Pathogen inactivation (PI) technologies for platelets aim to improve transfusion safety by preventing the replication of contaminating pathogens. However, as a consequence of treatment, aspects of the platelet storage lesion are amplified. Mirasol treatment also affects platelet signal transduction and apoptotic protein expression. The aim of this study was to examine the effect of Mirasol treatment on the generation of reactive oxygen species (ROS) and subsequent oxidative stress.
Pooled platelet concentrates were prepared in platelet-additive solution (70% SSP+ / 30% plasma). ABO-matched platelets were pooled and split, and treated with the Mirasol system (TerumoBCT) or left untreated as a control. Platelet samples were tested on day 1, 5, and 7 post-collection.
Mirasol-treated platelets had increased formation of ROS by day 5 of storage. Oxidative damage, in the form of protein carbonylation, was higher in Mirasol-treated platelets, whilst no effect on nitrotyrosine formation or lipid peroxidation was detected. The NF-κB signaling pathway was also activated in Mirasol-treated platelets, with increased expression and phosphorylation of NF-κB p65 and IκBα.
These data demonstrate that Mirasol-treated platelets produce more ROS and display protein alterations consistent with oxidative damage.
Pathogen inactivation; Riboflavin; Ultraviolet light; Platelet; Platelet-additive solution; Reactive oxygen species
On September 11, 2014, a workshop entitled ‘Advanced Therapy Medicinal Products: How to Bring Cell-Based Medicinal Product Successfully to the Market’ was held at the 47th annual meeting of the German Society for Transfusion Medicine and Immunohematology (DGTI), co-organised by the European Medicines Agency (EMA) and the DGTI in collaboration with the German Stem Cell Network (GSCN). The workshop brought together over 160 participants from academia, hospitals, small- or medium-sized enterprise developers and regulators. At the workshop, speakers from EMA, the Committee for Advanced Therapies (CAT), industry and academia addressed the regulatory aspects of development and authorisation of advanced therapy medicinal products (ATMPs), classification of ATMPs and considerations on cell-based therapies for cardiac repair. The open forum discussion session allowed for a direct interaction between ATMP developers and the speakers from EMA and CAT.
Advanced therapy medicinal products; ATMP; Committee for Advanced Therapies; CAT
Mirasol® pathogen reduction technology (PRT) uses UV light and riboflavin to chemically inactivate pathogens and white blood cells in blood components. In the EU, Mirasol PRT is CE-marked for both plasma and platelet treatment. In Poland, the decision to introduce PRT treatment of the national supply of fresh frozen plasma has spurred interest in evaluating the cost-effectiveness of this strategy.
A decision-analytic model evaluated the incremental costs and benefits of introducing PRT to the existing blood safety protocols in Poland.
Addition of PRT treatment of plasma to current screening in Poland is estimated to cost 2.595 million PLN per quality-adjusted life year (QALY) (610,000 EUR/QALY); treating both plasma and platelet components in addition to current safety interventions had a lower cost of 1.480 million PLN/QALY (348,000 EUR/QALY).
The results suggest that in Poland the cost per QALY of PRT is high albeit lower than found in previous economic analyses of PRT and nucleic acid testing in North America. Treating both platelets and plasma components is more cost-effective than treating plasma alone. Wide confidence intervals indicate high uncertainty; to improve the precision of the health economic evaluation of PRT, additional hemovigilance data are needed.
Pathogen reduction technology; Mirasol PRT; Poland; Blood safety; Cost-effectiveness; ICER
The ability to predict transfusion requirements may improve perioperative bleeding management as an integral part of a patient blood management program. Therefore, the aim of our study was to evaluate preoperative thromboelastometry as a predictor of transfusion requirements for adult living donor liver transplant recipients.
The correlation between preoperative thromboelastometry variables in 100 adult living donor liver transplant recipients and intraoperative blood transfusion requirements was examined by univariate and multivariate linear regression analysis. Thresholds of thromboelastometric parameters for prediction of packed red blood cells (PRBCs), fresh frozen plasma (FFP), platelets, and cryoprecipitate transfusion requirements were determined with receiver operating characteristics analysis. The attending anesthetists were blinded to the preoperative thromboelastometric analysis. However, a thromboelastometry-guided transfusion algorithm with predefined trigger values was used intraoperatively. The transfusion triggers in this algorithm did not change during the study period.
