Red Blood Cell Exchange Research Articles

Effects of repleting organic phosphates in banked erythrocytes on plasma metabolites and vasoactive mediators after red cell exchange transfusion in sickle cell disease.

Red blood cell (RBC) exchange (RCE) transfusion therapy is indicated for certain patients with sickle cell disease (SCD). Although beneficial, this therapy is costly and inconvenient to patients, who may require it monthly or more often. Identification of blood and plasma biomarkers that could improve or help individualise RCE therapy is of interest. Here we examined relevant blood and plasma metabolites and biomarkers of vasoactivity and RBC fragility in a pilot study of SCD patients undergoing RCE using either standard RBC units or RBC units treated with a US Food and Drug Administration (FDA)-approved additive solution containing phosphate, inosine, pyruvate, and adenine ("PIPA"). In this prospective, single-blind, cross-over pilot clinical trial, patients were randomised to receive either standard RBC exchange or PIPA-treated RBC exchange transfusion with each RCE session over a 6-month treatment period. Pre- and post-transfusion blood samples were obtained and analysed for RBC O2 affinity, ATP, purine metabolites, RBC microparticles, and cell free haemoglobin. Red blood cell O2 affinity was maintained after PIPA-RCE in contrast to standard RCE, after which P50 fell (net O2 affinity rose). Plasma ATP did not change significantly after RCE using either of the RBC unit types. Exchange transfusion with PIPA-treated RBC units led to modest increases in plasma inosine and hypoxanthine. Plasma cell free haemoglobin fell after either standard or PIPA-treated RBC exchange transfusion (novel findings), and to a similar extent. RBC-derived microparticles in the plasma fell significantly and similarly after both standard and PIPA-treated RCE transfusion. In summary, treatment of RBCs with PIPA prior to RCE elicited favourable or neutral changes in key metabolic and vascular biomarkers. Further study of its efficacy and safety is recommended and could ultimately serve to improve outcomes in chronically transfused SCD patients.

Ferroportin inhibition attenuates plasma iron, oxidant stress, and renal injury following red blood cell transfusion in guinea pigs.

Red blood cell (RBC) transfusions result in the sequestration and metabolism of storage-damaged RBCs within the spleen and liver. These events are followed by increased plasma iron concentrations that can contribute to oxidant stress and cellular injury. We hypothesized that administration of a ferroportin inhibitor (FPN-INH) immediately after acute RBC exchange transfusion could attenuate posttransfusion circulatory compartment iron exposure, by retaining iron in spleen and hepatic macrophages. Donor guinea pig blood was leukoreduced, and RBCs were preserved at 4°C. Recipient guinea pigs (n = 5/group) were exchange transfused with donor RBCs after refrigerator preservation and dosed intravenously with a small-molecule FPN-INH. Groups included transfusion with vehicle (saline), 5 mg/kg or 25 mg/kg FPN-INH. A time course of RBC morphology, plasma non-transferrin-bound iron (NTBI) and plasma hemoglobin (Hb) were evaluated. End-study spleen, liver, and kidney organ iron levels, as well as renal tissue oxidation and injury, were measured acutely (24-hr after transfusion). RBC transfusion increased plasma NTBI, with maximal concentrations occurring 8 hours after transfusion. Posttransfusion iron accumulation resulted in tubule oxidation and acute kidney injury. FPN inhibition increased spleen and liver parenchymal/macrophage iron accumulation, but attenuated plasma NTBI, and subsequent renal tissue oxidation/injury. In situations of acute RBC transfusion, minimizing circulatory NTBI exposure by FPN inhibition may attenuate organ-specific adverse consequences of iron exposure.

“Dual-gene” malaria-resistance: Therapeutically-rational exchange (T-REX) of group-O sickle trait and group-O C-traittrait red blood cells can be evaluated in Benin and Nigeria

BackgroundUsing indicators of disease severity, clinicians can predict which Plasmodium falciparum (Pf) malaria patients being treated with artesunate or quinine are likely to die despite these drugs. Effective “rescue adjuncts” are needed when drugs alone are inadequate. “Therapeutically-rational exchange” (T-REX) of special malaria-resistant red blood cells (RBCs) has been proposed to optimize adjunctive exchange transfusion. MethodsStudies were reviewed that (1) quantified how group-O status and “sickle-trait” (HbAS) and “C-trait” (HbAC) hemoglobins affect Pf mortality, risk of thrombosis, or birth outcomes for women with pregnancy associated malaria (PAM), (2) reported prevalences of “dual-gene” malaria-resistant RBCs, or (3) reflected the level of exchange-transfusion and malaria-related expertise in Benin and Nigeria. ResultsData show that the malaria- and thrombosis-resistance of RBCs depend on specific genes and the patient’s clinical status and medical history. In malaria-endemic Benin and Nigeria, prevalences of “dual-gene” malaria-resistant group-O HbAS and group-O HbAC RBCs are substantial, and both malaria- and exchange-related expertise are outstanding. ConclusionsT-REX of “dual-gene” malaria-resistant RBCs is feasible in Benin and Nigeria and warrants evaluation as a rescue adjunct for 3 subsets of Pf-malaria patients. For therapeutic use, group-O HbAS RBCs are likely to be more effective than non-O HbAS RBCs for Pf-infected patients who (1) have a history of thrombosis or (2) are taking birth-control hormones while group-O HbAC RBCs may substantially improve birth outcomes for women with PAM. Studies suggest it is prudent to assume – until proven otherwise – that T-REX of “dual-gene” malaria-resistant RBCs can improve (“personalize”) rescue of these patient subsets.

