Red Blood Cell Survival Research Articles

Role of oral lactoferrin as a source of iron supplementation in correction of anemia in pediatric patients with chronic kidney disease stages 2–4

Background Children with chronic kidney disease (CKD) have multiple risk factors for anemia such as primary erythropoietin deficiency, blood loss, decreased red blood cell (RBC) survival, bone marrow suppression, iron deficiency, inflammation and infection, malnutrition, hyperparathyroidism, vitamin B12 and folate deficiency, aluminum toxicity, and carnitine deficiency. This study was performed to evaluate the effect of oral bovine lactoferrin on patients with iron deficiency with CKD stages 2–4. Patients and methods This follow-up cohort clinical study was conducted on children with CKD in the conservative clinic, Pediatric Nephrology Unit, Children's Hospital, Ain Shams University. It included 45 pediatric patients with CKD stages from 2 to 4 for 6 months without a control group. This is a follow-up case study in which all the included patients were on erythropoietin therapy ranging from 150 to 300 IU/kg once per week. The patients were subjected to history and laboratory evaluation, including hemoglobin (Hb), serum iron, serum ferritin, and total iron-binding capacity (TIBC), which were done for the patients at baseline and 6 months after treatment with bovine lactoferrin for 6 months. Results Blood Hb and RBC volume were significantly increased beginning from first month after oral lactoferrin therapy, serum iron and serum ferritin were significantly increased 6 months after intervention, and serum TIBC was significantly decreased after intervention. The current study had shown no significant difference between males and females regarding laboratory changes 6 months after intervention. Laboratory improvements were significantly lowest among cases with stage 4, followed by stage 3, and the highest among cases with stage 2. There was a decrease in all anemia clinical manifestations after 6 months of lactoferrin administration; the differences were significant only in easy fatigability, constipation, and gastrointestinal upset, which were the most frequent adverse effects. Conclusion Oral lactoferrin was found to be effective in treating iron-deficiency anemia regarding blood Hb, blood RBCs, serum iron, serum ferritin, and TIBC in association with erythropoietin therapy. The effect declines with the progression of CKD.

Synthetic Amphipathic β-Sheet Temporin-Derived Peptide with Dual Antibacterial and Anti-Inflammatory Activities.

Temporin family is one of the largest among antimicrobial peptides (AMPs), which act mainly by penetrating and disrupting the bacterial membranes. To further understand the relationship between the physical-chemical properties and their antimicrobial activity and selectivity, an analogue of Temporin L, [Nle1, dLeu9, dLys10]TL (Nle-Phe-Val-Pro-Trp-Phe-Lys-Phe-dLeu-dLys-Arg-Ile-Leu-CONH2) has been developed in the present work. The design strategy consisted of the addition of a norleucine residue at the N-terminus of the lead peptide sequence, [dLeu9, dLys10]TL, previously developed by our group. This modification promoted an increase of peptide hydrophobicity and, interestingly, more efficient activity against both Gram-positive and Gram-negative strains, without affecting human keratinocytes and red blood cells survival compared to the lead peptide. Thus, this novel compound was subjected to biophysical studies, which showed that the peptide [Nle1, dLeu9, dLys10]TL is unstructured in water, while it adopts β-type conformation in liposomes mimicking bacterial membranes, in contrast to its lead peptide forming α-helical aggregates. After its aggregation in the bacterial membrane, [Nle1, dLeu9, dLys10]TL induced membrane destabilization and deformation. In addition, the increase of peptide hydrophobicity did not cause a loss of anti-inflammatory activity of the peptide [Nle1, dLeu9, dLys10]TL in comparison with its lead peptide. In this study, our results demonstrated that positive net charge, optimum hydrophobic−hydrophilic balance, and chain length remain the most important parameters to be addressed while designing small cationic AMPs.

P-060: A HIGHER GRANULOCYTE-LYMPHOCYTE RATIO IS ASSOCIATED WITH IMPROVED RED BLOOD CELL INDICES AND AGE IN DUFFY ANTIGEN-NEGATIVE SICKLE CELL DISEASE PATIENTS.