Univariate analysis confirmed significant correlations between PRBCs, FFP, platelets or cryoprecipitate transfusion requirements and most thromboelastometric variables. Backward stepwise logistic regression indicated that EXTEM coagulation time (CT), maximum clot firmness (MCF) and INTEM CT, clot formation time (CFT) and MCF are independent predictors for PRBC transfusion. EXTEM CT, CFT and FIBTEM MCF are independent predictors for FFP transfusion. Only EXTEM and INTEM MCF were independent predictors of platelet transfusion. EXTEM CFT and MCF, INTEM CT, CFT and MCF as well as FIBTEM MCF are independent predictors for cryoprecipitate transfusion. Thromboelastometry-based regression equation accounted for 63% of PRBC, 83% of FFP, 61% of cryoprecipitate, and 44% of platelet transfusion requirements.
Preoperative thromboelastometric analysis is helpful to predict transfusion requirements in adult living donor liver transplant recipients. This may allow for better preparation and less cross-matching prior to surgery. The findings of our study need to be re-validated in a second prospective patient population.
Adult living donor liver transplantation; Allogeneic blood transfusion; Blood coagulation; Point-of-care testing; Thromboelastometry
Liberal versus restrictive red blood cell (RBC) transfusion triggers have been debated for years. This review illustrates the human body's physiologic response to acute anemia and summarizes the evidence from prospective randomized trials (RCTs) for restrictive use of RBC transfusions in high-risk patients. During progressive anemia, the human body maintains the oxygen delivery to the tissues by an increase in cardiac output and peripheral oxygen extraction. Seven RCTs with a total of 5,566 high-risk patients compared a restrictive hemoglobin (Hb) transfusion trigger (Hb < 70 or < 80 g/l) with a liberal Hb transfusion trigger (Hb < 90 or < 100 g/l). Unanimously these studies show non-inferiority, safety, and a significant reduction in RBC transfusions in the restrictive groups. In one RCT mortality was higher in the liberal Hb transfusion group, and in two additional RCTs mortality of subgroups or after risk adjustment was significantly higher in the liberal Hb transfusion trigger groups.
Strong RCT evidence suggests the safety of restrictive transfusion triggers. As a consequence, an Hb transfusion trigger of <70 g/l is recommended for high risk patients.
Red blood cell transfusions; Blood transfusion; Transfusion trigger; Patient blood management
More blood components are required in cardiac surgery than in most other medical disciplines. The overall blood demand may increase as a function of the total number of cardiothoracic and vascular surgical interventions and their level of complexity, and also when considering the demographic ageing. Awareness has grown with respect to adverse events, such as transfusion-related immunomodulation by allogeneic blood supply, which can contribute to morbidity and mortality. Therefore, programmes of patient blood management (PBM) have been implemented to avoid unnecessary blood transfusions and to standardise the indication of blood transfusions more strictly with aim to improve patients' overall outcomes.
A comprehensive retrospective analysis of the utilisation of blood components in the Department of Cardiac Surgery at the University Hospital of Münster (UKM) was performed over a 4-year period. Based on a medical reporting system of all medical disciplines, which was established as part of a PBM initiative, all transfused patients in cardiac surgery and their blood components were identified in a diagnosis- and medical procedure-related system, which allows the precise allocation of blood consumption to interventional procedures in cardiac surgery, such as coronary or valve surgery.
This retrospective single centre study included all in-patients in cardiac surgery at the UKM from 2009 to 2012, corresponding to a total of 1,405-1,644 cases per year. A blood supply was provided for 55.6-61.9% of the cardiac surgery patients, whereas approximately 9% of all in-patients at the UKM required blood transfusions. Most of the blood units were applied during cardiac valve surgery and during coronary surgery. Further surgical activities with considerable use of blood components included thoracic surgery, aortic surgery, heart transplantations and the use of artificial hearts. Under the measures of PBM in 2012 a noticeable decrease in the number of transfused cases was observed compared to the period from 2009 to 2011 before implementation of the PBM initiative (red blood cells p < 0.002; fresh frozen plasma p < 0.0006; platelets p < 0.00006).
