Hemoglobin E diseases: Hematological,analytical, and biosynthetic studies in homozygotes and double heterozygotes for α-thalassemia

Two families with Hb E diseases are described. In the Laotian family S, three homozygous Hb E were found. In the Vietnamese family H, double heterozygous Hb E-α-thalassemia-2 and Hb E-Hb H diseases were found. Anemia or hemolysis was absent in Hb E carriers, unless complicated by iron deficiency, the presence of severe α-thalassemia gene (Hb H disease), or oxidative drug (paraaminosalicylic acid). Moreover, iron deficiency or concurrent α-thalassemia genes resulted in a decreased amount of Hb E in its heterozygous carriers. Mild microcytosis and hypochromia were observed in Hb E heterozygotes, whereas the microcytosis and hypochromia were more pronounced in Hb E homozygotes. Globin chain synthesis studies yielded unbalanced α/non-α ratios in both heterozygotes and homozygotes (average ratios were 1.13 and 1.56, respectively). The unbalanced biosynthetic ratios with microcytosis and hypochromia in Hb E carriers represented a β-thalassemia phenotype, which could be a result of reduced synthesis of β^E-globin mRNA, as suggested by recent hybridization studies.     

Iron deficiency due to excessive therapeutic phlebotomy in hemochromatosis

Thirteen adults (eight men, five women) with hemochromatosis had undergone routine iron depletion therapy but while on maintenance phlebotomies developed iron deficiency which persisted for 25 +/- 13 (mean +/- 1 SD) months before diagnosis. All had symptoms and signs of iron deficiency. Levels of transferrin saturation were 10% +/- 5% (1 SD), and serum ferritin concentrations were 8 +/- 3 ng/mL. Eleven had anemia; eight had hypochromia and microcytosis. Bone marrow specimens obtained in five patients revealed no stainable iron. Medical records indicated that parameters of body iron status were infrequently or incorrectly used for adjusting the frequency of phlebotomies. Two patients developed iron deficiency due to additional blood loss from esophageal varices and bilateral hip replacement, respectively. Ten of the patients were treated with ferrous sulfate, 325 mg daily, for 2-6 weeks when anemia was corrected. In patients who were not given iron, anemia and microcytosis recovered in 8-24 months. We conclude that (i) sustained iron deficiency in hemochromatosis patients should be prevented by monitoring hemoglobin levels and serum ferritin; and (ii) hemoglobin concentrations and values of mean corpuscular hemoglobin may be higher in iron-deficient persons with hemochromatosis than in individuals without hemochromatosis. Symptomatic iron deficiency in hemochromatosis patients may be treated safely with a brief course of ferrous sulfate. Recovery is slower when iron is not given. However, iron supplementation is unnecessary and not recommended for the mild, self-limited anemia and decreased serum iron and ferritin concentrations encountered after initial iron depletion therapy for hemochromatosis.     

First description in Tunisia of a point mutation at codon 119 (CCT-->TCT) in the alpha1-globin gene: Hb Groene Hart in association with the -alpha3.7 deletion

Herein we describe the case of a Tunisian girl who presented with 3% Hb Bart's (gamma4) at birth. At the age of 3 years, she showed microcytosis and hypochromia in the absence of iron deficiency. The first step of molecular analysis was to test for the common Mediterranean mutations and the classical -alpha3.7 deletion was found in the heterozygous state. Since this finding could not explain the level of Hb Bart's at birth, or the hypochromia and microcytosis, all the alpha-globin genes were sequenced. This revealed a rare point mutation at codon 119 (CCT-->TCT) in the alpha1-globin gene, identified for the first time in Tunisia, and which has previously been described as an unstable hemoglobin (Hb) variant named Hb Groene Hart [alpha119(H2)Pro-->Ser (alpha1)]. Here the -alpha3.7/alpha(alpha)119(CCT-->TCT) genotype is responsible for the alpha-thalassemia (thal) trait phenotype.     

Prevalence of hypochromia (without microcytosis) vs microcytosis (without hypochromia) in iron deficiency

The usefulness of hypochromia (MCH or = 80 (fl) vs. counterparts with MCV < 80 fl (in the presence of MCH > or = 26 pg). Fifteen per cent of the 201 iron deficient subjects were also shown to have coexisting vitamin B12 deficiency. There was a comparable (16%) prevalence of this haematinic deficiency in the subgroup of 31 iron deficient patients with MCH < 26 pg in the presence of MCH > or = 80 fl.     

