Red cell distribution width in sickle cell disease

Red cell distribution width (RDW), an electronically determined index of anisocytosis, was examined in 60 patients with sickle cell anemia (Hb SS), 28 patients with hemoglobin sickle cell (SC) disease, and seven patients with sickle cell-beta(+) thalassemia (S-thal). All patients were adults and in the steady state of their disease. The RDW was greater in sickle cell patients than in 39 healthy, age and race matched controls without hemoglobinopathy (Hb AA). Patients with sickle cell anemia had higher mean RDW than those with Hb SC disease or with S-thal. The mean RDWs in the latter two disorders were not significantly different. In SS patients, the RDW correlated significantly with the degree of anemia and reticulocytosis. A group of 18 SS patients was studied while in acute painful crisis. Their mean RDW was not different from that in the steady state. Mean WBC and red cell volume, however, were significantly higher during pain crisis.     

Quantitation of hemoglobin A2. An interlaboratory study.

In the 1976 hemoglobinopathy proficiency testing survey of the Center for Disease Control (CDC), whole-blood samples from hematologically normal adults and from individuals heterozygous for beta-thalassemia were shipped to survey participants. The object of this survey was to determine the state of the art for technics used to quantitate hemoglobin A2 (Hb A2) and to test the ability of laboratories to differentiate between blood samples having normal Hb A2 levels and those having elevated levels (i.e., those from individuals with beta-thalassemia trait). The results of Hb A2 quantitation obtained from 183 volunteer participant laboratories were compared with those obtained from 24 reference laboratories. Individual values varied greatly among laboratories and among methods for both normal and elevated Hb A2 samples. The results returned by many laboratories were not within 2 SD of the reference laboratory mean and also were not sufficiently accurate to differentiate between the normal blood samples and those with beta-thalassemia trait. The results suggest that methods for quantitating Hb A2 need to be standardized and a suitable method for determining laboratory performance found.     

Increased circulating levels of soluble HLA class I heterodimers in patients with sickle cell disease.

This study examined the presence of a persistent state of low-grade inflammation in sickle cell anemia patients by measuring circulating sHLA-I heterodimers and C-reactive protein during the steady state and after recent crises. Thirty-nine pediatric sickle hemoglobinopathy patients were studied during the steady state and 11 patients were evaluated within 1 month of a painful crisis. A disease severity score was generated for each patient, and soluble HLA-I (sHLA-I) and C-reactive protein levels were determined. Soluble HLA-I was significantly elevated in 55% of the steady-state group and in 36% of the recent-crisis group. The percentage of patients with elevated sHLA-I differed in the various disease subgroups in the steady state: 46% of Hb SS patients, 70% of Hb SC patients, 75% of Hb S beta-thal patients, and 20% of Hb SSF patients. Steady-state and recent-crisis sHLA-I levels were not significantly different. C-reactive protein levels were elevated in 11% of steady-state patients and in 9% of recent-crisis patients. Soluble HLA-I levels did not correlate with C-reactive protein levels or disease severity score, age, hemoglobin, reticulocyte count, platelet count, or white cell count. These results show that the majority of sickle hemoglobinopathy patients have elevated sHLA-I levels during the steady state and after recent crisis, suggesting the presence of chronic inflammation during the steady state.     

Hemolysis in sickle cell disease as measured by endogenous carbon monoxide production. A preliminary report

