Polycythemia Vera Masked by Megaloblastic Anemia.

Polycythemia vera (PV) is a chronic myeloproliferative disorder characterized by uncontrolled red blood cell production. Megaloblastic anemia is caused by deficiency of cobalamin (vitamin B12) and/or folate (vitamin B9). While B12 deficiency may be caused by insufficient dietary intake or impairment of its utilization, its association with PV is described without exact knowledge of the physiopathology. We herein report the occurrence of megaloblastic anemia due to Vitamin B12 deficiency in an 85-year-old North African woman patient with PV. This case highlights this atypical presentation of PV and challenges that comes with it causing the delay of diagnosis and the complexity of its diagnosis and treatment. Keywords: megaloblastic anemia, polycythemia vera, association, case report.

Severe megaloblastic anemia in a patient with advanced lung adenocarcinoma during treatment with erlotinib: a case report and literature review.

BACKGROUND: Erlotinib is a first-generation, tyrosine kinase inhibitor of the epidermal growth factor receptor (EGFR-TKI) used for the treatment patients with NSCLC. Erlotinib is considered as a safe and effective treatment option, with generally good tolerance. Diarrhea and rash are the most common side effects, and more rare side effects appear in long-term real-world applications. Severe erlotinib related megaloblastic anemia is rare and remains unreported. This is the first case report of severe megaloblastic anemia in a patient with advanced lung adenocarcinoma with an EGFR L858R mutation treated with erlotinib. In this report, the clinical manifestations, diagnosis and treatment of erlotinib related severe megaloblastic anemia are described, and the possible pathogenesis and related treatment options are discussed. CASE DESCRIPTION: Herein, we present a 57- year-old non-smoking female diagnosed with metastatic lung adenocarcinoma harboring an EGFR L858R mutation, who had received erlotinib as the first-line therapy. After 44 weeks of treatment, the patient developed severe anemia. Anemia was manifested as megaloblastic anemia with elevated mean corpuscular volume and mean corpuscular hemoglobin. The total vitamin B12 level was below the detection limit of 50.00 pg /mL. Bone marrow smear suggested megaloblastic anemia. Her hematologic parameters were markedly recovered following the withdrawal of erlotinib and vitamin B12 supplement. As a result, the patient was diagnosed with erlotinib-associated megaloblastic anemia. CONCLUSIONS: This is the first case of severe megaloblastic anemia reported with erlotinib. Few of these hematologic adverse effects have been observed in studies on erlotinib, this case report highlights this possibility for long-term erlotinib administration. Close clinical and blood monitoring is recommended for patients receiving long-term TKI therapy.

Flow cytometry-detected changes in megaloblastic anemia secondary to cobalamin deficiency.

Introduction: Megaloblastic anemias secondary to Vitamin B12 deficiency are a group of pathologies produced by defective nuclear DNA synthesis. Objective: To describe the maturation alterations found in hematopoietic precursors of the bone marrow in a series of patients with megaloblastic anemia. Methods: Were included patients attended at the Regional Hospital of Concepción with bone marrow samples sent for the study of cytopenia by flow cytometry whose final diagnosis was megaloblastic anemia. The immunophenotype was performed with CD45, CD34, CD117, HLA-DR, markers of neutrophil (CD13, CD11b, CD10, CD16) and/or erythroblast (CD105, CD71, CD36) maturation. Results: From the flow cytometry laboratory database, 8 patients with megaloblastic anemia were identified, and myelodysplastic syndromes (n=9) and normal or reactive bone marrow (n=10) were used as controls. 44% were men, with a median age of 58 years. Megaloblastic anemia was associated with a higher proportion of size and complexity of erythroid and myeloid progenitors compared to lymphocytes compared to controls. The total percentage of erythroblasts and the proportion of CD34+ myeloid cells associated with erythroid lineage was higher in megaloblastic anemia, associated with a maturation arrest in the CD105+ precursor stage (69% vs 19% and 23%, p<0.001). The heterogeneity of CD36 and CD71 in megaloblastic anemia was similar to myelodysplastic syndromes. Conclusions: Megaloblastic anemia produces a heterogeneous involvement of hematopoiesis, characterized by a greater size and cellular complexity of precursors of the neutrophil and erythroid series and a maturation arrest of the erythroblasts.