Transfusion Medicine Equations Made Internet Accessible.

Multiple mathematical equations inform the practice of transfusion medicine. These equations apply to a wide range of topics: dosage of blood products, calculation of fluid volumes, and even specific treatment decisions (e.g. corrected count increment for determination of platelet refractoriness). The calculation of these equations can be complicated, prone to error, and time-consuming. A trusted source is needed to accurately perform these calculations 24 hours a day without error and without monetary cost. We sought to build internet-enabled calculators relevant to the practice of transfusion medicine. We partnered with MDCalc, an online host of medical calculators with 1 million monthly users in 196 countries, to design and host the calculators. The calculators guide users in the application of transfusion medicine equations by providing indications for use, inputs for the equations variables, error-checking, warnings for bad inputs, and interpretive guidance of the result. The following calculators were built: blood volume, corrected count increment (CCI), plasma dosage, cryoprecipitated antihemophilic factor dosage, approximate number of units for compatibility testing, maternal-fetal hemorrhage Rh(D) immune globulin dosage, intrauterine RBC transfusion dosage, neonatal polycythemia partial exchange, theoretical removal of a substance by plasmapheresis, sickle cell RBC exchange volume, peripheral blood stem cell collection, and a calculator relevant to donor lymphocyte infusion. Clinicians can now utilize this reputable and highly visible online source to access these common transfusion medicine equations at any time with an internet-enabled device (https://www.mdcalc.com/search?filter=transfusion+medicine).

Rate of Sickle Hemoglobin Recovery in Sickle Cell Disease Patients Undergoing Red Blood Cell (RBC) Exchange Transfusion Is Associated with Age of Patients and Number of RBC Units Transfused

Rate of Sickle Hemoglobin Recovery in Sickle Cell Disease Patients Undergoing Red Blood Cell (RBC) Exchange Transfusion is Associated with Age of Patients and Number of RBC Units Transfused Introduction: Automated and manual red blood cell exchange (RBCX) transfusions are useful in the primary and secondary prevention of sickle cell disease (SCD) complications (Ware et al., 2012). The ability to consistently maintain sickle hemoglobin (HbS) below target (30% or 50% depending on indication) is quite variable (Kuo et al., 2012). With emerging indications such as silent cerebral infarction, it is imperative that effective means of chronic transfusion to maintain appropriate hematological and clinical targets be identified. We hypothesize the rate of HbS recovery is dependent on the individual's hemolytic and erythropoietic rate. The purpose of this study is to evaluate the effect of the rate of erythropoiesis and hemolysis on HbS recovery in SCD patients undergoing RBCX. Methods: Fifteen (15) patients were prospectively recruited from the adult SCD transfusion program (9 automated, 6 partial manual), from December 2018 to July 2019, and followed through one exchange cycle (4 weeks). Automated and partial manual exchange transfusion protocols have been previously described elsewhere (Canadian Haemoglobinopathy Association Consensus Statement on the Care of Patients with Sickle Cell Disease in Canada, Version 2.0, Ottawa; 2015). Exclusion criteria included active hydroxyurea or erythropoietic stimulating agents use, reported ill health in the preceding 4 weeks, co-morbid hemolytic condition or non-HbSS genotype. Hemoglobin, hematocrit, HbS, lactate dehydrogenase (LDH), reticulocyte count, indirect bilirubin, and serum erythropoietin level were determined for each patient: pre- and post- first exchange, weekly for 3 weeks and pre- second exchange (the 4th week). Descriptive variables were either expressed as means ± SD or median (IQR), based on normality, while linear regression was performed for continuous variables. Co-variates were included in multivariable analysis if P < 0.10. Multivariable linear regression was conducted to examine the potential association between the change in HbS over one RBCX cycle and age of patients, pre-RBCX hematocrit, LDH, and number of RBC units transfused. Results: We identified 36 eligible patients from the Program database, after which 15 consented to participate in the study. Mean age was 32.9 ± 12.3 years, consisting of 7 males and 8 females. There was an association between the rate of change in HbS and age of patients (p=0.035), pre-RBCX hematocrit (p=0.030) and number of transfused RBC units (p=0.030). LDH showed a trend towards reduced rate of change in HbS (p=0.069). Rate of change in HbS was not associated with automated vs. partial RBCX (Figure), female vs. male patients, pre-RBCX HbS, erythropoietin, indirect bilirubin, reticulocyte and age of transfused RBCs. Age of patients (p<0.001) and number of units transfused (p=0.010) were independently associated with the rate of change of HbS, after adjusting for hematocrit and LDH. For every decade increase in age, the rate of HbS recovery was 3% lower in one RBCX cycle. For each additional unit of RBC exchanged, the rate of HbS recovery was 0.78% higher in one RBCX cycle. Conclusion: This is the first study to evaluate the determinants of variability in the rate of HbS recovery in SCD patients on RBCX. Age of patients and number of RBC units transfused may underlie the significant variability in achieving HbS targets in SCD patients on RBCX. We failed to show a significant difference in the rate of change in HbS between automated and partial manual exchange transfusion. Reduction in HbS recovery with advancing age may be related to erythropoietic reserve in the patients' marrow. However, the influence of units of RBC recovery appeared paradoxical, and the finding may be spurious due to small sample size. It may therefore be possible to appropriately titrate the number of RBC units with advancing age of SCD patients with a view to achieving desired HbS targets. Disclosures Patriquin: Ra Pharma: Consultancy, Research Funding; Apellis: Consultancy, Honoraria, Research Funding; Alexion: Consultancy, Honoraria, Research Funding; Octapharma: Consultancy, Honoraria, Research Funding. Kuo:Agios: Consultancy; Alexion: Consultancy, Honoraria; Apellis: Consultancy; Bioverativ: Other: Data Safety Monitoring Board; Bluebird Bio: Consultancy; Celgene: Consultancy; Novartis: Consultancy, Honoraria; Pfizer: Consultancy.

