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.

Mixed Infection with Plasmodium falciparum and Plasmodium ovale in a Returned Traveller: the First Case in Korea.

Mixed-species malaria infections are often unrecognized or underestimated. We hereby report the first described case of mixed infection with Plasmodium falciparum and Plasmodium ovale malaria in a returned traveller in Korea. In August 2016, a 25-year-old returned traveller from Cameroon and Democratic Republic of Congo presented with fever. He was diagnosed as P. falciparum malaria and successfully treated with artesunate. And 5 weeks after the completion of treatment, he presented with fever and diagnosed as P. ovale infection. P. ovale infection is a rare cause of malaria and often shows delayed presentation due to its dormant liver stage as hypnozoites. At re-presentation, the immunochromatographic test and microscopic examinations of our patient did not reveal P. ovale, which was only detected via polymerase chain reaction (PCR) assay. This case highlights the importance of considering malaria infection even in persons who have previously received malaria treatment. It also shows the usefulness of PCR testing for diagnosing P. ovale infections, which often present with a low level of parasitaemia.

Plasma CC-chemokine ligand 28 level is correlated with hematopoietic stem cells in human cord blood.

BACKGROUND: CC-chemokine ligand 28 (CCL28) was previously identified as a novel growth factor in vitro for hematopoietic stem cells (HSCs) from cord blood (CB). However, there is no report on the relationship between CCL28 and HSCs in a human body. STUDY DESIGN AND METHODS: To reveal the effect of CCL28 on hematopoietic cells in human CB at birth, we measured CCL28 in frozen CB plasma, which was preserved as a reference sample for cryopreserved CB units for HSC transplantation. We also evaluated the correlation of CCL28 level with CB components. RESULTS: A total of 81 cryopreserved nonconforming CB units for transplantation were selected. The level of CCL28 was 2540 ± 377 pg/mL. The CCL28 levels correlated with the number of CD34+ cells (r = 0.222, p = 0.047) and white blood cells (r = 0.254, p = 0.022) in the CB units. The CCL28 levels also correlated with hemoglobin levels (r = 0.221, p = 0.048) in fresh CB. CONCLUSION: This finding of positive correlation between CCL28 level and CD34+ cell numbers in vivo, together with the previous report that CCL28 influences the proliferation of hematopoietic cells in CB in vitro, may give a clue for better understanding the variability in HSC content in CB that is cryopreserved for HSC transplantation.

Comparison of xTAG respiratory virus panel and Verigene Respiratory Virus Plus for detecting influenza virus and respiratory syncytial virus.

BACKGROUND: Nucleic acid amplification tests have allowed simultaneous detection of multiple respiratory viruses. METHODS: We compared the results of a liquid bead array xTAG Respiratory Virus Panel (RVP; (Luminex Corporation, Toronto, Canada) and a solid microarray Verigene Respiratory Virus Plus (RV+; Nanosphere, Northbrook, IL) for the detection of influenza A virus (INF A), influenza B virus (INF B), and respiratory syncytial virus (RSV) in 170 respiratory specimens from hospitalized patients. RESULTS: Overall, xTAG RVP demonstrated sensitivities and specificities of 97.6 and 100% for INF A, 100 and 99.4% for INF B, and 100 and 100% for RSV, while the Verigene RV+ test sensitivities and specificities were 95.1 and 98.5%, 100.0 and 99.4%, and 97.1 and 100%, respectively. There were no significant differences in the area under the curves between the two assays for each virus (P = 0.364 for INF A, P = 1.000 for INF B, P = 0.317 for RSV). Comparing the results of two assays, discordant results were present mostly due to subtype assignments and identification of coinfections. The detection of viruses was not significantly different (P = 1.000) and the virus/subtype assignment showed good agreement with kappa coefficients of 0.908. CONCLUSION: The xTAG RVP and Verigene RV+ showed high sensitivities and specificities, and good overall agreement in detection and identification of INF and RSV. These assays can be used in clinical settings for a reliable detection of respiratory viruses found commonly in hospitalized patients.

Aldehyde dehydrogenase-bright cells correlated with the colony-forming unit-granulocyte-macrophage assay of thawed cord blood units.