Purpose: A higher Neutrophil-Lymphocyte ratio (NLR) has been associated with poor prognosis in many diseases. Most Africans are neutropenic due to the duffy antigen null status. The duffy antigen null status however, has been associated with a higher risk of organ damage in people living with sickle cell disease (SCD). We therefore sought to determine the effect of the proportion of these blood cells to one another on SCD prognosis in Nigeria. Materials and methods: One hundred and thirty (130) sickle cell disease patients in steady state and 117 healthy age- and sex-matched controls were recruited from a tertiary institution in Nigeria. All the participants gave informed consents and blood samples were taken for Full Blood Count and phenotyping by High Performance Liquid Chromatography. Demographic and clinical details were obtained by questionnaire administration. Neutrophils make up over 90% of granulocytes, hence the granulocyte-lymphocyte ratio was determined from the available absolute counts of granulocytes and lymphocytes. A subset of 110 patients who were not on hydroxyurea was used for the analysis. The patients were divided into 3 age groups (< 7years, 8 – 17years and >17years). Data analysis was done using IBM SPSS version 23. Results: The mean absolute lymphocyte counts (ALC) and absolute granulocyte counts (AGC) in SCD patients (5.142 and 5.295 x103/µL respectively) were higher than in controls (2.952 and 2.171 x 103/µL respectively) (p<0.001). ALC and AGC decreased with age (p<0.001, p=0.02 respectively) in the SCD patients. A similar trend in ALC was observed in the control group while there was no significant difference in the AGC of children <7years and adults (>17years) (Fig 1). The mean granulocyte-lymphocyte ratio (GLR) in SCD patients increased from 1.01 in children <8years to 1.40 in adults. For the control group, the GLR decreased from 0.75 in children <8years to 0.66 in children 8–17years old and an increase to 0.95 in adults (Fig 2). In the SCD patients, GLR was positively correlated with RBC (rs=0.351, p<0.001), HGB (rs=0.256, p=0.004), HCT (rs=0.295, p<0.001) and HbA2 (rs=0.293, p<0.001). HbA2 was positively correlated with RBC (rs=0.201, p=0.028) while HbF was negatively correlated with RBC (rs=-0.257, p=0.006) and showed no correlation with the GLR (rs=-0.008, p=0.930). ALC however had a negative correlation with RBC (rs=-0.395, p<0.001), HGB (rs=-0.452, p<0.001) and HCT (rs=-0.395, p<0.001). AGC also had a negative correlation with HGB (rs=-0.245, p=0.006) and HCT (rs=-0.179, p=0.047). These relationships were not observed in the control group except for a positive correlation between HGB and GLR (rs=0.273, p=0.003) and a negative correlation between HGB and ALC (rs=-0.295, p=0.001). GLR was negatively associated with the frequency of painful crisis in the last one year (p<0.001). Conclusion: AGC and ALC decreased with age in our patients with an increase in the GLR. A positive correlation of GLR with RBC, HGB, HCT and HbA2 infers a protective role of a higher GLR/NLR to RBC survival in our patients. A higher GLR may be associated with better clinical outcomes, and neutropenia due to the duffy antigen null status may exacerbate the course of SCD in blacks.Fig 1. The mean absolute counts of granulocyte and lymphocytes in both cases and controls.Figure 1. The percentage of granulocytes and lymphocytes in both cases and controls The authors do not declare any conflict of interest

Measurement of post-transfusion red blood cell survival kinetics in sickle cell disease and β-Thalassemia: A biotin label approach.

Red blood cell (RBC) transfusions are an important treatment modality for patients with sickle cell disease (SCD) and β-thalassemia. A subgroup of these patients relies on a chronic RBC transfusion regimen. Little is known about RBC survival (RCS) of the transfused allogeneic RBCs. In this study, we aimed to study the RCS kinetics of transfused RBCs in SCD and β-thalassemia and to investigate factors that determine RCS. We performed a prospective cohort study on fourteen adults with SCD and β-thalassemia disease receiving a chronic transfusion regimen. RCS and the influence of donor and patient characteristics on RCS were assessed by simultaneous transfusion of two allogeneic RBCs using RBC biotinylation. Phenotyping of well-known RBC markers over time was performed using flow cytometry. RCS of the two transfused RBC units was similar in most patients. Although intra-individual variation was small, inter-individual variation in RCS kinetics was observed. Most patients demonstrated a non-linear trend in RCS that was different from the observed linear RCS kinetics in healthy volunteers. After an initial slight increase in the proportion of biotinylated RBCs during the first 24 h, a rapid decrease within the first 10-12 days was followed by a slower clearance rate. These are the first data to demonstrate that patient-related factors largely determine post-transfusion RCS behavior of donor RBC in SCD and β-thalassemia, while donor factors exert a negligible effect. Further assessment and modeling of RCS kinetics and its determinants in SCD and β-thalassemia patients may ultimately improve transfusion therapy.

