Asthma is a risk factor for acute chest syndrome and cerebral vascular accidents in children with sickle cell disease

BACKGROUND: Asthma and sickle cell disease are common conditions that both may result in pulmonary complications. We hypothesized that children with sickle cell disease with concomitant asthma have an increased incidence of vaso-occlusive crises that are complicated by episodes of acute chest syndrome. METHODS: A 5-year retrospective chart analysis was performed investigating 48 children ages 3-18 years with asthma and sickle cell disease and 48 children with sickle cell disease alone. Children were matched for age, gender, and type of sickle cell defect. Hospital admissions were recorded for acute chest syndrome, cerebral vascular accident, vaso-occlusive pain crises, and blood transfusions (total, exchange and chronic). Mann-Whitney test and Chi square analysis were used to assess differences between the groups. RESULTS: Children with sickle cell disease and asthma had significantly more episodes of acute chest syndrome (p = 0.03) and cerebral vascular accidents (p = 0.05) compared to children with sickle cell disease without asthma. As expected, these children received more total blood transfusions (p = 0.01) and chronic transfusions (p = 0.04). Admissions for vasoocclusive pain crises and exchange transfusions were not statistically different between cases and controls. SS disease is more severe than SC disease. CONCLUSIONS: Children with concomitant asthma and sickle cell disease have increased episodes of acute chest syndrome, cerebral vascular accidents and the need for blood transfusions. Whether aggressive asthma therapy can reduce these complications in this subset of children is unknown and requires further studies.     

Population heterogeneity of the Hpa I restriction site associated with the beta globin gene: implications for prenatal diagnosis

The Hpa I restriction endonuclease site polymorphism that results in some human beta globin genes being contained in a 13-kilobase (kb) DNA restriction fragment rather than in the usual 7.6-kb fragment has been reported to be in linkage disequilibrium with the beta S mutation. The frequency of the 13-kb fragment among Baltimore black sickle cell (SS) disease patients (58%) is lower than that reported for San Francisco black SS disease patients (87%) and similar to that reported for such New York patients (59%). There is, then, considerable heterogeneity among American black populations. Therefore, for the purposes of prenatal diagnosis, the frequency in the particular population at risk should be established. When the frequency of association of the 13-kb fragment and the beta S mutation is low, the linkage phase must also be established. When the linkage phase is known, the Hpa I pattern alone can exclude SS disease 54% of the time for Baltimore AS X AS couples.     

HPLC determination of hemoglobins to establish reference values with the aid of statistics and informatics

The purpose of the present study was to establish reference values for hemoglobins (Hb) using HPLC, in samples containing normal Hb (AA), sickle cell trait without alpha-thalassemia (AS), sickle cell trait with alpha-thalassemia (ASH), sickle cell anemia (SS), and Hb SC disease (SC). The blood samples were analyzed by electrophoresis, HPLC and molecular procedures. The Hb A2 mean was 4.30 +/- 0.44% in AS, 4.18 +/- 0.42% in ASH, 3.90 +/- 1.14% in SS, and 4.39 +/- 0.35% in SC. They were similar, but above the normal range. Between the AS and ASH groups, only the amount of Hb S was higher in the AS group. The Hb S mean in the AS group was 38.54 +/- 3.01% and in the ASH it was 36.54 +/- 3.76%. In the qualitative analysis, using FastMap, distinct groups were seen: AA and SS located at opposite extremes, AS and ASH with overlapping values and intermediate distribution, SC between heterozygotes and the SS group. Hb S was confirmed by allele-specific polymerase chain reaction. The Hb values established will be available for use as a reference for the Brazilian population, drawing attention to the increased levels of Hb A2, which should be considered with caution to prevent incorrect diagnoses.     

