Anti-erythropoietin Antibodies Research Articles

Effectiveness of anti-erythropoietin producing Hepatocellular receptor Type-A2 antibody in pancreatic cancer treatment

Erythropoietin-producing hepatocyte receptor type A2 (EphA2) is a tyrosine kinase that binds to ephrins (e.g., ephrin-A1) to initiate bidirectional signaling between cells. The binding of EphA2 and ephrin-A1 leads to the inhibition of Ras-MAPK activity and tumor growth. During tumorigenesis, the normal interaction between EphA2 and ephrin-A1 is hindered, which leads to the overexpression of EphA2 and induces cancer. The overexpression of EphA2 has been identified as a notable tumor marker in diagnosing and treating pancreatic cancer. In this study, we used phage display to isolate specific antibodies against the active site of EphA2 by using a discontinuous recombinant epitope for immunization. The therapeutic efficacy and inhibition mechanism of the generated antibody against pancreatic cancer was validated and clarified. The generated antibodies were bound to the conformational epitope of endogenous EphA2 on cancer cells, thus inducing cellular endocytosis and causing EphA2 degradation. Molecule signals pAKT, pERK, pFAK, and pSTAT3 were weakened, inhibiting the proliferation and migration of pancreatic cancer cells. The humanized antibody hSD5 could effectively inhibit the growth of the xenograft pancreatic cancer tumor cells BxPc-3 and Mia PaCa-2 in mice, respectively. When antibody hSD5 was administered with gemcitabine, significantly improved effects on tumor growth inhibition were observed. Based on the efficacy of the IgG hSD5 antibodies, clinical administration of the hSD5 antibodies is likely to suppress tumors in patients with pancreatic cancer and abnormal activation or overexpression of EphA2 signaling.

Serum anti-erythropoietin antibodies among pregnant women with Plasmodium falciparum malaria and anaemia: A case-control study in northern Ghana.

Anaemia in pregnancy is common in underdeveloped countries, and malaria remains the predominant cause of the condition in Ghana. Anti-erythropoietin (anti-EPO) antibody production may be implicated in the pathogenesis of Plasmodium falciparum malaria-related anaemia in pregnancy. This study ascertained the prevalence of anti-EPO antibody production and evaluated the antibodies' relationship with Plasmodium falciparum malaria and malaria-related anaemia in pregnancy. This hospital-based case-control study recruited a total of 85 pregnant women (55 with Plasmodium falciparum malaria and 30 controls without malaria). Venous blood was taken from participants for thick and thin blood films for malaria parasite microscopy. Complete blood count (CBC) analyses were done using an automated haematology analyzer. Sandwich enzyme-linked immunosorbent assay (ELISA) was used to assess serum erythropoietin (EPO) levels and anti-EPO antibodies. Data were analyzed using IBM SPSS version 22.0. Haemoglobin (p<0.001), RBC (p<0.001), HCT (p = 0.006) and platelet (p<0.001) were significantly lower among pregnant women infected with Plasmodium falciparum. Of the 85 participants, five (5.9%) had anti-EPO antibodies in their sera, and the prevalence of anti-EPO antibody production among the Plasmodium falciparum-infected pregnant women was 9.1%. Plasmodium falciparum-infected pregnant women with anti-EPO antibodies had lower Hb (p<0.001), RBC (p<0.001), and HCT (p<0.001), but higher EPO levels (p<0.001). Younger age (p = 0.013) and high parasite density (p = 0.004) were significantly associated with Plasmodium falciparum-related anti-EPO antibodies production in pregnancy. Also, younger age (p = 0.039) and anti-EPO antibody production (p = 0.012) related to the development of Plasmodium falciparum malaria anaemia in pregnancy. The prevalence of anti-EPO antibodies among pregnant women with Plasmodium falciparum malaria was high. Plasmodium falciparum parasite density and younger age could stimulate the production of anti-EPO antibodies, and the antibodies may contribute to the development of malarial anaemia in pregnancy. Screening for anti-EPO antibodies should be considered in pregnant women with P. falciparum malaria.