Until now, cardiac surgery comes along with a significant blood supply. By using a case-related data evaluation programme, the consumption of each blood component can be linked to clinical performance groups and, if necessary, to individual patients. Based on the results obtained from this retrospective analysis, prospective studies are underway to begin conducting target / actual performance comparisons to better understand the individual decision-making by the attending physicians with respect to transfusions.
Cardiac surgery; Haemotherapy; Blood supply; Blood transfusion; Patient blood management
In the last years it has become evident that the use of blood products should be reduced whenever possible. There is increasing evidence regarding serious adverse events, including higher mortality and morbidity, related to transfusions. The use of point of care (POC) devices integrated in algorithms is one of the important mechanisms to limit blood product exposure. Any type of algorithm, especially the POC-based ones, allows goal-directed transfusions of blood products and even better targeted factor concentrate substitutions. Different types of algorithms in different surgical settings (cardiac surgery, trauma, liver surgery etc.) have been established with growing interest in their use as they offer objective therapy for management and reduction of blood product use. The use of POC devices with evidence-based algorithms is important in the bleeding patient independent of its origin (traumatic vs. surgical). The use of factor concentrates compared to the classical blood products can be cost-saving, beneficial for the patient, and in agreement with the WHO-requested standard of care. The empiric and uncontrolled use of blood products such as fresh frozen plasma, red blood cells, and platelets without POC monitoring should no longer be followed with regard to actual evidence in literature. Furthermore, the use of factor concentrates may provide better outcomes and potential for cost saving.
Bleeding; Cardiac surgery; Goal-directed transfusions; ROTEM®; Thrombelastometry; Transfusion management; Trauma; Point of care devices; POC; Patient blood management
The aim of our single-centre retrospective study presented here is to further analyse the utilisation of allogeneic blood components within a 5-year observation period (2009-2013) in trauma surgery (15,457 patients) under the measures of an educational patient blood management (PBM) initiative.
After the implementation of the PBM initiative in January 2012, the Institute of Transfusion Medicine und Transplantation Immunology educates surgeons and nurses at the Department of Trauma Surgery to avoid unnecessary blood transfusions. A standardised reporting system was used to document the utilisation of blood components carefully for the most frequent diagnoses and surgical interventions in trauma surgery. These measures served as basis for the implementation of an interdisciplinary systematic exchange of information to foster decision-making processes in favour of patient blood management.
Since January 2012, the proportion of patients who received a transfusion as well as the number of transfused red blood cell (RBC) (7.3%/6.4%; p = 0.02), fresh frozen plasma (FFP) (1.7%/1.3%; p < 0.05) and platelet (PLT) (1.0%/0.5%; p < 0.001) units were reduced as a result of our PBM initiative. However, among the transfused patients, the number of administered RBC, FFP and PLT units did not decrease significantly. Overall, patients who did not receive transfusions were younger than transfused patients (p = 0.001). The subgroup with the highest probability of blood transfusion administered included patients with intensive care and long-term ventilation (before/after implementation of PBM: RBC 81.5%/75.9%; FFP 33.3%/20.4%; PLT 24.1%/13.0%). Only a total of 60 patients of 531 patients suffering multiple traumas were massively transfused (before/after implementation of PBM: RBC 55.6%/49.8%; FFP 28.4%/20.4%; PLT 17.6%/8.9%).
According to our educational PBM initiative, at least the proportion of trauma patients who received allogeneic blood transfusions could be reduced significantly. However, in case of blood transfusions, the total consumption of RBC, FFP and PLT units remained stable in both time periods. This phenomenon might indicate that the actual need of blood transfusions rather depends on the severity of trauma-related blood loss, the coagulopathy rates or the complexity of the surgical intervention which mainly determines the intra-operative blood loss. Taken together, educational training sessions and systematic reporting systems are suitable measures to avoid unnecessary allogeneic blood transfusions and to continuously improve their restrictive application.
Trauma surgery; Patient blood management; Blood supply; Haemotherapy; Health services research
A multicomponent, evidence-based and interdisciplinary Patient Blood Management (PBM) program was introduced at the University Hospital Frankfurt in July 2013. The implementation strategy included practical and tactical components aimed to increase knowledge on the risks of preoperative anemia, to standardize hemotherapy, and to facilitate PBM components.
