Transfusion practices for pediatric oncology and hematopoietic stem cell transplantation patients: Data from the National Heart Lung and Blood Institute Recipient Epidemiology and Donor Evaluation Study-III (REDS-III)

BACKGROUND

To evaluate transfusion practices in pediatric oncology and hematopoietic stem cell transplant (HSCT) patients.

STUDY DESIGN AND METHODS

This is a multicenter retrospective study of children with oncologic diagnoses treated from 2013 to 2016 at hospitals participating in the National Heart Lung and Blood Institute Recipient Epidemiology and Donor Evaluation Study-III. Transfusion practices were evaluated by diagnosis codes and pre-transfusion laboratory values.

RESULTS

A total of 4766 inpatient encounters of oncology and HSCT patients were evaluated, with 39.3% (95% confidence interval [CI]: 37.9%-40.7%) involving a transfusion. Red blood cells (RBCs) were the most commonly transfused component (32.4%; 95% CI: 31.1%-33.8%), followed by platelets (22.7%; 95% CI: 21.5%-23.9%). Patients in the 1 to <6 years of range were most likely to be transfused and HSCT, acute myeloid leukemia, and aplastic anemia were the diagnoses most often associated with transfusion. The median hemoglobin (Hb) prior to RBC transfusion was 7.5 g/dl (10-90th percentile: 6.4-8.8 g/dl), with 45.7% of transfusions being given at 7 to <8 g/dl. The median platelet count prior to platelet transfusion was 20 × 10⁹ /L (10-90th percentile: 8-51 × 10⁹ /L), and 37.9% of transfusions were given at platelet count of >20-50 × 10⁹ /L. The median international normalized ratio (INR) prior to plasma transfusion was 1.7 (10-90th percentile: 1.3-2.7), and 36.3% of plasma transfusions were given at an INR between 1.4 and 1.7.

DISCUSSION

Transfusion of blood components is common in hospitalized pediatric oncology/HSCT patients. Relatively high pre-transfusion Hb and platelet values and relatively low INR values prior to transfusion across the studied diagnoses highlight the need for additional studies in this population.

Erythrocyte T-antigen activation in children: Patient characteristics and the hemolytic risk of transfusion

BACKGROUND

T-antigen activation usually occurs upon red blood cell (RBC) membrane cryptantigen exposure due to bacterial enzymes. Although uncommon, the condition is probably underrecognized. There is concern about hemolysis after plasma and plasma-containing platelet transfusions due to naturally occurring anti-T antibody in healthy blood donors. However, experts have debated the extent and severity of clinical hemolysis due to anti-T.

PROCEDURE

We retrospectively identified patients who tested positive for polyagglutination with Arachis hypogea and Glycine max lectins from 2008 to 2019. The records of the patients were reviewed to determine clinical symptoms, laboratory evidence of hemolysis, need for transfusion, and clinical outcomes.

RESULTS

Ten patients were identified. At diagnosis, all were anemic and four had thrombocytopenia. Severe Streptococcus pneumoniae infection affected seven patients; one died. Seven of 10 patients (70%) had laboratory evidence of hemolysis. Peripheral blood smear findings in six patients included RBC agglutination and changes suggesting hemolysis (spherocytes and schistocytes), but three had unremarkable RBC morphology. Four patients required plasma or platelet transfusions; all survived to discharge.

CONCLUSIONS

T-antigen activation is a rare entity. Most patients diagnosed at our hospital had hemolytic anemia and severe pneumococcal infection. Hemoglobin decreased after plasma and platelet transfusions in all patients assessed, but these transfusions were necessary to support treatment. RBCs were given to maintain appropriate hemoglobin levels.

Impact of universal irradiation on chronic transfusion for sickle cell disease

BACKGROUND

Irradiation of blood products prevents transfusion-associated graft-versus-host disease, but most patients do not require this modification which could have an adverse impact on transfusion outcomes. We hypothesized that irradiation may increase transfusion requirements for patients with sickle cell disease (SCD) receiving chronic transfusion.

STUDY DESIGN AND METHODS

Our pediatric hospital implemented a new policy of universal blood product irradiation in May 2018. We conducted a retrospective chart review of patients with SCD receiving chronic red blood cell (RBC) transfusion throughout the year before and after institution of this policy. The primary outcome was the change in RBC transfusion volume per patient weight transfused during the pre- vs. post- universal irradiation period. Secondary outcomes were the change in median pretransfusion laboratory values.

RESULTS

Among 17 patients, 8 (47%) received more RBCs the year before irradiation and 9 (53%) received more the year after irradiation. Implementation of universal irradiation did not significantly increase transfusion volumes needed to clinically manage this population (median change +1.7 ml/kg/year, p = .54). Additionally, there were no significant changes in absolute reticulocyte count, hemoglobin, hemoglobin S%, white blood cell count, lactate dehydrogenase, total bilirubin, serum potassium, and ferritin during the two time periods.

CONCLUSION

In a cohort of patients with SCD receiving simple chronic transfusion, irradiation did not impact transfusion requirements or pertinent pretransfusion laboratory values. Irradiation does not appear to have clinically significant consequences for SCD chronic transfusion management.

Screening for new red blood cell alloantibodies after transfusion in patients with sickle cell disease

BACKGROUND

Patients with sickle cell disease (SCD) are frequent recipients of red blood cell (RBC) transfusions and are at risk for RBC alloimmunization. RBC alloimmunization is diagnosed by identifying RBC alloantibodies as part of pre-transfusion testing, but this testing fails to detect alloantibodies that have evanesced. It may be beneficial to screen for new RBC alloantibody development after transfusion before possible antibody evanescence.

STUDY DESIGN AND METHODS

Our institution started a new initiative for episodically transfused patients with SCD to obtain at least one antibody screen 2-6 months after transfusion as part of their clinical care. A database was created to prospectively track all transfused patients for 1 year and their post-transfusion antibody screen results. Patients received prophylactically CEK-matched RBC units.

RESULTS

During the study year, 138 patients with SCD received a total of 242 RBC transfusions. Patients with a history of an RBC alloantibody (n = 13, 9.4%) had previously received more RBC units than non alloimmunized patients (median 11 vs. 2 RBC units, p = .0002). A total of 337 post-transfusion antibody screens were obtained in 127 patients (92.0%) with 110 patients (79.7%) having at least one antibody screen 2-6 months post-transfusion. With this prospective testing, two new RBC alloantibodies (anti-C and -M) were identified in two patients.

CONCLUSION

It is feasible to test for new RBC alloantibody development in most episodically transfused patients with SCD as part of their routine care. The yield of this screening appears low with CEK matching, but it could still provide important information for individual patients.

Transfusion practices in a large cohort of hospitalized children

BACKGROUND

While previous studies have described the use of blood components in subsets of children, such as the critically ill, little is known about transfusion practices in hospitalized children across all departments and diagnostic categories. We sought to describe the utilization of red blood cell, platelet, plasma, and cryoprecipitate transfusions across hospital settings and diagnostic categories in a large cohort of hospitalized children.

STUDY DESIGN AND METHODS

The public datasets from 11 US academic and community hospitals that participated in the National Heart Lung and Blood Institute Recipient Epidemiology and Donor Evaluation Study-III (REDS-III) were accessed. All nonbirth inpatient encounters of children 0-18 years of age from 2013 to 2016 were included.

RESULTS

61,770 inpatient encounters from 41,943 unique patients were analyzed. Nine percent of encounters involved the transfusion of at least one blood component. RBC transfusions were most common (7.5%), followed by platelets (3.9%), plasma (2.5%), and cryoprecipitate (0.9%). Children undergoing cardiopulmonary bypass were most likely to be transfused. For the entire cohort, the median (interquartile range) pretransfusion laboratory values were as follows: hemoglobin, 7.9 g/dl (7.1-10.4 g/dl); platelet count, 27 × 10⁹ cells/L (14-54 × 10⁹ cells/L); and international normalized ratio was 1.6 (1.4-2.0). Recipient age differences were observed in the frequency of RBC irradiation (95% in infants, 67% in children, p < .001) and storage duration of RBC transfusions (median storage duration of 12 [8-17] days in infants and 20 [12-29] days in children, p < .001).