Introducción: Anemias megaloblásticas secundarias a la deficiencia de vitamina B12 son patologías producidas por una síntesis defectuosa del ADN nuclear. Objetivo: Describir las alteraciones madurativas encontradas en precursores hematopoyéticos de la médula ósea de una serie de pacientes con anemia megaloblástica. Métodos: Se incluyeron pacientes atendidos en el Hospital Regional de Concepción con muestras de médula ósea enviadas para estudio de citopenias por citometría de flujo cuyo diagnóstico fue anemia megaloblástica. El inmunofenotipo se realizó con CD45, CD34, CD117, HLA-DR, marcadores de maduración de serie de neutrófilo (CD13, CD11b, CD10, CD16) y/o eritroblasto (CD105, CD71, CD36). Resultados: Se identificaron 8 pacientes con anemia megaloblástica y como controles se utilizaron síndromes mielodisplásicos (n=9) y médula ósea normal o reactiva (n=10). El 44% eran hombres, con una mediana de edad de 58 años. La anemia megaloblástica se asoció con una mayor proporción de tamaño y complejidad de progenitores eritroides y mieloides con respecto de los linfocitos en comparación a los controles. El porcentaje total de eritroblastos y la proporción de células mieloides CD34+ comprometidas con el linaje eritroide fue mayor en anemia megaloblástica, asociado a una parada madurativa en la etapa de precursor CD105+ (69% vs 19% y 23%, p <0.001). La heterogeneidad de CD36 y CD71 en anemia megaloblástica fue similar a los síndromes mielodisplásicos. Conclusiones: la anemia megaloblástica produce una afectación heterogénea de la hematopoyesis, caracterizada por un mayor tamaño y complejidad celulares de precursores de la serie neutrófilo y eritroide y una detención madurativa de los eritroblastos.

Polimorfismo de proteína 5, 10-metilentetrahidrofolatoreductasa en población venezolana / Polymorphisms proteína 5, 10-metilentetrahidrofolatoreductasa in venezuelan people

El folato es un miembro del grupo de la vitamina B y está relacionado con enfermedades crónicas como anemia megaloblástica, enfermedad cardiovascular, cáncer, disfunción cognitiva y riesgo de defectos del tubo neural. La proteína 5,10-metilentetrahidrofolato reductasa (MTHFR) juega un papel clave en el metabolismo del folato mediante la síntesis de nucleótidos y reacciones de metilación. El gen MTHFR se encuentra en el cromosoma 1 (1p36.3), y se han descrito dos alelos comunes, el alelo C677T (termolábil) y el alelo A1298C.El objetivo de este estudio es evaluar la distribución de los polimorfismos genéticos en MTHFR C677T y A1298C en la población venezolana. METODOS: estudio de tipo transversal, descriptivo, experimental y correlacional Las muestras de sangre se colectaron en 314 donantes no emparentados y sanos de la población. Los polimorfismos de un solo nucleótido(SNP) MTHFR 677C>T y 1298A>C se analizaron mediante polimorfismo de longitud de fragmento de restricción de reacción en cadena de polimerasa (PCR-RFLP). El desequilibrio de ligamiento (LD) entre pares de SNP se calculó mediante la prueba X. usando Prism 5 (GraphPad software, Inc). RESULTADOS: Encontramos mayor frecuencia genotípica de heterocigotos para el polimorfismo MTHFR C677T en la población general venezolana, con excepción del grupo caucásico. El polimorfismo MTHFR A1298C en el 70%de la población de estudio es homocigoto de tipo salvaje, encontrándose una baja frecuencia de homocigoto mutado. CONCLUSIONES: Se encontraron diferencias significativas entre grupos étnicos, destacando la importancia del genotipado racial de estos polimorfismos en la población venezolana(AU)