Thalassaemia genes in Peninsular Arabs

The haematological indices of Peninsular Arabs (United Arab Emirate Nationals, Yemeni and Omani) have been examined. The most outstanding feature, seen in 40-50% of all subjects, was one of hypochromia, microcytosis associated with erythrocytosis. In approximately 5% the hypochromia was severe (MCH 19-22 pg) and 20% of these were found to have beta thalassaemia trait. In 10% of subjects the hypochromia was moderate (MCH 23-24 pg) and beta thalassaemia was confirmed in only 10%. The remaining 25% had a mild hypochromia (MCH 25-27 pg) and no beta thalassaemia was detected. The cause of the hypochromia in subjects with a normal Hb A2 (30% of the total population) is probably alpha thalassaemia, firstly because in those patients with an MCH of 19-24 pg the other haematological parameters are statistically the same as those with proven beta thalassaemia and, secondly, in those with an MCH of 25-27 pg iron deficiency is not common (6% of the population). The degree and pattern of the distribution of hypochromia of the three major ethnic groups of the Peninsular Arabs could be explained either by different alpha and beta thalassaemia genes being operative or by different degrees of inbreeding of the same genes.     

Serum ferritin in evaluation of iron status in children

The value of serum ferritin in assessing iron status was studied in 192 preschool age children between the ages of 3 and 60 months. Children were considered to have iron deficiency if the transferrin saturation was less than 16% and the peripheral smear revealed microcytosis and hypochromia. Anemia was present when hemoglobin level was 10.5 g/dl. According to this criteria, 46% of children screened had either iron deficiency (11.5%) or iron deficiency anemia (34.4%). Mean serum ferritin for the iron deficiency anemia group was 39.1 ng/mg as compared to 41.7 ng/ml for the iron deficiency group and 84.7 ng/ml for the normal group. Even though the serum ferritin level was lower in the iron deficiency group, the difference in the means did not reach statistical significance. Furthermore, only 30% of children who had either iron deficiency or iron deficiency anemia had serum ferritin level of less than 12 ng/ml, the level considered diagnostic for iron deficiency. It can be concluded that serum ferritin cannot be used alone for iron status determination. Multiple parameters will make the assessment more reliable.     

First Description in Tunisia of a Point Mutation at Codon 119 (CCT→TCT) in the α1-Globin Gene: Hb Groene Hart in Association with the − α3.7 Deletion

Herein we describe the case of a Tunisian girl who presented with 3% Hb Bart's (γ₄) at birth. At the age of 3 years, she showed microcytosis and hypochromia in the absence of iron deficiency. The first step of molecular analysis was to test for the common Mediterranean mutations and the classical ? α^3.7 deletion was found in the heterozygous state. Since this finding could not explain the level of Hb Bart's at birth, or the hypochromia and microcytosis, all the α-globin genes were sequenced. This revealed a rare point mutation at codon 119 (CCT→TCT) in the α1-globin gene, identified for the first time in Tunisia, and which has previously been described as an unstable hemoglobin (Hb) variant named Hb Groene Hart [α119(H2)Pro→Ser (α1)]. Here the ? α^3.7/αα^{119(CCT→TCT)} genotype is responsible for the α-thalassemia (thal) trait phenotype.     

Combined use of erythrocyte zinc protoporphyrin and mean corpuscular volume in differentiation of thalassemia from iron deficiency anemia

Abstract: In a retrospective study the diagnostic value of erythrocyte zinc protoporphyrin (ZPP) measurement as a means of distinguishing iron deficiency anemia from thalassemia syndromes in patients with microcytosis was explored. ZPP values were increased in all patients with iron deficiency and in part of the patients with thalassemia. The combined measurement of erythrocyte mean corpuscular volume (MCV) and ZPP resulted in a correct classification of patients with iron deficiency and with thalassemia in more than 95%. The predictive value of this method is better than the results obtained by using formulae derived from red cell indices. In population screening programs for thalassemia syndromes, in which MCV determination is used as the initial test, the ZPP test is recommended as a second test, in order to discriminate between patients with microcytosis due to iron deficiency and patients with microcytosis due to thalassemia syndromes.     