CONCLUSION

Based on a cohort of patients from 2013 to 2016, the transfusion of blood components is relatively common in the care of hospitalized children. The frequency of transfusion across all pediatric hospital settings, especially in children undergoing cardiopulmonary bypass, highlights the opportunities for the development of institutional transfusion guidelines and patient blood management initiatives.

Transfusion-Associated Hyperkalemic Cardiac Arrest in Neonatal, Infant, and Pediatric Patients

Red blood cell (RBC) transfusions are a life-saving intervention, with nearly 14 million RBC units transfused in the United States each year. However, the safety and efficacy of this procedure can be influenced by variations in the collection, processing, and administration of RBCs. Procedures or manipulations that increase potassium (K⁺) levels in stored blood products can also predispose patients to hyperkalemia and transfusion-associated hyperkalemic cardiac arrest (TAHCA). In this mini review, we aimed to provide a brief overview of blood storage, the red cell storage lesion, and variables that increase extracellular [K⁺]. We also summarize cases of TAHCA and identify potential mitigation strategies. Hyperkalemia and cardiac arrhythmias can occur in pediatric patients when RBCs are transfused quickly, delivered directly to the heart without time for electrolyte equilibration, or accumulate extracellular K⁺ due to storage time or irradiation. Advances in blood banking have improved the availability and quality of RBCs, yet, some patient populations are sensitive to transfusion-associated hyperkalemia. Future research studies should further investigate potential mitigation strategies to reduce the risk of TAHCA, which may include using fresh RBCs, reducing storage time after irradiation, transfusing at slower rates, implementing manipulations that wash or remove excess extracellular K⁺, and implementing restrictive transfusion strategies.

Application of a plasmin generation assay to define pharmacodynamic effects of tranexamic acid in women undergoing cesarean delivery

Essentials Tranexamic acid (TXA) is an antifibrinolytic drug used to reduce bleeding. Assaying plasmin generation (PG) in plasma detects clinically relevant TXA levels in vitro and ex vivo. 3.1-16.2 µg/mL TXA half-maximally inhibits PG in plasma from women undergoing cesarean delivery. PG velocity shows the strongest dose-relationship at low TXA concentrations (≤10 µg/mL). ABSTRACT: Background Tranexamic acid (TXA) is used to reduce bleeding. TXA inhibits plasmin(ogen) binding to fibrin and reduces fibrinolysis. TXA antifibrinolytic activity is typically measured by clot lysis assays; however, effects on plasmin generation (PG) are unclear due to a lack of tools to measure PG in plasma. Aims Develop an assay to measure PG kinetics in human plasma. Determine effects of TXA on PG and compare with fibrinolysis measured by rotational thromboelastometry (ROTEM). Methods We characterized effects of plasminogen, tissue plasminogen activator, fibrinogen, and α2 -antiplasmin on PG in vitro. We also studied effects of TXA on PG in plasma from 30 pregnant women administered intravenous TXA (5, 10, or 15 mg/kg) during cesarean delivery. PG was measured by calibrated fluorescence. PG parameters were compared with TXA measured by mass spectrometry and ROTEM of whole blood. Results The PG assay is specific for plasmin and sensitive to tissue plasminogen activator, fibrin(ogen), and α2 -antiplasmin. Addition of TXA to plasma in vitro dose dependently prolonged the clot lysis time and delayed and reduced PG. For all doses of TXA administered intravenously, the PG assay detected delayed time-to-peak (≤3 hours) and reduced the velocity, peak, and endogenous plasmin potential (≤24 hours) in plasma samples obtained after infusion. The PG time-to-peak, velocity, and peak correlated significantly with TXA concentration and showed less variability than the ROTEM lysis index at 30 minutes or maximum lysis. Conclusions The PG assay detects pharmacologically relevant concentrations of TXA administered in vitro and in vivo, and demonstrates TXA-mediated inhibition of PG in women undergoing cesarean delivery.

Potential Consequences of the Red Blood Cell Storage Lesion on Cardiac Electrophysiology

Background The red blood cell (RBC) storage lesion is a series of morphological, functional, and metabolic changes that RBCs undergo following collection, processing, and refrigerated storage for clinical use. Since the biochemical attributes of the RBC unit shifts with time, transfusion of older blood products may contribute to cardiac complications, including hyperkalemia and cardiac arrest. We measured the direct effect of storage age on cardiac electrophysiology and compared it with hyperkalemia, a prominent biomarker of storage lesion severity. Methods and Results Donor RBCs were processed using standard blood-banking techniques. The supernatant was collected from RBC units, 7 to 50 days after donor collection, for evaluation using Langendorff-heart preparations (rat) or human induced pluripotent stem cell-derived cardiomyocytes. Cardiac parameters remained stable following exposure to "fresh" supernatant from red blood cell units (day 7: 5.8±0.2 mM K+), but older blood products (day 40: 9.3±0.3 mM K+) caused bradycardia (baseline: 279±5 versus day 40: 216±18 beats per minute), delayed sinus node recovery (baseline: 243±8 versus day 40: 354±23 ms), and increased the effective refractory period of the atrioventricular node (baseline: 77±2 versus day 40: 93±7 ms) and ventricle (baseline: 50±3 versus day 40: 98±10 ms) in perfused hearts. Beating rate was also slowed in human induced pluripotent stem cell-derived cardiomyocytes after exposure to older supernatant from red blood cell units (-75±9%, day 40 versus control). Similar effects on automaticity and electrical conduction were observed with hyperkalemia (10-12 mM K+). Conclusions This is the first study to demonstrate that "older" blood products directly impact cardiac electrophysiology, using experimental models. These effects are likely caused by biochemical alterations in the supernatant from red blood cell units that occur over time, including, but not limited to hyperkalemia. Patients receiving large volume and/or rapid transfusions may be sensitive to these effects.

New Approaches and Trials in Pediatric Transfusion Medicine

Blood transfusions are frequently lifesaving, but there is growing awareness of their associated infectious and noninfectious adverse events. Patient blood management advocates for judicious use of transfusions and considerations of alternatives to correct anemia or achieve hemostasis. Several transfusion practices, either already implemented or under investigation, aim to further improve the safety of transfusions. An enduring challenge in pediatric and neonatal transfusion practice is that studies typically focus on adults, and findings are extrapolated to younger patients. This article aims to summarize some of the newer developments in transfusion medicine with a focus on the neonatal and pediatric population.

High-dose intravenous immunoglobulin is strongly associated with hemolytic anemia in patients with Kawasaki disease

BACKGROUND

Hemolysis is a reported side effect of intravenous immunoglobulin (IVIG) therapy in adults, but pediatric data are scarce. We determined the frequency of IVIG-associated hemolysis in patients with Kawasaki disease (KD) and characterized risk factors for hemolysis. We hypothesized that hemolysis is more common in children with KD than adults with other disorders, and hemolysis risk is related to IVIG dose and degree of inflammation.

STUDY DESIGN AND METHODS

This was an 8-year, single-center, retrospective cohort study. A total of 419 KD patients were identified; 123 had pre- and post-treatment complete blood counts allowing for assessment of anemia. Hemolytic anemia was defined as decrease in hemoglobin after IVIG greater than 1 g/dL with immunohematologic or biochemical studies supporting hemolysis.

RESULTS

123 patients were stratified as having hemolysis (n = 18, 15%) or nonhemolysis (n = 105, 85%). Patients with hemolysis were more likely to have complete versus incomplete KD (65% vs. 39%, p = 0.04) and refractory versus nonrefractory course (78% vs. 16%, p < 0.001). Patients receiving 4 g/kg versus 2 g/kg IVIG were more likely to hemolyze (89% vs. 34%, p < 0.001). Patients with hemolysis had mostly non-O blood group (94%), positive direct antiglobulin tests (89%), and positive eluates (72%). Two-thirds of patients with hemolysis required RBC transfusion.

CONCLUSIONS

Hemolysis occurred in 15% of KD patients evaluated for anemia and is strongly associated with high-dose (4 g/kg) IVIG. KD patients receiving high-dose IVIG should have close hematologic monitoring to identify hemolysis.