Folate is a member of the vitamin B and it has also been indicated that may be related to chronic diseases such as megaloblastic anemia, cardiovascular disease, cognitive dysfunction and risk of neural tube. Methylenetetrahydro folatereductase (MTHFR) is a key enzyme of folate pathway by nucleotide synthesis and methylation reactions. Several polymorphisms were reported in MTHFR gene but C677Tand A1298 polymorphism are most studied and these have been reported to be risk factor for several diseases/disorders. The present study was designed to determine the frequency of MTHFR polymorphisms in Venezuelan healthy population. METHODS: The blood samples were collected from 314 unrelated and healthy donors from population. Both the MTHFR 677C>T and 1298A>C single nucleotide polymorphisms (SNPs) were analyzed by Polymerase chainreaction-restriction fragment length polymorphism (PCR-RFLP). Linkage disequilibrium (LD) between pair of SNPs was calculated through the .. test using Prism 5 (GraphPad sftoware, Inc). RESULTS: We find higher genotypic frequency of heterozygotes for the MTHFR C677T polymorphism in the Venezuelan general population, with the exception of the Caucasian group. MTHFR A1298C polymorphism in 70%of the study population is homozygous wild type, finding alow frequency of homozygous mutated. CONCLUSIONS: Significant differences between ethnic groups were found,highlighting the importance of racial genotyping of these polymorphisms in the Venezuelan population(AU)

Computational analysis of peripheral blood smears detects disease-associated cytomorphologies.

Many hematological diseases are characterized by altered abundance and morphology of blood cells and their progenitors. Myelodysplastic syndromes (MDS), for example, are a group of blood cancers characterised by cytopenias, dysplasia of hematopoietic cells and blast expansion. Examination of peripheral blood slides (PBS) in MDS often reveals changes such as abnormal granulocyte lobulation or granularity and altered red blood cell (RBC) morphology; however, some of these features are shared with conditions such as haematinic deficiency anemias. Definitive diagnosis of MDS requires expert cytomorphology analysis of bone marrow smears and complementary information such as blood counts, karyotype and molecular genetics testing. Here, we present Haemorasis, a computational method that detects and characterizes white blood cells (WBC) and RBC in PBS. Applied to over 300 individuals with different conditions (SF3B1-mutant and SF3B1-wildtype MDS, megaloblastic anemia, and iron deficiency anemia), Haemorasis detected over half a million WBC and millions of RBC and characterized their morphology. These large sets of cell morphologies can be used in diagnosis and disease subtyping, while identifying novel associations between computational morphotypes and disease. We find that hypolobulated neutrophils and large RBC are characteristic of SF3B1-mutant MDS. Additionally, while prevalent in both iron deficiency and megaloblastic anemia, hyperlobulated neutrophils are larger in the latter. By integrating cytomorphological features using machine learning, Haemorasis was able to distinguish SF3B1-mutant MDS from other MDS using cytomorphology and blood counts alone, with high predictive performance. We validate our findings externally, showing that they generalize to other centers and scanners. Collectively, our work reveals the potential for the large-scale incorporation of automated cytomorphology into routine diagnostic workflows.

CD36 relative mean fluorescence intensity of CD105+ nucleated erythroid cells can be used to differentiate myelodysplastic syndrome from megaloblastic anemia.