The effects of erythrocyte membranes on the nucleation of sickle hemoglobin

Pathology in sickle cell disease begins with nucleation-dependent polymerization of deoxyhemoglobin S into stiff, rodlike fibers that deform and rigidify red cells. We have measured the effect of erythrocyte membranes on the rate of homogeneous nucleation in sickle hemoglobin, using preparations of open ghosts (OGs) with intact cytoskeletons from sickle (SS) and normal adult (AA) red cells. Nucleation rates were measured by inducing polymerization by laser photolysis of carboxy sickle hemoglobin and observing stochastic variation of replicate experiments of the time for the scattering signals to reach 10% of their respective maxima. By optical imaging of membrane fragments added to a hemoglobin solution we contrast the rate of nucleation immediately adjacent to membrane fragments with nucleation in a region of the same solution but devoid of membranes. From analysis of 29,272 kinetic curves obtained, we conclude that the effect of AA OGs is negligible (10% enhancement of nucleation rates +/-20%), whereas SS OGs caused 80% enhancement (+/-20%). In red cells, where more membrane surface is available to Hb, this implies enhancement of nucleation by a factor of 6. These experiments represent a 10-fold improvement in precision over previous approaches and are the first direct, quantitative measure of the impact of erythrocyte membranes on the homogeneous nucleation process that is responsible for polymer initiation in sickle cell disease.     

Autologous immune complex nephritis associated with sickle cell trait: diagnosis of the haemoglobinopathy after renal structural and immunological studies.

A renal tubular epithelial antigen (RTE)--anti-RTE autologous immune complex nephritis associated with sickle cell anaemia (SS) has been reported, but immune complex nephritis has never been described in patients with sickle cell trait (SA). During investigation of a child with "asymptomatic proteinuria" cryoprecipitable complexes of RTE-anti-RTE were detected in the serum and granular deposits of RTE, immunoglobulins, and complement localised on the glomerular basement membranes. Morphological and ultrastructural studies showed increased mesangial matrix, sickled red blood cells in the glomeruli and vessels, and tubular and interstitial abnormalities. These findings prompted haemoglobin electrophoretic studies, which showed previously undiagnosed haemoglobin SA in this patient and her family. These observations suggest that nephritis mediated by similar immunopathogenic mechanisms may be associated with SS and SA haemoglobinopathy. Under some conditions patients with sickle cell trait may experience haemodynamic and oxygenation abnormalities, which may be aetiological factors in the immune complex nephritis associated with SS disease.     

Glycosylated hemoglobins in a diabetic patient with sickle cell anemia

Results of analysis of blood samples from a diabetic sickle cell anemia (SS) patient and 4 nondiabetic SS patients for glycosylated hemoglobins by Bio-Rex 70 chromatography, high-pressure liquid chromatography, and affinity chromatography are presented. Glycosylated components of Hb S and Hb A2 and total glycosylated hemoglobins were quantitated in this manner. The levels of the various glycosylated hemoglobins were increased twofold in the diabetic patient compared to nondiabetic SS patients. The glycosylated hemoglobin levels in the diabetic SS patient and in the nondiabetic SS patients, however, were significantly lower than the levels normally seen in nonsickle diabetics and normal adults, respectively. In contrast to a previously reported diabetic SS patient, the present case appears to be not severely affected by sickle cell disease.     

Altered amount and activity of superoxide dismutase in sickle cell anemia

The amount and activity of superoxide dismutase (SOD) (EC 1.15.1.1) were measured in red cells collected from 50 white controls, 101 black controls, 50 patients with sickle hemoglobin (SS Hb), 12 with sickle trait, and 11 with other sickling hemoglobinopathies. Red cells from normal black subjects had more SOD amount and activity than normal whites (1.77 U/mg Hb and 2.96 micrograms/mg Hb vs. 1.47 U/mg Hb and 2.64 micrograms/mg Hb, respectively) or blacks with SS Hb or other sickling hemoglobinopathies. Patients with more severe manifestations of SS Hb had lower levels of SOD activity than those with milder symptoms but had the same amount of enzyme protein. Individuals with sickle trait had amounts and activities of SOD comparable to black controls. An alteration in defense to free radical oxygen may play a role in the severity of symptoms experienced by patients with homozygous sickle cell disease.     