Consensus Recommendations for RBC Transfusion Practice in Critically Ill Children From the Pediatric Critical Care Transfusion and Anemia Expertise Initiative

OBJECTIVES

To date, there are no published guidelines to direct RBC transfusion decision-making specifically for critically ill children. We present the recommendations from the Pediatric Critical Care Transfusion and Anemia Expertise Initiative.

DESIGN

Consensus conference series of multidisciplinary, international experts in RBC transfusion management of critically ill children.

SETTING

Not applicable.

INTERVENTION

None.

SUBJECTS

Children with, or children at risk for, critical illness who receive or are at risk for receiving a RBC transfusion.

METHODS

A panel of 38 content and four methodology experts met over the course of 2 years to develop evidence-based, and when evidence lacking, expert consensus-based recommendations regarding decision-making for RBC transfusion management and research priorities for transfusion in critically ill children. The experts focused on nine specific populations of critically ill children: general, respiratory failure, nonhemorrhagic shock, nonlife-threatening bleeding or hemorrhagic shock, acute brain injury, acquired/congenital heart disease, sickle cell/oncology/transplant, extracorporeal membrane oxygenation/ventricular assist/ renal replacement support, and alternative processing. Data to formulate evidence-based and expert consensus recommendations were selected based on searches of PubMed, EMBASE, and Cochrane Library from 1980 to May 2017. Agreement was obtained using the Research and Development/UCLA Appropriateness Method. Results were summarized using the Grading of Recommendations Assessment, Development, and Evaluation method.

MEASUREMENTS AND RESULTS

The Transfusion and Anemia Expertise Initiative consensus conference developed and reached consensus on a total of 102 recommendations (57 clinical [20 evidence based, 37 expert consensus], 45 research recommendations). All final recommendations met agreement, defined a priori as greater than 80%. A decision tree to aid clinicians was created based on the clinical recommendations.

CONCLUSIONS

The Transfusion and Anemia Expertise Initiative recommendations provide important clinical guidance and applicable tools to avoid unnecessary RBC transfusions. Research recommendations identify areas of focus for future investigation to improve outcomes and safety for RBC transfusion.

Hemoglobin A clearance in children with sickle cell anemia on chronic transfusion therapy

BACKGROUND

Chronic transfusion therapy for sickle cell anemia reduces disease complications by diluting sickle-erythrocytes with hemoglobin A (HbA)-containing erythrocytes and suppressing erythropoiesis. Minor antigen mismatches may result in alloimmunization, but it is unknown if antigen mismatches or recipient characteristics influence HbA clearance posttransfusion.

STUDY DESIGN AND METHODS

Children with sickle cell anemia on chronic transfusion therapy were followed prospectively for 12 months. All patients received units serologically matched for C/c, E/e, and K; patients with prior red blood cell (RBC) antibodies had additional matching for Fy^a , Jk^b , and any previous alloantibodies. Patients' RBC antigen genotypes, determined by multiplexed molecular assays (PreciseType Human Erythrocyte Antigen, and RHCE and RHD BeadChip, Immucor) were compared to genotypes of transfused RBC units to assess for antigen mismatches. Decline in hbA (ΔHbA) from posttransfusion to the next transfusion was calculated for each transfusion episode.

RESULTS

Sixty patients received 789 transfusions, 740 with ΔHbA estimations, and 630 with donor Human Erythrocyte Antigen genotyping. In univariate mixed-model analysis, ΔHbA was higher in patients with past RBC antibodies or splenomegaly and lower in patients with splenectomy. RBC antigen mismatches were not associated with ΔHbA. In multivariate linear mixed-effects modeling, ΔHbA was associated with RBC antibodies (2.70 vs. 2.45 g/dL/28 d, p = 0.0028), splenomegaly (2.87 vs. 2.28 g/dL/28 d, p = 0.019), and negatively associated with splenectomy (2.46 vs. 2.70 g/dL/28 d, p = 0.011).

CONCLUSIONS

HbA decline was increased among patients with sickle cell anemia with prior immunologic response to RBC antigens and decreased among those with prior splenectomy, demonstrating that recipient immunologic characteristics influenced the clearance of transfused RBCs.

Mutation in the leucine-rich repeat C-flanking region of platelet glycoprotein Ibβ impairs assembly of von Willebrand factor receptor

We describe a syndrome of thrombocytopenia, bleeding episodes, congenital heart disease and facial dysmorphism in a newborn infant, and trace the cause to mutations on chromosome 22 that involve the gene for platelet glycoprotein Ibβ (GPIbβ, Human Genome Organisation gene symbol GPIBB), a critical component of the von Willebrand factor (vWF) receptor. Fluorescence in situ hybridization in transformed lymphoblasts revealed hemizygous microdeletion of 22q11.2 containing the GP1BB locus. DNA sequencing revealed a C to T transition in the patient’s remaining GP1BB allele, predicting a novel proline to serine substitution (Pro96Ser) in the carboxyterminal flanking domain of a leucine-rich repeat. We characterized the mutant GP1BB allele by expression in a cell line (CHOαIX) that stably expresses two other components of the vWF receptor, GPIbα and GPIX. Flow cytometry and confocal imaging of transfected CHOαIX cells demonstrated that P96S GPIbβ abrogates surface assembly of the complex, consistent with platelet flow cytometry studies in the patient. Based on sequence homology to the known crystal structures of two other leucine-rich repeat proteins, the human Nogo receptor and GPIbα, we propose a new structural model of GPIbβ. The model refutes earlier assumptions about cysteine-cysteine interactions in the amino-terminal region of GPIbβ, and predicts a hydrophobic patch the burial of which may contribute to proper conformation of the fully assembled vWF receptor complex.

Parental versus non-parental-directed donation: an 11-year experience of infectious disease testing at a pediatric tertiary care blood donor center

BACKGROUND

Directed donation is associated with a higher prevalence of donations that are positive for infectious disease markers; however, little is known about the positive rates among parental-directed, non-parental-directed, and allogeneic donations.

STUDY DESIGN AND METHODS

We reviewed blood-collection records from January 1997 through December 2008, including infectious disease results, among parental, non-parental, and community donations. Infectious disease rates were compared by Mann-Whitney U test.

RESULTS

In total, 1532 parental, 4910 non-parental, and 17,423 community donations were examined. Among parental donors, the median rate of positive infectious disease testing was 8.66% (interquartile range (IQR), 4.49%) for first-time donors and 1.26% (IQR, 5.86%) for repeat donors; among non-parental donors, the rate was 1.09% (IQR, 0.98%) for first-time donors and 0% (IQR, 0.83%) for repeat donors; and, among community donors, the rate was 2.95% (IQR, 1.50%) for first-time donors and 0.45% (IQR, 0.82%) for repeat donors. The mean rate of positive infectious disease testing for first-time parental donors was significantly higher (7.63%), whereas all repeat donors had similar rates. However, the rate of positive infectious disease testing among first-time non-parental donors was significantly lower than that in the other groups, especially for the period from 2001 through 2008.

CONCLUSION

First-time non-parental and community donors had significantly higher infectious disease risk than the respective repeat donors. First-time parental donors had the highest rates of positive infectious disease testing. We suggest that first-time parental blood donation should be discouraged. Repeat community donors or first-time non-parental donors provide a safer alternative. These findings can foster better patient education, donor selection, and possibly a reduced risk of infectious disease.

Red blood cell minor antigen mismatches during chronic transfusion therapy for sickle cell anemia

BACKGROUND

Red blood cell (RBC) alloimmunization occurs at a high frequency in sickle cell anemia (SCA) despite serologic matching for Rh (C/c, E/e) and K antigens. RBC minor antigen genotyping allows for prediction of antigens and RH variants that may lead to alloimmunization.

STUDY DESIGN AND METHODS

RBC antigen genotyping was performed on chronically transfused pediatric SCA patients, using PreciseType human erythrocyte antigen (HEA), RHCE, and RHD BeadChip arrays. All patients received C/c, E/e, and K serologically matched units (Category 1); patients with prior RBC antibodies were also matched for Fy^a , Jk^b , and any antibodies (Category 2). The RBC genotypes of all leukoreduced (LR) units transfused over a 12-month period were determined by the prototype HEA-LR BeadChip assay.