360o View of a Day Hospital Program Performing Exchange Transfusion and Outpatient Pain Management on Adults with Sickle Cell Disease

Purpose: Therapeutic erythrocytapheresis, known also as automated red blood cell exchange transfusion (RBC exchange), is standard of care for patients with sickle cell disease (SCD) presenting with severe complications and for primary prevention of CNS events in those with increased risks. There is limited data on the framework and experience of performing this procedure in a large adult population and even less on challenges and outcomes. Here, we present demographic and statistical data highlighting characteristics of the chronic exchange transfusion program at a comprehensive and multidisciplinary adult SCD center. Methods: Data were collected from adults (18 years and older) with a diagnosis of SCD that were receiving blood transfusions in the outpatient treatment facility from September 1st, 2017 to August 31st, 2018. Data gathered included age, gender, procedure indications and frequency, hemoglobin S percentage (Hb S%), target pre and post Hb S%, ferritin trend, and type of intravascular device used for procedure. Three hundred and forty-four (344) episodes of transfusions, were performed in 52 unique patients, corresponding to 21 % of the unique patients treated at our center during that period. Two hundred and sixty-two (262) of the transfusion procedures were RBC exchanges. These RBC exchanges were performed in 35 (14%) of the unique patients. Since a sizable proportion of our patients received pain treatment during RBC exchange, we explored how the pain visual analog score (VAS) changed while undergoing pain treatment during RBC exchange and in relation to multiple opiate doses. Descriptive and basic statistical analysis were performed on the data obtained for those receiving RBC exchange alone or in combination with pain management. Results: Thirty-five unique patients underwent RBC exchange during the study period. All but two (2) patients had the procedure via an implanted dual lumen Vortex port, one (1) by an arteriovenous fistula and one (1) via his native veins. Most of the RBC exchanges were performed as part of a chronic transfusion program for one of the following indications: primary prevention of stroke; secondary prevention of stroke; recurrent acute chest syndrome (ACS); intractable pain; presence of multiple comorbidities including pulmonary hypertension, chronic kidney disease and intractable leg ulcers. One patient received RBC exchange in preparation for bone marrow transplant. The three (3) other patients that only received one (1) RBC exchange during that period were previously on exchange transfusion but discontinued the procedure due lack of venous access or benefit from the procedure. The frequency of RBC exchange varied depending of the patient's specific indication for the procedure and the ability to reach a target Hb S% goal of < 30%. The RBC exchange occurred in patients as frequently as every four (4) to seven (7) weeks. The number of transfusions per patient/year ranged from one (1) to thirteen (13) with a mean and median of eight (8). Number of RBC units used per procedure ranged from four (4) to thirteen (13) with a mean of eight (8.6), with each unique patient usually receiving the same amount. Twenty-three (66%) unique patients received, at least once, acute pain treatment - oral, intravenous, or a combination during RBC exchange. The mean change of VAS between presentation and end of the pain management period was 1.9 (p<0.0001). Conclusion: Our data shows that therapeutic RBC exchange are performed on a regular basis on a small but significant subgroup of patients living with SCD and treated at a comprehensive SCD center. Intravenous opioid management of acute pain can be effectively performed while receiving RBC exchange which provides patients with multimodal interventions in the outpatient setting. The relationship between change in VAS and concurrent transfusion deserves further investigation. Although there are standard indications for RBC exchange, we and others use it for indications for which there is low level of evidence or no evidence of efficacy (i.e. leg ulcers). We found that there great variability on the frequency of the procedure, total number of RBC exchanges per year and number of RBC units used. Prospective studies are needed to better understand the short and long-term effects, complications and outcomes of chronic RBC exchange in adults living with SCD. Figure Disclosures Kato: Bayer: Research Funding; Novartis, Global Blood Therapeutics: Consultancy, Research Funding. De Castro:Pfizer: Consultancy; Novartis: Membership on an entity's Board of Directors or advisory committees; Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees.