Direct and continuous measurement of hydroperoxide-induced oxidative stress on the membrane of intact erythrocytes

Having minimized spectroscopic interference by hemoglobin (Hb), peroxidation processes in intact erythrocytes could be monitored in a continuous assay using the fluorescent polyunsaturated fatty acid, parinaric acid (PnA), as a peroxidation probe. Control experiments to establish the character of the method are described in detail. As a practical application, comparative studies were performed to monitor the response of normal and sickle Hb-containing human erythrocytes to oxidative stress in the PnA assay. After 10 min of incubation with 200 microM cumene hydroperoxide (cumOOH), peroxidation of PnA was found to be enhanced in erythrocytes from sickle cell disease patients (SS: 48 +/- 9% (n = 6) of initial amount had been peroxidized) compared to healthy controls (AA: 30 +/- 4% (n = 9)). PnA peroxidation in erythrocytes from sickle cell trait individuals (AS: 30 +/- 3% (n = 4)) was equal to that in control cells. The increased oxidation of PnA in sickle erythrocytes was accompanied by enhanced oxidation of Hb (metHb and hemichrome formation), indicating that sickle Hb mediates enhanced cumOOH-derived radical generation. It is concluded that PnA can be a useful tool in studying membrane peroxidation processes in intact normal and pathological erythrocytes.     

Prenatal diagnosis of sickle hemoglobinopathies: The experience of the Columbia university comprehensive center for sickle cell disease

We report here an evaluation of 55 pregnancies at risk for a sickle hemoglobinopathy prenatally diagnosed by restriction-endonuclease analysis, with the endonucleases MstII and HpaI, of amniocyte DNA. The diagnosis was completed in all cases. Eleven fetuses were predicted to be affected, of which six were terminated. Forty-one of the 55 cases were confirmed. One false-negative was reported in a case predicted to be hemoglobin AS but that was determined to be hemoglobin SS at birth. We estimate that the 55 cases represent only 5% of the pregnancies at risk for a sickle hemoglobinopathy in the New York metropolitan area during the study period. We conclude that the prenatal diagnosis of sickle hemoglobinopathies by molecular methods is reliable. However, the efficiency of utilization and effectiveness of prenatal testing is dependent on the early prospective identification of couples at risk and on the education of communities concerning the significant morbidity of the sickle hemoglobinopathies and the reproductive choices now available to them.     

Mechanism of CD47-induced alpha4beta1 integrin activation and adhesion in sickle reticulocytes

We recently reported that CD47 (integrin-associated protein) on sickle red blood cells (SS RBCs) activates G-protein-dependent signaling, which promotes cell adhesion to immobilized thrombospondin (TSP) under relevant shear stress. These data suggested that signal transduction in SS RBCs may contribute to the vaso-occlusive pathology observed in sickle cell disease. However, the CD47-activated SS RBC adhesion receptor(s) that mediated adhesion to immobilized TSP remained unknown. Here we demonstrate that the alpha4beta1 integrin (VLA-4) is the receptor that mediates CD47-stimulated SS RBC adhesion to immobilized TSP. This adhesion requires both the N-terminal heparin-binding domain and the RGD site of TSP. CD47 signaling induces an "inside-out" activation of alpha4beta1 on SS RBCs as indicated by an RGD-dependent interaction of this integrin with soluble, plasma fibronectin. However, CD47 engagement also induces an alpha4beta1-mediated, RGD-independent adhesion of SS RBCs to immobilized vascular cell adhesion molecule-1 (VCAM-1). CD47 signaling in SS RBCs appears to be independent of large scale changes in cAMP formation but nonetheless promotes alpha4beta1-mediated adhesion via a protein kinase A-dependent, serine phosphorylation of the alpha4 cytoplasmic domain. CD47-activated SS RBC adhesion absolutely requires the Src family tyrosine kinases and is also enhanced by treatment of SS RBCs with low concentrations of cytochalasin D, which may release alpha4beta1 from cytoskeletal restraints. In addition, CD47 co-immunoprecipitates with alpha4beta1 in a sickle reticulocyte-enriched fraction of SS RBCs. These studies therefore identify the alpha4beta1 integrin on SS RBCs as a CD47-activated receptor for TSP, VCAM-1, and plasma fibronectin, revealing novel binding characteristics of this integrin.     