This study aims to evaluate the differences in CD105+ nucleated erythroid cell (NEC) immunophenotypes between myelodysplastic syndrome (MDS) and megaloblastic anemia (MA) using multiparameter flow cytometry and to screen potential markers. We analyzed bone marrow sample data from 37 patients with MDS, 35 with MA, 53 with iron-deficiency anemia (anemic controls), and 35 without anemia (normal controls). Compared with normal controls, the MDS and MA groups showed a decrease in the proportion of CD117+CD105+NEC and the relative mean fluorescence intensity (RMFI) of CD71 in CD105+NEC, accompanied by an increase in the coefficient of variation (CV) of CD71 and CD36. Additionally, CD36 RMFI of CD105+NEC increased in the MA group. Compared with anemia controls, the MDS and MA groups showed a significant increase in CD36 CV of CD105+NEC, and the CD36 RMFI in the MA group increased while that in the MDS group decreased. The proportions of CD117+CD105+NEC, CD36 CV, and CD36 RMFI in CD105+NEC differed significantly between MDS and MA groups. Among them, CD36 RMFI had good diagnostic performance (area under the curve: 0.844, 95% confidence interval: 0.753-0.935). CD36 RMFI of CD105+NEC may be a helpful marker in differentiating MDS and MA using multiparameter flow cytometry.

Anemia: Macrocytic Anemia.

Macrocytic anemia is divided into megaloblastic and nonmegaloblastic causes, with the former being more common. Megaloblastic anemia results from impaired DNA synthesis, leading to release of megaloblasts, which are large nucleated red blood cell precursors with chromatin that is not condensed. Vitamin B12 deficiency is the most common cause for megaloblastic anemia, although folate deficiency also can contribute. Nonmegaloblastic anemia entails normal DNA synthesis and typically is caused by chronic liver dysfunction, hypothyroidism, alcohol use disorder, or myelodysplastic disorders. Macrocytosis also can result from release of reticulocytes in the normal physiologic response to acute anemia. Management of macrocytic anemia is specific to the etiology identified through testing and patient evaluation.

Pancytopenia in celiac disease-A case series of 20 children.

Pancytopenia in children with celiac disease (CeD) is postulated to be due to nutritional deficiency such as vitamin B12, folate and copper or an autoimmune process resulting in aplastic anemia with hypoplastic marrow. In the present case series, we report the profile and explore the etiology of pancytopenia among children with CeD. There are only a few case reports of pancytopenia in children with CeD. We enrolled newly diagnosed cases of CeD and pancytopenia presenting in the celiac disease clinic over three years. Detailed evaluation was carried out for the cause of pancytopenia. We followed up on the cases for compliance and response to gluten-free diet at three months, six months and 12 months. Twenty patients were eligible for inclusion. They were divided into two groups: one with aplastic anemia with hypoplastic marrow labeled as Gp CeD-AA and the other with megaloblastic/nutritional anemia labeled as Gp CeD-MA. Patients in Gp CeD-MA presented with classical symptoms of CeD as recurrent diarrhea, abdomen distension, pallor and poor weight gain. They had none or just one transfusion requirement and had an early and complete recovery from pancytopenia. Patients in Gp CeD-AA presented with atypical symptoms such as epistaxis, short stature, fever, pallor and weakness. They had a multiple blood transfusion requirement and had delayed and partial recovery from pancytopenia. Pancytopenia is not a disease in itself but is the presentation of an underlying disease. It can occur due to various coexisting disorders in children with CeD, which can be as simple as nutritional deficiencies to as complex as an autoimmune process or malignancy. CeD should be included in the differential diagnosis of aplastic anemia as CeD and aplastic anemia both have a similar pathological process involving T cell destruction of tissues.

Vitamin B12: For more than just the treatment of megaloblastic anemia?

Vitamin B12, or cobalamin, belongs to the group of water-soluble vitamins and is ingested through food of animal origin such as eggs, milk, red meat and poultry, fish, and shellfish. Its clinical indication is the treatment of hypovitaminosis B12 administered orally or intramuscularly in the form of hydroxocobalamin. Hypovitaminosis B12 is mainly caused by deficient dietary intake (individuals with malnutrition, vegetarians or vegans, older adults, pregnant people, individuals with alcohol use disorder); when intestinal absorption is reduced (atrophic gastritis, malabsorption syndrome, gastrointestinal surgery); and for causes associated with the intake of drugs (antacids, metformin). Hypervitaminosis B12 has been associated with renal failure; liver diseases such as cirrhosis and acute-phase hepatitis; alcohol use disorder with or without liver involvement; solid tumors of the lung, liver, esophagus, pancreas, and colorectum; and in hematological malignancies such as leukemia and bone marrow dysplasia.