Safe and Efficient Peripheral Blood Stem Cell Collection in Patients with Sickle Cell Disease Using Plerixafor

Background: Hematopoietic stem cell (HSC) gene therapy is potentially curative for sickle cell disease (SCD) provided that a sufficient quantity of long-term engrafting CD34+ HSCs can be safely collected and infused. In patients with SCD, peripheral blood (PB) mobilization with granulocyte colony stimulating factor is contraindicated, and steady-state bone marrow (BM) harvesting is associated with suboptimal HSC quality and yield. Hence, agents that promote safe and effective peripheral HSC mobilization in SCD are required. Methods: This phase I multicenter study investigated the safety and efficacy of plerixafor mobilization (240 µg/kg) followed by apheresis, processing, and HSC enrichment in 15 adult subjects with SCD (NCT03226691). Hydroxyurea treatment was stopped at least two weeks prior to mobilization and all participants who were not receiving long-term transfusion therapy received prophylactic red blood cell exchange prior to plerixafor administration to achieve a target sickle Hb (HbS) <30%. The primary endpoint was efficient collection of PB HSCs (target 2.0x106 CD34+ cells/kg, minimum 1.5x106) after plerixafor mobilization without serious adverse events (SAEs). Collection products were assessed for total WBC, CD34+, CD3+, and CD19+ composition by flow cytometry. Spearman's correlation test was used to assess the relationship between baseline CD34/µL, total CD34+ cells/kg collected, and total blood volume processed. Findings: Fifteen participants with SCD (HbSS n=13, HbSC n=1, HbSβ+ n=1) who met inclusion criteria were enrolled at St. Jude Research Children's Hospital (n=3) or NIH (n=12) between July 2017 and February 2019. All participants except one successfully met the minimum target CD34+ cells/kg yield with 2 or fewer mobilization and apheresis procedures, with almost half the participants (n=7) achieving ≥5.0x106 CD34+ cells/kg. The total WBC count increased by an average of 3.2-fold over baseline (range 1.7-5.0) to an average peak WBC count of 26.5x103/µL (range 14.1-47.4), with counts returning to baseline within 1-2 days. Median total WBC, CD34+, CD19+, and CD3+ cells/kg in the final apheresis product after one (n=12) or two (n=3) collection procedures were 0.9 x109 WBC/kg (range 0.4-1.7), 4.5x106 CD34+ cells/kg (range 0.9-12.0), 3.4x108 CD19+ cells/kg (range 0.5-4.9), and 3.6x108 CD3+ cells/kg (range 1.7-7.3), respectively. There was a strong positive correlation between baseline CD34/µL and total CD34+ cells/kg (rs = 0.7776, 95% CI 0.446-0.9215, p = 0.001). Participants with the lowest pre-apheresis CD34 cell count generally underwent higher blood volume processing (rs = - 0.1443, 95% CI -0.6075 to 0.3921, p = 0.59) in an effort to achieve target yields. However, higher blood volume processing did not translate to higher total CD34+ cells/kg collection yields (rs = - 0.2104, 95% CI -0.6488 to 0.3328, p = 0.43). A median of 97% of positively selected CD34+ cells were CD34high (range 73.6-99.4%) compared to 1.3% CD34low (range 0.09-24.4%) phenotype suggesting enrichment for long-term engrafting HSCs. Seven grade III AEs (two non-pain and five pain related) and one grade IV AE (non-pain - hemolysis) occurred and each resolved with symptomatic treatment. Plerixafor mobilization was overall safe and in most cases generated CD34+ cell yields that were sufficient for both genetic modification and back-up allogeneic transplantation (median cell yield 4.2x106 CD34+ cells/kg). Interpretation: This first multi-institutional phase I study suggests the efficiency and safety of plerixafor mobilization and apheresis collection in 15 adult subjects with SCD. The primary endpoint to obtain a target of 2.0x106 CD34+ cells/kg from the PB was exceeded without SAEs. Importantly, immunophenotyping data suggest that for individuals with SCD, the plerixafor mobilized cell product is more enriched for long-term engrafting HSCs compared to CD34+ cells isolated from BM. Given the risks of general anesthesia and the low quality and yield of CD34+ cells harvested from the BM of individuals with SCD, plerixafor mobilization represents a safe and potentially superior alternative for HSC isolation. Disclosures Hankins: Novartis: Research Funding; ASPHO: Honoraria; NHLBI: Research Funding; LYNKS Foundation: Research Funding; NHLBI: Honoraria; National Committee for Quality Assurance: Consultancy; Global Blood Therapeutics: Research Funding; Bluebird Bio: Consultancy. Sharma:Vertex Pharmaceuticals: Other: Study PI; Doris Duke Foundation: Research Funding. Weiss:GlaxoSmithKline: Consultancy; Rubius INC: Consultancy; Esperian: Consultancy; Beam Therapeutics: Consultancy; Cellarity INC: Consultancy.

