Erythrocyte Enzyme Deficiencies Research Articles

Aautoimmune Hemolytic Anemia: Pattern of Clinical Presentation and Management Outcome — a Nine Year Observation from a Tertiary Care Hospital in Saudi Arabia

Introduction: Autoimmune hemolytic anemia (AIHA) is characterized by production of auto-antibodies that bind to antigen on the erythrocyte surface that leads to its premature destruction and removal from the circulation by macrophages. Occurrence of AIHA in children and adolescents is rare, exact incidence unknown. Objective of this retrospective study was to assess clinical and laboratory characteristics, and management outcome of patients diagnosed with AIHA seen at Pediatric Hematology/Oncology department of King Faisal specialist Hospital and Research Center ,Riyadh from 2005 to 2014. Method: Retrospective chart review of patients (1-14 yrs.) diagnosed with AIHA was conducted. Children were excluded if they have congenital hemolytic anemia, such as hemoglobinopathies, congenital membranopathy and erythrocyte enzyme deficiencies. Result: Thirty-one patients identified, 19(61%) female and 12(39%) male with a median age at diagnosis of 6 years (0.1-12.4). The direct Coombs test was positive in 23 (74%) patients. Underlying diseases observed as cause of AIHA in 14 (45%) patients: majority secondary to viral infections followed by severe combined immunodeficiency syndrome post bone marrow transplant GVHD complication, while systemic lupus erythematosus, antiphospholipid antibody syndrome, autoimmune hepatitis, hypereosinophilic syndrome, Hyper IgE syndrome, post-liver transplant, diabetes was observed in individual cases. Remaining 17 (55%) patients diagnosed as primary AIHA .Corticosteroids and/or immunoglobulin was given as first line of treatment to 64.5% (20) patients while 35.5% (11) required Rituximab and/or splenectomy as second line of treatment, of which 73%(8) were diagnosed as primary AIHA. Five-year overall survival (Kaplan-Meir) rate of 89% was observed with twenty-seven alive patients showing partial or complete response ,while four patients died due to underlying diseases.Conclusion: Our results demonstrates patients responding to first line of treatment, however serious cases required management through second line of treatment. Further, a regional multicenter observational study will enable better understanding of differences in disease presentation and treatment outcomes. DisclosuresNo relevant conflicts of interest to declare.

MicroRNAs in erythropoiesis and red blood cell disorders

MicroRNAs (miRNAs) are 19-24 nucleotide non-coding ribonucleic acids binding DNA or RNA and controlling gene expression via mRNA degradation or its transcription inhibition. Erythropoies is a multi step differentiation process of erythroid progenitors to nucleate red blood cells. Maturation, proliferation and differentiation of red blood cells is affected by erythroid factors, signaling pathways in niche of hematopoietic cells, transcription factors as well as miRNAs. Expression of different types of miRNAs during erythroid development provides a background for the study of these molecules to control erythroid differentiation and maturation as well as their use as diagnostic and prognostic markers to treat erythroid disorders like thalassemia, sickle cell disease and erythrocyte enzyme deficiencies. In this paper, with reference to biosynthesis of miRNAs, their function in normal and anemic erythropoiesis has been investigated. The target molecule of each of these miRNAs has been cited in an attempt to elucidate their role in erythropoiesis.

Nitrite as undesirable substances in animal feed ‐ Scientific Opinion of the Panel on Contaminants in the Food Chain

Nitrite as undesirable substances in animal feed ‐ Scientific Opinion of the Panel on Contaminants in the Food Chain

Pathogenesis, laboratory diagnosis, and clinical implications of erythrocyte enzyme deficiencies in dogs, cats, and horses