Black Cohosh Herbal Extract and Hematologic Alterations in B6C3F1/N Mice.

Black cohosh is a readily available dietary supplement currently marketed as a remedy for dysmenorrhea and menopausal symptoms and is one of the top-selling herbal supplements in the United States. Black cohosh extract (BCE) was nominated to the National Toxicology Program (NTP) by the National Cancer Institute and the National Institute of Environmental Health Sciences due to its widespread use and lack of animal toxicity studies. Results of the NTP BCE subchronic mouse toxicity study revealed a dose-dependent, non-regenerative decrease in the erythron with an increase in the mean corpuscular volume (macrocytosis). Howell-Jolly bodies, or micronuclei, were significantly increased. These particular changes indicated an ineffective erythropoiesis consistent with a condition known as megaloblastic anemia. Megaloblastic anemia is due to disruptions in DNA synthesis during hematopoiesis and can be a result of an inherited or drug-induced disorder or a consequence of folate or cobalamin deficiency. Subsequent mouse studies revealed hematological and biochemical changes that were consistent with a functional cobalamin deficiency. This article will review basic mechanisms and laboratory features of megaloblastic anemia. The results of our studies including morphological abnormalities of the erythron and biomarkers of folate and cobalamin deficiencies, as well as hepatic microarray gene changes, are also discussed.

Megaloblastic Anemia Masked by an Unrecognized Hemoglobinopathy.

BACKGROUND: Deficiency of vitamin B(12) or folate causes megaloblastic anemia (MA). The disease presents with pancytopenia due to the excessive cellular apoptosis of hematopoietic progenitor. MA is characterized by the presence of high mean corpuscular volume in the blood routine test and hyperlobulation nuclei of the granulocytes in the peripheral blood smears, and megaloblasts in the bone marrow. METHODS: We report a rare case, in which megaloblastic anemia was masked by an unrecognized hemoglobinopathy and presented with normocytic anemia and atypical morphological features of bone marrow. RESULTS: The patient was finally diagnosed with coexistence of MA and a-thalassemia minor due to determination of folate deficiency and genetic mutation for a-thalassemia. CONCLUSIONS: The case focuses on the contribution of the peripheral circulating blood smear examination in the diagnosis of anemia.

Diferentes formas de presentación de la anemia megaloblástica en el lactante / Different forms of presentation of megaloblastic anemia in the infant

Introducción: La anemia megalobástica es un trastorno madurativo de los precursores eritroides y mieloides causado por déficit de vitamina B12, ácido fólico, o ambos. Es poco común en la infancia y su prevalencia se desconoce por ser una enfermedad poco frecuente. Objetivo: Describir diferentes formas de presentación de la anemia megaloblástica en el lactante. Presentación de casos: Se presentan dos casos de lactantes, en el caso 1 la madre tuvo una alimentación precaria durante el embarazo y la lactancia, prolongó la lactancia materna exclusiva más de 6 meses. La paciente comenzó a perder las habilidades ganadas en el desarrollo psicomotor y presentó trastornos neurológicos graves, por lo que se consideró que se trataba de una enfermedad progresiva del sistema nervioso central. En el caso 2, en el que se prolongó la lactancia materna exclusiva, apareció trombocitopenia, por lo que se sospechó una enfermedad hematológica maligna. Resultados: En ambos casos después de realizar diversas pruebas para descartar enfermedades neurológicas (caso 1) y enfermedades hematológicas (caso 2) se diagnosticó anemia megaloblástica por déficit de vitamina B12 por disminución en la ingesta y una reserva limítrofe en la madre que lacta. En ambos casos los síntomas desaparecieron con el tratamiento vitamínico sustitutivo. Conclusiones: En el lactante la anemia megaloblástica se puede presentar de diferentes formas clínicas a pesar de tener la misma causa, un déficit en la ingesta y una reserva escasa de la madre durante el embarazo y lactancia(AU)