Excellent Survival and Immune Reconstitution Following Matched/Mismatched Unrelated and Mismatched Related Transplantation in Adult Patients with Sickle Cell Disease: Updated Results from a Single Center Experience

Excellent Survival and Immune Reconstitution Following Matched/Mismatched Unrelated and Mismatched Related Transplantation in Adult Patients with Sickle Cell Disease: Updated Results from a Single Center Experience

Identification of the Pitfalls in the Attempted Use of Extracorporeal Membrane Oxygenation in an Adult Patient with Sickle Cell Disease and Severe Acute Chest Syndrome

BACKGROUNDAcute chest syndrome (ACS) is a life-threatening complication of sickle cell disease (SCD). Despite being the leading cause of death in adult patients with SCD, current recommendations for treatment of ACS remain largely supportive, consisting of pain management, aggressive fluid resuscitation, respiratory support, and transfusion therapy. Despite these measures, it is not uncommon for patients to require intubation due to progression to acute respiratory distress syndrome (ARDS). Recently, there have been a number of case reports that have successfully utilized extracorporeal membrane oxygenation (ECMO) for the management of ACS in those patients who fail to respond to conventional therapy [Kuo et al., 2013, Sewaralthahab et al, 2018]. However, the use of ECMO in this patient population remains uncommon, and further evaluation of this intervention is needed. This case report details an unsuccessful attempt at the use of ECMO in the case of ARDS secondary to ACS, in an attempt to identify critical pitfalls.CASE REPORTA 32-year-old African-American female with HbSS disease on hydroxyurea therapy was transferred from an outside hospital following 3 days of respiratory decompensation. Prior to arrival, patient coded once at the outside hospital and once on transfer. Veno-arterial ECMO was initiated with improving oxygen saturation and volume status with continuous renal replacement therapy. To maintain an ECMO-specific goal hemoglobin level of 10 g/dL, 1:1 manual exchange transfusions were performed due to an inability to access equipment for automated RBC exchange. Once stable enough for CT, patient was found to have gray-white inversion suggestive of irreversible severe brain damage. Following another 28 days of supportive care with no neurologic improvement, the family decided to withdraw care, and the patient expired.CONCLUSIONWhile unsuccessful, this patient's case revealed a need for defining parameters regarding the initiation of ECMO in SCD patients with severe ACS. A review of previously-published literature has shown that the use of ECMO for the management of ARDS in adults is more efficacious than conventional ventilation support [Peek et al., 2009]. In patients with SCD, this improvement in efficacy is not readily reproduced, likely due to unique challenges presented by the pathophysiology of the disease. Notably, patients with SCD face additional risks of venous thromboembolism and strokes while on prolonged bed rest due to a baseline prothrombotic state [Sewaralthahab et al., 2018]. A systematic review of available case reports is needed to develop a protocol for the management of severe ACS that takes SCD-specific risks into account.The present report also makes a case for the training of providers in the early recognition of severe ACS in SCD patients. SCD remains largely undertreated in the United States, likely due to a complex interplay of patient, physician, and institutional factors. Had this patient been transferred immediately to a facility better equipped to provide a higher level of care, her condition could have arguably taken a different course. Despite the aforementioned challenges, ECMO remains a feasible option for the management of severe ACS in patients with SCD, and efforts should be made to standardize current treatment protocols.REFERENCESKuo KW, Cornell TT, Shanley TP, Odetola FO, and Annich GM. The use of extracorporeal membrane oxygenation in pediatric patients with sickle cell disease. Perfusion. 2013 September; 28(5): 424-432.Peek GJ, Mugford M, Tiruvoipati R, Wilson A, Allen E, Thalanany M, et al. Efficacy and economic assessment of conventional ventilatory support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR): a multicentre randomised controlled trial. The Lancet. 2009 October; 374(9698): 1351-1363.Sewaralthahab SS, Menaker J, Law JY. Successful use of veno-venous extracorporeal membrane oxygenation in an adult patient with sickle cell anemia and severe acute chest syndrome. Hemoglobin. 2018 42(1): 65-67.DisclosuresNo relevant conflicts of interest to declare.

Red Blood Cell Exchange Transfusion as a Novel Treatment for GLUT1 Deficiency Syndrome

Red Blood Cell Exchange Transfusion as a Novel Treatment for GLUT1 Deficiency Syndrome

Haptoglobin therapy has differential effects depending on severity of canine septic shock and cell-free hemoglobin level.

During sepsis, higher plasma cell-free hemoglobin (CFH) levels portend worse outcomes. In sepsis models, plasma proteins that bind CFH improve survival. In our canine antibiotic-treated Staphylococcus aureus pneumonia model, with and without red blood cell (RBC) exchange transfusion, commercial human haptoglobin (Hp) concentrates bound and compartmentalized CFH intravascularly, increased CFH clearance, and lowered iron levels, improving shock, lung injury, and survival. We now investigate in our model how very high CFH levels and treatment time affect Hp's beneficial effects. Two separate canine pneumonia sepsis Hp studies were undertaken: one with exchange transfusion of RBCs after prolonged storage to raise CFH to very high levels and another with rapidly lethal sepsis alone to shorten time to treat. All animals received continuous standard intensive care unit supportive care for 96 hours. Older RBCs markedly elevated plasma CFH levels and, when combined with Hp therapy, created supraphysiologic CFH-Hp complexes that did not increase CFH or iron clearance or improve lung injury and survival. In a rapidly lethal bacterial challenge model without RBC transfusion, Hp binding did not increase clearance of complexes or iron or show benefits seen previously in the less lethal model. High-level CFH-Hp complexes may impair clearance mechanisms and eliminate Hp's beneficial effect during sepsis. Rapidly lethal sepsis narrows the therapeutic window for CFH and iron clearance, also decreasing Hp's beneficial effects. In designing clinical trials, dosing and kinetics may be critical factors if Hp infusion is used to treat sepsis.