To detect and quantitate temporal variations of the hemolytic rate in sickle cell disease, the authors measured endogenous carbon monoxide (CO) production in five normal subjects, nine patients with sickle cell anemia (SS) in steady clinical state, and two patients with sickle cell-hemoglobin C (SC) disease in and out of pain crises. The red blood cell life span calculated from these data (RCLSco) ranged from 81.2 to 102.9 days (mean +/- standard deviation [SD] 88.0 +/- 9.2, coefficient of variation [CV] 10.2%) for the normal subjects and 8.0-24.7 days (mean +/- SD 12.1 +/- 5.1, CV 42.1%) for those with SS. Although the individual figures for RCLSco for the normal subjects and those with SS fell within the range previously obtained by radioisotopic techniques for the respective groups, the mean values calculated from the CO technique were slightly (though not significantly) shorter for the normal subjects and about 25% shorter for the subjects with SS (P less than 0.01). Repetitive studies were performed in four subjects with SS who were clinically stable; the temporal variability in the calculated hemolytic rate differed considerably from patient to patient (CV 3.6%, 7.0%, 17.0%, 28.0%). In two patients concurrent RCLS studies were performed by the CO technique and 51Cr tagged red blood cells. In one patient, the RCLS was similar by the two techniques, in the other, a two exponent 51Cr curve did not permit calculation of RCLS. In the two patients with SC disease there was no difference in RCLSco during and after recovery from pain crisis. Although the CO technique may overestimate the turnover of circulating heme mass, especially in the presence of hemolysis, the results of serial studies in a small number of patients with SS suggest but do not prove temporal variations in hemolytic rate in SS.     

The detection and diagnosis of hemoglobin A2' by high-performance liquid chromatography

Hemoglobin (Hb) A2' is a hematologically silent variant of HbA2 that is detected easily by high-performance liquid chromatography (HPLC), where it elutes in the S window. Our purposes were to define diagnostic criteria for the HbA2' trait using the Variant II (Bio-Rad, Hercules, CA) and to determine the prevalence of HbA2' in a metropolitan patient population. All Hb screens (N = 5,862) performed during a 26-month period were reviewed for new hemoglobinopathies. We identified 57 cases of HbA2' trait, making it the fourth most prevalent Hb variant detected in this population after HbS, HbC, and beta-thalassemia minor For HbA2' trait cases, the mean HbA2 level was 1.7% (SD, 0.17%), and the mean HbA2' level was 1.3% (SD, 0.18%). Six possible HbA2'/beta-thalassemia double heterozygotes were identified, for whom the sum of the HbA2 and HbA2' exceeded 4% of total Hb. Hb variants that might interfere with detection of HbA2' include HbS, glycosylated HbC, and HbG2. Diagnostic criteria proposed for the HbA2' trait by HPLC are HbA2 of 2% or less, S window peak of 1% to 2%, no previous diagnosis of HbS, and absence of HbG and HbC.     

Serial evaluation of iron stores in pregnant Nigerians with hemoglobin SS or SC

Iron status of nonpregnant and pregnant Nigerian patients with hemoglobin SS or SC were assessed using serial hematological parameters, measured by Coulter counter, and serial serum ferritin concentrations measured by radioimmunoassays. The median value of 393 micrograms/L (range, 175 to 900 micrograms/L) for serum ferritin in nonpregnant patients with Hb SS and SC was significantly higher than that found in nonpregnant patients with Hb AA (median, 89.8 micrograms/L; range, 13 to 250 micrograms/L). Apart from packed cell volume values, there were no other significant differences between patients with Hb SS or SC and Hb AA in the other parameters assessed: mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration. In both the normal pregnant patients (Hb AA) and pregnant patients with Hb SS and SC the serum ferritin values decreased as pregnancy advanced to 28 weeks and rose gradually thereafter. At similar stages of gestation serum ferritin values were significantly higher in patients with Hb SS or SC than in those with Hb AA. Pregnancy seems to have induced a significant rise in mean corpuscular volume and mean corpuscular hemoglobin values in the patients with Hb SS or SC, especially in the third trimester, than in patients with Hb AA. The pattern of change in mean corpuscular hemoglobin concentration values was similar in both groups of patients. From the data obtained, it seems the iron status in the patients with Hb SS or SC was good, and pregnancy did not push the patients into an iron deficiency state. The use of prophylactic iron supplementation in pregnant patients with Hb SS or SC appears unjustified.     

The detection of hemoglobin variants by isoelectrofocusing using EDTA-collected and filter paper-dried cord blood specimens.

