Reduced Reticulocyte Counts Research Articles

Positive response of a hemodialysis patient with pure red cell aplasia on recombinant human erythropoietin therapy to cyclosporine and Roxadustat

Recombinant human erythropoietin (rHuEPO) is commonly used to treat anemia associated with chronic kidney disease (CKD). EPO-induced Pure Red Cell Aplasia (PRCA) is a rare condition of profound anemia with EPO treatment. Upon finding the development of EPO-induced PRCA, the treatment requires immediate withdrawal of EPO therapy and initiate new treatments with immunosuppression or renal transplantation. Anti-EPO antibody assay is not always positive in EPO-induced PRCA. Here, we report a case on the sudden development of PRCA in a hemodialysis patient receiving EPO and how we treated the condition successfully with cyclosporine and subsequently maintained the hemoglobin with Roxadustat, a hypoxia-inducible factor prolyl hydroxylase inhibitor (HIF-PHI). Even though the anti-EPO antibody was negative by Enzyme Linked Immunosorbent Assay (ELISA) in our case, the clinical course, the markedly reduced reticulocyte count < 10,000/μL, the bone marrow (BM) biopsy revealing reduced erythroblasts, and its subsequent response to cyclosporine, were similar to EPO-induced PRCA. The clinical picture of EPO-induced PRCA, the limitation of the EPO-neutralizing antibody (Ab) assay, and treatment strategies were discussed.

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

Proof in the Peripheral Smear: Severe Vitamin B12 Deficiency Mimicking Thrombotic Thrombocytopenic Purpura

Introduction: Thrombotic thrombocytopenic purpura (TTP) is a hematologic emergency where timely plasmapheresis reduces mortality. There are a few cases where benign etiologies mimic TTP and patients may receive unnecessary plasma exchange. Interdisciplinary decision-making is invaluable to avoid expenses and complications of more invasive treatments. Case Presentation: A 38-year-old male with self-reported history of asthma presented with generalized weakness and syncope. He endorses 2-week of bilateral leg pain with numbness, loss of taste, and nausea. Vital signs were remarkable for tachycardia in 110s and hypotension at 101/52. Labs showed hemoglobin 3.3, WBC 3.6, platelet 83, MCV 93.9, reticulocyte 1.1%, total bilirubin 1.4, haptoglobin &amp;lt;8, LDH 2652, negative Coombs test, and creatinine 1.2. Vitamin B12 level was &amp;gt;2000, however value was drawn near the time of administration of intramuscular vitamin B12. There was concern for TTP due to an intermediate PLASMIC score of 5. However, given that presentation was more consistent with vitamin B12 deficiency, plasmapheresis was deferred after a discussion with pathology. Peripheral blood smear showed anisocytosis, macrocytes, schistocytes, and hypersegmented neutrophils. ADAMTS13 activity returned 62%. Pernicious anemia was diagnosed with labs revealed homocysteine &amp;gt;50, methylmalonic acid 41.97, positive anti-parietal cell antibody, and positive intrinsic factor antibody. Hemoglobin stabilized at around 8 after transfusions. Lab showed haptoglobin 13 and LDH 1211 on discharged after daily vitamin B12 injections. Patient was discharged with weekly injections and last gastric biopsy reveal atrophic gastritis. Discussion: The decision to closely monitor our patient versus initiation of plasmapheresis was based on clinical symptoms of neuropathy and reduced taste consistent with vitamin B12 deficiency. Our patient's lab values and peripheral smear were also more reassuring of a nutritional deficiency. Severe vitamin B12 deficiency is thought to cause both intramedullary and extramedullary hemolysis. Intramedullary hemolysis caused by destruction of erythrocytes leading to ineffective erythropoiesis is more common. Conversely, the mechanism of extramedullary hemolysis is not well established. It is thought that the pro-oxidative qualities of homocysteine can promote thrombosis and endothelial dysfunction and subsequent microangiopathy. This phenomenon, commonly called pseudothrombotic microangiopathy, mimics TTP. Few laboratory values can help distinguish between TTP and an intramedullary process. First, reduced reticulocyte count suggests defective DNA synthesis and destruction of megaloblastic cells by bone marrow macrophages. A high MCV in the setting of low reticulocyte count is suggestive of vitamin B12 deficiency. Blood smear may also show multiple hypersegmented polymorphonuclear cells and macrocytosis in addition to schistocytes. Additionally, LDH tends to be more substantially elevated in intramedullary hemolytic processes like vitamin B12 deficiency. This is attributed to high LDH content of nucleated erythrocytes when compared to mature red blood cells. Immature erythrocytes contain less hemoglobin than mature red blood cells and bilirubin is relatively less elevated in vitamin B12 deficiency. Lastly, platelet counts tend to be higher in vitamin B12 deficiency than in TTP. Disclosures No relevant conflicts of interest to declare.