BACKGROUND: The number of aldehyde dehydrogenase-bright (ALDH(br) ) cells has been suggested as a viable marker of hematopoietic stem cell function. We evaluated the suitability of ALDH(br) cell analysis in the quality assessment of postthaw cord blood (CB) units. STUDY DESIGN AND METHODS: A total of 245 CB units were obtained for estimating the numbers of total nucleated cells (TNCs), CD34+ cells, ALDH(br) cells, ALDH(br) cells among CD34+ cells (CD34+ALDH(br) cells), CD34+ cells among ALDH(br) cells (ALDH(br) CD34+ cells), colony-forming unit (CFU)-granulocyte-macrophages (GMs), and CFU-granulocyte-erythrocyte-macrophage-megakaryocytes (GEMMs). Simple linear regression analysis was performed to assess the correlation between the number of TNCs and CD34+ cells before and after crypreservation and CD34+ALDH(br) cells, ALDH(br) cells, and ALDH(br) CD34+ cells after cryopreservation and the number of CFU-GEMMS and CFU-GMs. RESULTS: The number of CFU-GMs was found to be significantly correlated with the number of CD34+ cells before and after cryopreservation (r = 0.418 and r = 0.359, respectively), CD34+ALDH(br) cells, ALDH(br) cells, and ALDH(br) CD34+ cells (r = 0.426, r = 0.455, and r = 0.469, respectively). The number of CFU-GEMMs was found to be significantly correlated with the number of TNCs and CD34+ cells before and after cryopreservation (TNCs, r = 0.251 and r = 0.250, respectively; CD34+ cells, r = 0.391 and r = 0.347, respectively), CD34+ALDH(br) cells, ALDH(br) cells, and ALDH(br) CD34+ cells (r = 0.297, r = 0.297, and r = 0.252, respectively). CONCLUSION: The high correlation found between ALDH activity and CFU-GM number supports the suitability of ALDH analysis in the quality assessment of postthaw CB units.

Proposal of standardized guidelines for the production and quality control of autologous serum eye drops in Korea: based on a nationwide survey.

BACKGROUND: Autologous serum eye drops (ASEDs) have been used to treat many eye diseases. However, there are no standardized guidelines for the production and quality control (QC) of ASEDs in Korea. Our aim was to propose standardized guidelines for the production and QC of ASEDs. STUDY DESIGN AND METHODS: We conducted a nationwide survey consisting of questions regarding the methods used in each hospital for the production and QC of ASEDs. The survey was sent by e-mail to 89 doctors responsible for the blood banks at different hospitals. RESULTS: Thirty-two hospitals replied, and 13 hospitals reported using the ASEDs in the treatment of patients with eye diseases. The screening test for patients, amount of blood sampling, type of bottle used for blood collection, details about the production of the eye drops, and storage methods and shelf life of unopened and opened bottles of eye drops varied between hospitals. CONCLUSION: Based on an analysis of the survey results and a review of the standard operating procedures and protocols for ASEDs used in Japan, Germany, England and Wales, and the United States, we proposed standardized guidelines for the production and QC of ASEDs in Korea. ASEDs are not cell therapy products in the strictest sense. However, because eye drops are composed of serum isolated from blood and are used in patients, we consider ASEDs to be the basis for cell therapy products. Therefore, ASEDs should be produced and stored according to standardized guidelines based on the Good Manufacturing Practice guidelines.

Identification of the novel HLA-DQA1*05:75 allele by next-generation sequencing in a Korean cord blood donor.

HLA-DQA1*05:75 differs from DQA1*05:05:01:01 by a single substitution at nucleotide 701 (G/A) in exon 4.

Increased numbers of total nucleated and CD34+ cells in blood group O cord blood: an analysis of neonatal innate factors in the Korean population.

BACKGROUND: We analyzed neonatal factors that could affect hematopoietic variables of cord blood (CB) donated from Korean neonates. STUDY DESIGN AND METHODS: The numbers of total nucleated cells (TNCs), CD34+ cells, and CD34+ cells/TNCs of CB in neonates were compared according to sex, gestational age, birth weight, birth weight centile for gestational age, and ABO blood group. RESULTS: With 11,098 CB units analyzed, blood group O CB showed an increased number of TNCs, CD34+ cells, and CD34+ cells/TNCs compared with other blood groups. Although TNC counts were lower in males, no difference in the number of CD34+ cells was demonstrated because the number of CD34+ cells/TNCs was higher in males. An increase in the gestational age resulted in an increase in the number of TNCs and decreases in the number of CD34+ cells and CD34+ cells/TNCs. The numbers of TNCs, CD34+ cells, and CD34+ cells/TNCs increased according to increased birth weight centile as well as birth weight. CONCLUSION: CB with blood group O has unique hematologic variables in this large-scale analysis of Korean neonates, although the impact on the storage policies of CB banks or the clinical outcome of transplantation remains to be determined.