Association between Anti-Erythropoietin Receptor Antibodies and Cardiac Function in Patients on Hemodialysis: A Multicenter Cross-Sectional Study.

Cardiac dysfunction is an important prognostic predictor of cardiovascular mortality in patients on hemodialysis (HD). Erythropoietin (EPO) has been reported to improve cardiac function by binding to the EPO receptor (EPOR) on cardiomyocytes. This study investigated whether anti-EPOR antibodies were associated with left ventricular cardiac function in patients undergoing HD. This multicenter, cross-sectional observational study included 377 patients (median age, 70 years; 267 (70.8%) males) with chronic kidney disease (CKD) undergoing stable maintenance HD. Serum levels of anti-EPOR antibodies were measured, and echocardiography was used to assess the left ventricular mass index (LVMI) and left ventricular ejection fraction (LVEF). Anti-EPOR antibodies were found in 17 patients (4.5%). LVMI was greater (median of 135 g/m2 vs. 115 g/m2, p = 0.042), and the prevalence of LVEF < 50% was higher (35.3% vs. 15.6%, p = 0.032) in patients with anti-EPOR antibodies than in those without. Multivariable linear regression and logistic regression analysis (after adjusting for known risk factors of heart failure) revealed that anti-EPOR antibodies were independently associated with LVMI (coefficient 16.2%; 95% confidence interval (CI) 1.0–35.0%, p = 0.043) and LVEF <50% (odds ratio 3.20; 95% CI 1.05–9.73, p = 0.041). Thus, anti-EPOR antibody positivity was associated with left ventricular dysfunction in patients undergoing HD.

Erythropoietin-induced pure red cell aplasia.

Erythropoietin-induced antibody-mediated PRCA is a well-known but rare complication of erythropoiesis-stimulating agent (ESA) therapy. The demonstration of absence or near absence of erythroblasts in bone marrow is crucial for its diagnosis. Other characteristics include reticulocytopenia, resistance to ESA therapy, and presence of anti-erythropoietin neutralizing antibodies. Management includes the cessation of ESA and the use of immunosuppressive treatment. I wish to express my greatest gratitude to Dr. Kate Leung for her guidance and supervision.

Prevalence of Anti-erythropoietin Antibody in Prevalent Hemodialysis Patients Receiving Erythropoietin Hormone

Prevalence of Anti-erythropoietin Antibody in Prevalent Hemodialysis Patients Receiving Erythropoietin Hormone

Detection of Anti-Erythropoietin Antibodies in Patients with Chronic Renal Failure Undergoing Hemodialysis

Background: Erythropoietin, a hormone produced by the kidney, activates the bone marrow upon demand. Recombinant erythropoietin can be subcutaneously injected to maintain red blood cell counts in chronic renal failure patients. Some time being recognized as foreign antigens, the patient occasionally produces antibodies against erythropoietin. Objective of current study was to investigate the existence of Anti-Erythropoietin Antibodies in Chronic Renal Failure (CRF) affected individuals during hemodialysis. Methods: The current study was performed at the Pathology Department, Khyber Teaching Hospital, Peshawar, Pakistan. After the assent of ethical committee, data collection was initiated to carry out the study. All the patients filled the informed consent proforma. The blood sample was collected in two EDTA and Gel tubes for complete blood count and for anti-EPO-antibodies respectively. ELISA tests for anti-EPO antibodies were performed on all patients who were classified into two groups based on whether antibodies were present or not. The data was analyzed using SPSS version 25.0. Results: In this study, 150 patients suffering from Chronic Kidney Disease on dialysis were included in which 79 (52.7%) were males. Moreover, age-wise group 41-60 years (n=93, 62%) were more suffering as compared to age group 21-40 years (n=24, 16%). In our study, hypertension was found to be a leading cause of death for 65(43.3%), diabetes 32(21.3%), hypertension and diabetes mellitus 10(6.7%), and miscellaneous accounted for 28.7%. There were 56(37.3%) patients who received dialysis twice a week, and 94 patients (62.6%) received it three times a week. Patients had transfusion history were 136(90.7%), while 92 (61.3%) patients were found to have anti-EPO antibodies. Conclusion: Anti-EPO antibodies are frequently demonstrated in patients with CKD undergoing hemodialysis. Due to the lack of correlation between antibody levels and Hb or reticulocyte counts, these antibodies might not be neutralizing antibodies. Keywords: Anti-EPO antibodies, Chronic Renal Failure, Hypertension, Peshawar.