In utero nanoparticle delivery for site-specific genome editing

Genetic diseases can be diagnosed early during pregnancy, but many monogenic disorders continue to cause considerable neonatal and pediatric morbidity and mortality. Early intervention through intrauterine gene editing, however, could correct the genetic defect, potentially allowing for normal organ development, functional disease improvement, or cure. Here we demonstrate safe intravenous and intra-amniotic administration of polymeric nanoparticles to fetal mouse tissues at selected gestational ages with no effect on survival or postnatal growth. In utero introduction of nanoparticles containing peptide nucleic acids (PNAs) and donor DNAs corrects a disease-causing mutation in the β-globin gene in a mouse model of human β-thalassemia, yielding sustained postnatal elevation of blood hemoglobin levels into the normal range, reduced reticulocyte counts, reversal of splenomegaly, and improved survival, with no detected off-target mutations in partially homologous loci. This work may provide the basis for a safe and versatile method of fetal gene editing for human monogenic disorders.

Alemtuzumab plus cyclosporine treatment of the autoimmune hemolytic anemia in an adult bowel transplant.

An adult male underwent a bowel transplant for tufting enteropathy, receiving alemtuzumab, tacrolimus, and steroids as immunosuppressants. Five years later, he developed an autoimmune hemolytic anemia (AIHA), anti-IgG positive, with reduced reticulocyte count, leukopenia, and thrombocytopenia with antiplatelet antibodies. After an unsuccessful initial treatment with high dose steroids, reduction in tacrolimus dose, and intravenous immunoglobulin (IVIG), a bone marrow biopsy revealed absence of erythroid maturation with precursor hyperplasia. The patient was switched to sirolimus and received four doses of rituximab plus two courses of plasmapheresis, which decreased his transfusion requirements. After a febrile episode one month later, the AIHA relapsed with corresponding decreases in platelet and leukocyte count: cyclosporine A (CsA) was started with a second course of rituximab and IVIG without response, even though repeat bone marrow biopsy did not reveal morphology correlated to an acquired pure red cell aplasia (APRCA). Considering the similarity in his clinical and laboratory findings to APRCA, alemtuzumab was added (three doses over a week) with CsA followed by steroids. The patient was eventually discharged transfusion-independent, with increasing hemoglobin (Hb) levels and normal platelet and leukocyte count. One year later he is still disease-free with functioning graft.

Burn Injury Dampens Erythroid Cell Production Through Reprioritizing Bone Marrow Hematopoietic Response