Predictors of Red Blood Cell Transfusion in Elderly COVID-19 Patients in Korea.

Background: Patients who experience clinical deterioration from coronavirus disease (COVID-19) require blood transfusion support. We analyzed blood component usage in COVID-19 patients and identified the predictors of red blood cell (RBC) transfusion in elderly (≥65 years) patients. Methods: Blood component usage in 882 COVID-19 patients hospitalized between January 24, 2020 and April 30, 2021 was analyzed. Elderly patients were categorized into transfused and non-transfused groups according to their RBC transfusion history; their demographic and clinical characteristics, disease severity, and outcomes were compared. Associations were determined using multiple logistic regression. Results: The overall transfusion rate was 8.3% (73/882), and the transfusion rate was 2.7% (14/524) in patients aged <65 years and 16.5% (59/358) in those aged ≥65 years. Among the 358 elderly patients, 344 patients, including 50 who received transfusion and 294 who did not, were enrolled for the analysis. The prevalence of diabetes mellitus (DM), white blood cell count, absolute neutrophil count, and neutrophil-to-lymphocyte ratio (NLR) on admission were significantly higher in the transfused group, whereas Hb and platelet counts were significantly lower. Disease severity in the transfused group was relatively high on admission and increased thereafter. DM, intensive care unit entrance on admission, Hb, platelet count, and NLR on admission were independently associated with RBC transfusion. Conclusions: This study presents transfusion rates in COVID-19 patients according to age groups and predictors of RBC transfusion in elderly patients. The results provide a basis for developing a strategy for the medical treatment of infectious diseases emerging during pandemics.

Perspectives of potential donors on cord blood and cord blood cryopreservation: a survey of highly educated, pregnant Korean women receiving active prenatal care.

BACKGROUND: The aim of the study was to investigate the knowledge of cord blood (CB) and attitudes toward CB banking among high-potential donors (i.e., well-educated pregnant Koreans) because their voluntary donation is indispensable to the success of unrelated CB transplantation. STUDY DESIGN AND METHODS: Questionnaires examining perspectives on CB were distributed to and completed by 1001 women attending a maternity education program from April to October 2008; 863 women answered that they had heard of CB. We analyzed the 863 questionnaires to identify the sources of information, the plan for CB, the reasons for decisions, beliefs about the potential uses of CB, and knowledge about current therapeutic uses. RESULTS: Most subjects received information from promotional materials distributed by CB banks and the media; however, minimal information was obtained from obstetricians. More than 90% of women who planned to donate cited "altruism," and 75.0% of the "private preservation" group indicated that a desire to "safeguard for the future" was the reason for their decision. The probability of autologous CB transplantation (p = 0.001) and current usefulness were significantly overestimated in the private preservation group (p = 0.02). In addition, 56% of subjects underestimated the probability of identifying a matched CB in the public bank, and the overall rate of correct answers about current usefulness was 57.4%. CONCLUSIONS: A considerable portion of educated pregnant Korean women has more than minimal knowledge of CB, but the levels of knowledge regarding the potency of the public bank and the current usefulness and limitations of CB are generally low; in addition, obstetricians play insignificant roles in disseminating knowledge. Providing accurate and detailed information to pregnant women not only via brochures and the media and/or Internet but also by obstetricians would encourage CB donation.

Increased Nucleated RBCs in Cord Blood: Not an Exclusion Criterion but a Quality Indicator for Hematopoietic Progenitor Cell Transplantation.