Introduction: Megaloblastic anemia is a maturing disorder of the erythroid and myeloid precursors caused by deficiency of vitamin B12, folic acid, or both. It is uncommon in childhood and its prevalence is unknown because it is a rare disease. Objective: To describe different forms of presentation of megaloblastic anemia in infants. Presentation of cases: Two cases of infants are presented, in case 1 the mother had a precarious diet during pregnancy and lactation, and prolonged exclusive breastfeeding more than 6 months. The patient began to lose the skills gained in psychomotor development and presented severe neurological disorders, so it was considered that it was a progressive disease of the central nervous system. In case 2, in which exclusive breastfeeding was prolonged, thrombocytopenia appeared, so a malignant hematological disease was suspected. Results: In both cases, after performing various tests to rule out neurological diseases (case 1) and hematological diseases (case 2), megaloblastic anemia was diagnosed due to vitamin B12 deficiency due to a decrease in intake and a borderline reserve in the breastfeeding mother. In both cases the symptoms disappeared with vitamin replacement therapy. Conclusions: In the infant, megaloblastic anemia can occur in different clinical ways despite having the same cause, a deficit in intake and a low reserve of the mother during pregnancy and lactation(AU)

[Vitamin B12 deficiency in an infant child of a mother with pernicious anemia]. / Déficit de vitamina B12 en un lactante hijo de madre portadora de anemia perniciosa.

INTRODUCTION: In infants, vitamin B12 deficiency is mainly due to nutritional deficiencies related to maternal deficit. Most cases of maternal deficiencies are associated with vegetarian diets. Pernicious anemia is an au toimmune disease that affects the absorption of this vitamin. Although it is less common than nutri tional deficiency, is also an important cause of maternal deficiency. OBJECTIVE: to report a case of an infant with vitB12 deficiency, secondary to pernicious anemia in his mother, and to review the most important aspects of this disease in childhood. CLINICAL CASE: Nine months-old male infant, without pathological perinatal history, exclusively breastfed, with persistent rejection of solid food from 6 months of age. One month before hospitalization, he progressively presented hyporesponsiveness, with fluctuating state of alertness, regression of motor development milestones, and vomiting. The blood count showed macrocytic anemia and neutropenia. Vitamin B12 deficiency was confirmed in the patient. He received treatment with intramuscular vitamin B12 with good clinical and laboratory response. Maternal B12 deficiency was confirmed as the cause of the infant's deficiency. Since the mother reported no dietary restrictions, anti-intrinsic factor and anti-parietal cell antibodies were measured, leading to the diagnosis of pernicious anemia. CONCLUSIONS: Early recognition is essential to prevent the development of potentially irreversible neurological damage. Maternal pernicious ane mia should be considered in children with megaloblastic anemia, especially in those whose mothers do not follow vegetarian diets.

An infantile case of hereditary folate malabsorption with sudden development of pulmonary hemorrhage: a case report.