Anemia in burn patients is due to surgical blood loss and anemia of critical illness. Because the commitment paradigm of common bone marrow progenitors dictates the production of erythroid, myeloid, and lymphoid cells, we hypothesized that skewed bone marrow lineage commitment decreases red cell production and causes anemia after a burn injury. After anesthesia, B(6)D(2)F(1) mice received a 15% total body surface area dorsal scald burn. The sham group did not receive scald burn. Femoral bone marrow was harvested on 2, 5, 7, 14, and 21 postburn days (PBD). Total bone marrow cells were labeled with specific antibodies to erythroid (CD71/Ter119), myeloid (CD11b), and lymphoid (CD19) lineages and analyzed by flow cytometry. To test whether erythropoietin (EPO) could increase red blood cell production, EPO was administered to sham and burn animals and their reticulocyte response was measured on PBD 2 and PBD 7. Burn injury reduced the erythroid cells of the bone marrow from 35% in sham to 17% by PBD 5 and remained at similar level until PBD 21. Myeloid cells, however, increased from 42% in sham to 60% on PBD 5 and 77% on PBD 21. Burn injury reduced reticulocyte counts on PBD 2 and PBD 7 indicating that the erythroid compartment is severely depleted. This depleted compartment, however, responded to EPO but was not sufficient to change red cell production. Burn injury skews the bone marrow hematopoietic commitment away from erythroid and toward myeloid cells. Shrinkage of the erythroid compartment contributes to resistance to EPO and the anemia of critical illness.

Aging of red blood cells and impaired erythropoiesis following prolonged administration of dichloromethylene diphosphonate containing liposomes in rats

To investigate whether macrophage-depleted rats may serve as a model for studying red blood cell (RBC) aging. Rats were macrophage-depleted by 4 weekly injections of dichloromethylene diphosphonate-containing liposomes (Cl2MDP-CL). The macrophage content of spleens and bone marrows (BMs) was investigated by immunohistochemistry and light microscopy and by flow cytometry, respectively, after staining with macrophage-specific monoclonal antibodies. In addition, the ultrastructure of residual BM macrophages and their ability to phagocytose zymosan was studied. BM was also studied for apoptosis (by the TUNEL reaction) and for erythroid progenitor cell content. Furthermore, RBC indices, morphology, life span (by 51Cr labeling) and aging features (MCV, density, 4.1a/4.1b membrane protein ratio, anti-spectrin IgG binding, microvesiculation) were investigated. Serum TNF-alpha, iron, total iron-binding capacity (TIBC) and ferritin were also determined. Prolonged treatment with Cl2MDP-CL caused an almost complete depletion of macrophages in the spleen and a 58% reduction of those in the BM; the residual BM macrophages were activated as judged by their ultrastructure and phagocytic capacity in vitro. These alterations were accompanied by an increase in RBC life span and age-related RBC changes, as well as by mild anemia associated with a reduced reticulocyte count, reduced BM erythroid progenitors, increased numbers of apoptotic cells in the BM, low serum iron, high TIBC and increased serum TNF-alpha levels. Rats subjected to prolonged macrophage depletion showed an increased prevalence of senescent RBC in the circulation due to their impaired clearance by macrophages. Hence, these animals provide a model system in which mechanisms of RBC aging can be delineated. They also showed impaired erythropoiesis, presumably related to a reduction in BM macrophages and increased production of proinflammatory cytokines by residual activated marrow macrophages and other cells.

Importance of Anemia and Transferrin Levels in the Regulation of Intestinal Iron Absorption in Hypotransferrinemic Mice

AbstractThe hypotransferrinemic mouse (trf hpx) is a mutant strain exhibiting transferrin deficiency, marked anemia, hyperabsorption of iron, and elevated hepatic iron stores. We set out to investigate the relative roles of anemia and of transferrin in the malregulation of intestinal iron absorption in these animals. Transfusion of erythrocytes obtained from littermate controls increased hemoglobin levels and reduced reticulocyte counts in recipient animals. Although mucosal to carcass 59Fe transfer was reduced, total duodenal iron uptake was not significantly affected. Iron absorption in homozygotes, in contrast to littermate controls, was not reduced by hyperoxia. Mouse transferrin injections, in the short term, increased delivery of iron to the marrow and raised hemoglobin levels. Although mucosal transfer and total iron uptake were reduced at the higher transferrin doses, total uptake was still higher than in controls. Daily injections of mouse/human transferrin for 3 weeks from weaning, normalized hemoglobin values, and markedly reduced liver iron and intestinal iron absorption values in trf hpxanimals. When such daily-injected mice were left for a week to allow transferrin clearance, iron absorption values were significantly enhanced; hemoglobin or hepatic iron levels were, however, not significantly altered. These data indicate that hyperabsorption of iron in trf hpx mice is not solely because of the anemia; transferrin levels per se do affect iron absorption, possibly via a direct effect on the intestinal mucosa.