This article analyzes barriers to PBM implementation and outlines a strategy to introduce and manifest PBM. The effects in Frankfurt were measured in a before and after questionnaire study distributed among groups of physicians immediately before and 1 year after PBM implementation.
142 clinicians completed the questionnaire in July 2013 and 101 clinicians in August 2014. Absolute certainty that the treatment of preoperative anemia favorably influences morbidity and mortality rose from 25 to 37%. Transfusion behavior seems to have been affected: In 2014, 56% of clinicians stated that they clinically reassess the patient and analyze hemoglobin following each single red blood cell unit compared to only 38% stating this in 2013.
These results show that our implementation strategy was effective in changing physicians' risk perception, attitude, and knowledge on PBM principles. Our experience highlights key success factors for the implementation of a comprehensive PBM program.
Patient blood management; Anemia; Blood transfusion; Surgery – preoperative period; Medical decision-making; Implementation strategy
Holley (Hy) is a high-incidence antigen of the Dombrock blood group system (ISBT 014), present in almost 100% of most populations and more than 99% of Blacks. Since anti-Hy is an extremely rare antibody, data on its clinical relevance and in particular on a possible hemolytic disease of the fetus and newborn (HDFN) are scarce.
The pregnant patient underwent two autologous whole blood collections at weeks 17 and 19 of gestation with cryopreservation. In our case autologous whole blood collection was well tolerated. There were no signs of HDFN in the healthy newborn.
Our case improves our understanding of anti-Hy alloantibodies during pregnancy. Additionally, autologous whole blood collection of RBC units with cryopreservation is a safe and feasible way to manage pregnancies in women with rare alloantibodies, when no compatible donor can be found.
Anti-Holley alloantibody; Hemolytic disease of the fetus and newborn; HDFN; Pregnancy
Safety is an important consideration for the clinical application of dendritic cells (DC) loaded with autologous tumor lysate (TL). Thus, avitalization of TL from living autologous tumor tissue has to be guaranteed.
Composition of TL was investigated by static image analysis (SIA) with the Morphologi G3 device, which simultaneously measures size and shape of up to 100,000 particles within one sample run. This approach was compared with sample characterization by high-resolution automated cell counting, trypan blue staining, and ATP quantification.
Using SIA, we only detected fragmented, non-cellular structures in completely avitalized TL, indicating complete destruction of living cells. Analysis of particle size distribution by SIA as well as CASY cell counter showed that 95% of particles had a diameter of <10 µm as a sign of cell fragmentation. Complete avitalization of TL was confirmed with trypan blue staining and ATP analysis.
Regarding generation of DC vaccines, the proof of avitality of TL from living tumor tissue can clearly be achieved by SIA alone or in combination with standard assays. Our data show that SIA is a highly precise method for TL characterization. The SIA device complies with FDA regulation and, therefore, might be suitable for characterization of cellular therapy medicinal products.
Avitality; Autologous tumor lysate; Bioinactivity; DC vaccine
Small animal models have been previously used in transfusion medicine studies to evaluate the safety of blood transfusion products. Although there are multiple studies on the effects of blood banking practices on human red blood cells (RBCs), little is known about the effect of blood component manufacturing on the quality of rat RBCs.
Blood from Sprague-Dawley rats and human volunteers (n = 6) was collected in CPD anticoagulant, resuspended in SAGM or AS3, and leukoreduced. In vitro quality was analyzed, including deformability, aggregation, microvesiculation, phosphatidylserine (PS) expression, percent hemolysis, ATP, 2,3-DPG, osmotic fragility, and potassium concentrations.
Compared to human RBCs, rat RBCs had decreased deformability, membrane rigidity, aggregability, and microvesiculation after component manufacturing process. Rat RBCs in SAGM showed higher hemolysis compared to human RBCs in SAGM (rat 4.70 ± 0.83% vs. human 0.34 ± 0.07%; p = 0.002). Rat RBCs in AS3 had greater deformability and rigidity than in SAGM. The number of microparticles/µl and the percentage PS expression were lower in rat RBCs in AS3 than in rat RBCs in SAGM. Hemolysis was also significantly lower in AS3 compared to SAGM (2.21 ± 0.68% vs. 0.87 ± 0.39%; p = 0.028).