RESULTS

There were 2320 RBC units transfused to 90 patients in 1135 transfusion episodes. Thirty-five (38.9%) patients had homozygous or compound heterozygous RH variants. Seven new alloantibodies were detected, with alloantibody incidence of 0.706 in 100 units for Category 2 transfusions and 0.068 in 100 units for Category 1 (p = 0.02). Three patients on Category 2 transfusions formed new anti-Js^a and had a higher rate of exposure to Js^a than those who did not form anti-Js^a (20.4 vs. 8.33 exposures/100 units, p = 0.02). The most frequent mismatches were S (43.9%), Do^a (43.9%), Fy^a (29.2%), M (28.4%), and Jk^b (28.1%).

CONCLUSIONS

Alloimmunization incidence was higher in those with prior RBC antibodies, suggesting that past immunologic responders are at higher risk for future alloimmunization and therefore may benefit from more extensive antigen matching beyond C/c, E/e, K, Fy^a , and Jk^b .

Thromboelastography in term neonates: an alternative approach to evaluating coagulopathy

OBJECTIVE

To develop normative ranges for citrate-modified and heparinase-modified thromboelastography (TEG) in term neonates.

DESIGN

Prospective observational study.

SETTING

An outborn neonatal and cardiac intensive care unit in a free-standing academic children's hospital.

PATIENTS

Thirty term neonates were enrolled as control subjects. Seventeen infants with clinically documented bleeding requiring blood transfusion were enrolled in the comparison group.

MAIN OUTCOME MEASURES

Citrate-modified and heparinase-modified TEG parameters were calculated from blood specimens drawn via peripheral arterial stick or arterial line.

RESULTS

TEG in neonates differs from older children and adults; clotting time (R) and clot kinetics (K) values are generally lower while fibrinolysis or rate of clot breakdown (LY30) and coagulation index (CI) are often higher in neonates. TEG values in term neonates calculated as median (Q1-Q3) are as follows: R 4.150 (3.200-6.200), K 1.550 (1.200-1.800), α angle (α) 70.100 (66.000-72.900), maximum amplitude (MA) 61.850 (59.400-66.000), LY30 1.050 (0.100-1.600) and CI 1.950 (0.100 to 2.900). Cut points selected for optimal predictive value for bleeding using receiver operating curve analyses were R>6.3 (sensitivity 82.4%, specificity 80%); K>2.5 (sensitivity 82.4%, specificity 96.7%); α<59 (sensitivity 82.4%, specificity 96.7%); MA<57 (sensitivity 82.4%, specificity 86.7%); CI<-0.15 (sensitivity 88.2%, specificity 83.3%).

CONCLUSIONS

The reference ranges and cut points for citrate-modified and heparinase-modified TEG can be used to diagnose and evaluate coagulopathy in term neonates.

Unusual serological findings associated with ceftriaxone-induced immune hemolytic anemia in a child with disseminated low-grade glioma

Ceftriaxone-induced immune hemolytic anemia (CIHA) is the second most common cause of drug-induced hemolytic anemia. Prompt recognition of this drug reaction is essential because brisk hemolysis can be deadly. The extent to which ceftriaxone antibodies persist after CIHA is unknown; rechallenging patients who have experienced CIHA is not recommended. We report a case of CIHA in a neurooncology patient, which is the first to show anticeftriaxone antibodies with Rh specificity and persisted for 8 months after the drug reaction. These findings have implications for understanding the mechanism of CIHA.

Examination of Reticulocytosis among Chronically Transfused Children with Sickle Cell Anemia

Sickle cell anemia (SCA) is an inherited hemolytic anemia with compensatory reticulocytosis. Recent studies have shown that increased levels of reticulocytosis during infancy are associated with increased hospitalizations for SCA sequelae as well as cerebrovascular pathologies. In this study, absolute reticulocyte counts (ARC) measured prior to transfusion were analysed among a cohort of 29 pediatric SCA patients receiving chronic transfusion therapy (CTT) for primary and secondary stroke prevention. A cross-sectional flow cytometric analysis of the reticulocyte phenotype was also performed. Mean duration of CTT was 3.1 ± 2.6 years. Fifteen subjects with magnetic resonance angiography (MRA) -vasculopathy had significantly higher mean ARC prior to initiating CTT compared to 14 subjects without MRA-vasculopathy (427.6 ± 109.0 K/μl vs. 324.8 ± 109.2 K/μl, p<0.05). No significant differences in hemoglobin or percentage sickle hemoglobin (HbS) were noted between the two groups at baseline. Reticulocyte phenotyping further demonstrated that the percentages of circulating immature [CD36(+), CD71(+)] reticulocytes positively correlated with ARC in both groups. During the first year of CTT, neither group had significant reductions in ARC. Among this group of children with SCA, cerebrovasculopathy on MRA at initiation of CTT was associated with increased reticulocytosis, which was not reduced after 12 months of transfusions.

Effectiveness of red blood cell exchange, partial manual exchange, and simple transfusion concurrently with iron chelation therapy in reducing iron overload in chronically transfused sickle cell anemia patients

BACKGROUND

Chronic transfusion therapy (CTT) is indicated for stroke prevention in children with sickle cell anemia (SCA) and is complicated by iron overload and alloimmunization. CTT is performed by simple transfusion (ST), partial manual exchange (PME), or erythrocytapheresis (RCE). Although small case series have demonstrated RCE in combination with iron chelation therapy stabilizes and/or decreases ferritin, there are no reports comparing the effect of ST, PME, and RCE on liver iron concentration (LIC). CTT modality effect on serum ferritin and LIC were compared in SCA patients on iron chelation, with hemoglobin (Hb)S goal of 30%.

STUDY DESIGN AND METHODS

Medical records of SCA patients on CTT and deferasirox (≥25 mg/kg/day) were retrospectively reviewed. Mean HbS%, change in ferritin and LIC, and alloimmunization rate were determined for each CTT group.

RESULTS

Twenty-eight patients were included; six crossed over (one from ST to PME, one from ST to PME then to RCE, three from ST to RCE, and one from PME to RCE) to include 36 transfusion modality intervals. Median pretransfusion HbS% levels were 32.7% (ST), 36.2% (PME), and 34.7% (RCE; p = 0.732). Median ferritin changes were +15 (-17 to +45), +38 (+24 to +105), and -91 (-141 to -48) ng/mL/month (p = 0.003), and median LIC changes (available in 22 patient transfusion modality intervals) were +1.3 (-1.6 to +4.3), +2.3 (-6.5 to +8.9), and -5.7 (-10.7 to -0.5) mg/g/year (p = 0.024) in ST, PME, and RCE, respectively. There was no significant difference in alloimmunization rate between ST/PME and RCE groups.

CONCLUSION

We recommend RCE plus chelation as an effective method for reducing iron overload, while maintaining HbS at 30% to 35%.

Hydroxycarbamide versus chronic transfusion for maintenance of transcranial doppler flow velocities in children with sickle cell anaemia-TCD With Transfusions Changing to Hydroxyurea (TWiTCH): a multicentre, open-label, phase 3, non-inferiority trial

BACKGROUND

For children with sickle cell anaemia and high transcranial doppler (TCD) flow velocities, regular blood transfusions can effectively prevent primary stroke, but must be continued indefinitely. The efficacy of hydroxycarbamide (hydroxyurea) in this setting is unknown; we performed the TWiTCH trial to compare hydroxyurea with standard transfusions.