Transfusion Challenges and Use of Best Match Blood Transfusion in Autoimmune Hemolytic Anemia Patients

Background and Objectives: In autoimmune hemolytic anemia (AIHA) patients, there is decreased survival of red blood cells (RBCs) because of increased destruction by patients' autoantibodies. Due to decreased survival of RBCs, there is an increase in erythropoiesis and other biochemical parameters of hemolysis. One of the vital tests in AIHA is direct Coombs test (DCT). In this study, we share our experience on the difficulties faced by us during the compatibility testing and providing transfusion support to these patients. Methods: This is a retrospective study done in the department of transfusion medicine in a tertiary care hospital of South India. Patients from January 2020 to March 2021 with the diagnosis of AIHA requiring transfusion were included in this study. A total of 136 patients with positive DCT with AIHA diagnosis requiring transfusion support were included in our study. Results: Out of 136 cases, 58% (n=79) of patients had incompatibility during cross matching while in 42% (n=57) had cross matched compatible unit. In all incompatible cases best match blood was transfused. Most transfusions were done for patients with DCT Grade 4+. Out of 45 patients with mixed AIHA, 40 (88.8%) patients required a transfusion (P &lt; 0.05). Of that 104 patients with transfusion support, 66 (63%) were with primary AIHA and 38 (36.04%) with secondary AIHA. Conclusion: It is tough and challenging to get compatible units in AIHA patients. Best-matched blood is useful when transfusion becomes essential during life-threatening anemia.

Early and Late-Phase 24h Responses of Stored Red Blood Cells to Recipient-Mimicking Conditions.

The 24-hour (24 h) post-transfusion survival of donor red blood cells (RBCs) is an important marker of transfusion efficacy. Nonetheless, within that period, donated RBCs may encounter challenges able to evoke rapid stress-responses. The aim of the present study was to assess the effect of exposure to plasma and body temperature upon stored RBCs under recipient-mimicking conditions in vitro from the first hours “post-transfusion” up to 24 h. For this purpose, packed RBCs from seven leukoreduced CPD/SAGM units were reconstituted with plasma of twenty-seven healthy individuals and incubated for 24 h at 37oC. Three units were additionally used to examine stress-responses in 3-hour intervals post mixing with plasma (n = 5) until 24 h. All experiments were performed in shortly-, medium-, and long-stored RBCs. Hemolysis, redox, morphology, membrane protein binding and vesiculation parameters were assessed. Even though spontaneous hemolysis was minimal post-reconstitution, it presented a time-dependent increase. A similar time-course profile was evident for the concentration of procoagulant extracellular vesicles and the osmotic fragility (shortly-stored RBCs). On the contrary, mechanical fragility and reactive oxygen species accumulation were characterized by increases in medium-stored RBCs, evident even from the first hours in the recipient-mimicking environment. Finally, exposure to plasma resulted in rapid improvement of morphology, especially in medium-stored RBCs. Overall, some RBC properties vary significantly during the first 24 h post-mixing, at levels different from both the storage ones and the standard end-of-24 h. Such findings may be useful for understanding the performance of RBCs and their possible clinical effects −especially on susceptible recipients− during the first hours post-transfusion.

NonFreezable Preservation of Human Red Blood Cells at -8 °C.