Prevalence of Anti-Erythropoietin Antibodies in Patients with ESRD on Regular Hemodialysis: A Single-Centre Experience

Prevalence of Anti-Erythropoietin Antibodies in Patients with ESRD on Regular Hemodialysis: A Single-Centre Experience

Baseline Soluble Anti-erythropoietin Antibody Level Is an Independent Associated Factor for Follow-Up Erythropoietin Demand in Maintenance Dialysis Patients With End-Stage Renal Disease: A Prospective Cohort Study.

Aims: The aim of this study was to identify the predictive role of baseline anti-erythropoietin (anti-EPO) antibody levels in follow-up EPO demand in maintenance dialysis patients with end-stage renal disease (ESRD).Methods: Baseline routine blood parameters, clinical data, dialysis-related parameters, EPO, anti-EPO antibody, and anti-EPO-receptor antibody were also measured. Differences in the abovementioned variables were compared among four intervals of the EPO demand index (EDI). Further univariate and adjusted logistic regression analyses were performed to identify the independent predictors for higher EPO demand.Results: The predialysis potassium ion concentration was significantly higher in the fourth quartile (Q4) population than in the other three populations (p < 0.05). Furthermore, the anti-EPO antibody level showed significant differences among the four intervals (p = 0.006). The baseline anti-EPO antibody level was correlated with the follow-up EDI (r2 = 0.0377, p = 0.030). Furthermore, the follow-up EDI was significantly higher in the anti-EPO antibody-positive group (p = 0.02). Age (OR = 1.071, p = 0.005), ferritin (OR = 1.001, p = 0.038), potassium ion concentration before dialysis (OR = 2.781, p = 0.012), dialysis duration (OR = 1.025, p = 0.030), and anti-EPO antibody level (OR = 7.694, p = 0.004) were potential predictors for higher EPO demand. After adjustment, age (OR = 1.072, p = 0.026), potassium ion concentration before dialysis (OR = 3.425, p = 0.013), and EPO level (OR = 5.27, p = 0.007) were independent predictors for higher EDI demand.Conclusion: The baseline anti-EPO antibody level combined with an older age and a higher predialysis potassium ion concentration are independent predictors for a higher follow-up EPO demand in maintenance dialysis patients with ESRD.

Antierythropoietin Antibody Production Is Not Associated with Malaria and Malaria-Related Anaemia in Humans.

Introduction The pathophysiology of malaria-related anaemia is not fully understood although increased destruction of parasitized and nonparasitized erythrocytes, as well as inadequate erythropoiesis, has been proposed. Circulating antierythropoietin (anti-EPO) antibodies have also been implicated in malaria and malaria-related anaemia in mice. However, studies on this association have not been investigated in humans. This study therefore determined the prevalence of anti-EPO antibody production and assessed its association with malaria and malaria-related anaemia in humans. Methods A total of 86 children aged 1-10 years (57 children with malaria serving as the case group and 29 healthy children serving as control), all residents of Duayaw Nkwanta, Ghana, were recruited for this case-control study. Venous blood was collected for thick and thin films for malaria microscopy, full blood count by automated haematology analyzer, and antierythropoietin antibody and erythropoietin estimation by sandwich ELISA method. Results Out of the 86 participants recruited, only 3 (3.5%) were positive for anti-EPO antibody; 2.3% of the case group; and 1.2% of the control group. There was no association between the cases and the controls in the production of anti-EPO antibodies. Erythropoietin concentration was significantly higher in malaria-related anaemic subjects (p=0.032). Conclusion Antierythropoietin antibodies are not associated with malaria infection and malaria-related anaemia in humans. Erythropoietin concentration is associated with malaria-related anaemia.