METHODS

TWiTCH was a multicentre, phase 3, randomised, open-label, non-inferiority trial done at 26 paediatric hospitals and health centres in the USA and Canada. We enrolled children with sickle cell anaemia who were aged 4-16 years and had abnormal TCD flow velocities (≥ 200 cm/s) but no severe vasculopathy. After screening, eligible participants were randomly assigned 1:1 to continue standard transfusions (standard group) or hydroxycarbamide (alternative group). Randomisation was done at a central site, stratified by site with a block size of four, and an adaptive randomisation scheme was used to balance the covariates of baseline age and TCD velocity. The study was open-label, but TCD examinations were read centrally by observers masked to treatment assignment and previous TCD results. Participants assigned to standard treatment continued to receive monthly transfusions to maintain 30% sickle haemoglobin or lower, while those assigned to the alternative treatment started oral hydroxycarbamide at 20 mg/kg per day, which was escalated to each participant's maximum tolerated dose. The treatment period lasted 24 months from randomisation. The primary study endpoint was the 24 month TCD velocity calculated from a general linear mixed model, with the non-inferiority margin set at 15 cm/s. The primary analysis was done in the intention-to-treat population and safety was assessed in all patients who received at least one dose of assigned treatment. This study is registered with ClinicalTrials.gov, number NCT01425307.

FINDINGS

Between Sept 20, 2011, and April 17, 2013, 159 patients consented and enrolled in TWiTCH. 121 participants passed screening and were then randomly assigned to treatment (61 to transfusions and 60 to hydroxycarbamide). At the first scheduled interim analysis, non-inferiority was shown and the sponsor terminated the study. Final model-based TCD velocities were 143 cm/s (95% CI 140-146) in children who received standard transfusions and 138 cm/s (135-142) in those who received hydroxycarbamide, with a difference of 4·54 (0·10-8·98). Non-inferiority (p=8·82 × 10(-16)) and post-hoc superiority (p=0·023) were met. Of 29 new neurological events adjudicated centrally by masked reviewers, no strokes were identified, but three transient ischaemic attacks occurred in each group. Magnetic resonance brain imaging and angiography (MRI and MRA) at exit showed no new cerebral infarcts in either treatment group, but worsened vasculopathy in one participant who received standard transfusions. 23 severe adverse events in nine (15%) patients were reported for hydroxycarbamide and ten serious adverse events in six (10%) patients were reported for standard transfusions. The most common serious adverse event in both groups was vaso-occlusive pain (11 events in five [8%] patients with hydroxycarbamide and three events in one [2%] patient for transfusions).

INTERPRETATION

For high-risk children with sickle cell anaemia and abnormal TCD velocities who have received at least 1 year of transfusions, and have no MRA-defined severe vasculopathy, hydroxycarbamide treatment can substitute for chronic transfusions to maintain TCD velocities and help to prevent primary stroke.

FUNDING

National Heart, Lung, and Blood Institute, National Institutes of Health.

Early Reticulocytosis and Anemia Are Associated with Abnormal and Conditional Transcranial Doppler Velocities in Children with Sickle Cell Anemia

OBJECTIVE

To improve prediction of sickle cell anemia severity at an early age, we evaluated whether absolute reticulocyte count (ARC) or hemoglobin (Hb) levels during early infancy (2-6 months of age) in patients with sickle cell anemia predict the risk of later developing an abnormal (abTCD) or conditional (cdTCD) Transcranial Doppler (TCD).

STUDY DESIGN

We used chart review to identify 121 consecutive patients who underwent TCD screening and had steady state ARC and Hb levels recorded between 2 and 6 months of age. Cox regression analysis was used to determine the relationship between ARC, Hb levels, and risk of developing cdTCD/abTCD over time.

RESULTS

Mean ARC in early infancy was highest and mean Hb lowest in those children with abTCDs and cdTCDs. Cox regression analysis revealed that those subjects with an ARC ≥200 K/μL in early infancy had nearly 3 times the risk of having an abTCD/cdTCD than the group with an ARC <200 K/μL, and patients with a Hb <8.5 g/dL had 2.7 times the risk of having an abTCD/cdTCD.

CONCLUSIONS

These data suggest that both elevated ARC and low baseline Hb during early infancy are associated with an increased risk of developing a cdTCD or abTCD later in childhood.

Are Immune Modulating Single Nucleotide Polymorphisms Associated with Necrotizing Enterocolitis?

Necrotizing enterocolitis (NEC) is a devastating gastrointestinal emergency. The purpose of this study is to determine if functional single nucleotide polymorphisms (SNPs) in immune-modulating genes pre-dispose infants to NEC. After Institutional Review Board approval and parental consent, buccal swabs were collected for DNA extraction. TaqMan allelic discrimination assays and BglII endonuclease digestion were used to genotype specific inflammatory cytokines and TRIM21. Statistical analysis was completed using logistic regression. 184 neonates were analyzed in the study. Caucasian neonates with IL-6 (rs1800795) were over 6 times more likely to have NEC (p = 0.013; OR = 6.61, 95% CI 1.48–29.39), and over 7 times more likely to have Stage III disease (p = 0.011; OR = 7.13, (95% CI 1.56–32.52). Neonates with TGFβ-1 (rs2241712) had a decreased incidence of NEC-related perforation (p = 0.044; OR = 0.28, 95% CI: 0.08–0.97) and an increased incidence of mortality (p = 0.049; OR = 2.99, 95% CI: 1.01 – 8.86). TRIM21 (rs660) was associated with NEC-related intestinal perforation (p = 0.038; OR = 4.65, 95% CI 1.09–19.78). In premature Caucasian neonates, the functional SNP IL-6 (rs1800795) is associated with both the development and increased severity of NEC. TRIM21 (rs660) and TGFβ-1 (rs2241712) were associated with NEC- related perforation in all neonates in the cohort. These findings suggest a possible genetic role in the development of NEC.

2015 proceedings of the National Heart, Lung, and Blood Institute's State of the Science in Transfusion Medicine symposium

On March 25 and 26, 2015, the National Heart, Lung, and Blood Institute sponsored a meeting on the State of the Science in Transfusion Medicine on the National Institutes of Health (NIH) campus in Bethesda, Maryland, which was attended by a diverse group of 330 registrants. The meeting's goal was to identify important research questions that could be answered in the next 5 to 10 years and which would have the potential to transform the clinical practice of transfusion medicine. These questions could be addressed by basic, translational, and/or clinical research studies and were focused on four areas: the three "classical" transfusion products (i.e., red blood cells, platelets, and plasma) and blood donor issues. Before the meeting, four working groups, one for each area, prepared five major questions for discussion along with a list of five to 10 additional questions for consideration. At the meeting itself, all of these questions, and others, were discussed in keynote lectures, small-group breakout sessions, and large-group sessions with open discourse involving all meeting attendees. In addition to the final lists of questions, provided herein, the meeting attendees identified multiple overarching, cross-cutting themes that addressed issues common to all four areas; the latter are also provided. It is anticipated that addressing these scientific priorities, with careful attention to the overarching themes, will inform funding priorities developed by the NIH and provide a solid research platform for transforming the future practice of transfusion medicine.

Genetics of transfusion recipient alloimmunization: can clues from susceptibility to autoimmunity pave the way?

The search for genetic determinants of alloimmunization in sickle cell disease transfusion recipients was based on two premises: i) that polymorphisms responsible for stronger immune and/or inflammatory responses and hemoglobin β(S) mutation were co-selected by malaria; and ii) that stronger responder status contributes to development of lupus. We found a marker of alloimmunization in the gene encoding for Ro52 protein, also known as Sjögren syndrome antigen 1 (SSA1) and TRIM21. Surprisingly, the nature of the association was opposite of that with lupus; the same variant of a polymorphism (rs660) that was associated with lupus incidence was also associated with induction of tolerance to red blood cell antigens during early childhood. The dual function of Ro52 can explain this apparent contradiction. We propose that other lupus/autoimmunity susceptibility loci may reveal roles of additional molecules in various aspects of alloimmunization induced by transfusion as well as during pregnancy.

Coagulopathy in newborns with hypoxic ischemic encephalopathy (HIE) treated with therapeutic hypothermia: a retrospective case-control study

Background

Newborns with hypoxic ischemic encephalopathy (HIE) are at risk for coagulopathy due to systemic oxygen deprivation. Additionally, therapeutic hypothermia (TH) slows enzymatic activity of the coagulation cascade, leading to constitutive prolongation of routinely assessed coagulation studies. The level of laboratory abnormality that predicts bleeding is unclear, leading to varying transfusion therapy practices.