A comparative study was conducted aimed at the detection of abnormal hemoglobin conditions (mainly AS, SS, AC, CC, SC, AE, AD, Hb Bart's or gamma 4) by isoelectrofocusing of cord blood samples stored as liquid blood and as dried hemoglobin on filter paper. Analyses were made within four to six days after the collection of the samples; storage conditions mimicked those of testing programs using liquid blood samples (as in Georgia) or dried blood filter paper samples (as in several other states). During analysis of hemoglobin solutions extracted from dried blood samples, considerable difficulties were encountered in detecting significant hemoglobinopathies such as SS and SC, whereas even simple abnormalities such as AS, AC, AD, and AE were also often not diagnosed. Detection of the fast-moving variant Hb Bart's or gamma 4 was not possible. These results again cause doubt regarding the general use of dried blood filter paper samples in newborn hemoglobin testing programs. Perhaps special precautions--such as speed in analyzing the samples, storage at -20 degrees C (or perhaps 4 degrees C) instead of at room temperature, and removal of unstable hemoglobin from the filter paper extract by centrifugation--might eliminate some of the problems that were observed.     

Hereditary hemolytic disorders among the Ashram school children in Mayurbhanj district of Orissa

Hemoglobinopathy and allied hemolytic disorders are important genetic and public health problems in Orissa. These cause high degree of hemolytic anemia, morbidity and mortality in the vulnerable populations. A total of 465 Ashram School children aged 6-15 years belonging to Bathudi, Bhumiz, Kolha and Santal tribes in six localities of Mayurbhanj district of Orissa were screened for hemoglobinopathy, glucose-6-phosphate dehydrogenase (G-6-PD) deficiency, ABO and Rhesus blood groups serology and any other hereditary condition. The sickle cell trait (Hb AS) was detected in Santal (1.0%), Bathudi (1.0%) and Bhumiz (0.9%) tribals. No case of homozygous sickle cell disease was detected among the tribes of Mayurbhanj district. The beta-thalassemia trait was detected in Santal (8.0%), Kolha (2.0%), Bhumiz (1.7%) and other tribal (3.8%) students. Sickle cell hemoglobinopathy and beta-thalassemia are prevalent in this district among the tribes, but the frequency is very low. The prevalence of G-6-PD deficiency is considerably high (7.7-9.8%) among the tribes of Mayurbhanj district in Orissa. Out of total 43 G-6-PD deficient subjects, there were 32 males, 9 heterozygote females and 2 homozygous females. This shows that the antimalarial drugs should be administered with caution as these cause hemolytic anemia, sometimes fatal also. The distribution of ABO and Rhesus blood groups shows the preponderance of B blood group (33.8%) over O (29.6%) and 2.1% cases of Rhesus negativity were detected among the Bathudi tribe. This pattern is consistent with the characteristic features of tribal populations in India.     

Screening for hemoglobinopathies during routine hemoglobin A1c testing using the Tosoh G7 Glycohemoglobin Analyzer

Approximately 5.1% of the US population has diabetes mellitus, and hemoglobin (Hb) A1c levels are routinely measured to monitor long-term glycemic control in these patients. Many laboratories use ion exchange chromatography for such measurements, and the presence of hemoglobin variants and hemoglobinopathies often results in abnormal peaks on the chromatogram. The goal of this study was to evaluate the potential that detection of these abnormal peaks provides as a screening tool for Hb variants and hemoglobinopathies. We examined 366 specimens with abnormal peaks observed during routine Hb A1c measurements using the G7 Glycohemoglobin Analyzer (Tosoh Bioscience, Inc.). Hb variants and hemoglobinopathies were characterized by alkaline and acid electrophoresis, solubility testing for Hb S, and clinical parameters. In 252 cases, sickle cell trait was identified with a mean retention time (RT) of 1.44 (SD +/-0.02) min. In 82 cases, Hb C trait was identified with a mean RT of 1.66 +/-0.03 min. RTs for other Hb abnormalities, including sickle cell disease, homozygous Hb C disease, C Harlem trait, alpha-chain Hb variants, Hb D trait, Hb G trait, Hb J trait, Hb Raleigh, and Hb Lepore were also determined. Our results demonstrate that routine Hb A1c testing provides a potential screening tool for the detection of common hemoglobin variants and hemoglobinopathies.The previously unreported RTs for the G7 Glycohemoglobin Analyzer are provided, which can facilitate further testing in previously undiagnosed patients and confirm the cause of abnormal peaks in patients with known hemoglobin abnormalities.     