Evaluation of derived Coulter red blood cell parameters for the assessment of iron deficiency in adults with congenital heart disease

Introduction: The aim of our study was to evaluate derived red blood cell parameters in determining the presence of iron depletion and iron‐deficient erythropoiesis, as states that precede iron deficiency anemia, in adults with congenital heart disease. Methods: Eighty‐eight adults who were diagnosed with congenital heart disease were divided into two groups (cyanotic and acyanotic). In both groups, congenital heart disease patients were then divided into three subgroups: with iron depletion, with iron‐deficient erythropoiesis, and a control group. The following parameters were measured: complete blood count, reticulocytes, ferritin, soluble transferrin receptor, haptoglobin, lactate dehydrogenase, and calculated parameters: low hemoglobin density (LHD), red cell size factor (RSF), and microcytic anemia factor (MAF). Results: Discriminant analysis indicated statistically significant differences in the first discriminant function: Function 1 – body iron, LHD, MAF, sTfR, and RSF (P < 0.001) in patients with acyanotic congenital heart disease and significant differences in both discriminant functions in patients with cyanotic congenital heart disease: Function 1 – body iron, soluble transferrin receptor, LHD, RSF, MAF, lactate dehydrogenase, and haptoglobin (P = 0.008) and Function 2 – reticulocytes (#), immature reticulocyte fraction and reticulocytes (%) (P = 0.049). Conclusions: Beside parameters that describe iron metabolism dynamics (body iron and soluble transferrin receptor), LHD, indicator of hypochromia, have the highest potential to differentiate and classify iron deficiency in patients with congenital heart disease.     

Blood viscosity and its relationship to iron deficiency, symptoms, and exercise capacity in adults with cyanotic congenital heart disease.

OBJECTIVES: This study sought to determine the relationship between blood viscosity and iron deficiency and their impact on symptoms and exercise function in adults with cyanotic congenital heart disease. BACKGROUND: Iron deficiency is believed to raise whole blood viscosity in cyanotic congenital heart disease, although available data are inconsistent. METHODS: Thirty-nine cyanotic adults were prospectively assessed for iron deficiency (transferrin saturation < or =5%), hyperviscosity symptoms, and exercise capacity. Same-day measurement of whole blood viscosity and hematocrit (Hct) adjusted viscosity (cells resuspended in autologous plasma to Hct of 45%) was performed at shear rates ranging from 0.277 s(-1) to 128.5 s(-1). RESULTS: Viscosity did not differ between patients with iron deficiency (n = 14) and those without (n = 25). Whole blood viscosity correlated with Hct (r = 0.63, p < 0.001 at low shear and r = 0.84, p < 0.001 at high shear) but not with red blood cell size or iron indices. Hyperviscosity symptoms were independent of iron indices but directly correlated with increased Hct-adjusted viscosity (r = 0.41, p = 0.01). Exercise capacity did not differ in iron-deficient patients. However, peak oxygen consumption was higher in those with Hct > or = 65% (12.6 +/- 3.4 ml/kg/m2 vs. 9.8 +/- 2.6 ml/kg/m2, mean +/- SD, p = 0.036) despite higher whole blood viscosity in these same individuals (p < 0.01 for all shear rates). CONCLUSIONS: Iron deficiency is common in cyanotic adults but does not alter viscosity. Hyperviscosity symptoms are associated with a higher Hct-adjusted viscosity independent of cell size or iron stores. Higher Hct is associated with better exercise capacity. Further work to understand the origin of hyperviscosity symptoms is warranted.     

Evaluation of microcytosis using serum ferritin and red blood cell distribution width

Out of 104 patients with microcytosis (MCV less than 80 fl), 69% had an iron deficiency, 21% a chronic disease and 10% hemoglobinopathy or thalassemia trait. The absence of bone marrow iron stores or the response to iron supplementation were used to establish the diagnosis iron deficiency. On the basis of sensitivity (90%) and specificity (100%), the serum ferritin concentration is more suitable for assessment of iron deficiency than the serum iron concentration, the total iron-binding capacity or the percentual saturation of transferrin. The red cell distribution width (RDW) is the parameter with the highest sensitivity for iron deficiency (94%). An RDW value within the reference interval can be used to exclude iron deficiency in those cases in which the serum ferritin concentration does not accurately reflect the iron stores owing to severe tissue damage, as in inflammation or malignancy.     