Red blood cell (RBC) preservation is very important in human health. The RBCs are usually preserved at 4 ± 2 °C without freezing or at a very low temperature (-80 °C or liquid nitrogen) with deep freezing. Herein, non freezable preservation of RBCs at a subzero temperature is reported to prolong the preservation time compared with that at 4 ± 2 °C. By adding glycerol and poly(ethylene glycol) (PEG) (average number molecular weight 400, PEG-400) into the preservation solution, the freezing point is decreased and the hemolysis is kept low. The cell metabolism of stored RBCs at -8 °C is reduced, and the shelf life of RBCs extends up to at least 70 days. At the end of preservation, the pH decreases a little bit to demonstrate the low metabolic rate of RBCs stored at subzero temperatures. After quick washing, the RBC survival rate is ca. 95%. The adenosine triphosphate, 2,3-diphosphoglycerate, and cell deformation ability of the washed RBCs are maintained at a high level, while the malondialdehyde is relatively low, which verifies the high quality of RBCs stored at this condition.

Hereditary elliptocytosis discovered during work-up for infective endocarditis: About a case

Hereditary elliptocytosis is a group of red blood cell membrane disorders that are characterized by elliptical-shaped erythrocytes and shortened red blood cell survival [1]. It is due to protein abnormalities involving the horizontal skeletal network of the red cell membrane, including the spectrin dimer-dimer interaction or the spectrin-actin-protein 4.1 junction complex [2].

Blockage of the Na-K-ATPase signaling-mediated oxidant amplification loop elongates red blood cell half-life and ameliorates uremic anemia induced by 5/6th PNx in C57BL/6 mice.

We have previously demonstrated that the Na-K-ATPase signaling-mediated oxidant amplification loop contributes to experimental uremic cardiomyopathy and anemia induced by 5/6th partial nephrectomy (PNx). This process can be ameliorated by systemic administration of the peptide pNaKtide, which was designed to block this oxidant amplification loop. The present study demonstrated that the PNx-induced anemia is characterized by marked decreases in red blood cell (RBC) survival as assessed by biotinylated RBC clearance and eryptosis as assessed by annexin V binding. No significant change in iron homeostasis was observed. Examination of plasma samples demonstrated that PNx induced significant increases in systemic oxidant stress as assessed by protein carbonylation, plasma erythropoietin concentration, and blood urea nitrogen. Systemic administration of pNaKtide, but not NaKtide (pNaKtide without the TAT leader sequence) and a scramble "pNaKtide" (sc-pNaKtide), led to the normalization of hematocrit, RBC survival, and plasma protein carbonylation. Administration of the three peptides had no significant effect on PNx-induced increases in plasma erythropoietin and blood urea nitrogen without notable changes in iron metabolism. These data indicate that blockage of the Na-K-ATPase signaling-mediated oxidant amplification loop ameliorates the anemia of experimental renal failure by increasing RBC survival.NEW & NOTEWORTHY The anemia of CKD is multifactorial, and the current treatment based primarily on stimulating bone marrow production of RBCs with erythropoietin or erythropoietin analogs is unsatisfactory. In a murine model of CKD that is complicated by anemia, blockade of Na-K-ATPase signaling with a specific peptide (pNaKtide) ameliorated the anemia primarily by increasing RBC survival. Should these results be confirmed in patients, this strategy may allow for novel and potentially additive strategies to treat the anemia of CKD.

Erythrocyte Indices in Creutzfeldt-Jakob Disease Predict Survival Time.

BackgroundCreutzfeldt–Jakob disease (CJD) is a devastating neurodegenerative disease caused by propagation of abnormally folded prion proteins (PrPSc). Some fluid biomarkers have been reported to be associated with disease duration in CJD. Based on studies which have found that prion protein (PrPC) played a role in erythrocytic hematopoiesis, we evaluated the association between peripheral red blood cell indices and survival time in CJD.MethodsWe retrospectively collected data on peripheral red blood cell indices, including red blood cell (RBC) count, hemoglobin (Hb), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and red cell distribution width (RDW), from 125 CJD patients. Cox proportional hazard models were generated to determine whether red cell indices correlated with survival time of patients with CJD.ResultsOf the 125 included participants, 70 (56%) were male, and the mean age at diagnosis (SD) was 60.3 (9.5) years. Hemoglobin levels (hazard ratio 1.710, 95% CI 1.124–2.600, p = 0.012) and HCT (hazard ratio 1.689, 95% CI 1.112–2.565, p=0.014) were significantly associated with survival time after controlling for sex, age, and Barthel Index. Red blood cell count, MCV, MCH, MCHC, and RDW were not associated with survival time before or after adjusting for covariates.ConclusionsOur study found that Hb and HCT were significantly associated with survival time in patients with CJD. These results may inform evaluation of the mechanisms of interaction between prion disease and hematopoiesis, and indicate that Hb and HCT may be potential prognostic biomarkers.