First observations on the main plasma parameters of oxidative stress in homozygous sickle cell disease]

The present study report 7 cases of sickle homozygous disease which have been analysed using markers of the oxidative-stress, 26 african male subjects were studied: 7 Hb SS subjects (age: m = 20) and 19 control subjects (Hb AA, age: m = 40). Plasma concentrations of F-MDA, T-MDA, TBARS, alpha tocopherol, retinol and beta carotene were measured. Plasma MDA and TBARS mean levels increased in sickle homozygous patients more than in controls. However, only TBARS mean concentrations were significantly increased between patients and controls: TBARS: 4.14 +/- 1.49 nMol/ml for Hb SS versus 2.10 +/- 1.21 nMol/ml for Hb AA (P less than 0.005). Vitamin A and vitamin E concentrations were significantly lower in Hb SS than in Hb AA. Beta carotene was significantly increased in patients vs controls. The significant increase of TBARS explains the great importance of the oxidative damage, whereas the significant decrease of vitamins A and E, may contribute, at least for a part, to maintain the autoxidation process or reveals its intensity in these patients.     

Microcytosis associated with sickle cell anemia.

Sickle cell (Hb SS) anemia is considered a normochromic-normocytic hemolytic disorder. In 53 patients with Hb SS (mean reticulocyte values 16.8%), the authors observed that mean corpuscular hemoglobin (MCH) was 29.8 +/- 2.4 mu microgram and mean corpuscular hemoglobin (MCV) was 88.1 +/- 6.8 cu micrometers. In contrast, patients in a comparable hemolytic-disease group unrelated to hemoglobinopathies (mean reticulocyte count = 15.7%) had a higher MCH (33.0 +/- 1.8 mu microgram) and larger MCV (97 +/- 5.3 cu micrometers). These data indicate that Hb SS disease is associated with "relative microcytosis," presumably a consequence of reduced hemoglobin production.     

Arterialization of peripheral venous blood in sickle cell disease

Arterialization of the venous blood is thought to be indicative of cutaneous shunting, and occurs in patients with sickle cell disease (SCD) during vaso-occlusive crisis (VOC). We performed the present study to quantify the amount of shunting that occurs in sickle cell patients presenting at the Howard University Sickle Cell Center, Washington, D.C., as outpatients and for hospitalizations associated with sickle cell crisis. Peripheral venous blood was drawn anaerobically into heparinized syringes from 9 normal control subjects (NC), 24 outpatients (steady-state group), and 14 inpatients during crisis (VOC group). Spectrophotometric measurements were made for the following species of hemoglobin (Hb): oxy-Hb (O2Hb), reduced Hb (RHb), carboxy-Hb (COHb), and met-Hb (MHb). In addition, fetal hemoglobin (HbF) was measured by high-pressure liquid chromatography (HPLC). The O2Hb saturations of the steady state group were not significantly different than those of the NC group (55 +/- 4% vs. 40 +/- 6%). However, the O2Hb saturations of the VOC group were 73 +/- 3%, and this value was found to be significantly greater than those of both the steady-state and the NC groups (p < 0.05). Reduced hemoglobin saturations were inversely related to the O2Hb values, as expected. Compared to the NC group, the steady-state, and VOC groups had greater dyshemoglobin (COHb and MHb) levels (p < 0.05). These findings suggest that the percentages of venous O2Hb and dyshemoglobins may be increased in sickle cell disease even in the absence of VOC. Therefore, the venous O2Hb saturation may be a useful biochemical marker for the arteriovenous shunting and hemodynamic adaptations associated with sickle cell disease.     