BACKGROUND: Hereditary folate malabsorption-a rare disorder caused by impairment of the folate transporter-can develop into severe folate deficiency manifesting as megaloblastic anemia and occasionally thrombocytopenia. Reportedly, megaloblastic anemia can manifest with hemorrhagic episodes, possibly due to ineffective platelet production and platelet dysfunction. However, life-threatening hemorrhage events in hereditary folate malabsorption have not been well investigated. CASE PRESENTATION: A 3-month-old Japanese boy was transferred to our hospital due to thrombocytopenia and severe megaloblastic anemia. During a thorough examination of hematopoietic abnormalities, the patient suddenly went into cardiac arrest due to pulmonary hemorrhage. Although intravenous folate supplementation was started soon after the identification of folate deficiency, the patient died of circulatory defect and multiple organ failure. The cause of pulmonary hemorrhage, such as respiratory infection, could not be confirmed. Genetic investigation revealed a mutation in the SLC46A1 gene to be the cause of the hereditary folate malabsorption. CONCLUSION: We report an infantile case of hereditary folate malabsorption that progressed to lethal pulmonary hemorrhage before folate deficiency was identified. Clinicians should consider that megaloblastic anemia could lead to severe bleeding without warning, and that nutrient supplementation should be initiated as soon as possible.

Absolute Neutrophil Count in Cases of Pancytopenia.

Pancytopenia is a common cause of hematological consultation. Common underlying causes include vitamin deficiency (vitamin B12, folic acid), drugs (hydroxyurea, phenytoin, methotrexate), and bone marrow failure syndrome. Aplastic anemia is one of the rarest hematological diseases and presents as pancytopenia. However, it is the most sinister one and is a hematological emergency that needs urgent medical attention. Absolute neutrophil count (ANC) is a measure of disease severity and is expected to be low in patients with pancytopenia of any cause. Aim & Objective: We aimed to analyze the absolute neutrophil count (ANC) level in patients presenting with pancytopenia. Material & Method: This prospective, observational study was conducted at a tertiary care hospital in northern India. We included patients with pancytopenia diagnosed at our center or reported to our center for therapy. ANC was measured before starting therapy. Observation: One hundred twenty-seven patients were included in this study. After evaluation, megaloblastic anemia was the commonest underlying cause in 42 (33%) patients followed by myelodysplastic syndrome in 31 (24.4%) patients. Twenty-three (18.1%) patients having pancytopenia were diagnosed with aplastic anemia. Other causes included leukemia, paroxysmal nocturnal hemoglobinuria and drugs. The median age was 37 years (range 18-75 years), and 67 (52.75%) were male. The mean hemoglobin was 5.5 g/dL (95% CI ±1.9). The median WBC was 2570/cmm (300-3130) and the median platelet was 36000/cmm (2000-92000). The median ANC in patients with aplastic anemia was 594/cmm (range 25- 3850). When compared, the ANC level was significantly lower in aplastic anemia than other causes of pancytopenia (p<0.001). Conclusion: On univariate and multivariate analysis ANC was significantly lower at baseline in patients of aplastic anemia. A longer follow-up of the patients will be required to assess the value of ANC in predicting response to therapy.

Vitamin B12 absorption and malabsorption.

Vitamin B12 is assimilated and transported by complex mechanisms that involve three transport proteins, intrinsic factor (IF), haptocorrin (HC) and transcobalamin (TC) and their respective membrane receptors. Vitamin deficiency is mainly due to inadequate dietary intake in vegans, and B12 malabsorption is related to digestive diseases. This review explores the physiology of vitamin B12 absorption and the mechanisms and diseases that produce malabsorption. In the stomach, B12 is released from food carrier proteins and binds to HC. The degradation of HC by pancreatic proteases and the pH change trigger the transfer of B12 to IF in the duodenum. Cubilin and amnionless are the two components of the receptor that mediates the uptake of B12 in the distal ileum. Part of liver B12 is excreted in bile, and undergoes an enterohepatic circulation. The main causes of B12 malabsorption include inherited disorders (Intrinsic factor deficiency, Imerslund-Gräsbeck disease, Addison's pernicious anemia, obesity, bariatric surgery and gastrectomies. Other causes include pancreatic insufficiency, obstructive Jaundice, tropical sprue and celiac disease, bacterial overgrowth, parasitic infestations, Zollinger-Ellison syndrome, inflammatory bowel diseases, chronic radiation enteritis of the distal ileum and short bowel. The assessment of B12 deficit is recommended in the follow-up of subjects with bariatric surgery. The genetic causes of B12 malabsorption are probably underestimated in adult cases with B12 deficit. Despite its high prevalence in the general population and in the elderly, B12 malabsorption cannot be anymore assessed by the Schilling test, pointing out the urgent need for an equivalent reliable test.