Normal Muscle Oxygen Consumption and Fatigability in Sickle Cell Patients Despite Reduced Microvascular Oxygenation and Hemorheological Abnormalities

Background/Aim

Although it has been hypothesized that muscle metabolism and fatigability could be impaired in sickle cell patients, no study has addressed this issue.

Methods

We compared muscle metabolism and function (muscle microvascular oxygenation, microvascular blood flow, muscle oxygen consumption and muscle microvascular oxygenation variability, which reflects vasomotion activity, maximal muscle force and local muscle fatigability) and the hemorheological profile at rest between 16 healthy subjects (AA), 20 sickle cell-hemoglobin C disease (SC) patients and 16 sickle cell anemia (SS) patients.

Results

Muscle microvascular oxygenation was reduced in SS patients compared to the SC and AA groups and this reduction was not related to hemorhelogical abnormalities. No difference was observed between the three groups for oxygen consumption and vasomotion activity. Muscle microvascular blood flow was higher in SS patients compared to the AA group, and tended to be higher compared to the SC group. Multivariate analysis revealed that muscle oxygen consumption was independently associated with muscle microvascular blood flow in the two sickle cell groups (SC and SS). Finally, despite reduced muscle force in sickle cell patients, their local muscle fatigability was similar to that of the healthy subjects.

Conclusions

Sickle cell patients have normal resting muscle oxygen consumption and fatigability despite hemorheological alterations and, for SS patients only, reduced muscle microvascular oxygenation and increased microvascular blood flow. Two alternative mechanisms can be proposed for SS patients: 1) the increased muscle microvascular blood flow is a way to compensate for the lower muscle microvascular oxygenation to maintain muscle oxygen consumption to normal values or 2) the reduced microvascular oxygenation coupled with a normal resting muscle oxygen consumption could indicate that there is slight hypoxia within the muscle which is not sufficient to limit mitochondrial respiration but increases muscle microvascular blood flow.     

Effect of sickling on dimyristoylphosphatidylcholine-induced vesiculation in sickle red blood cells

To study the effect of sickling on dimyristoylphosphatidylcholine (DMPC)-induced vesiculation, sickle (SS) red blood cells were incubated with sonicated suspensions of DMPC under either room air or nitrogen. Like normal red cells, when sickle cells were incubated with DMPC under oxygenated conditions, incorporation of DMPC into the erythrocyte membrane occurred, followed by echinocytic shape transformation and subsequent release of membrane vesicles. On the other hand, when SS cells were induced to sickle by deoxygenation, DMPC-induced vesiculation of these cells was dramatically reduced. However, upon reoxygenation, release of vesicles from these sickle erythrocytes occurred immediately. When SS cells were incubated under hypertonic (500 mosM) and deoxygenated conditions (where hemoglobin polymerization occurs but red cells do not show the typical sickle morphology), a similar decrease in the extent of vesiculation was observed. Experiments with radiolabelled lipid vesicles indicated that incorporation of DMPC into erythrocyte membranes occurred in all cases and therefore was not the limiting factor in the reduction of vesiculation in deoxygenated SS cells. Taken together, these results indicate that cellular viscosity and membrane rigidity, both of which are influenced by hemoglobin polymerization, are two important factors in process of vesicle release from sickle erythrocytes.     