Study of haemoglobin S percentage and haematological parameters in sickle cell trait

A total of 101 individuals who showed AS pattern on haemoglobin electrophoresis were included in this study and various haematological investigations were carried out on them. Of these, 79 cases were grouped as AS patients. Twenty two healthy relatives of sickle anemia patients were grouped as AS controls. Twenty AA controls were also included in this study. Haemoglobin S (HbS) and hemoglobin A (HbA) quantitation was carried out. The frequency distribution of HbS percentage showed that maximum subjects had HbS levels above 33%. A female predominance was seen in subjects of sickle cell trait. Haemoglobin levels and total red cell counts of AS patients were found to be significantly lower than those of AS controls. Reticulocyte counts and hematocrit values of AS patients were found to be significantly higher than AS controls. MCV and MCH values of AS patients were found to be significantly lower, but MCHC was not significantly altered.     

Benign sickle cell disease in Saudi Arabia: survival estimate and population dynamics

A survey of 8,084 adult Saudi male employment applicants yielded 872 with the sickle cell trait (AS) and 51 with sickle cell disease. Based on the known distribution of hemoglobin S genes between oasis and non-oasis populations in Saudi Arabia, and on calculation of the expected number of abnormal homozygotes within the non-oasis and oasis subgroups as well as the entire employment applicant group, it appears that virtually 100% of Saudis with SS disease survive to adult life. Saudi Arabs and other Caucasian populations in the Middle East exhibit a benign type of SS disease as compared with Blacks in Africa and the Americas. In the Middle East, gene contributions from SS individuals will shift equilibrium frequencies to higher levels than encountered in Black populations under sustained selective pressures, and the polymorphism will tend to be stable with decline in selective pressure. There are some indications that the hemoglobin S gene may have been a recent import into the Middle East.     

The sickle gene: a marker for blood pressure?

Blood pressure patterns were studied in 224 Nigerians comprising 22 families with at least one child with sickle cell anemia (SS) and 18 families without sickle cell anemia (AA) in a community with a high frequency of the sickle trait (AS). Among the offspring (n = 162; mean age: 10.1 years), systolic blood pressure did not differ between the SS, AS, or AA groups. However, the SS group had significantly lower diastolic blood pressure than the AS or AA groups (60.6 versus 66.5 and 65.4 mm Hg, respectively; P < .01). After controlling for genotype, age, body mass index, and sex, regression analysis revealed that age was the only independent correlate of blood pressure.     

Negro alpha-thalassaemia: genetic studies in homozygous sickle cell disease.

Interaction with the alpha-thalassaemia phenotypes lowers the proportion of Hb S in the sickle cell trait and influences the mean cell volume and proportional Hb A2 in homozygous sickle cell (SS) disease. By assigning somewhat arbitrary values to the alpha-thalassaemia 1 and alpha-thalassaemia 2 phenotypes in these conditions, it has been possible to investigate the patterns of inheritance of alpha-thalassaemia in black populations. The results strongly support the hypothesis that the alpha-thalassaemia 1 phenotype represents homozygosity for alpha-thalassaemia 2.     

Parasitic infections in sickle cell crisis: Nigerian experience.

Data collected on 150 sickle cell patients in Nigeria were analyzed to determine the frequency of parasitic infections in clinical and hematologic crisis. Fifty-three adult and 97 pediatric patients (mean age: 27.6 years and 9.7 years, respectively) were studied. Of these patients, 82 were males and 68 females. One hundred thirty-nine had the SS and 11 the SC genotype. Blood samples collected from patients on admission for sickle cell-related illnesses were examined microscopically for evidence of Plasmodium sp, and stool samples were analyzed for presence of any helminth. A total of 102 parasitic infections associated with clinical cases of sickle cell crisis were recorded (malaria, 36[35.3%]; helminths, 49 ([48%]; and malaria and helminths together, 17 [16.7%]). Of the 49 helminthic infections, 26 (53.1%) were due to Ascaris lumbricoides, 15 (30.6%) were due to hookworms, 7 (14.3%) were due to Trichuris trichiura, and 1 (2%) was due to Strongyloides stercoralis. The mean hemoglobin levels during clinical crisis were 7.1 g/dL for helminths, 6.4 g/dL for malaria, and 6.1 g/dL for malaria and helminths together. Reticulocyte counts were 1.4% for helminths, 1.5% for malaria, and 1.2% for both malaria and helminths together. Severity and duration of the clinical crisis were longer for events associated with a single parasitic organism infection than for those with multiple organisms. Routine blood smear examination for malaria and stool analysis should be included in the laboratory evaluation of individuals with sickle cell anemia in developing countries as these infestations could play an important role in precipitating a crisis.     