Quantitative anisocytosis as a discriminant between iron deficiency and thalassemia minor

The coefficient of variation (CV) of red cell size, as measured by electronic red cell sizing (erythrography), was less than 14.0% in 20 normal subjects. In 22 of 25 patients with beta-thalassemia minor and microcytosis (mean corpuscular volume [MCV] less than 70 fl), CV was less than 14.0%; in the other 3, CV was 14.0%--14.9%. In 53 patients with iron deficiency anemia and MCV less than 70 fl, CV always was greater than 14.0%. In 7 patients with alpha-thalassemia minor and MCV less than 70 fl, CV was less than 14.0% in all 7. Among patients with microcytosis, erythrography appears to be an excellent technique for rapidly distinguishing between iron deficiency and alpha or beta thalassemia minor.     

Cerebrovascular events in adult patients with cyanotic congenital heart disease

Objectives. We sought to determine the frequency of spontaneous cerebrovascular events in adult patients with cyanotic congenital heart disease and to evaluate any contributing factors.Background. Cerebrovascular events are a serious complication of cyanotic congenital heart disease in infants and children but are said to be uncommon in adults.Methods. Between 1988 and 1995, 162 patients with cyanotic congenital heart disease (mean age 37 years, range 19 to 70) were retrospectively evaluated for any well documented cerebrovascular events that occurred at ≥18 years of age. Events related to procedures, endocarditis or brain abscess were excluded.Results. Twenty-two patients (13.6%) had 29 cerebrovascular events (1/100 patient-years). There was no significant difference between those with and without a cerebrovascular event in terms of age, smoking history, degree of erythrocytosis, ejection fraction or use of aspirin or warfarin (Coumadin). Patients who had a cerebrovascular event had a significantly increased tendency to develop hypertension, atrial fibrillation, microcytosis (mean corpuscular volume <82) and history of phlebotomy (p < 0.05). Even when patients with hypertension or atrial fibrillation were excluded, there was an increased risk of cerebrovascular events associated with microcytosis (p < 0.01).Conclusions. Adults with cyanotic congenital heart disease are at risk of having cerebrovascular events. This risk is increased in the presence of hypertension, atrial fibrillation, history of phlebotomy and microcytosis, the latter condition having the strongest significance (p < 0.005). This finding leads us to endorse a more conservative approach toward phlebotomy and a more aggressive approach toward treating microcytosis in adults with cyanotic congenital heart disease.     

Reticulocytosis, hypochromia, and microcytosis: an unusual presentation of the preleukemic syndrome

Two patients exhibiting a highly unusual preleukemic syndrome with marked reticulocytosis, hypochromia, and microcytosis are reported. This red cell phenotype has been investigated by means of HbF, HbA2, and i-antigen activity dosages, immunofluorescence labeling of F cells, reticulocyte survival, globin chain synthesis, and electron microscopy study. The marked reticulocytosis is explained by a delayed disappearance of the reticulum. Serum iron is normal, and a thalassemic syndrome is excluded because of a balanced alpha/non-alpha globin chain synthesis. Electron microscopy studies are consistent with a defect in iron uptake by erythroid cells. All the hematologic data and investigations are similar to those observed for the Belgrade laboratory rat. It is hypothesized that the low expression of HbF and i- Ag associated with microcytosis are related to a prolongation of erythroid maturation as reflected by abnormal reticulocyte survival.     