Deficiencies of enzymes involved in erythrocyte metabolism can have significant effects on erythrocyte function and survival. Animals with pyruvate kinase (PK) or phosphofructokinase (PFK) deficiencies have shortened erythrocyte life spans and regenerative anemia. PK-deficient dogs (but not PK-deficient cats) develop progressive myelofibrosis and osteosclerosis of bone marrow and hemochromatosis and cirrhosis of the liver. PFK-deficient dogs have sporadic episodes of hyperventilation-induced intravascular hemolysis and hemoglobinuria. Cytochrome b5 reductase (Cb5R) deficiency in dogs and cats results in persistent methemoglobinemia and cyanotic mucous membranes. Severe deficiency of glucose-6-phosphate dehydrogenase, the rate-controlling enzyme in the pentose phosphate pathway, resulted in anemia with eccentrocytosis in an American saddlebred colt. Horses with erythrocyte flavin adenine dinucleotide (FAD) deficiency have both eccentrocytosis (attributable to severe deficiency in glutathione reductase activity) and methemoglobinemia (attributable to Cb5R deficiency); the dual enzyme deficiency occurs because FAD is a required cofactor for both enzymes. Erythrocyte enzyme deficiencies do not usually shorten life expectancy, except for PK-deficient dogs and potentially PFK-deficient dogs during a hemolytic crisis. Although enzyme deficiencies are rare causes of anemia and methemoglobinemia, the ability to diagnose deficient animals allows for the possibility of eliminating these undesirable traits in future breeding. DNA-based assays are available for PK and PFK deficiencies; whereas, biochemical tests of enzyme activity are required for other deficiencies. Continued research is needed to document additional enzyme deficiencies that likely occur and to develop additional DNA-based assays to detect heterozygous animals.

Anemia, splenomegaly, and increased osmotic fragility of erythrocytes in Abyssinian and Somali cats.

To determine clinical and clinicopathologic features of a chronic intermittent severe hemolytic anemia characterized by erythrocyte osmotic fragility in Abyssinian and Somali cats. Case series. 13 Abyssinian and 5 Somali cats. History, pedigree information, and results of routine laboratory tests, special erythrocyte studies, and histologic evaluation of splenic and hepatic specimens were analyzed. Age at which clinical signs of anemia were first apparent ranged from 6 months to 5 years. Ten cats had splenomegaly. Most often, the PCV was between 15 and 25%, but it was as low as 5% at some times. The anemia was characterized by macrocytosis and mild to moderate reticulocytosis, but no poikilocytosis. Hyperglobulinemia, lymphocytosis, mild hyperbilirubinemia, and high hepatic enzyme activities were common findings. Results of Coombs tests and tests for infectious diseases were negative. The erythrocytic osmotic fragility was high in affected cats (mean osmotic fragility, 0.66 to 0.78%), compared with healthy cats (0.48 to 0.58). No specific membrane protein abnormality, erythrocyte enzyme deficiency, or hemoglobinopathy was identified. Histologic evaluation of splenic and hepatic specimens revealed extramedullary hematopoiesis and hemosiderosis. Four of the 5 Somali cats were closely related. On the basis of results of pedigree analyses, the apparent breed predilection, and the exclusion of other known causes of anemia in cats, we believe that the hemolytic anemia in these cats was likely a result of a novel hereditary erythrocyte defect. A genetic predisposition to immune-mediated destruction of erythrocytes could not be ruled out.

Other erythrocyte enzyme deficiencies associated with non-haematological symptoms: phosphoglycerate kinase and phosphofructokinase deficiency

Phosphoglycerate kinase (PGK) deficiency is associated with hereditary haemolytic anaemia and often with central nervous system dysfunction and/or myopathy. Twenty-three families have been discovered with this condition. Nine have manifested both symptoms, six only haemolysis, and seven central nervous system dysfunction and/or myopathy without haemolysis; one case is asymptomatic. Among them, the structural abnormalities of 14 mutants, including 11 missense mutations, 1 gene deletion, 1 gene insertion, and 1 splicing mutation, have been identified. The correlation between the phenotypic and structural differences in PGK deficiency remains to be defined. Splenectomy obviates transfusion in most patients but does not correct the haemolytic disorder. Phosphofructokinase (PFK) deficiency is associated with myopathy and/or haemolysis. More than half reported had the typical features of glycogen storage disease type VII (Tarui disease). The other cases exhibited myopathy alone, haemolytic anaemia alone, or no clinical symptom at all. Eight missense, 1 nonsense, 1 frame-shift and 5 splicing mutations have been determined in the PFK-M gene. In classic PFK-M deficiency, the avoidance of undue exertion is the key to prevent muscle symptoms.