The health orientation scale: A measure of feelings about sickle cell trait

Abstract

The Health Orientation Scale (HOS), a written self‐report instrument, was developed to objectively appraise the psychological implications of identification as a sickle cell gene carrier (AS). The HOS uses the semantic differential technique and consists, of nine situations thought to be of importance in identification as a carrier. The instrument was completed by respondents during the various phases of the screening and counseling process. Discussion will focus on a comparison of carrier and noncarrier (AA) reactions to situations which involve the diagnoses of sickle cell trait (AS), sickle cell disease (SS), cancer, and hypertension along with a comparison of feelings before and after counseling. Results suggest that noncarriers have more negative feelings about sickle cell than carriers. Further, counseling, as it is currently practiced, does not contribute to any significant differences in feelings about sickle cell for either carriers or noncarriers. The attitudes and feelings of noncarriers toward sickle cell trait and disease suggest that carrier identification is a stigma.     

Assessment of care of children with sickle cell disease: implications for neonatal screening programmes.

OBJECTIVE--To assess the quality of care provided by hospitals for young children with sickle cell disease. DESIGN--Retrospective survey. SETTING--Teaching hospital in London. PATIENTS--31 Children (mean age 4 years 4 months, range 4 months to 7 years 5 months) born with sickle cell disease between 1978 and 1985 identified from Hospital Activity Analysis data, an outpatient diagnostic register, and registers of the haematology department. Eight had been diagnosed on neonatal screening and at least four of these had not been followed up. MAIN OUTCOME MEASURES--Aspects of quality of outpatient care (blood testing, clinic attendance, and prophylactic drug treatment) and family care (adequate support and carers'' knowledge about the disease) as assessed by reviewing the notes and administering a semistructured questionnaire to the carers, in relation to a devised list of standards deemed necessary to ensure achievement of the aims of screening. RESULTS--There were 93 outpatient attendances during the previous 12 months, but 13 children had not attended at least every six months and four not at all for more than a year. Only eight children had had three of the blood tests considered to be necessary for good care; three had had none. Prophylactic treatment with penicillin and folic acid was erratic; three children with sickle cell anaemia were not receiving regular prophylactic penicillin. IMPLICATION--Diagnosis of sickle cell disease on neonatal screening must be linked with follow up to ensure optimal management.     

Nitric oxide-mediated heme oxidation and selective beta-globin nitrosation of hemoglobin from normal and sickle erythrocytes

Nitric oxide (NO) has been reported to modulate the oxygen affinity of blood from sickle cell patients (SS), but not that of normal adult blood (AA), with little or no heme oxidation. However, we had found that the NO donor compounds 2-(N, N-diethylamino)-diazenolate-2-oxide (DEANO) and S-nitrosocysteine (CysNO) caused increased oxygen affinity of red cells from both AA and SS individuals and also caused significant methemoglobin (metHb) formation. Rapid kinetic experiments in which HbA(0), AA, or SS erythrocytes were mixed with CysNO or DEANO showed biphasic time courses indicative of initial heme oxidation followed by reductive heme nitrosylation, respectively. Hemolysates treated with CysNO showed by electrospray mass spectrometry a peak corresponding to a 29 mass unit increase (consistent with NO binding) of both the beta(A) and beta(S) chains but not of the alpha chains. Therapeutic use of NO in sickle cell disease may ultimately require further optimization of these competing reactions, i.e., heme reactivity (nitrosylation or oxidation) versus direct S-nitrosation of hemoglobin on the beta-globin.     