Microcytic and hypochromic anemias

In the majority of cases, microcytosis is the result of impaired hemoglobin synthesis. Disorders of iron metabolism and protoporphyrin and heme synthesis, as well as impaired globin synthesis, lead to defective hemoglobin production and to the generation of microcytosis and microcytic anemia. Iron deficiency anemie, anemia of chronic diseases, thalassemias, congenital sideroblastic anemias and homozygous HbE disease are the main representatives of microcytosis and microcytic anemias. Serum iron, total iron binding capacity, transferrin saturation, serum ferritin, serum transferrin receptor, transferrin receptor-ferritin index, and zinc-protoporhyrin concentration in erythrocytes are tests used for assessment of iron deficiency. The convention laboratory test for diagnosing iron deficiency is the measurement of serum ferritin. The most precise method for evaluating body iron stores is the examination for iron on aspirated bone marrow or marrow biopsy. Increased content of Hb A2 over 3.5% is diagnostic for beta-thalassemia. Presence of ringed sideroblasts is characteristic of sideroblastic anemias. Hemoglobin electrophoresis is required for the diagnosis of hemoglobinopathy E. The optimal therapeutic regimen in iron deficiency anemia used in this country is to administer 100 mg of elemental iron twice daily separately from meals. Ferrous sulphate (Ferronat Retard tbl. or Sorbifer Dulures tbl.) which are slow-releasing iron formulations are preferred because of their low cost, high bioavailability and low side-effects. Parenteral iron therapy is justified only in patients who cannot absorb iron, who have blood losses that exceed the maximal absorptive capacity of their intestinal tract or who are totally intolerant of oral iron. However, parenteral iron therapy may be associated with serious and even fatal side-effects.     

Combined use of zinc protoporphyrin (ZPP), mean corpuscular volume and haemoglobin measurements for classifying microcytic RBC disorders in children and young adults

The diagnostic potential of the combined use of zinc-protoporphyrin (ZPP), mean corpuscular volume (MCV) and haemoglobin measurements for discriminating between iron deficiency anaemia, beta-thalassaemia minor and lead poisoning has been studied. Lead poisoning could be identified by ZPP greater than 50 micrograms/dl in the presence of normal MCV or ZPP greater than 150 micrograms/dl in the presence of microcytosis (MCV less than 80 fl) with a sensitivity of 97% and specificity 94%. Beta-thalassaemia minor was identified by the coexistence of microcytosis and ZPP less than 50 micrograms/dl with a sensitivity of 91% and specificity 79%. Iron deficiency anaemia defined by the combination of microcytosis and ZPP ranging from 50 to 150 micrograms/dl was identified with a sensitivity of 95%, but the specificity was only 51%, with many of the patients overlapping with thalassaemia minor. This problem did not exist in iron-deficiency anaemia with haemoglobin less than 10 g/dl as at that range no patients with uncomplicated thalassaemia minor have been encountered. A great advantage of the combined use of ZPP, MCV and haemoglobin for the initial screening of microcytic anaemia is its ease of performance and low cost. However, this information should only be regarded as presumptive evidence of disease, requiring subsequent confirmation by appropriate direct measurements such as transferrin saturation, serum ferritin, haemoglobin electrophoresis, or blood lead determinations.     

Incidence of ATRX mutations in myelodysplastic syndromes,the value of microcytosis

Acquired α‐thalassemia myelodysplastic syndrome (MDS) (ATMDS) is an acquired syndrome characterized by a somatic point mutation or splicing defect in the ATRX gene in patients with myeloid disorders, primarily MDS. In a large MDS patient series, the incidence of ATMDS was below 0.5%. But no large series has yet assessed the incidence of ATMDS in microcytic MDS. In this study, we focused on patients with MDS and unexplained microcytosis, which was defined as absence of iron deficiency, inflammatory disease, or history of inherited hemoglobinopathy. Our data confirm the low frequency of ATRX mutations in MDS: 0% in an unselected clinical trial cohort of 80 low risk MDS, 0.2–0.8% in a multicenter registry of 2,980 MDS and 43% of MDS with unexplained microcytosis in this same registry. In addition, we reported four novel mutations of the ATRX gene in ATMDS. This study further determines the frequency of ATRX mutations and highlights the importance of microcytosis to detect ATRX mutations within MDS patients. Am. J. Hematol. 90:737–738, 2015. © 2015 Wiley Periodicals, Inc.     