Methods

HIE infants treated with TH between 2008–2012 were included in this retrospective study. Initial, minimum (min) and maximum (max) values of International Normalized Ratio (INR), activated partial thromboplastin time (aPTT), fibrinogen (Fib) and platelet (PLT) count (measured twice daily during TH) were collected. Bleeding was defined as clinically significant if associated with 1) decreased hemoglobin (Hb) by 2 g/dL in 24 hours, 2) transfusion of blood products for hemostasis, or 3) involvement of a critical organ system. Laboratory data between the bleeding group (BG) and non-bleeding group (NBG) were compared. Variables that differed significantly between groups were evaluated with Receiver Operating Characteristic Curve (ROC) analyses to determine cut-points to predict bleeding.

Results

Laboratory and bleeding data were collected from a total of 76 HIE infants with a mean (±SD) birthweight of 3.34 ± 0.67 kg and gestational age of 38.6 ± 1.9 wks. BG included 41 infants. Bleeding sites were intracranial (n = 13), gastrointestinal (n = 19), pulmonary (n = 18), hematuria (n = 11) or other (n = 1). There were no differences between BG and NBG in baseline characteristics (p > 0.05). Both groups demonstrated INR and aPTT values beyond the acceptable reference ranges utilized for full tem newborns. BG had higher initial and max INR, initial aPTT, and lower min PLT and min Fib compared to NBG. ROC analyses revealed that platelet count <130 × 10⁹/L, fib level <1.5 g/L, and INR >2 discriminated BG from NBG.

Conclusions

Laboratory evidence of coagulopathy is universal in HIE babies undergoing TH. Transfusion strategies to maintain PLT counts >130 × 10⁹/L, fib level >1.5 g/L, and INR <2 may prevent clinical bleeding in this high risk population.

Red blood cell alloimmunization is influenced by recipient inflammatory state at time of transfusion in patients with sickle cell disease

Sickle cell disease (SCD) patients are at increased risk of red blood cell (RBC) alloimmunization. Recipient inflammatory state at time of transfusion has been shown to regulate alloimmunization in murine models, but evidence is lacking in SCD patients. We retrospectively studied a cohort of alloimmunized SCD patients to determine the influence of pro-inflammatory SCD-related complications at time of transfusion on alloimmunization. For each transfusion, the presence of pro-inflammatory state, degree of RBC antigen matching, unit age, storage solution and alloantibody detection date were ascertained. Transfusion-associated pro-inflammatory events were compared between transfusions resulting and not resulting in new alloantibodies. Univariate analysis and multivariate logistic regression were performed. Fifty-two patients received 3166 pre-storage leuco-reduced transfusions of which 128 resulted in alloantibodies. Transfusions during inflammatory events were associated with increased alloantibody risk on univariate and multivariate analysis; acute chest syndrome and vaso-occlusive crisis showed strongest associations with alloimmunization. Increased antigen matching demonstrated a protective effect on alloimmunization (univariate and multivariate analysis). Although an association was seen between citrate-phosphate-dextrose (adenine) stored units and alloimmunization on univariate analysis, no effect was found on multivariate analysis. Identifying recipient pro-inflammatory states at time of transfusion that promote alloimmunization can impact RBC unit selection decisions for SCD patients at risk for alloimmunization.

High multi-cytokine levels are not a predictive marker of alloimmunization in transfused sickle cell disease patients

Patients with sickle cell disease (SCD) receive multiple red blood cell (RBC) transfusions for both prevention of and therapy for disease-related complications. In some patients, transfusion results in development of both allo- and auto-antibodies to RBC antigens. What precipitates the antibody formation is currently unclear. It has been hypothesized that a pro-inflammatory state preceding the therapeutic transfusion may be a predisposing factor. Plasma levels of ten cytokines were evaluated upon recruitment to the study of 83 children with SCD undergoing therapeutic RBC transfusions. The levels of cytokines were correlated with development of anti-RBC antibodies prior, or during seven years post recruitment. Twelve subjects displayed significantly higher levels of all cytokines examined, with pro-, as well as anti-inflammatory properties. Surprisingly, the elevated levels of cytokines were preferentially found in patients without anti-RBC allo- and/or auto-antibodies. Further, presence of high cytokine levels was not predictive of anti-RBC antibody development during the subsequent seven year follow up. These data suggest that the increased concentration of multiple cytokines is not a biomarker of either the presence of or susceptibility to the development of RBC alloimmunization.

Increased reticulocytosis during infancy is associated with increased hospitalizations in sickle cell anemia patients during the first three years of life

Objective

Among older children with sickle cell anemia, leukocyte counts, hemoglobin, and reticulocytosis have previously been suggested as disease severity markers. Here we explored whether these blood parameters may be useful to predict early childhood disease severity when tested in early infancy, defined as postnatal ages 60–180 days.

Study Design

Data from fifty-nine subjects who were followed at Children’s National Medical Center’s Sickle Cell Program for at least three years was retrospectively analyzed. Comparisons were made between white blood cell counts, hemoglobin and reticulocyte levels measured at ages 60–180 days and the clinical course of sickle cell anemia during infancy and childhood.

Results

A majority of subjects had demonstrable anemia with increased reticulocytosis. Only increased absolute reticulocyte levels during early infancy were associated with a significant increase in hospitalization during the first three years of life. Higher absolute reticulocyte counts were also associated with a markedly shorter time to first hospitalizations and a four-fold higher cumulative frequency of clinical manifestations over the first three years of life. No significant increase in white blood cell counts was identified among the infant subjects.

Conclusions

These data suggest that during early infancy, increased reticulocytosis among asymptomatic SCA subjects is associated with increased severity of disease in childhood.

An assessment of hepatitis E virus (HEV) in US blood donors and recipients: no detectable HEV RNA in 1939 donors tested and no evidence for HEV transmission to 362 prospectively followed recipients

BACKGROUND

Hepatitis E virus (HEV) infection has become relevant to blood transfusion practice because isolated cases of blood transmission have been reported and because HEV has been found to cause chronic infection and severe liver disease in immunocompromised patients.

STUDY DESIGN AND METHODS

We tested for immunoglobulin (Ig)G and IgM antibodies to the HEV and for HEV RNA in 1939 unselected volunteer US blood donors. Subsequently, we tested the same variables in pre- and serial posttransfusion samples from 362 prospectively followed blood recipients to assess transfusion risk.

RESULTS

IgG anti-HEV seroprevalence in the total 1939 donations was 18.8%: 916 of these donations were made in 2006 at which time the seroprevalence was 21.8% and the remaining 1023 donations were in 2012 when the seroprevalence had decreased to 16.0% (p < 0.01). A significant (p < 0.001) stepwise increase in anti-HEV seroprevalence was seen with increasing age. Eight of 1939 donations (0.4%) tested anti-HEV IgM positive; no donation was HEV RNA positive. Two recipients had an apparent anti-HEV seroconversion, but temporal relationships and linked donor testing showed that these were not transfusion-transmitted HEV infections.

CONCLUSION

No transfusion-transmitted HEV infections were observed in 362 prospectively followed blood recipients despite an anti-HEV seroprevalence among donations exceeding 16%.

Massive transfusion in children and neonates

Resuscitation of children and neonates with severe or refractory bleeding due to surgery or trauma often requires massive transfusion (MT). Findings from recent studies have led to a better understanding of the complex pathophysiology in massive haemorrhage and the effects of MT on haemostasis. Current management of the massively bleeding adult patient has evolved over the past few decades, shifting to early transfusion of products in a balanced ratio as part of MT protocols (MTPs). Paediatric data on successful management of MT are limited and the optimal transfusion approach is currently unknown, leading to practice variability among institutions, depending on resource availability and patients' needs. Here, we review new important concepts in the biology of massive bleeding and MT, outline important management principles and current practices, and highlight available relevant adult and paediatric data.

Absence of transfusion-associated microchimerism in pediatric and adult recipients of leukoreduced and gamma-irradiated blood components

BACKGROUND

Transfusion-associated microchimerism (TA-MC), the persistence of significant levels of donor white blood cells (WBCs) in blood recipients for prolonged periods, has been demonstrated after nonleukoreduced and leukoreduced transfusion to patients with severe traumatic injury. Development of TA-MC has not been rigorously studied in settings that do not involve massive trauma where the blood is leukoreduced and irradiated.