Increased nucleated red blood cell (NRBC) counts have been reported to be associated with adverse fetal outcomes, and cord blood units (CBUs) with increased NRBC counts require a 2nd questionnaire to determine their suitability for transplantation. However, a recent study demonstrated a positive correlation of NRBCs with CD34+ cells and total nucleated cells (TNCs). We evaluated the association between the NRBC count and hematopoietic progenitor cell (HPC) content (TNC and CD34+ cell counts) in Korean full-term newborn CBUs. In addition, we assessed whether an increased NRBC count is associated with newborn health problems that impair CBU safety. Among the 32,876 units processed from May 2006 to December 2018, a total of 23,385 CBUs with a TNC count ≥ 7 × 108 and reliable perinatal information were analyzed to assess the association of the NRBC count with CBU parameters, and the newborns associated with 457 CBUs that required the 2nd questionnaire due to an increased NRBC (≥ 15 NRBCs/100 WBCs) were assessed at one year for health problems that threatened CBU safety. The majority of the CBUs that required the 2nd questionnaire due to an increased NRBC count (96.9%) were determined to be suitable for transplantation. Those with an increased NRBC count showed significantly higher CD34+ cell and TNC counts and a higher rate of transplantation (P < 0.001, < 0.001 and 0.025, respectively). NRBCs showed a significant positive correlation with TNCs and CD34+ cells and a significant negative correlation with birth weight (all P < 0.001; adjusted r = 0.185, 0.369 and - 0.029, respectively). In the multiple linear regression analysis, NRBCs showed independent and positive correlations with TNCs and CD34+ cells after adjustments for birth weight and gestational age (all P < 0.001; ß = 0.182, adjusted R2 = 0.053 and ß = 0.367, adjusted R2 = 0.418). An increased NRBC count in full-term normal delivery is a surrogate marker of HPCs in CBUs rather than an exclusion criterion for CBU safety. Moreover, providing the NRBC count together with the NRBC-corrected TNC count will be useful for clinicians to select CBUs for transplantation.

Novel multiplex PCR using dual-priming oligonucleotides for detection and discrimination of the Mycobacterium tuberculosis complex and M. bovis BCG.

We developed a novel multiplex PCR assay using dual-priming oligonucleotide primers targeting the RD1 gene for simultaneous identification of the Mycobacterium tuberculosis complex and M. bovis bacillus Calmette-Guérin (BCG). This assay would be useful both for detection of the M. tuberculosis complex and for differentiation of M. bovis BCG from pathogenic M. tuberculosis complex species.

Association of HLA-A, -B and -DRB1 genotype with birthweight and CD34+ cell content: analysis of Korean newborns and their cord blood.

Birthweight and the hematopoietic progenitor cell content in cord blood affect and reflect fetal development, and MHC has been reported to play an important role in intrauterine growth. In this study, we assessed HLA-A, -B and -DRB1 polymorphisms, birthweight and cord blood CD34(+) cell content in 1628 full-term healthy neonates to identify the HLA alleles that are associated with fetal growth in Koreans. HLA-A*31, B*47, B*51, DRB1*04 showed positive association and HLA-A*03, A*24, A*30, B*07, B*52, B*58, DRB1*03 showed negative association with birthweight and/or CD34(+) cell content; additionally, there was a greater association in homozygotes than heterozygotes revealed in the trend analysis of birthweight centile with candidate allele zygosity (A*24, P= 0.018; DRB1*04, P= 0.047). Among these alleles, HLA-A*24 and DRB1*03 showed significant negative association with birthweight and/or CD34(+) cell content after Bonferroni correction, suggesting a significant association of these alleles with fetal growth in late pregnancy (A*24, P= 0.002, P(c) = 0.026; DRB1*03, P < 0.001, P(c) < 0.001). Various populations should be analyzed to identify different or consistent factors among ethnicities. Furthermore, a larger scale study that includes pre-terms will aid in the comprehensive understanding of these associations.

Genital group B Streptococcus carrier rate and serotype distribution in Korean pregnant women: implications for group B streptococcal disease in Korean neonates.

AIMS: We investigated the genital group B streptococcus (GBS) carrier rate in Korean pregnant women and the serotype distribution in face of the recent increase of late-onset GBS disease in Korea. METHODS: GBS screening was performed on 4045 healthy pregnant women at 35-37 weeks' gestation. In case of positive GBS culture, serotyping was performed by using GBS typing antisera. RESULTS: When both vaginal and anorectal culture were performed, the GBS carrier rate was 10.0% (n=121/1205), which is the highest rate ever reported in Korea. Type III was more common (36%), and type Ia (13%) and Ib (7%) were less prevalent. CONCLUSIONS: Increased maternal genital GBS carrier rate and difference in serotype distribution pattern of GBS may be related to the recent increase of late-onset GBS disease in Korea.

Antiplatelet Therapy Combinations and Thrombogenicity in Patients with Non-Valvular Atrial Fibrillation.