Rat RBCs significantly differ from human RBCs in metabolic and membrane-related aspects. SAGM, which is commonly used for human RBC banking, causes high hemolysis and is not compatible with rat RBCs.
Red blood cells; Additive solutions; Blood manufacturing; Blood banking
In the present study, different methods for preparation of platelet-rich plasma (PRP) are investigated in order to standardize the component in terms of growth factor content. The effects of concentration technique and storage duration are also analyzed.
PRP was collected from 40 donors by plateletpheresis as well as by the buffy coat and tube method. Concentration of growth factors was performed using double freeze thaw- and CaCl2-induced degranulation techniques. Growth factor estimation was performed using ELISA.
The levels of growth factors were highest in PRP from buffy coat, moderately lower in plasma gained by plateletpheresis and lowest in that obtained by the tube method. Mean levels of platelet-derived growth factors (PDGF) AB and BB are significantly higher when CaCl2 was used for concentrating the growth factors. The mean levels of transforming growth factor β1 and insulin-like growth factor I were higher when applying the double freeze thaw technique. There was a substantial decline in the levels of growth factors during storage.
The buffy coat method is suitable as preparation method for PRP in most settings. The double freeze thaw technique is better suited as concentration technique as it causes lysis of both platelets and white blood cells for releasing growth factors and is easier to perform. Growth factors are not stable in plasma, thus PRP should be frozen immediately after preparation.
Buffy coat; Growth factors; Platelet transfusion; Plateletpheresis
Reports on unexpected events (UEs) during blood donation (BD) inadequately consider the role of technical UEs.
Defined local and systemic UEs were graded by severity; technical UEs were not graded. On January 1, 2008, E.B.P.S.-Logistics (EBPS) installed the UE module for plasma management software (PMS). Donor room physicians entered UEs daily into PMS. Medical directors reviewed entries quarterly. EBPS compiled data on donors, donations, and UEs from January 1, 2008 to June 30, 2011.
6,605 UEs were observed during 166,650 BDs from 57,622 donors for a corrected incidence of 4.30% (0.66% local, 1.59% systemic, 2.04% technical UEs). 2.96% of BDs were accompanied by one UE and 0.45% by >1 UE (2-4). 6.3% of donors donating blood for their first time, 3.5% of those giving blood for their second time, and 1.9% of donors giving their third or more BD experienced UEs. Most common UEs were: discontinued collections due to venous access problems, repeated venipuncture, and small hematomas. Severe circulatory UEs occurred at a rate of 16 per 100,000 BDs.
Technical UEs were common during BD. UEs accompanied first and second donations significantly more often than subsequent donations.
Donor hemovigilance; Blood donation; Unexpected events
To investigate the extent of oxidative damage and changes in morphology of manually isolated red blood cells (RBCs) from whole blood, cold stored (up to 20 days) in polystyrene tubes and subjected to pre-storage irradiation (50 Gy) and to compare the properties of SAGM-preserved RBCs stored under experimental conditions (polystyrene tubes) with RBCs from standard blood bag storage.
The percentage of hemolysis as well as the extracellular activity of LDH, thiobarbituric acid-reactive substances, reduced glutathione (GSH), and total antioxidant capacity (TAC) were measured. Changes in the topology of RBC membrane, shape, and size were evaluated by flow cytometry and judged against microscopy images.
Irradiation caused significant LDH release as well as increased hemolysis and lipid peroxidation, GSH depletion, and reduction of TAC. Prolonged storage of irradiated RBCs resulted in phosphatidylserine exposure on the cell surface. By day 20, approximately 60% of RBCs displayed non-discoid shape. We did not notice significant differences in percentage of altered cells and cell volume between RBCs exposed to irradiation and those not exposed.
Irradiation of RBC transfusion units with a dose of 50 Gy should be avoided. For research purposes such as studying the role of antioxidants, storage of small volumes of RBCs derived from the same donor would be more useful, cheaper, and blood-saving.
Red blood cell; Gamma irradiation; Storage; Oxygen-free radical; Flow cytometry
Sensitive and accurate methods to detect hematopoietic chimerism after hematopoietic stem cell transplantation (HSCT) are essential to evaluate engraftment and to monitor response to therapeutic procedures such as donor lymphocyte infusion. Continuous long-term follow up, however, requires large amounts of pre-HSCT samples limiting the application of many widely used techniques for sensitive chimerism monitoring.