Antibody-mediated pure red cell aplasia after treatment with darbepoetin-alpha postrenal transplantation

Pure red cell aplasia (PRCA) is a rare normochromic, normocytic anemia with a near-to-complete absence of erythroblasts in the bone marrow. Erythropoiesis-stimulating agents have been used widely to improve anemia in patients with chronic kidney disease. We present a case of a 38-year-old woman who was detected to have anemia (hemoglobin: 10 g/dl) and renal dysfunction (creatinine: 3 mg/dl) on a routine health check in December 2016. Her kidney biopsy showed chronic interstitial nephritis. She received intravenous (IV) iron and was started on darbepoetin-alpha. Her hemoglobin after 3 months of treatment was 12 mg/dl. She underwent preemptive one haplomatch renal transplantation on June 2017. She was discharged with serum creatinine of 0.9 mg/dl and hemoglobin of 8 g/dl. She was not on any Erthropoietin stimulating agents (ESA) at discharge. In the 4th week after transplant, her hemoglobin dropped to 7 g/dl, and she was restarted on darbepoetin-alpha 40 μg subcutaneously once a week. In the 6th week posttransplant, her hemoglobin dropped to 6 g/dl. Her peripheral smear showed normocytic normochromic anemia with no evidence of hemolysis. Transferrin saturation was 81%, serum ferritin levels were 1812 ng/ml, and reticulocyte count was 0.1%. Bone marrow biopsy showed suppression of erythroid precursors with myeloid-to-erythroid ratio of 8:1, adequate iron stores, and normal white blood cell and platelet precursors with no dysplastic cells. Paroxysmal Nocturnal hemoglobinuria (PNH) workup; antinuclear antibody; and screening for hepatitis B, hepatitis C, HIV, CMV, and human parvovirus B19 were negative. Anti-erythropoietin (EPO) antibody by enzyme-linked immunosorbent assay was positive. She was diagnosed to have PRCA secondary to anti-EPO antibodies. She was managed with pulse doses of methylprednisolone, adequate dose of tacrolimus, IV immunoglobulin of 125 g (2 g/kg) over 5 days, and two packed red cell transfusions. Darbepoetin-alpha was stopped. At present, her hemoglobin is 12.5 g/dl with serum creatinine of 1 mg/dl on triple immunosuppression with no requirement of ESA.

Agrobacterium-mediated genetic transformation of Dictyosphaerium pulchellum for the expression of erythropoietin

Recombinant proteins are extensively used for a growing number of fields in biology. However, microalgal species have not been widely adopted as cell factories for recombinant protein production. Unique metabolic properties, ease of cultivation, fast growth rates, and continuous progress in genetic engineering of microalgae have raised interest in the use of microalgae species for recombinant protein production. Here, we report an Agrobacterium-mediated genetic transformation system for the heterologous expression of a therapeutic protein, “erythropoietin,” in a nonmodel green microalga, Dictyosphaerium pulchellum. Hygromycin resistance gene (Hyg) was used as a selectable marker. The genetic transformation of D. pulchellum was performed in modified AF6 medium supplemented with 150 μM acetosyringone, co-cultivated for 48 h at 25 ± 2 °C and a light intensity of 18 ± 2 μmol photons m−2 s−1. Co-cultivation of D. pulchellum with Agrobacterium tumefaciens harboring the binary expression vector pCAMBIA1301-Hyg-EPO-Histag yielded hygromycin-resistant colonies on selective medium after 2–3 weeks. Gene integration into the D. pulchellum nuclear genome was confirmed by PCR amplification of T-DNA from the genomic DNA of hygromycin-resistant and wild-type strains. Interestingly, SDS-PAGE and subsequent Western blotting with His-tag monoclonal and anti-erythropoietin monoclonal antibodies revealed an EPO-specific signal slightly below 34 kDa. Furthermore, EPO gene expression and transgene copy numbers were estimated by quantitative real-time PCR. Approximately, 500 μg L−1 of extracellular recombinant erythropoietin protein was purified by His-tag affinity chromatography. The developed genetic transformation system would allow the metabolic engineering and a better alternative to produce recombinant therapeutic proteins from nonmodel freshwater microalgae species.

Immunogenicity considerations for antibody-drug conjugates: a focus on neutralizing antibody assays.