Importance of Anemia and Transferrin Levels in the Regulation of Intestinal Iron Absorption in Hypotransferrinemic Mice

The hypotransferrinemic mouse (trf hpx) is a mutant strain exhibiting transferrin deficiency, marked anemia, hyperabsorption of iron, and elevated hepatic iron stores. We set out to investigate the relative roles of anemia and of transferrin in the malregulation of intestinal iron absorption in these animals. Transfusion of erythrocytes obtained from littermate controls increased hemoglobin levels and reduced reticulocyte counts in recipient animals. Although mucosal to carcass 59Fe transfer was reduced, total duodenal iron uptake was not significantly affected. Iron absorption in homozygotes, in contrast to littermate controls, was not reduced by hyperoxia. Mouse transferrin injections, in the short term, increased delivery of iron to the marrow and raised hemoglobin levels. Although mucosal transfer and total iron uptake were reduced at the higher transferrin doses, total uptake was still higher than in controls. Daily injections of mouse/human transferrin for 3 weeks from weaning, normalized hemoglobin values, and markedly reduced liver iron and intestinal iron absorption values in trf hpxanimals. When such daily-injected mice were left for a week to allow transferrin clearance, iron absorption values were significantly enhanced; hemoglobin or hepatic iron levels were, however, not significantly altered. These data indicate that hyperabsorption of iron in trf hpx mice is not solely because of the anemia; transferrin levels per se do affect iron absorption, possibly via a direct effect on the intestinal mucosa.

Reticulocyte maturity as an indicator for estimating qualitative abnormality of erythropoiesis.

To determine the maturity of reticulocytes in patients with anaemia as a result of various haematological disorders including those with qualitative abnormalities such as ineffective erythropoiesis or dyserythropoiesis. The number of mature reticulocytes was measured with flow cytometry in venous blood samples from 122 patients with haematological disorders and 100 healthy controls. Reticulocytes were classified into three categories by the fluorescence intensity of auramin O staining: low fluorescence ratio (LFR), medium fluorescence ratio (MFR), and high fluorescence ratio (HFR). Immature reticulocytes were determined as the aggregate of MFR and HFR (%). The mean (2SD) number of immature reticulocytes in 100 normal subjects was 9.0 (7.0)%. Significantly high mean values of immature reticulocytes with a normal or reduced reticulocyte count were shown in 90 patients with dyserythropoietic or ineffective erythropoietic conditions, such as acute myeloid leukaemia (AML) (n = 37), myelodysplastic syndrome (MDS) (n = 35), aplastic anaemia (AA) (n = 8), or megaloblastic anaemia (MA), (n = 6). Reticulocyte ratios returned to normal after successful treatment of patients with AML (n = 10) and MA (n = 3). However, high percentages of immature reticulocytes with increased reticulocyte counts were consistently observed in patients with enhanced erythropoiesis such as those with acquired autoimmune haemolytic anaemias (AIHA) (n = 4) or acute blood loss (ABL) (n = 4). Reticulocyte maturity was within the normal range in patients with reduced erythropoiesis such as occurs in chronic renal failure (CRF) (n = 11), or in iron deficiency anaemia (IDA) (n = 13). The evaluation of reticulocyte maturity with total reticulocyte count seems to be clinically useful for estimating the qualitative impairment of erythropoiesis, and so could help differentiate haematological disorders.