Glucose-6-Phosphate Dehydrogenase Deficiency and Neonatal Jaundice in Al-Hofuf Area

Glucose-6-Phosphate Dehydrogenase Deficiency and Neonatal Jaundice in Al-Hofuf Area

Chapter 3 Hemolytic anemias due to erythrocyte enzyme deficiencies

Red blood cells can only fulfil their functions over the normal period of approximately 120 days with 1.7 × 10 5 circulatory cycles efficiently if they withstand external and internal loads. This requires ATP and redox equivalents, which have to be permanently regenerated by the energy and redox metabolism. These pathways are neccessary to maintain the biconcave shape of the cells, their specific intracellular cation concentrations, the reduced state of hemoglobin with a divalent iron and the sulfhydryl groups of enzymes, glutathione and membrane components. If an enzyme deficiency of one of these metabolic pathways limits the ATP and/or NADPH production, distinct membrane alterations result causing a removal of the damaged cells by the monocyte-macrophage system. Most metabolic needs of erythrocytes are covered by glycolysis, the oxidative pentose phosphate pathway (OPPP), the glutathione cycle, nucleotide metabolism and MetHb reductase. Hereditary enzyme deficiencies of all these pathways have been identified; those that cause non-spherocytic hemolytic anemia are listed in Table 4. Their frequencies differ markedly both with respect to the affected enzyme and geographic distribution. Glucose-6-phosphate dehydrogenase enzymopathies (G6PD) are with more than 400 million cases by far the most common deficiency. The highest gene frequency has been found with 0.7 among Kurdish Jews. G6PD deficiencies are furthermore prevalent with frequencies of about 0.1 among Africans, Black Americans, and populations of Mediterranean countries and South East Asia. In Middle and Northern Europe the frequency of G6PD is much lower, and with approximately 0.0005, comparable with the frequency of pyruvate kinase (PK) enzymopathies, the most frequent enzyme deficiency in glycolysis in this area (Luzzatto, 1987; Beutler and Kuhl, 1990). The relationship between the degree of enzyme deficiency and the extent of metabolic dysfunction in red blood cells and other tissues depend on several factors: on the importance of the affected enzyme; its expression rate; the stability of the mutant enzyme against proteolytic degradation and functional abnormalities; the possibility to compensate the deficiency by an overexpression of the corresponding isoenzyme or by the use of an alternative metabolic pathway. Difficulties in estimating the quantitative degree of disorder in severe cases are due to the fact that these populations contain many reticulocytes, which generally have higher enzyme activities and concentrations of intermediates than erythrocytes. An alternative approach to predict metabolic changes is the analysis by mathematical modeling. Mathematical modeling of the main metabolic pathways of human erythrocytes has reached an advanced level (Rapoport et al., 1976; Holzhütter et al., 1985; Schuster et al., 1988). Models have been succesfully employed to describe stationary and time-dependent metabolic states of the cell under normal conditions as well as in the presence of enzyme deficiencies. Figure 5 shows computational results of erythrocyte enzyme deficiencies. This analysis is based on the comprehensive mathematical model of the energy and redox metabolism for human erythrocyte presented in Fig. 6. Stationary states of the cell metabolism have been calculated by varying the activity of each of the participating enzymes by several orders of magnitude. To predict consequences of enzyme deficiencies a performance function has been introduced (Schuster and Holzhütter, 1995). It takes into account the homeostasis of three essential metabolic variables: the energetic state (ATP), the reductive capacity (reduced glutathione) and the osmotic state. From the data given in Fig. 5 one can conclude that generally the metabolic impairment resulting in deficiences occurs earlier for enzymes with high control coefficients than for those catalyzing equilibrium reactions. On the other hand the flux curves of latter enzymes decrease more steeply below a critical threshold. Furthermore, one can estimate the range of enzyme activities in which the metabolic alterations should be either tolerable or associated with non-chronic or chronic hemolytic anemia. Enzymes responsible for maintenance of glutathione in its reduced state have a wide range of activity where hemolytic crises are expected only under stress conditions, whereas most enzymopathies of glycolysis lead to chronic hemolytic anemia.