Immunogenicity considerations for antibody-drug conjugates: a focus on neutralizing antibody assays.

Darbepoetin Alfa for the Treatment of Anemic Patients with Myelodysplastic Syndrome: A Belgian Single-Arm, Companion Trial to the Arcade Phase 3 Study

Darbepoetin Alfa for the Treatment of Anemic Patients with Myelodysplastic Syndrome: A Belgian Single-Arm, Companion Trial to the Arcade Phase 3 Study

Comparison of different immunoassay methods to detect human anti-drug antibody using the WHO erythropoietin antibody reference panel for analytes

Development of an appropriate assay to detect anti-drug antibody (ADA) is important for assessing immunogenicity to therapeutic protein products. However, characterizing ADA assay methods is difficult because human ADA as a reference standard is not available in most cases. We compared the analytical performance of three ligand-binding assay methods for ADA, namely, surface plasmon resonance (SPR), electrochemiluminescence (ECL), and biolayer interferometry (BLI) methods, by using the anti-erythropoietin (EPO) monoclonal antibody reference panel developed by the World Health Organization (WHO) in 2015. Dose-dependent binding responses were observed for all nine anti-EPO antibodies in the anti-EPO panel by the SPR and BLI methods. In contrast, the ECL method did not clearly detect binding of low-affinity anti-EPO antibodies. Regarding IgG2 and IgM antibodies derived from the same clone, IgG2 exhibited a higher binding response in the SPR assay, whereas the IgM binding response was higher than that of IgG2 in the ECL assay. In the case of the BLI method, there was no consistent pattern observed in the binding responses of IgG2 or IgM. Results of the anti-EPO antibody reference panel, which contains a variety of monoclonal antibodies, indicated that the ability to detect ADAs differed among these assay methods. Therefore, with ligand-binding assays, differences in assay platforms can affect the sensitivity and other characteristics of assays to detect ADAs. These results show that understanding the analytical performance of ADA assays is important for an appropriate assessment of immunogenicity. Our study also indicated the benefits of using the established human ADA reference panel to assess the assay methods for ADA detection.

Evaluation of the safety and immunogenicity of subcutaneous HX575 epoetin alfa in the treatment of anemia associated with chronic kidney disease in predialysis and dialysis patients .

Aim: To assess the safety and immunogenicity of subcutaneous (SC) HX575 (epoetin-α) in dialysis- and nondialysis-dependent adult patients with chronic kidney disease (CKD). Methods: Open-label, single-arm, multicenter study in patients (n = 416) from Germany, Italy, Poland, Romania, Russia, Turkey, and Ukraine. Results: Mean (standard deviation (SD)) age was 52.3 (15.8) years, all patients were Caucasian, and similar proportions were male/female. 250 patients (60.1%) were erythropoiesis-stimulating agent (ESA)-naïve, and 166 (39.9%) were receiving ESA maintenance therapy at study start; mean (SD) on-study treatment duration with HX575 was 43.4 (15.8) weeks and 45.3 (13.7) weeks, respectively. Binding antierythropoietin (EPO) antibodies were detected by radioimmunoprecipitation (RIP) assay in 7 patients (1.7%; incidence 0.019); 5 of these were ESA-naïve at study entry. No patient developed neutralizing antibodies as determined in a cell-based epoetin neutralizing assay. Of the 7 patients with a positive binding anti-EPO RIP assay, 4 tested negative at later time points while continuing HX575 treatment. Three patients had low titers of anti-EPO antibodies at the last study assessment. There were no clinical signs of immunogenicity or hypersensitivity. Conclusions: SC HX575 was effective for correcting and maintaining correction of anemia, and the mean weekly dose remained stable over time.

Evaluation of AMGEN clone 9G8A anti-Epo antibody for application in doping control.