Ice Recrystallization Inhibition Is Insufficient to Explain Cryopreservation Abilities of Antifreeze Proteins.

Antifreeze proteins (AFPs) and glycoproteins (AFGPs) are exemplary at modifying ice crystal growth and at inhibiting ice recrystallization (IRI) in frozen solutions. These properties make them highly attractive for cold storage and cryopreservation applications of biological tissue, food, and other water-based materials. The specific requirements for optimal cryostorage remain unknown, but high IRI activity has been proposed to be crucial. Here, we show that high IRI activity alone is insufficient to explain the beneficial effects of AF(G)Ps on human red blood cell (hRBC) survival. We show that AF(G)Ps with different IRI activities cause similar cell recoveries of hRBCs and that a modified AFGP variant with decreased IRI activity shows increased cell recovery. The AFGP variant was found to have enhanced interactions with a hRBC model membrane, indicating that the capability to stabilize cell membranes is another important factor for increasing the survival of cells after cryostorage. This information should be considered when designing novel synthetic cryoprotectants.

Diagnosis of microcytic hypochromic anemia with red blood cell survival via carbon monoxide breath-red blood cell survival

Measuring red blood cell survival (RBCS) by a carbon monoxide breath test can help diagnose and analyze disease type and progression of anemia. In this study, we reported the application of RBCS in the differential diagnosis of thalassemia and iron deficiency anemia (IDA). A total of 233 patients were selected in this study, including 48 IDA, 60 thalassemia, and 125 healthy individual controls. The endogenous alveolar CO of each subject was measured by RBCS-01 red blood cell lifespanmeter to obtain the RBCS values. The mean RBCS for mild β-thalassemia, severe β-thalassemia, α-thalassemia, IDA and the control were 67.5±22.0, 31.3±13.9, 69.3±27.7, 78.2±28.2 and 114.3±33.8 days, respectively (P<0.05). RBCS values for thalassemia and IDA patients showed obvious shorter lifespan compared to healthy controls. The cutoff points for thalassemia, IDA and control were <72.5 and <83.5, respectively. RBCS showed a strong positive correlation to red blood cells (RBC) and hemoglobin (HGB) in thalassemia patients. In IDA patients, RBCS demonstrated a moderate positive correlation with HGB, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and red cell distribution width (RDW). There were significant differences between RBCS in different types of thalassemia. RBCS by endogenous alveolar CO testing is a rapid and reliable method for the differential diagnosis of thalassemia and IDA.

A Fractional Order Delay Differential Model for Survival of Red Blood Cells in an Animal: Stability Analysis

Abstract In this paper, we analyse stability of survival of red blood cells in animal fractional order model with time delay. Results have been illustrated by numerical simulations.

Should Cell Salvage be Used in Liver Resection and Transplantation? A Systematic Review and Meta-Analysis

Introduction: Intraoperative red blood cell (RBC) transfusions are common in liver surgery and associated with increased morbidity. Intraoperative blood salvage and autotransfusion (IBSA) can be utilized to minimize transfusion. A theoretical risk of cancer dissemination has restrained IBSA adoption in oncologic surgery. The objective of this work is to evaluate the effect of IBSA use on RBC transfusion and survival outcomes in liver surgery.

Predictive value of the glycated albumin versus glycosylated hemoglobin in follow-up of glucose homeostasis in hemodialysis-maintained type-2 diabetic patients.