6-Phosphogluconolactonase deficiency, a hereditary erythrocyte enzyme deficiency: possible interaction with glucose-6-phosphate dehydrogenase deficiency.

Partial deficiency of 6-phosphogluconolactonase (EC 3.1.1.31) of the erythrocytes was discovered as an autosomal dominant disorder. Hemolytic anemia occurred in an individual who had inherited both the gene for 6-phosphogluconolactonase deficiency and that for deficiency of a nonhemolytic variant of glucose-6-phosphate dehydrogenase (EC 1.1.1.49). It is proposed that the interaction of this hereditary erythrocyte abnormality with glucose-6-phosphate dehydrogenase deficiency may explain hemolysis in some other patients who have inherited polymorphic variants of glucose-6-phosphate dehydrogenase.

Favism: erythrocyte metabolism during haemolysis and reticulocytosis.

The reduced activity of glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate; NADP+ 1-oxidoreductase; G6PF) in Mediterranean erythrocytes explains the precarious equilibrium of the hexose monophosphate pathway (HMP) and the susceptibility of these cells to haemolytic agents. G6PD-deficient erythrocytes, in steady-state conditions, have a low NADPH/NADP+ ratio, thus allowing the HMP to operate at its maximal intracellular rate and to compensate the intrinsic erythrocyte enzyme deficiency. Studies started soon after accidental intake of fava beans by sensitive G6PD-deficient subjects demonstrate a decrease of both NADPH/NADP+ ratio and reduced glutathione. The metabolic effects induced by fava beans may be attributed to oxidative stress probably associated with an inhibitor effect of some unknown metabolite on the HMP. The availability of erythrocytes from subjects recovering from haemolysis with high reticulocyte counts and increased G6PD activity, provides new information on the rate of synthesis as well as on the in vivo decay of the mutant enzyme. Correlation of G6PD activity to reticulocyte count and extrapolation to an ideally homogenous population of reticulocytes reveal that the mutant enzyme is synthesized at a nearly normal rate. Furthermore, the present correlation allows an estimate of the in vivo half-life of Mediterranean G6PD. The rate of decline of about 8 d observed in this study well correlates to the intracellular metabolic aspects of G6PD Mediterranean erythrocytes.

Erythrocyte enzyme deficiencies assessed with a miniature centrifugal analyzer.

Methods for assaying 16 erythrocyte enzymes have been adapted to the miniature centrifugal analyzer. Less than 15 micro L of whole blood is required for all 16 assays. Variation attributable to temporal effects, rotor effects, and random residual error is minor. Initial population studies of blood from adults and cord-blood samples suggest a CV of less than 12% for 12 of the 16 enzymes; thus it should be possible to identify the heterozygous deficient individual. Preliminary data suggest that three such individuals, with enzyme activity (adenylate kinase, pyruvate kinase, phosphoglycerate kinase) about half the expected, have been identified, as well as two individuals deficient in glucose-6-phosphate dehydrogenase.