BACKGROUND AND OBJECTIVES: Combination antiplatelet therapy reduces the risk of ischemic stroke compared with aspirin monotherapy in non-valvular atrial fibrillation (NVAF) patients. The underlying mechanism, however, remains unclear. In addition, the association between platelet inhibition and thrombogenicity in NVAF has not been evaluated. SUBJECTS AND METHODS: We randomized 60 patients with NVAF that were taking 100 mg of aspirin daily (>1 month) to adding 75 mg of clopidogrel daily (CLPD group), 100 mg of cilostazol twice daily (CILO group), or 1000 mg of omega-3 polyunsaturated fatty acid twice daily (PUFA group). Biomarkers (von Willebrand factor antigen [vWF:Ag], fibrinogen, D-dimer, and high-sensitivity C-reactive protein [hs-CRP]) and platelet reactivity (PR), which were the levels stimulated by adenosine diphosphate (ADP), thrombin-receptor agonist peptide, collagen, and arachidonic acid, were measured at baseline and 30-day follow-up. RESULTS: Combination antiplatelet therapy significantly reduced vWF:Ag and fibrinogen levels (7.7 IU/dL, p=0.015 and 15.7 mg/dL, p=0.005, respectively), but no changes were found in D-dimer and hs-CRP levels. The CLPD and CILO groups showed fibrinogen and vWF:Ag level reductions (24.9 mg/dL, p=0.015 and 9.3 IU/dL, p=0.044, respectively), whereas the PUFA group did not show any differences in biomarkers. Irrespective of regimen, the changes in fibrinogen and vWF:Ag levels were mainly associated with the change in ADP-mediated PR (r=0.339, p=0.008 and r=0.322, p=0.012, respectively). CONCLUSION: In patients with NVAF, combination antiplatelet therapy showed reductions for vWF:Ag and fibrinogen levels, which may be associated with the inhibitory levels of ADP-mediated PR. The clinical implications of these findings need to be evaluated in future trials.

Reference Intervals of Hematology and Clinical Chemistry Analytes for 1-Year-Old Korean Children.

BACKGROUND: Reference intervals need to be established according to age. We established reference intervals of hematology and chemistry from community-based healthy 1-yr-old children and analyzed their iron status according to the feeding methods during the first six months after birth. METHODS: A total of 887 children who received a medical check-up between 2010 and 2014 at Boramae Hospital (Seoul, Korea) were enrolled. A total of 534 children (247 boys and 287 girls) were enrolled as reference individuals after the exclusion of data obtained from children with suspected iron deficiency. Hematology and clinical chemistry analytes were measured, and the reference value of each analyte was estimated by using parametric (mean±2 SD) or nonparametric methods (2.5-97.5th percentile). Iron, total iron-binding capacity, and ferritin were measured, and transferrin saturation was calculated. RESULTS: As there were no differences in the mean values between boys and girls, we established the reference intervals for 1-yr-old children regardless of sex. The analysis of serum iron status according to feeding methods during the first six months revealed higher iron, ferritin, and transferrin saturation levels in children exclusively or mainly fed formula than in children exclusively or mainly fed breast milk. CONCLUSIONS: We established reference intervals of hematology and clinical chemistry analytes from community-based healthy children at one year of age. These reference intervals will be useful for interpreting results of medical check-ups at one year of age.

Attached segment has higher CD34+ cells and CFU-GM than the main bag after thawing.

A contiguous segment attached to the cord blood unit (CBU) is required for verifying HLA types, cell viability, and, possibly, potency before transplantation since such a segment is considered to be representative of the CBU. However, little is known regarding the characteristics of contiguous segments in comparison to main bag units due to the difficulty experienced in accessing a large number of cryopreserved CBUs. In this study, we used 245 nonconforming CBUs for allogeneic transplantation. After thawing the cryopreserved CBU, the number of total nucleated cells (TNCs), CD34(+) cells, and CFUs in CB from main bags and segments, as well as cell viability and apoptosis, were examined. The comparative analysis showed that the number of TNCs was significantly higher in CB from main bags, whereas the numbers of CD34(+) cells and CFU-GM were significantly higher in CB from segments. While the cell viability of TNCs in segments was higher, the proportion of apoptotic TNCs was also higher. In contrast, no difference was observed between the proportion of apoptotic CD34(+) cells in main bags and segments. In the correlation analysis, the numbers of TNCs, CD34(+) cells, and CFU-GM in main bags were highly correlated with those in segments, indicating that CB from segments is indeed representative of CB in main bags. Taken together, we conclude that segments have higher CD34(+) cells and CFU-GM and lower TNCs than the main cryopreserved bag, although the two compartments are highly correlated with each other.