Objectives. Markers for glucose control in hemodialysis patients (HDP) are debated. Glycosylated hemoglobin (HbA1c%) relies on the stable red blood cell survival. Albumin turnover is faster than hemoglobin. Glycated albumin (GA%) may be used as an index of short-term glycemic control. The predictive value of GA% versus HbA1c% in monitoring the glucose homeostasis in type-2 diabetic HDP is studied. Methods. Forty type-2 diabetic HDP and 20 healthy non diabetic subjects matched age and sex as a control group were included. Calculation of body mass index and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) and urea reduction ratio were done. Glycosylated hemoglobin, glycated albumin, fasting blood glucose, insulin, total lipid, kidney and liver functions tests, hepatitis markers, electrolytes, complete blood count, and international normalized ratio were performed. Patients were followed up after 6 months. Results. The study showed that GA% is more sensitive than HbA1c%, but less specific in the follow-up of the glucose homeostasis in type-2 diabetic HDP. Diagnostic accuracy is higher in HbA1c% than in GA%. HOMA-IR is superior regarding the sensitivity and the diagnostic accuracy. Conclusion. The present data show that GA% is more sensitive than HbA1c% and has more diagnostic accuracy in the follow-up of the glucose homeostasis in type-2 diabetic HDP.

Prevalence of Anemia and Morphological Variation in RBC among COPD Patients admitted at a Tertiary Health Care Center, Kathmandu, Nepal

Many studies have depicted that anemia is one of the most common co-morbidity among Chronic Obstructive Pulmonary Disease (COPD) patients. Therefore, its correction in those patients is an important aspect of the treatment protocol. Our study was designed to explore the prevalence of anemia and morphological alteration, if any, in RBC among COPD patients. The study was conducted from November 2020 to June 2021 among the COPD patients admitted in the Medical ward of Nepal Medical College Teaching Hospital. If hemoglobin level was &lt;13gm/dl in males and &lt;12gm/dl in females and/or hematocrit level was &lt;39%, the patient was considered anemic. Anemia was morphologically classified following standardized procedure with RBC indices as a reference. Among the COPD patients (n=101), 40 (39.6%) were anemic, out of which 21(52.5%) was normocytic normochromic, 10 (25%) were microcytic hypochromic, 5 (12.5%) were normocytic hypochromic, 3 (7.5%) were microcytic normochromic and (2.5%) was macrocytic hyperchromic. Anisocytosis was commonly noted (25.7%) among the COPD patients with microcytosis (20.8%) and macrocytosis (4.9%) among them. Among the patients, 23.8% showed hypochromia while only 0.9% showed hyperchromia. Polycythemia was present in 24 (23.8%) of them. Inflammatory mediators and cytokines in COPD causes a compromised response of marrow cells to erythropoietin and shortens the survival of red blood cells.

Enhanced Anti-Atherosclerotic Efficacy of pH-Responsively Releasable Ganglioside GM3 Delivered by Reconstituted High-Density Lipoprotein

Recently, the atheroprotective role of endogenous GM3 and an atherogenesis-inhibiting effect of exogenous GM3 suggested a possibility of exogenous GM3 being recruited as an anti-atherosclerotic drug. This study seeks to endow exogenous GM3 with atherosclerotic targetability via reconstituted high-density lipoprotein (rHDL), an atherosclerotic targeting drug nanocarrier. Unloaded rHDL, rHDL loaded with exogenous GM3 at a low concentration (GM3L-rHDL), and rHDL carrying GM3 at a relatively high concentration (GM3H-rHDL) were prepared and characterized. The inhibitory effect of GM3-rHDL on lipid deposition in macrophages was confirmed, and GM3-rHDL did not affect the survival of red blood cells. In vivo experiments using ApoE−/− mice fed a high fat diet further confirmed the anti-atherosclerotic efficacy of exogenous GM3 and demonstrated that GM3 packed in HDL nanoparticles (GM3-rHDL) has an enhanced anti-atherosclerotic efficacy and a reduced effective dose of GM3. Then, the macrophage- and atherosclerotic plaque-targeting abilities of GM3-rHD, most likely via the interaction of ApoA-I on GM3-rHDL with its receptors (e.g., SR-B1) on cells, were certified via a microsphere-based method and an aortic fragment-based method, respectively. Moreover, we found that solution acidification enhanced GM3 release from GM3-rHDL nanoparticles, implying the pH-responsive GM3 release when GM3-rHDL enters the acidic atherosclerotic plaques from the neutral blood. The rHDL-mediated atherosclerotic targetability and pH-responsive GM3 release of GM3-rHDL enhanced the anti-atherosclerotic efficacy of exogenous GM3. The development of the GM3-rHDL nanoparticle may help with the application of exogenous GM3 as a clinical drug. Moreover, the data imply that the GM3-rHDL nanoparticle has the potential of being recruited as a drug nanocarrier with atherosclerotic targetability and enhanced anti-atherosclerotic efficacy.