Mechanisms of the acquired erythrocyte enzyme deficiencies in blood diseases

Acquired enzymatic activity defects of erythrocyte pyruvate kinase, glucose phosphate isomerase and phosphofructokinase have been studied in patients with acute myeloid leukemias, sideroblastic refractory anemias and unclassified acquired dyserythropoiesis. 6 patients with acute myeloid leukemia had a lowered erythrocyte pyruvate kinase activity; in 5 of them the concentration of the “pyruvate kinase ”-antigen was parallely decreased, in such a manner that the ratio enzyme activity / immunologie reactivity (i.e. the molecular specific activity) was normal. In 1 patient with acute leukemia, 4 with refractory anemia and 1 with acquired dyserythropoiesis the defect of the pyruvate kinase activity was associated with a normal antigen concentration (and, therefore, the molecular specific activity in whole hemolysate was lowered). The enzyme activity was restored by incubation with SH reagents in two cases and by partial purification as often as it was performed. The electrofocusing pattern of erythrocyte pyruvate kinase was normal in both these types of defects. In two patients with so-called “acquired dyserythropoiesis” an erythrocyte glucose phosphate isomerase deficiency has been detected; in both the cases it was associated with a parallel decrease of the antigen concentration. The residual enzyme had a normal electrofocusing and electrophoretic pattern and a normal heat stability; the enzyme activity could not be restored by any treatment. In 1 patient with erythroleukemia and in 1 other with acquired dyserythropoiesis the erythrocyte phosphofructokinase activity was lowered. The enzyme activity was not restored by cross incubation in isologous plasma or by the SH reagents. In one case immunologie study could be performed, kinase. Whether or not this finding is typical of the foetal erythrocytes is now under study in our laboratory. In conclusion the direct mechanism of the acquired red cell enzyme defects in some hematological diseases is not single and seems to involve either a nongenetic alteration of the enzyme after its synthesis or a modification of the enzyme-synthesis rate. In different patients some enzyme defects can be due to different mechanisms, and in a single patient several enzyme defects can also be due to different mechanisms.

Blood Disorders Due to Drugs and Other Agents

This book is a welcome addition to the voluminous literature on drug-induced blood disorders. The introductory chapter is a general consideration of fundamental problems with therapeutic agents, drug interactions, host responses to drugs and problems related to the physician's judgment. Other chapters are concerned with hemolytic anemias, erythrocyte enzyme deficiency states, megaloblastic and hypoplastic anemias, agranulocytosis, and thrombocytopenic states. Each chapter is a comprehensive review of the subject, with profuse bibliographical citations (eg, 535 references in the chapter on agranulocytosis, dated through 1971). Nonhematological drug-induced diseases such as systemic lupus erythematosus are not included in the book. A more serious omission is the recently emphasized recognition that acute leukemia may be induced by the prolonged use of melphalan, chlorambucil, and other antineoplastic agents. Appropriately, an entire chapter is devoted to chloramphenicol, but one can question the inclusion of a chapter on hematological aspects of radiation in a book on drug-induced

Disorders of the red cell membrane: a review of biochemical and physiologic alterations of erythrocyte membranes which may lead to morphologic changes and shortened cell survival.

Morphologically similar cells can be seen in such varied conditions as liver disease, renal disease, a-betalipoproteinemia, malab sorption states, congenital nonspherocytic anemias, thalassemia, iron deficiency, pykno cytosis, hemolytic-uremic syndrome, erythro cyte enzyme deficiencies, etc. The common denominator in these condi tions may be an increase in membrane rigid ity, resulting from a diversity of causes. These would include altered protein-lipid- carbohydrate composition, abnormally struc tured hemoglobins, the presence of Heinz bodies due to altered glycolysis or unstable hemoglobins. The end result of such altered membrane elasticity, regardless of cause, would be fragmentation and destruction of the red cells during passage through small vascular channels, particularly in the spleen. Changes in erythrocyte stromal composi tion often seem to reflect more generalized systemic metabolic disorders. Whether any of the alterations of membrane composition are causally related to either the morpho logic changes or the shortened cell survival still remains to be proven.

Hemolysis due to inherited erythrocyte enzyme deficiencies.

Annals of the New York Academy of SciencesVolume 151, Issue 2 p. 765-776 HEMOLYSIS DUE TO INHERITED ERYTHROCYTE ENZYME DEFICIENCIES Paul E. Carson, Paul E. Carson Department of Medicine and the Section on Genetics and International Health, University of Chicago, Chicago, Ill.Search for more papers by this author Paul E. Carson, Paul E. Carson Department of Medicine and the Section on Genetics and International Health, University of Chicago, Chicago, Ill.Search for more papers by this author First published: July 1968 https://doi.org/10.1111/j.1749-6632.1968.tb48260.xCitations: 4AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume151, Issue2PharmacogeneticsJuly 1968Pages 765-776 RelatedInformation