DNAs from 42 normal healthy donors and 16 HSCT donor/recipient pairs were employed to validate the use of allele-specific insertion/deletion (indel) quantitative real-time polymerase chain reaction (qPCR) to quantify chimerism in samples with low amounts of DNA. Consequently, indel-qPCR analyses of samples from 16 HSCT patients were compared to short-tandem repeat (STR) specific PCR analyses.
Typing with reduced amounts of input DNA (15 vs. 60 ng) allowed for the reliable distinction of positive (mean threshold cycle (ct) 28.05) and negative (ct >36) signals. The high informativity of primer/probe sets, with 12 out of 19 markers exceeding 20% informativity, was confirmed in our cohort (n = 74). Importantly, a fourfold reduction of input DNA compared to published protocols did not alter PCR efficiencies and allowed for a more sensitive detection of chimerism in 7 of 16 HSCT patients compared to results obtained by STR-PCR.
Our data suggest that indel-qPCR is a more sensitive technique for the detection of hematopoietic chimerism compared to STR-PCR and works efficiently for samples with low amounts of DNA.
Stem cell transplantation; Chimerism; Molecular diagnostic techniques; Quantitative real-time polymerase chain reaction
Liver transplantation (LT) has traditionally been associated with major blood loss and consequently high blood transfusion requirements. Our objective was to analyze transfusion management and incidence of immunohematologic complications in patients undergoing LT at our institution.
A retrospective analysis of immunohematologic events and transfusion outcomes was carried out at La Fe University Hospital in Valencia. Data from 654 patients were reviewed: 654 underwent only one LT while 36 underwent second LT.
Patients received a median of 3 red blood cell (RBC) concentrates, 2 platelets concentrates (PCs) and 2 fresh frozen plasma units (FFPs). Variables significantly influencing RBC transfusions were: the MELD score, hemoglobin levels, and the platelet counts before LT. 27 patients (4.1%) had a positive antibody screening before transplant. Immunohematologic events occurred in 8% of the patients, mostly in the first month after LT, and involved hemolysis in 13 cases. Mortality was significantly higher in patients developing immunohematologic disorders (42.8 vs. 18.3%; p < 0.001). In the multivariable analysis, only ABO minor incompatibility between donor and recipient significantly increased the appearance of immunohematologic incidences (OR 4.92, 95% CI 2.31–10.50; p < 0.001).
Transfusion management of patients that underwent LT can be complicated by immunohematologic problems. Blood banks should implement the DAT test in each transfusion to detect them.
Liver transplantation; Blood transfusion; Hemolysis; Immunohematologic event; Transfusion alloimmunization
To evaluate biochemical and cellular changes associated with the storage of leukocyte-depleted red blood cells (RBCs).
We investigated 10 leukocyte-depleted RBC units, randomly chosen from volunteer donors. Every week an aliquot was collected for laboratorial evaluation, which included complete cell blood count, glucose-6-phosphate dehydrogenase (G6PD) activity, extracellular sodium, potassium and pH, membrane-bound hemoglobin (MBH), band 3 profile, and quantification of RBC membrane proteins composition.
We observed an increase in mean cell volume (from 91.86 ± 4.65 fl to 98.10 ± 5.80 fl, day 0 vs. day 21; p < 0.05), red cell distribution width, percentage of macrocytic RBCs, reticulocyte hemoglobin content and a decreased percentage of microcytic RBCs, mean cell volume concentration and G6PD activity. The extracellular concentration of sodium decreased, and that of potassium increased significantly over time. RBC membrane composition revealed an increase in spectrin/ankyrin ratio after 21 days (from 4.84 ± 0.99 to 5.27 ± 0.94, day 0 vs. day 21; p < 0.05). At day 35, a decrease in ankyrin (from 6.44 ± 1.70% to 5.49 ± 1.96%, day 0 vs. day 35; p < 0.05), in protein 4.1/band 3, protein 4.2/band 3, and ankyrin/band 3 ratios and in band 5 was observed.
Our data show that leukocyte-depleted RBCs present changes in the RBC morphology, membrane protein composition, enzymatic activity, and extracellular electrolyte concentration and pH.