Reversal of a rheologic cardiomyopathy following hematopoietic stem cell transplantation for sickle cell disease

AbstractCardiac complications have been well-described in sickle cell disease; however, it has been rare to see improvements in cardiac abnormalities following any interventions. Previous work has shown no significant structural changes after treatment with hydroxyurea. The cardiac effects of red blood cell exchange transfusion (RBCx) and hematopoietic stem cell transplantation (HSCT) have not been well described. We studied 56 patients undergoing HSCT (41 HLA-matched, 15 haploidentical), of whom 32 had RBCx within 3 months before HSCT. Echocardiograms and laboratory parameters were obtained at baseline, and at 3, 6, and 12 months following HSCT. Although hemolytic parameters and anemia improved following RBCx, there was a small increase in left ventricular volume index. Following successful HSCT, however, there were significant improvements in cardiac size, function, and diastolic filling parameters at 3 months followed by continued smaller improvements up to 1 year. There was a significant improvement in N-terminal pro B-type natriuretic peptide levels and a trend toward improvement in 6-minute walk time 1 year after HSCT. The magnitude of cardiac improvement seen following HSCT was comparable to that observed following correction of a volume overload state as seen in pregnancy or after repair of chronic valvular regurgitation. Further studies in sickle cell disease patients will help delineate which cardiac complications and what level of severity should be considered indications for HSCT.

2397 Successful Reversal of Sickle Cell Intrahepatic Cholestasis Associated Acute Liver Failure With Combined pRBC and Plasma Exchange Transfusion: A Case Report

INTRODUCTION: Sickle cell intrahepatic cholestasis (SCIC) with acute liver failure (ALF) is a severe variant of Sickle cell hepatopathy that has significant mortality despite aggressive supportive therapy. Even though packed red blood cells (pRBCs) exchange has vastly improved outcomes, there is little evidence on alternative therapies to treat those who show inadequate response to pRBC exchange transfusion (ET). CASE DESCRIPTION/METHODS: A 37-year-old African American male with Hemoglobin SS disease complicated by chronic pain and nephropathy ESRD on dialysis, who was referred to our liver transplant program for ALF. Patient presented with lethargy and fever. Upon arrival he was somnolent, jaundiced, cardiopulmonary and abdominal exam was unremarkable, no focal neurological deficits but presence of asterixis was noted. Hb 6 g/dL, WBC 13,000/µL, Platelet 147,000/µL, corrected reticulocyte count 5.9%, LDH 1816 IU/L, Total bilirubin 49 mg/dl, direct bilirubin 37 mg/dL, ALT 112 IU/L, AST 259 IU/L, ALP 296 IU/L, albumin 3.5 g/dL and INR 1.9. CT head was unremarkable. MRCP revealed hepatomegaly, cholecystectomy without evidence of biliary obstruction. Ultrasound duplex liver showed patent hepatic vessels. Other causes of ALF including drugs, alcohol, acetaminophen, and viral hepatitis etiology were excluded. N-acetylcysteine infusion protocol was initiated. Patient received 10 units pRBC ET. Despite successful reduction of HbS fraction from 79.5% to 16%, the patient remained encephalopathic with asterixis and developed severe headache. Furthermore, bilirubin and INR continued to rise (Figure 1). Transjugular liver biopsy revealed portosystemic gradient of 20 mmHg. Liver pathology showed sinusoidal distension by sickled erythrocytes, zone 3 predominant intracanalicular cholestasis with ballooned hepatocytes and hepatocyte siderosis (Figure 2). Total 9L of plasma ET was performed on 2 consecutive days with successful reversal of headache, encephalopathy, and coagulopathy. His bilirubin levels continue to decline. He did not require a liver transplant and was discharged home with prophylaxis pRBC ET to maintain HbS fraction < 30%. DISCUSSION: SCIC with ALF is rare with significant mortality. Plasma ET was used in our patient whom ALF was refractory despite adequate pRBC ET (HbS < 30%). Larger studies are needed to evaluate plasma ET benefit in sickle cell disease patients with end organ damage, regarding treatment outcome as well as transplant-free survival.

Clinical phenotypes and outcomes of precapillary pulmonary hypertension of sickle cell disease.

