: CB was collected under field conditions. Flow cytometry was used to determine leukocytes, CD34/CD45+ cells, viability, and nucleated red blood cells (NRBC). Clonogenic activity was determined using isolated mononuclear cells (MNC). RESULTS: Neither plasma citrate concentrations nor storage temperature (within 24 h) affected cell viability or colony formation. After storage for 49-80 h, leukocyte viability declined by about 16% compared to CB stored up to 24 h. In contrast, the clonogenic activity and CD34/CD45+ cell content were not affected. A higher gestational age was associated with a lower yield of clonogenic activity compared to midterm deliveries. NRBC varied widely (median 7.3%; range 0.63-17.3%) without relation to gestational age or colony formation. There was a close correlation between the percentage of viable CD34/CD45+ cells and colony formation (r = 0.77 for CFU-GM; r = 0.75 for CFU-C). CONCLUSIONS: The content of viable CD34/CD45+ cells represents the clonogenic activity of CB preparations. Therefore, determination of viable CD34/CD45+ cells should be generally performed as a routine quality control assay.