RBC; Membrane proteins; Transfusion; Leukocyte depletion; Red cell aging
This study assessed the diagnostic accuracy of a non-invasive approach to fetal RHD genotyping using cell-free fetal DNA in maternal plasma and a combination of methodological strategies.
Real-time PCR (qPCR) was performed on 216 RhD-negative women between weeks 10+0 and 14+6 of gestation (1st qPCR). qPCR was repeated (2nd qPCR) to increase the amount of each sample for analysis, on 95 plasma aliquots that were available from first trimester blood collection (group 1) and on 13 samples that were collected between weeks 18+0 and 25+6 of gestation (group 2). qPCR was specific for exons 5 and 7 of the RHD gene (RHD5 and RHD7). The results were interpreted according to the number of positive replicates of both exons.
1st qPCR: diagnostic accuracy was of 93.3%. Diagnostic accuracy increased from 90.5% (1st qPCR) to 93.7% (2nd qPCR) in group 1 and from 84.6% (1st qPCR) to 92.3% (2nd qPCR) in group 2. These increments were not statistically significant.
Our approach to RHD genotyping in early pregnancy yielded high diagnostic accuracy. Increasing the amount of DNA analyzed in each sample did not improve significantly the diagnostic accuracy of the test.
Fetal DNA; Hemolytic disease of the fetus and newborn; Prenatal RHD genotyping
The D antigen is highly immunogenic, requiring only a small quantity of transfused red blood cells (RBCs) to cause alloimmunization in D– immunocompetent recipients. DEL was reported arousing alloimmunization to true Rh– patients. Molecular studies of the RHD gene have revealed that DEL individuals retain a grossly intact RHD gene or have a portion of RHD in their genomes. Avoiding immunization with clinically important antibodies is a primary objective in transfusion medicine.
In order to determine whether pregnant DEL women carrying an RhD+ fetus are at risk of anti-D alloimmunization, 808 Rh– pregnant women with a history of gestations or parturitions who regularly visited hospitals for their prenatal anti-D screening and postpartum care from January 2011 to December 2012 were investigated. Samples were analyzed for DEL by PCR with specific primers, PCR-sequence-specific primers (PCR-SSP), reverse transcription-PCR (RT-PCR), PCRrestriction fragment length polymorphism (PCR-RFLP), and by gene sequencing to characterize different alleles.
Among the 808 Rh– pregnant women of our sample, 178 (22.0%) were typed as DEL; 168 DEL samples were confirmed to have the RHD (1,227 G>A) allele, 8 DEL samples were characterized by one base mutation of the RHD (3G >A) allele, and the remaining two DEL samples were determined to carry RHD-CE(4–9)-D or RHD-CE(2–5)-D. The observation of allo-anti-D in two prominent D epitope loss cases confirmed the partial nature of these DEL phenotypes.
In conclusion, evidence is provided that different DEL genotypes code either for partial or complete D antigen expression. It is suggested that the use of RhD+ RBCs in complete D antigen DEL patients does not induce adverse reaction.
DEL variant; Pregnant women; Complete DEL; Partial DEL; Alloimmunization
Upshaw-Schulman syndrome (USS) is usually suspected based on severe deficiency of ADAMTS13 activity without ADAMTS13 antibody, but the definitive diagnosis is made by ADAMTS13 gene analysis. We present a unique case of USS with low titers of ADAMTS13 antibodies before pregnancy. Interestingly, titers of ADAMTS13 antibodies decreased to almost undetectable levels after delivery.
In patient LL4, the diagnosis of USS was confirmed at age 27 by ADAMTS13 gene analysis. She became pregnant at age 30. During the pregnancy, she received regular fresh frozen plasma (FFP) infusion. Plasma von Willebrand factor levels increase as pregnancy progresses. To prevent platelet thrombi, much more ADAMTS13 supplementation is necessary during late gestation in patients with USS. Therefore, we shortened the interval between and increased the volume of FFP infusions as pregnancy progressed. At 39 weeks, she delivered a healthy baby girl. Before pregnancy, she had low titers of both neutralizing and binding anti-ADAMTS13 antibodies. Despite frequent FFP infusions, titers of the antibodies did not increase, but rather decreased to almost undetectable levels during pregnancy.
Both the neutralizing and binding antibodies against ADAMTS13 decreased to almost undetectable levels after delivery in this patient, which can be caused by an immunological reset.