Polymerization in erythrocytes containing S and non-S hemoglobins

We analyzed the effects of protein and water nonideality and of erythrocyte heterogeneity on the polymerization of hemoglobin S in cells where there were significant amounts of non-S hemoglobins, sickle trait (AS), and SC disease. For AS erythrocytes, the calculated predicted results were in good agreement with measured polymer formation as previously reported (Noguchi C.T., D.A. Torchia, and A.N. Schnechter, 1981, J. Biol. Chem. 256:4168-4171). Throughout much of the physiologically relevant oxygen saturation region, polymer was not formed in AS erythrocytes. Measurements of polymer formation in SC erythrocytes as a function of oxygen saturation using 13C NMR are reported here and also are in good agreement with the calculated predicted results. As in sickle (SS) erythrocytes, polymer can be detected in SC erythrocytes in the region above 60% oxygen saturation. The increased polymer formation in SC erythrocytes as compared with AS erythrocytes can be explained in terms of hemoglobin composition and concentration in SC erythrocytes, with the concomitant increase in the proportion of dense cells. These findings provide a basis for understanding the pathophysiology of sickle cell and of SC disease, in contrast to benign sickle trait, in terms of intracellular polymer formation.     

Glucose-6-phosphate dehydrogenase deficiency and sickle cell disease in Brazil.

The frequency of glucose-6-phosphate dehydrogenase (G-6-PD) deficiency was determined in 54 male patients with sickle cell diseases: 31 sickle cell anemia (SS), 14 sickle cell hemoglobinopathy (SC) and 9 HbS/beta-thalassemia (S/B-thal) by a combination of quantitative assay, fluorescent spot test and electrophoresis. Of the 54 patients tested, 7 were found to be G-6-PD deficient (G-6-PD-) (3 SS, 3 SC and 1 S/B-thal) and 47 G-6-PD normal (G-6-PD+) (6 G-6-PD A and 41 G-6-PD B). All the deficient patients were G-6-PD A-. The frequency of G-6-PD deficiency did not differ significantly from that observed in the general population. Compared to patients who were not G-6-PD-, there were no significant differences in the hemoglobin concentration and reticulocyte count in patients with sickle cell diseases who were G-6-PD-.     

Role of age and neuroinflammation in the mechanism of cognitive deficits in sickle cell disease

This study aims to determine whether sickle cell mice could recapitulate features of cognitive and neurobehavioral impairment observed in sickle cell patients and whether neuroinflammation could be a potential therapeutic target as in other non-sickle cell disease-related cognitive dysfunction. Cognitive (learning and memory) and behavioral (anxiety) deficits in 13- and later 6-month-old male Townes humanized sickle cell (SS) and matched control (AA) mice were evaluated using novel object recognition (NOR) and fear conditioning tests. Immunohistochemistry was performed to quantify peripheral immune cell (CD45⁺) and activated microglia (Iba1⁺) as markers of neuroinflammation in the dentate and peri-dentate gyrus areas. We evaluated cell fate by measuring 5''-bromodeoxyuridine and doublecortin fluorescence and phenotyped proliferating cells using either glial fibrillary acid protein (GFAP⁺), neuronal nuclei (NeuN⁺), CD45⁺, and Iba1⁺. In addition, Golgi-Cox staining was used to assess markers of neuroplasticity (dendritic spine density and morphology and density of dendrite arbors) on cortical and hippocampal pyramidal neurons. Compared to matched AA controls, 13-month-old SS mice showed significant evidence of cognitive and behavioral deficit on NOR and fear conditioning tests. Also, SS mice had significantly higher density of CD45⁺ and activated microglia cells (i.e. more evidence of neuroinflammation) in the dentate and peri-dentate gyrus area. Additionally, SS mice had significantly lower dendritic spine density, but a higher proportion of immature dendritic spines. Treatment of 13-month-old SS mice with minocycline resulted in improvement of cognitive and behavioral deficit compared to matched vehicle-treated SS mice. Also, treated SS mice had significantly fewer CD45⁺ and activated microglia cells (i.e. less evidence of neuroinflammation) in the dentate and peri-dentate gyrus, as well as a significant improvement in markers of neuroplasticity.Impact statementThis study provides crucial information that could be helpful in the development of new or repurposing of existing therapies for the treatment of cognitive deficit in individuals with sickle cell disease (SCD). Its impact is in demonstrating for the first time that neuroinflammation and along with abnormal neuroplasticity are among the underlying mechanism of cognitive and behavioral deficits in SCD and that drugs such as minocycline which targets these pathophysiological mechanisms could be repurposed for the treatment of this life altering complication of SCD.     