Unrestricted growth of Plasmodium falciparum in microcytic erythrocytes in iron deficiency and thalassaemia

The mechanism(s) underlying the apparent resistance to malaria in certain inherited red cell disorders and iron deficiency anaemia remain poorly understood. The possibility that microcytic erythrocytes might inhibit parasite development, by physical restriction or reduced supply of nutrients, has been considered for many years, and never formally investigated. We sought to determine whether in vitro growth studies of P. falciparum could provide evidence to suggest that small red cell size contributes to malaria resistance in those red cell disorders in which microcytosis is a characteristic feature.
Invasion and development of P. falciparum in iron deficient red cells (mean values for mean cell volume [MCV] 66 fl, mean cell haemoglobin [MCH] 19 pg) and in the red cells of two gene deletion forms of α-thalassaemia (mean MCV 71 fl, MCH 22 pg) were normal, assessed both morphologically, and by ³H-hypoxanthine incorporation. Although parasite appearances were normal in all cell types, morphological abnormalities were noted in iron deficient and thalassaemic cells parasitized by mature stages of P. falciparum , notably cellular ballooning and extreme hypochromia of the red cell cytoplasm. Using electron microscopy, the red cell cytoplasm in parasitized thalassaemic cells showed reduced electron density and abnormal reticulation. Normal invasion rates were observed following schizogony in microcytic cells of both types.
Our findings indicate that whilst minor morphological abnormalities may be detected in parasitized iron deficiency and thalassaemic erythrocytes, development of P. falciparum in these conditions is not limited by small erythrocyte size.     

Change in red blood cell distribution width with iron deficiency

Red cell volume distribution width (RDW-CV) was examined as a means of diagnosing iron deficiency. Iron deficiency was classified as iron deficiency anaemia, prelatent or latent iron deficiency in 1648 students. MCV and RDW-CV (mean +/- ISD) in each group were 89 +/- 4 ft, 12.7 +/- 0.7% in normal individuals, 89 +/- 4 fl, 13.2 +/- 0.8% in prelatent deficiency, 86 +/- 6 fl, 14.0 +/- 1.5% in latent deficiency, and 79 +/- 7 fl, 15.6 +/- 1.7% in iron deficiency anaemia, respectively. Although microcytosis was evident only in iron deficiency anaemia, RDW-CV showed larger values concomitant with the development of iron deficiency. The sensitivity of RDW-CV for the diagnosis of iron deficiency anaemia was 77.1%, and for iron deficiency anaemia and latent deficiency 49.2%, the specificity being 90.6%. In countries with a high prevalence of iron deficiency and low thalassaemia, iron deficiency should be screened by RDW-CV determination without serum iron or ferritin measurements.     

Antiretroviral treatment reverses HIV-associated anemia in rural Tanzania

Background

HIV-associated anemia is common and associated with poor prognosis. However, its response to antiretroviral treatment (ART) in rural Africa is poorly understood.

Methods

HIV-infected adults (≥15 years) who enrolled in HIV care at Haydom Lutheran Hospital in northern Tanzania were included in the study. The effect of ART (zidovudine/stavudine + lamivudine + efavirenz/nevirapine) on HIV-associated anemia was studied in a subset of patients who were anemic at the time they started ART and had a follow-up hemoglobin measurement 12 months later. Pregnant women were excluded from the study, as were women who had given birth within the past 6 weeks. Anemia was defined as hemoglobin <12 g/dL in women and <13 g/dL in men. We applied paired sample T-tests to compare hemoglobin levels before and one year after ART initiation, and logistic regression models to identify predictors of persistent anemia.

Results

At enrollment, mean hemoglobin was 10.3 g/dL, and 649 of 838 patients (77.4%) were anemic. Of the anemic patients, 254 (39.1%) had microcytosis and hypochromia. Among 102 patients who were anemic at ART initiation and had a follow-up hemoglobin measurement after 12 months, the mean hemoglobin increased by 2.5 g/dL (P < 0.001); however, 39 patients (38.2%) were still anemic after 12 months of ART. Independent predictors of persistent anemia were mean cell volume in the lower quartile (<76.0 fL; Odds Ratio [OR] 4.34; 95% confidence interval [CI] 1.22-15.5) and a zidovudine-containing initial regimen (OR 2.91; 95% CI 1.03-8.19).

Conclusions

Most patients had anemia at enrollment, of whom nearly 40% had microcytosis and hypochromia suggestive of iron deficiency. The mean hemoglobin increased significantly in patients who received ART, but one third were still anemic 12 months after ART initiation indicating that additional interventions to treat HIV-associated anemia in rural Africa might be warranted, particularly in patients with microcytosis and those treated with zidovudine.