The two mouse monoclonal anti-erythropoietin (EPO) antibodies clone AE7A5 (generated by using a 26 amino acid N-terminal EPO-peptide) and 9G8A (developed by immunizing mice with full length human EPO) are both directed against linear epitopes at the N-terminus of EPO. While AE7A5 has been commercially available for many years, 9G8A was made for Amgen's internal research purposes. In the past, the commercial antibody was shown to cross-react with several proteins unrelated to EPO (e.g. E. coli thioredoxin reductase, zinc-α2-glycoprotein, S. cerevisiae enolase, human neuron-specific enolase, and human non-neuronal enolase). However, it displayed high sensitivity for detecting recombinant EPO (rEPO) misuse by athletes on Western blots. We evaluated the potential use of clone 9G8A for doping control purposes. While 9G8A showed lower sensitivity than AE7A5 (ca 45% on isoelectric focusing (IEF)-polyacrylamide gel electrophoresis (PAGE), ca 40% on sodium dodecyl sulfate (SDS)- and sarcosyl (SAR)-PAGE), non-specific binding of the five proteins was not observed. The cross-reactivity of AE7A5 can be overcome by immunoaffinity purification of EPO before electrophoresis and Western blotting. Similar to AE7A5, clone 9G8A is also suited for Western double-blotting. Copyright © 2016 John Wiley & Sons, Ltd.

Far-western blotting as a solution to the non-specificity of the anti-erythropoietin receptor antibody.

The erythropoietin receptor (EpoR) is a member of the cytokine receptor family. The interaction between erythropoietin (Epo) and EpoR is important for the production and maturation of erythroid cells, resulting in the stimulation of hematopoiesis. The fact that EpoR was also detected in neoplastic cells has opened the question about the relevance of anemia treatment with recombinant Epo in cancer patients. Numerous studies have reported pro-stimulating and anti-apoptotic effects of Epo in cancer cells, thus demonstrating EpoR functionality in these cells. By contrast, a previous study claims the absence of EpoR in tumor cells. This apparent discrepancy is based, according to certain authors, on the use of non-specific anti-EpoR antibodies. With the aim of bypassing the direct detection of EpoR with an anti-EpoR antibody, the present authors propose a far-western blot methodology, which in addition, confirms the interaction of Epo with EpoR. Applying this technique, the presence of EpoR and its interaction with Epo in human ovarian adenocarcinoma A2780 and normal human umbilical vein endothelial cells was confirmed. Furthermore, modified immunoprecipitation of EpoR followed by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry analysis confirmed a 57 kDa protein as a human Epo-interacting protein in both cell lines.

Pure red cell aplasia induced by epoetin zeta.

Pure red cell aplasia (PRCA) may develop in patients with chronic kidney disease receiving erythropoiesis-stimulating agents (ESA). We report on a 72-year-old patient who developed hypo-proliferative anaemia unresponsive to ESA following the administration of epoetin zeta subcutaneously for 7 months. On the basis of severe isolated hypoplasia of the erythroid line in the bone marrow and high-titre neutralizing anti-erythropoietin antibodies (Ab), a diagnosis of Ab-mediated PRCA was made. Epoetin zeta was discontinued and the patient was given steroids. This was associated with anaemia recovery. To our knowledge this is the first PRCA case related to epoetin zeta.

Mechanisms of Erythropoietin–Stimulating Action of Anti-Erythropoietin Release-Active Antibodies in Complex Treatment of Experimental Anemia during Gestation

We studied the mechanisms of erythropoiesis stimulation and effectiveness of Poetam, a preparation containing release-active anti-erythropoietin antibodies as a supplement treatment for experimental iron deficiency anemia during gestation. The results confirmed potency of combined therapy to stimulate erythropoiesis, which was more efficacious in comparison with monotherapy as assessed by the count of erythrokaryocytes and erythroid progenitors in the hematopoietic tissue as well as by the content of erythrocytes and hemoglobin in the peripheral blood. Activation of erythropoiesis is related to the modulatory effect of Poetam on proliferative activity and differentiation of erythroid precursors, which in most aspects results from stimulatory action of Poetam on secretion of the hematopoietically active factors by adherent elements of the hematopoietic microenvironment.

Purification of human anti-erythropoietin polyclonal antibodies by precipitation and chromatography as an optimized method with potential application in vaccine studies

Purification of human anti-erythropoietin polyclonal antibodies by precipitation and chromatography as an optimized method with potential application in vaccine studies