Precapillary pulmonary hypertension (PH) is a devastating complication of sickle cell disease (SCD). Little is known about the influence of the SCD genotype on PH characteristics. To describe clinical phenotypes and outcomes of precapillary PH due to SCD according to disease genotype. A nationwide multicentre retrospective study including all patients with SCD-related precapillary PH from the French PH Registry was conducted. Clinical characteristics and outcomes according to SCD genotype were analysed. 58 consecutive SCD patients with precapillary PH were identified, of whom 41 had homozygous for haemoglobin S (SS) SCD, three had S-β0 thalassaemia (S-β0 thal) and 14 had haemoglobin SC disease (SC). Compared to SC patients, SS/S-β0 thal patients were characterised by lower 6-min walk distance (p=0.01) and lower pulmonary vascular resistance (p=0.04). Mismatched segmental perfusion defects on lung scintigraphy were detected in 85% of SC patients and 9% of SS/S-β0 thal patients, respectively, and 50% of SS/S-β0 thal patients had heterogeneous lung perfusion without segmental defects. After PH diagnosis, 31 patients (53%) received medical therapies approved for pulmonary arterial hypertension, and chronic red blood cell exchange was initiated in 23 patients (40%). Four patients were managed for chronic thromboembolic PH by pulmonary endarterectomy (n=1) or balloon pulmonary angioplasty (n=3). Overall survival was 91%, 80% and 60% at 1, 3 and 5 years, respectively, without influence of genotype on prognosis. Patients with precapillary PH related to SCD have a poor prognosis. Thrombotic lesions appear as a major component of PH related to SCD, more frequently in SC patients.

Therapeutic apheresis during pregnancy: A single center experience

IntroductionTherapeutic apheresis (TA) represents a treatment option for pre-existing conditions or diseases occurring during gestation. Although pregnancy is not a contraindication per se, due to the lack of evidence-based guidelines and presumed risk of maternal/fetal adverse events there is a general resistance to its application. Material and methodsBetween January 2005 and August 2017, at the Apheresis Unit of the University Hospital of Padua 936 TA procedures were performed during 57 pregnancies in 48 patients: 813 Plasma Exchange sessions, 119 Immunoadsorptions, 4 Red Blood Cell exchanges. The treated disease were as follows: antiphospholipid syndrome (18 patients), autoimmune congenital heart block (18), myasthenia gravis (3), Rh alloimmunization (2), systemic sclerosis (1), suspected autoimmune encephalitis (1), severe hypertriglyceridaemia (1), post partum hemolytic-uremic syndrome (1), sickle cell disease (1), lupus nephritis (1) and thrombotic thrombocytopenic purpura (1). ResultsIn the time period considered the apheresis sessions applied to pregnant women were 7.1% of the total (n = 13.251). The median age at the first treatment was 33 years. The median week of gestation (WG) at the beginning of treatments was 21. Twenty (2.1%) sessions were complicated by adverse events, none requiring or prolonging hospitalization. There were 50 live births, 5 spontaneous abortions and 2 voluntary terminations of pregnancy. Median WG at delivery was 35 and caesarean section was performed in 46 cases. ConclusionsOur data showed that TA in pregnancy is well tolerated. Close collaboration between clinician, obstetrician and TA specialist is crucial to ensure a good outcome of high-risk pregnancies.

Reversal of Severe Multiorgan Failure Associated With Sickle Cell Crisis Using Plasma Exchange: A Case Series.

Red blood cell exchange (RBCE) is the standard of care for patients with sickle cell disease (SCD) who present with severe vaso-occlusive crisis (VOC). However, subsets of these critically ill patients have progressive multiorgan failure (MOF) despite RBCE therapy. The purpose of this case series is to describe the use of plasma exchange (PLEX) for the treatment of SCD-related MOF that is refractory to RBCE. A retrospective case review of patients with severe MOF from sickle cell crisis unresponsive to RBCE who underwent PLEX in a 14-bed adult medical intensive care unit (ICU) at a tertiary care university hospital over a 4-year time period. Key laboratory data including complete blood count, indices of hemolysis, and markers of organ failure were recorded before and after both RBCE and PLEX. Our primary objective is to evaluate the effectiveness of PLEX, in addition to RBCE, on organ dysfunction, laboratory indices, and mortality. Of the 7 patients, 6 survived. Of the patients who survived, all remained hemodynamically stable during PLEX sessions and showed both clinical and laboratory evidences of improvement in hemolysis and organ function. Average time from completion of first PLEX treatment to initial laboratory signs of organ failure reversal for patients who survived was 15.6 hours, the average length of stay in the ICU was 5.6 days, and the average total length of stay in the hospital was 14 days. Plasma exchange, in addition to RBCE, may be a novel synergistic treatment option to decrease risk of mortality in patients with refractory VOC and MOF.

Management of Sickle Cell Intrahepatic Cholestasis: An Argument in Favor of Automated Exchange Transfusion

Sickle cell disease patients are commonly treated at transfusion medicine services, and understanding of the hepatic manifestations of the disease is key for optimal management, specifically, in individuals presenting with sickle cell intrahepatic cholestasis (SCIC). SCIC represents a rare, severe hepatic crisis wherein sinusoidal red cell sickling leads to massive hepatocyte dysfunction and cholestatic laboratory findings. Acute SCIC is defined by abdominal pain with progressive hepatic injury associated with hyperbilirubinemia, renal failure, encephalopathy, and coagulopathy. Patients are generally managed with red blood cell exchange transfusion (RBCEx), when available, as this is a potentially fatal condition. Simple transfusion may be utilized in resource-poor environment or when patients refuse RBCEx. As less than 50 adult cases have been described in the literature, many of them with limited follow-up, randomized clinical trials comparing RBCEx with other treatments are currently unfeasible. Likewise, a chronic form exists, but is less well characterized, and is associated with persistent bilirubinemia and a variable course in terms of progressive hepatic disease. We undertake a brief review of the literature and discuss two cases of SCIC managed with RBCEx at our institution.