How I investigate acquired megaloblastic anemia.

In this review of megaloblastic anemia (MA), an overview of vitamin B12 and folate body requirements, biochemical pathways, and laboratory testing strategies will be provided. However, the focus of this review is the classic and unique features of MA in blood and bone marrow. Acquired MA is a benign disorder for many, but can be detrimental for some. The clinical presentation can vary considerably, and the spectrum of symptoms and signs is diverse and quite broad. Prompt recognition and therapy are critical to prevent potential irreversible damage and clinical sequelae, especially in patients with vitamin B12 deficiency. A delay in diagnosis of vitamin B12 deficiency can result in significant neurologic sequelae that may not fully resolve with treatment, including in neonates and young infants. The blood and bone marrow features in MA can closely mimic thrombocytopenic purpura, myelodysplasia, and other myeloid neoplasms. Both pancytopenia and normal MCV at presentation are common in MA and raise unique challenges for the diagnostician. Partially treated MA is also a significant diagnostic "trap". MA is highly responsive to treatment, and patients tend to improve rapidly upon treatment initiation. However, the broad range of clinical and hematologic features makes the rapid, successful diagnosis of MA a unique challenge for the hematopathologist. Even in the era of state-of-the-art laboratory testing, a high suspicion is required.

A 17-Month-old Boy With Pancytopenia Caused by a Rare Genetic Defect of Vitamin B12 Malabsorption.

Imerslund-Gräsbeck syndrome is an autosomal recessive disorder of vitamin B12 malabsorption presenting with megaloblastic anemia and mild proteinuria in childhood. The disorder is caused by biallelic pathogenic variants in the CUBN or AMN genes, which encode proteins involved in B12 absorption. We present the case of a 17-month-old boy with failure to thrive, pancytopenia, and fevers. His megaloblastic anemia was overlooked leading to unnecessary invasive testing. Findings on bone marrow biopsy prompted investigation for genetic disorders of B12 metabolism. Exome sequencing uncovered 1 known pathogenic variant and 1 novel likely pathogenic variant in CUBN, confirming the diagnosis of Imerslund-Gräsbeck syndrome.

Leber congenital amaurosis as an initial manifestation in a Chinese patient with thiamine-responsive megaloblastic anemia syndrome.

Thiamine-responsive megaloblastic anemia syndrome (TRMA) is an autosomal recessive disorder, inherited by the defective SLC19A2 gene that encodes a high-affinity thiamine transporter (THTR-1). TRMA is characterized by the occurrence of classical triad manifestations including megaloblastic anemia, diabetes mellitus, and sensorineural deafness. In addition to the systemic manifestations, ophthalmic features can be present and include retinitis pigmentosa, optic atrophy, cone-rod dystrophy, maculopathy, and Leber congenital amaurosis. Here we report a 6-year-old boy presenting severe early-onset retinal dystrophy with the initial diagnosis of Leber congenital amaurosis, which followed for 12 years. Diabetes mellitus occurred 3 years after vision problem. Eosinophilic granuloma of the left scapula was confirmed at 13 years old. Whole-exome sequencing was performed to identify two novel compound heterozygous variants c.725dupC (p.Ala243Serfs*3) and c.121G>A (p.Gly41Ser) in SLC19A2 gene (NM_006996.3). Oral thiamine supplementation treatment was initiated at 13 years. This case demonstrates Leber congenital amaurosis can present as the first clinical feature before systemic manifestations. Phenotypic variety should be aware and multidisciplinary teamwork and regular follow-up are important for TRMA patient care.