Storage Differentially Impacts Immunization to Red Cell Antigens

Introduction: The impact of red blood cell (RBC) storage on alloimmunization rates after transfusion remains controversial, with clinical experience demonstrating conflicting results. Indeed, some reports suggest increased rates of alloimmunization associated with longer storage of RBC units, while others suggest no association between alloimmunization rates and length of storage. We hypothesized that this discrepancy may reflect the differential impact of storage on alloimmunization related to each unique antigen and the immune response elicited. Here we define the effect of red cell storage on two distinct antigens, including the Hel-Ova-Duffy (HOD) and KEL antigens, using a preclinical murine model of RBC storage and transfusion.Methods: RBCs singly expressing HOD (HOD RBC) or KEL (KEL RBC) antigens, in addition to those dually expressing both HOD and KEL (HOD x KEL RBC) antigens, were collected from respective transgenic donor mice into CPDA. Units of HOD, KEL or HOD x KEL RBC were generated and used immediately (fresh RBC), or stored for 8 (D8) or 14 (D14) days at 4C before transfusion into wildtype recipients. Recipient cytokine profiles were assessed 2 hours post-transfusion using a multiplex inflammation panel. Donor RBC survival at 24 hours post-transfusion was assessed by flow cytometry. Serum was collected from recipients on days 5 and 14 post-transfusion and analyzed for IgM or IgG development by flow-cytometric crossmatch using HOD or KEL RBC targets.Results: Post-transfusion RBC survival was decreased with increased storage, but was not significantly different between donor cell types (HOD, KEL or HOD x KEL). Recipient cytokine profiles demonstrated a distinct inflammatory profile associated with storage. Development of IgM antibodies against HOD in mice transfused fresh versus D8 or D14 HOD or HOD x KEL RBCs were not significantly different; however, significantly increased (p<0.05) IgG antibodies were detected in recipients transfused with D8 and D14 HOD or HOD x KEL RBCs as compared to those transfused fresh HOD or HOD x KEL RBCs. In contrast, and while the development of anti-KEL IgM antibodies was not significantly different in mice transfused fresh versus D8 or D14 KEL or HOD x KEL RBCs, the IgG response to KEL was abrogated with longer storage, with recipients generating significantly less (p<0.05) anti-KEL IgG following transfusion with stored KEL or HOD x KEL RBCs as compared to fresh HOD or HOD x KEL RBCs.Conclusions: Although the impact of RBC storage on various measures of transfusion efficacy have been determined, the impact of storage on alloimmunization remains incompletely understood. Using a murine model of transfusion, we demonstrate that storage differentially impacts immunization to red cell antigens, increasing the response to certain antigens, like HOD, while decreasing the response to others, like KEL. Although it is unclear whether these findings apply to other RBC antigens and what relevance this holds for human patients, our study provides insight into the impact of storage on red cell alloimmunization and may enlighten future storage protocols. DisclosuresStowell: Argenx: Speakers Bureau; Grifols: Speakers Bureau; Alexion: Consultancy.

Activation of Pyruvate Kinase-R with Etavopivat (FT-4202) Is Well Tolerated, Improves Anemia, and Decreases Intravascular Hemolysis in Patients with Sickle Cell Disease Treated for up to 12 Weeks

Activation of Pyruvate Kinase-R with Etavopivat (FT-4202) Is Well Tolerated, Improves Anemia, and Decreases Intravascular Hemolysis in Patients with Sickle Cell Disease Treated for up to 12 Weeks

Etavopivat, an Allosteric Activator of Pyruvate Kinase-R, Improves Sickle RBC Functional Health and Survival and Reduces Systemic Markers of Inflammation and Hypercoagulability in Patients with Sickle Cell Disease: An Analysis of Exploratory Studies in a Phase 1 Study

Etavopivat, an Allosteric Activator of Pyruvate Kinase-R, Improves Sickle RBC Functional Health and Survival and Reduces Systemic Markers of Inflammation and Hypercoagulability in Patients with Sickle Cell Disease: An Analysis of Exploratory Studies in a Phase 1 Study