Maternal circulating dendritic cell subtypes at delivery and during the 1-year postpartum period.

PROBLEM: Dendritic cells (DCs) play an important role in maintaining pregnancy by inducing tolerance toward the fetus. Such an immunologic change in the mother should be restored to normal after delivery, but few studies have reported postpartum maternal immune recovery, in terms of the types circulating DCs. METHOD OF STUDY: The level of each DC subtype and HLA-DR-positive immunoreactivity of the blood from 29 pregnant women with uncomplicated labor was serially analyzed by flowcytometry at delivery and at 1.5, 6, and 12 months after delivery. DC subtypes were characterized as myeloid, lymphoid, and less differentiated (ldDC). Mean fluorescence intensity (MFI) was evaluated for HLA-DR expression for each DC subtype. RESULTS: The total number and the percentage of DCs at delivery were lower than those at 12 months postpartum. The ldDC fractions were significantly higher at delivery and at 1.5 months than at 12 months postpartum. The MFI of HLA-DR expression on ldDCs at delivery was lower than that at 12 months postpartum. The myeloid-to-lymphoid DC ratio did not differ over the 1-year postpartum period. CONCLUSION: The maternal alteration in DCs rapidly normalized within 1.5 months, except for the ldDC fraction, which persisted between 1.5 and 6 months after delivery.

Synergistic thrombotic risk of antibodies against phosphatidylserine and prothrombin and ß-2-glycoprotein I.

BACKGROUND: Coagulation and anticoagulation systems are good targets of antiphospholipid antibodies. We assessed the contribution of the antiphospholipid antibodies to the thrombotic risk. METHODS: Enzyme-linked immunosorbent assays on antibodies against phosphatidylserine and prothrombin (PS/PT), protein C, protein S, protein Z, and thrombomodulin were performed in 164 patients who showed positive results for lupus anticoagulant or anticardiolipin antibody. RESULTS: Anti-ß-2-glycoprotein I (ß2GPI) and anti-PS/PT were significant risk factors for thrombotic events (P < .001, P = .049). However, there was no association between antiprotein C, antiprotein S, antiprotein Z, or antithrombomodulin and thrombosis. Coexistence of anti-ß2GPI and anti-PS/PT antibodies was significantly associated with thrombotic events (P = .001). Interestingly, the absence of both anti-ß2GPI and anti-PS/PT antibodies was a significant preventive factor for thrombosis (P = .003). CONCLUSION: Our data show a lack of association of antiprotein C, antiprotein S, antiprotein Z, and antithrombomodulin antibodies with thrombosis. However, the combination of conventional anti-ß2GPI with anti-PS/PT antibody is expected to enhance the predicting power of thrombotic risk.

Quality of cord blood cryopreserved for up to 5 years.

BACKGROUND: Although cord blood (CB) is a well-known source of hematopoietic stem cells, uncertainties exist regarding the quality of cryopreserved CB. We investigated the changes in quality of CB units according to the duration of cryopreservation. METHODS: We analyzed CB units that were rejected from the Seoul Metropolitan Government Public Cord Blood Bank inventory after conventional processing, because of unsuitability for allogeneic transplantation. Two hundred CB units that were cryopreserved from 1 year to 5 years were selected. After thawing the cryopreserved CB units, the total nucleated cell (TNC) count, CD34+ cell count, number of colony-forming units (CFU), aldehyde dehydrogenase (ALDH) level, cell viability, and apoptosis were analyzed. We conducted a comparative analysis to identify the presence of statistically significant differences in the recovery rates of the TNC and CD34+ cell counts and to compare the results of ALDH level, the cell viability test, the apoptosis test, and CFU analysis among groups according to the duration of cryopreservation. RESULTS: The recovery rates of the TNC count, the CD34+ cell count, and cell viability did not differ significantly according to the duration of cryopreservation. ALDH analysis, the cell viability test, and the apoptosis test did not reveal any increasing or decreasing trend according to the duration of cryopreservation. Further, the numbers of CFU-granulocyte/macrophage and CFU-granulocyte/erythrocyte/macrophage/megakaryocyte did not differ significantly according to the duration of cryopreservation. CONCLUSION: These results suggest that the quality of CB is not affected by cryopreservation for up to a period of 5 years.