alpha-thalassemia in Bantu population from Congo-Brazzaville: its interaction with sickle cell anemia

Deletional alpha(+)-thalassemia (-alpha(3.7)) was investigated in four groups of unrelated individuals from the Bantu population (newborns, normal adults, sickle cells trait carriers, sickle cell anemia patients) of Brazzaville, Congo. The frequency of the (-alpha(3.7)) chromosome was similar between newborns (f = 0.40) and adult subjects (f = 0.36), and between sicklers and nonsickler subjects. The frequency of the (-alpha(3.7)) chromosome in sickle cell anemia patients (SS patients) did not change when age was stratified. The hematological characteristics of SS patients with (-alpha/alphaalpha, -alpha/-alpha) and without (alphaalpha/alphaalpha) alpha(+)-thalassemia were similar to those reported in Jamaican and US sickle cell anemia patients. alpha(+)-Thalassemia had an effect on the percentage of hemoglobin S in sickle cell trait carriers. Thus, the high frequency of alpha(+)-thalassemia in the Congolese population presumably results from this disorder having a selective advantage favoring survival. However, the frequency of alpha(+)-thalassemia was not affected by age. Although in this selective tropical environment, alpha(+)-thalassemia as elsewhere markedly affects the hematological characteristics of sickle cell anemia patients, however our data provide no evidence that alpha(+)-thalassemia increases survival of SS patients.     

Association between apolipoprotein ε4 allele,factor V Leiden,and plasma lipid and lipoprotein levels with sickle cell disease in southern Iran

To investigate whether there is any association between various APOE alleles and factor V Leiden (FVL) with lipid profiles and sickle cell disease (SCD) in Southern Iran. 65 SCD patients consisting of 35 sickle cell anemia homozygous (SS), 15 sickle cell heterozygous (AS) and 15 sickle cell/βThalassemia (S/βthal) patients and 68 healthy individuals with normal hematological indices were studied. APOE and FVL polymorphisms were detected by PCR–RFLP and serum lipid level was measured enzymatically. The frequencies of FVL and APOE-ε4 allele were significantly higher in SCD patients than in control (15.4 vs. 4.4 and 13.7% vs. 3.3%, respectively). The distributions of APOE ε3ε3, ε2ε3 and ε2ε4 + ε3ε4 alleles in SCD patients were significantly different from those in the control group. The SCD subjects particularly SS/S βthal (SS + S/βthal) and SS patients have significantly lower frequency of APOE ε3ε3 allele (P < 0.05) whereas SCD, SS patients and AS individuals have a significantly higher frequency of APOE ε4 allele (ε2ε4 + ε3ε4; P = 0.003, P = 0.011 and P = 0.035, respectively) compared to the control group. The LDL-C (P = 0.006) and total cholesterol (P < 0.001) levels in SCD subjects were found to be significantly lower than those in the control group. In addition, the presence of non-APOE ε4 allele (ε2ε3 + ε3ε3) resulted in a significant decrease in the level of LDL-C and total cholesterol in SCD subjects in general and in SS and SS/S βthal patients in particular compared to controls. Furthermore, the presence of APOE ε4 allele (ε2ε4 + ε3ε4) was found to be associated with the risk of sickle cell anemia [OR = 4.1, P = 0.04]. The presence of either FVL mutation (OR = 4.6; CI: 0.91–24, P = 0.07) or APOE-ε4 allele (OR = 4.07; CI: 1.01–16.4, P = 0.048) is associated with the risk of sickle cell disease in Southern Iran. This data suggest that the activation of coagulation system enhances thrombus generation and decreases antioxidant activity in SCD patients from Southern Iran.