Metabolic impact of red blood cell exchange with rejuvenated red blood cells in sickle cell patients.

Red blood cell exchange (RCE) transfusions are a mainstay in the treatment of sickle cell anemia (SCA), and allow a temporary restoration of physiological parameters with respect to erythrocyte oxygen carrying capacity and systems metabolism. Recently, we noted that 1) RCE significantly impacts recipients' metabolism in SCA; 2) fresh and end-of-storage red blood cell (RBC) units differently impact systems of metabolism in healthy autologous recipients; and 3) phosphate/inosine/pyruvate/adenine (PIPA) solution reverses the metabolic age of stored RBCs. Therefore, we hypothesized that RCE with PIPA-treated RBC units could further increase the metabolic benefits of RCE in SCA patients. Circulating plasma and erythrocytes were collected from patients with SCA before and after RCE, with either conventional or PIPA-treated RBC units, prior to metabolomics analyses. Consistent with prior work, RCE significantly decreased circulating levels of markers of systemic hypoxemia (lactate, succinate) and decreased plasma levels of acyl-carnitines and amino acids. However, PIPA-treated exchanges were superior to untreated RCEs, with a higher energy state and an increased capacity to activate the pentose phosphate pathway and glutamine metabolism. In addition, RBCs and plasma from recipients of PIPA-treated RBC units resulted in significantly decreased levels of post-transfusion plasticizers, though at the expense of higher circulating levels of oxidized purines (hypoxanthine, xanthine, and the antioxidant urate). Transfusion of PIPA-treated RBCs further increases the metabolic benefits of RCE to patients with SCA, significantly reducing the levels of post-transfusion plasticizers.

Pathology's historic 2019 incoming residents: Why “the internationalization of pathology” may markedly advance transfusion medicine and cellular therapeutics

ObjectivesThis study had two objectives: (1) to determine if, in the United States of America (US), the proportion of non-US citizen international medical graduates (non-US IMGs) entering pathology residencies had increased (again) in 2019 and (2) to assess how this multi-year trend might impact transfusion medicine in the US. MethodsThe most recent (2019) “National Resident Matching Program” (NRMP) data were analyzed. To assess potential future impact, using controversies related to Plasmodium falciparum (Pf) malaria, conflicting US and non-US perspectives were reviewed. Differences between published US and non-US views were identified regarding, for example, the value of Pf-resistant (“variant”) red blood cells (RBCs) and exchange transfusions. ResultsYear 2019 is the first year non-US IMGs were the largest group to fill residency-training positions for a major US specialty via the “Main Residency Match.” Also notable, US and non-US views were found to differ markedly regarding (1) the value and safety of Pf-resistant RBC variants and exchange transfusions, and (2) the threat of drug-resistant Pf-malaria parasites. Non-US clinicians and researchers seem more concerned about Pf-malaria, and their interest in cellular therapies seems greater and more optimistic. ConclusionsIn 2019, the historically high proportion of non-US IMGs among incoming pathology residents dramatically highlights the steady demographic shift that began years ago: “the internationalization of pathology” in the US. Fortunately, a review of publications related to exchange transfusion, Pf-malaria, and variant RBCs suggests non-US IMGs may markedly promote and advance cell therapies such as therapeutically-rational exchange (T-REX) of disease-resistant RBCs.

Red blood cells modulate structure and dynamics of venous clot formation in sickle cell disease

AbstractSickle cell disease (SCD) is associated with chronic activation of coagulation and an increased risk of venous thromboembolism. Erythrocyte sickling, the primary pathologic event in SCD, results in dramatic morphological changes in red blood cells (RBCs) because of polymerization of the abnormal hemoglobin. We used a mouse model of SCD and blood samples from sickle patients to determine if these changes affect the structure, properties, and dynamics of sickle clot formation. Sickling of RBCs and a significant increase in fibrin deposition were observed in venous thrombi formed in sickle mice. During ex vivo clot contraction, the number of RBCs extruded from sickle whole blood clots was significantly reduced compared with the number released from sickle cell trait and nonsickle clots in both mice and humans. Entrapment of sickled RBCs was largely factor XIIIa–independent and entirely mediated by the platelet-free cellular fraction of sickle blood. Inhibition of phosphatidylserine, but not administration of antisickling compounds, increased the number of RBCs released from sickle clots. Interestingly, whole blood, but not plasma clots from SCD patients, was more resistant to fibrinolysis, indicating that the cellular fraction of blood mediates resistance to tissue plasminogen activator. Sickle trait whole blood clots demonstrated an intermediate phenotype in response to tissue plasminogen activator. RBC exchange in SCD patients had a long-lasting effect on normalizing whole blood clot contraction. Furthermore, RBC exchange transiently reversed resistance of whole blood sickle clots to fibrinolysis, in part by decreasing platelet-derived PAI-1. These properties of sickle clots may explain the increased risk of venous thromboembolism observed in SCD.