STUDY DESIGN AND METHODS

A cohort of 409 prospectively followed medical and surgical adult and pediatric female recipients of leukoreduced and mostly irradiated allogeneic red blood cell and platelet transfusions were evaluated to determine development of TA-MC. Four- and 8-weeks-posttransfusion samples were analyzed using quantitative real-time polymerase chain reaction for Y-chromosome sequences in WBC DNA, the marker for microchimeric cells in female blood recipients. Repeat testing was performed on Y-chromosome-positive samples to confirm microchimerism (MC), and subsequent posttransfusion samples were tested to investigate persistence of MC.

RESULTS

On initial testing, 40 of 207 (19%) adult and 44 of 202 (22%) pediatric female blood recipients demonstrated low-level MC. On repeat testing of these and additional specimens, 12 (3%) recipients demonstrated low-level transient MC, but none had persistent TA-MC similar to that seen in transfused trauma patients.

CONCLUSION

Persistence of MC was not demonstrated in adult and pediatric recipients of leukoreduced and mostly irradiated blood components. The risk of TA-MC appears to be dependent on the clinical setting and is rare other than in patients sustaining severe traumatic injury.

Acquired cytochrome C oxidase impairment in apheresis platelets during storage: a possible mechanism for depletion of metabolic adenosine triphosphate

BACKGROUND

Intracellular adenosine triphosphate (ATP) levels decline significantly during storage of platelet (PLT) products, in part due to PLT degranulation. However, metabolic ATP stores also become depleted during storage through an unclear mechanism. Since both anaerobic glycolysis and oxidative phosphorylation are important for PLT ATP production, it is possible that the reduction in metabolic ATP reflects impaired oxidative phosphorylation. To assess this, we evaluated the kinetic activity and protein expression of cytochrome C oxidase (CcOX) in stored apheresis PLTs.

STUDY DESIGN AND METHODS

Apheresis PLTs were collected and stored with agitation at 22 ± 2°C for 7 days. In vitro measurements of PLT metabolic state, function, and activation were performed on Days 0, 2, 4, and 7 of storage. Total PLT ATP content, steady-state CcOX kinetic activity, and protein immunoblotting for CcOX Subunits I and IV were also performed using isolated PLT mitochondria from simultaneously collected samples.

RESULTS

Intra-PLT ATP and steady-state PLT CcOX activity declined significantly and in a progressive manner throughout storage while steady-state levels of CcOX I and IV protein remained unchanged. Time-dependent decline in CcOX activity correlated with progressive ATP depletion over time.

CONCLUSION

During storage of apheresis PLTs for 7 days, the parallel decline in CcOX function and intra-PLT ATP suggests development of an acquired impairment in PLT oxidative phosphorylation associated with perturbed ATP homeostasis in stored PLTs.

Storage of aliquots of apheresis platelets for neonatal use in syringes with and without agitation

BACKGROUND

To facilitate volume control in neonates, platelets (PLTs) are aliquoted and stored for short periods in non-gas-permeable syringes before infusion. Although agitation of PLTs during storage in gas-permeable bags is performed to maintain their quality, the effect of syringe agitation during storage is unknown.

STUDY DESIGN AND METHODS

Double apheresis PLTs (n = 6) were collected and split, providing two identical products. On Days 2 and 4 of storage, aliquots from one bag of each pair were transferred to two syringes and stored for 6 hours on flatbed agitator or were left at 20 to 24 °C without agitation. A series of in vitro tests was performed on Days 0, 2 (Hours 0 and 6), and 4 (Hours 0 and 6). Control samples were obtained from the second matched bag that was stored on the agitator. Data were analyzed by one-way analysis of variance with differences considered significant if the p value was less than 0.05.

RESULTS

Comparable results for several PLT variables were obtained with or without agitation of the syringes. On Day 4 Hour 6, pH values were 7.18 ± 0.12 (agitated syringes) and 7.19 ± 0.1 (nonagitated syringes), and extent of shape change and hypotonic shock response measurements were not significantly different between agitated syringes and nonagitated syringes (23.7 ± 6.4 and 74.3 ± 9.8% vs. 23.3 ± 5.4 and 76.0 ± 7.6%), respectively.

CONCLUSION

Based on in vitro testing, apheresis PLT aliquots can be stored in syringes for at least 6 hours without agitation before transfusions.

Platelet disorders in children: A diagnostic approach

The investigation of children with suspected inherited platelet disorders is challenging. The causes of mucocutaneous bleeding are many, and specialized testing for platelet disorders can be difficult to access or interpret. An algorithm developed for the investigation of suspected platelet disorders provides a sequential approach to evaluating both platelet function abnormalities and thrombocytopenia. Investigation begins with a clinical evaluation and laboratory testing that is generally available, including platelet counting, peripheral blood cell morphology, and aggregometry. Based on results of initial investigations, the algorithm recommends specialized testing for specific diagnoses, including flow cytometry, immunofluorescence microscopy, electron microscopy, and mutational analysis.

Parvovirus B19 infection transmitted by transfusion of red blood cells confirmed by molecular analysis of linked donor and recipient samples

BACKGROUND

Extremely high viremic levels of parvovirus B19 (B19V) can be found in acutely infected, but asymptomatic donors. However, reports of transmission by single-donor blood components are rare. In this prospective study, paired donor-recipient samples were used to investigate the transfusion risk.

STUDY DESIGN AND METHODS

Posttransfusion plasma or blood samples from recipients were tested for B19V DNA by polymerase chain reaction, generally at 4 and 8 weeks, and for anti-B19V immunoglobulin (Ig)G by enzyme immunoassay, at 12 and 24 weeks. To rule out infection unrelated to transfusion, pretransfusion samples and linked donor's samples for each B19V DNA-positive recipient were assayed for B19V DNA and anti-B19V IgG and IgM. To confirm transmission, sequencing and phylogenetic analysis were performed.

RESULTS

A total of 14 of 869 (1.6%) recipients were B19V DNA positive, but only 1 of 869 (0.12%; 95% confidence interval, 0.0029%-0.6409%) was negative for B19V DNA and anti-B19V IgG before transfusion and seroconverted posttransfusion. This newly infected patient received 5 × 10(10) IU B19V DNA in one red blood cell (RBC) unit from an acutely infected anti-B19V-negative donor in addition to RBCs from three other donors that cumulatively contained 1320 IU of anti-B19V IgG. DNA sequencing and phylogenetic analysis showed that sequences from the linked donor and recipient were identical (Genotype 1), thus establishing transfusion transmission.

CONCLUSIONS

The 0.12% transmission rate documented here, although low, could nonetheless result in hundreds or thousands of infections annually in the United States based on calculated confidence limits. Although most would be asymptomatic, some could have severe clinical outcomes, especially in neonates and those with immunocompromised or hemolytic states.

rs660 polymorphism in Ro52 (SSA1; TRIM21) is a marker for age-dependent tolerance induction and efficiency of alloimmunization in sickle cell disease

Patients with sickle cell disease (SCD) who receive red blood cell (RBC) transfusions have a higher rate of anti-RBC (allo and auto) antibody development than other transfused subjects. We hypothesized that an incidence and/or kinetics of RBC-specific antibody formation in SCD patients is influenced by a linked inheritance of the hemoglobin beta S (HbbetaS) allele and a polymorphism rs660C/T in the neighboring Ro52 gene. We found that 75% of C/T heterozygous and only 30.8% of T/T homozygous patients that developed antibodies were first transfused before the age of five. In addition, there was a significant inverse correlation between time of exposure to antigen or number of transfusions received and the age when T/T patients received first transfusion, indicating progressive development of competence of their immune system. In contrast, this correlation was not observed in patients with C/T genotype. Finally, increased expression of Ro52 was associated with the presence of the T/T genotype. These results suggest that rs660 polymorphism is a marker of efficiency of tolerance induction in early childhood and immune competence development to RBC antigens in SCD patients of pre-teen/teen age.