Upshaw-Schulman syndrome; Pregnancy; ADAMTS13 antibody; ADAMTS13 gene mutation; Fresh frozen plasma
Alloimmunization is an adverse effect of blood transfusions. In Chile, alloimmunization frequency is not established, and for this reason the aim of this study was to investigate the prevalence and specificity of red blood cell (RBC) alloantibodies in Chilean transfused subjects.
Records from 4,716 multi-transfused patients were analyzed. In these patients, antibody screening was carried out prior to cross-matching with a commercially available two-cell panel by the microcolum gel test, and samples with a positive screen were analyzed for the specificity of the alloantibody with a 16-cell identification panel.
The incidence of RBC alloimmunization in transfused patients was 1.02% (48/4,716) with a higher prevalence in women (40/48). We detected 52 antibodies, the most frequent specificities identified were anti-E (30.8%), anti-K (26.9%), anti-D (7.7%), and anti-Fya (5.8%). The highest incidence of alloantibodies was observed in cancer and gastroenterology patients.
The data demonstrated a low alloimmunization frequency in Chilean transfused patients, principally associated with antibodies anti-E, anti-K, anti-D, and anti-Fya.
Alloimmunization; Unexpected antibodies; Red blood cell transfusion
KELnull (K0) persons can produce clinically significant anti-KEL5 antibody after transfusion and/or pregnancy, requiring K0 blood transfusion when indicated. 37 K0 alleles have been reported in studies over different populations, but none in Amerindian-Caucasian descendants from South America. The aim of this study was to identify the molecular basis of K0 phenotype in Brazilians.
We investigated three K0 samples from different Brazilian blood banks (Recife, Manaus, and Vila Velha) in women with anti-KEL5. KEL antigen typing was performed by serologic techniques, and the K0 status was confirmed by flow cytometry. PCR-RFLP and DNA sequencing of the KEL coding and exon-intron regions were also performed.
RBCs of the 3 patients were phenotyped as KEL:-1,−2,−3,−4,−7. The 3 patients had the same KEL*02/02 genotype and were negative for KEL*02.03 and KEL*02.06 alleles. The Recife K0 patient was homozygous for IVS16 + 1g>a mutation (KEL*02N.31 allele). The flow cytometry with anti-KEL1, anti-KEL2, anti-KEL3, anti-KEL4, and anti-CD238 confirmed the K0 phenotype. In addition, we found the c.10423C>T mutation (KEL*02N.04 allele) in both the Manaus K0 and the Vila Velha K0 patients.
This report represents the first study of K0 molecular basis performed in Amerindian-Caucasian descendants from South America.
Kell blood group system; KELnull phenotype; KELnull alleles
Hematopoietic stem and progenitor cell (HPC) motility is essential for HPC transplantation. The chemokine CXCL12 is key for HPC motility. Further regulators are of interest to improve HPC transplantation and regenerative medicine. Here the impact of the human chemokine CCL15 on HPC motility was investigated.
CCL15 plasma concentrations were determined during HPC mobilization in humans. Activity of CCL15 on HPCs was investigated in murine assays, including chemotaxis, adhesion, and CFU-A assays, and competitive repopulation assays.
During HPC mobilization with granulocyte colony-stimulating factor, blood plasma contains increased concentrations (1.1 ± 0.1 ng/ml) of activated CCL15(27–92) versus 0.4 ± 0.1 ng/ml in controls (p = 0.02). CCL15(27–92) significantly enhanced CXCL12-induced transwell migration of Lin-/Sca1+ HPCs and strengthened shear stress-dependent adhesion to vascular cell adhesion molecule-1 (VCAM-1). CCL15(27–92) dose-dependently reduced the colony size in CFU-A assays performed with murine bone marrow and Lin-/Sca1+ HPCs. CCL15(27–92) did not show a direct impact on cell cycle status of HPCs. In murine repopulation assays, pretreatment of bone marrow with CCL15(27–92) significantly increased competitive repopulation.
Our results point to a regulation of HPCs by CCL15 by modulating migratory and adhesive properties of HPCs with the potency to improve HPC short-term engraftment in stem cell transplantation.
Hematopoietic progenitor cells; Cell cycle; Cell migration; Cell adhesion; Chemokines