Management of anemia in the newborn

Red blood cell (RBC) transfusions are administered to neonates and premature infants using poorly defined indications that may result in unintentional adverse consequences. Blood products are often manipulated to limit potential adverse events, and meet the unique needs of neonates with specific diagnoses. Selection of RBCs for small volume (5-20 mL/kg) transfusions and for massive transfusion, defined as extracorporeal bypass and exchange transfusions, are of particular concern to neonatologists. Mechanisms and therapeutic treatments to avoid transfusion are another area of significant investigation. RBCs collected in anticoagulant-additive solutions and administered in small aliquots to neonates over the shelf life of the product can decrease donor exposure and has supplanted the use of fresh RBCs where each transfusion resulted in a donor exposure. The safety of this practice has been documented and procedures established to aid transfusion services in ensuring that these products are available. Less well established are the indications for transfusion in this population; hemoglobin or hematocrit alone are insufficient indications unless clinical criteria (e.g. oxygen desaturation, apnea and bradycardia, poor weight gain) also augment the justification to transfuse. Comorbidities increase oxygen consumption demands in these infants and include bronchopulmonary dysplasia, rapid growth and cardiac dysfunction. Noninvasive methods or assays have been developed to measure tissue oxygenation; however, a true measure of peripheral oxygen offloading is needed to improve transfusion practice and determine the value of recombinant products that stimulate erythropoiesis. The development of such noninvasive methods is especially important since randomized, controlled clinical trials to support specific practices are often lacking, due at least in part, to the difficulty of performing such studies in tiny infants.

Blood component therapy

Blood component transfusion is integral in the treatment of infants and children by pediatricians, surgeons, intensivists, and hematologists/oncologists. Technologic advances in blood collection, separation, anticoagulation, and preservation have resulted in component preparation of red blood cells, platelets, white blood cells, and plasma, which are superior to whole blood used in the past. Advances in donor selection, infectious disease testing, leukoreduction filters, and gamma irradiation have made products safer. Physicians prescribing blood components should have a basic understanding of indications (and contraindications) and be cognizant of methods of preparation, proper storage conditions, and requirements for modification of blood products to prevent potential adverse effects.

Blood transfusions in children: a multi-institutional analysis of practices and complications

BACKGROUND

Blood product transfusions are a valuable health-care resource. Guidelines for transfusion exist, but variability in their application, particularly in children, remains. The risk factors that threaten transfusion safety are well established, but because their occurrence in children is rare, single-institution studies have limited utility in determining the rates of occurrence. An epidemiologic approach that investigates blood transfusions in hospitalized children may help improve our understanding of transfused blood products in this vulnerable population.

STUDY DESIGN AND METHODS

This was a nonconcurrent cohort study of pediatric patients not more than 18 years of age hospitalized from 2001 to 2003 at 35 academic children's hospitals that are members of the Pediatric Health Information System (PHIS).

RESULTS

A total of 51,720 (4.8%) pediatric patients received blood product transfusions during the study period. Red blood cells (n = 44,632) and platelets (n = 14,274) were the two most frequently transfused products. The rate of transfusions was highest among children with neutropenia, agranulocytosis, and sickle cell crisis. Asian and American Indian patients had important differences in the rate of blood transfusions and their complications. Resource use in terms of length of stay and costs were higher in patients who received transfusion. Of those patients who received transfusions, 492 (0.95%) experienced a complication from the administered blood product. This accounted for a rate of complications of 10.7 per 1,000 units transfused.

CONCLUSIONS

The administration of blood products to children is a common practice in academic children's hospitals. Complications associated with these transfused products are rare.

The epidemiology of transfusion-associated hepatitis C in a children's hospital

BACKGROUND

Children transfused with blood and blood products before 1992 are at risk for chronic hepatitis C virus (HCV) infection. To determine the prevalence of HCV infection and risks associated with acquisition of HCV, a single-institution lookback study was performed.

STUDY DESIGN AND METHODS

A total of 5473 infants and children who received transfusions between 1982 and 1992 were identified. A control population of 600 age-, sex-, race- and zip code-matched children who did not receive transfusions with the same exclusions provided background seroprevalence data. Patients were tested for antibodies to HCV, confirmed with second generation recombinant immunoblot assay (RIBA) and when appropriate quantitative and qualitative HCV RNA by reverse transcription polymerase chain reaction (PCR). Viral persistence was assessed by serial PCR determinations for HCV RNA.

RESULTS

Of the 5473 eligible patients, 4726 were locatable and 2758 were tested. Forty-three children (1.6%) were persistently anti-HCV enzyme immunoassay (EIA)-positive, confirmed by RIBA; 39 were positive for the presence of HCV RNA. Four cleared their virus as assessed by two negative HCV PCRs 6 months apart. There was a borderline higher number of children with HCV who received fresh whole blood than those who tested HCV-negative.

CONCLUSION

Because HCV infection is generally asymptomatic, children are not identified unless they are specifically tested. We identified, enrolled, tested, and confirmed a new diagnosis of HCV infection in 43 patients. As HCV treatments become increasingly effective, it is important to identify silently infected individuals, particularly when the infection was iatrogenically induced.

High levels of GDF15 in thalassemia suppress expression of the iron regulatory protein hepcidin

In thalassemia, deficient globin-chain production during erythropoiesis results in anemia. Thalassemia may be further complicated by iron overload (frequently exacerbated by blood transfusion), which induces numerous endocrine diseases, hepatic cirrhosis, cardiac failure and even death. Accumulation of iron in the absence of blood transfusions may result from inappropriate suppression of the iron-regulating peptide hepcidin by an erythropoietic mechanism. To test this hypothesis, we examined erythroblast transcriptome profiles from 15 healthy, nonthalassemic donors. Growth differentiation factor 15 (GDF15), a member of the transforming growth factor-beta superfamily, showed increased expression and secretion during erythroblast maturation. Healthy volunteers had mean GDF15 serum concentrations of 450 +/- 50 pg/ml. In comparison, individuals with beta-thalassemia syndromes had elevated GDF15 serum levels (mean 66,000 +/- 9,600 pg/ml; range 4,800-248,000 pg/ml; P < 0.05) that were positively correlated with the levels of soluble transferrin receptor, erythropoietin and ferritin. Serum from thalassemia patients suppressed hepcidin mRNA expression in primary human hepatocytes, and depletion of GDF15 reversed hepcidin suppression. These results suggest that GDF15 overexpression arising from an expanded erythroid compartment contributes to iron overload in thalassemia syndromes by inhibiting hepcidin expression.

Pathology teach and tell: fibrinogen storage disease in a child with hypofibrinogenemia and decreased ceruloplasmin

The authors present a clinical case of a patient with mild liver disease and coagulopathy. The diagnosis was reached through careful histologic examination of liver biopsy. Electron microscopy played an important role in confirming the diagnosis.

Clinical spectrum and histopathologic features of chronic hepatitis C infection in children

OBJECTIVE

To define the natural history and outcomes of children infected with hepatitis C virus (HCV) at birth or in early childhood.

STUDY DESIGN

This retrospective, prospective study identified 60 HCV-infected children through a transfusion look-back program (group 1) and by referrals (group 2). Perinatal/transfusion history, clinical course, and laboratory studies were correlated with findings from 42 liver biopsy specimens.

RESULTS

Mean age at infection was 7.1 months, and duration of infection 13.4 years. The sources of infection were blood transfusion (68%), perinatal transmission (13%), and both (7%). Most patients were asymptomatic; three referral patients had advanced liver disease at presentation. Mean alanine aminotransferase level was normal in 25%, 1 to 3 times normal in 62%, and greater than 3 times normal in 13%. Liver biopsy specimens showed minimal to mild inflammation in 71%, absent or minimal fibrosis in 88%, and bridging fibrosis in 12%. Age at infection and serum gamma-glutamyltranspeptidase correlated with fibrosis; serum alanine aminotransferase correlated with inflammation unless complicated by comorbidity. Repeat biopsies within 1 to 4 years in four patients showed no significant progression in three and cirrhosis in one. Two patients died after liver transplantation.

CONCLUSIONS

Children with chronic HCV infection are generally asymptomatic. By 13 years after infection, 12% of patients had significant fibrosis. Patients enrolled by referral had more severe liver disease than those identified through the look-back program, demonstrating the importance of selection bias in assessing the long-term outcome of HCV infection.