Evaluation of 24-second cyanide-containing and cyanide-free methods for whole blood hemoglobin on the Technicon H*1TM analyzer with normal and abnormal blood samples

Automated methods, with and without cyanide (+CN and -CN), for whole blood hemoglobin (Hb) determination were evaluated on the Technicon H*1TM System. Both automated Hb methods were linear over the range 0-250 g/L (0-25 g/dL) and correlated well with the International Committee for Standardization of Hematology (ICSH) reference method and with the Coulter S+II. Both methods quantitatively converted whole blood containing up to 100% carboxyhemoglobin in less than 24 seconds to their respective end products. With respect to abnormal samples (sickle cell anemia, multiple myeloma, and hyperlipemia), both H*1 methods gave Hb results that were equivalent to the (postfiltration) ICSH method. For samples with white blood cell (WBC) counts less than 36 X 10(9)/L, the +CN method was equivalent to the (postfiltration) ICSH method, whereas for WBC counts greater than 20 X 10(9)/L, the -CN method showed acceptable recovery of the mean but unacceptable imprecision. For WBC counts of 36-164 X 10(9)/L, the +CN method yielded acceptable Hb recovery with unacceptable imprecision. Hyperlipemia, resulting from addition of Intralipid directly to the blood samples, caused large errors in both H*1 methods.     

Viral seroprevalence, transfusion and alloimmunization in adults with sickle cell anemia in Guadeloupe]

We retrospectively studied the prevalence of anti HIV 1 and 2, anti-HTLV-I, anti-Hepatitis B and C viruses (HBV and HCV) antibodies, anti-HBV vaccinal coverage, transfused patients and alloimmunizations frequencies among adult sickle cell patients attending the sickle cell center (SCC) of Guadeloupe. The data were collected from the medical files of the centre. Among the studied samples (n = 331) no transfusional HIV contamination was observed. All patients with HTLV-I (n = 11, 3.3% of whole sample) and anti-HCV (n = 9, 2.7%) positive serology had transfusion history. Five patients (1.5%) had an active hepatitis B. Vaccination against HBV efficiently protected 247 patients (74.4%) and 57 had post-hepatitis B antibodies. We observed that 213 patients (64%) had a history of transfusion (88% of SS patients and 36% of the SC patients, p < 0.05). Fifty-four patients (16%) presented alloimmunization, 4 of them have never been transfused. These results show that it is still necessary to optimise transfusion protocol and their safety, and to diagnose viral contamination in transfused sickle cell patients.     

Reliable estimation of hemoglobin A2 concentration by electrophoresis with densitometry.

Elevated hemoglobin A2 (Hb A2) levels can be identified conveniently by densitometry after electrophoresis on cellulose acetate strips. Because a recent report questioned the accuracy of this technic, the method was re-evaluated by paired comparison with microcolumn chromatography. Analysis of 100 patient specimens showed high correlation (r = +0.84), but an average Hb A2 concentration 0.7% higher by densitometry than by chromatography (P less than 0.001). With upper limits set at 4.5%, and 3.8%, respectively, results were divided into "normal" and "high" for each method. Concordant results were obtained in 97 of the 100 cases (82 normal, 15 high). Another densitometer of improved design was used for paired analysis of 50 additional specimens, 25 normal and 25 with beta-thalassemia trait. The two groups were well separated by both procedures, and Hb A2 levels were similar (r = +0.92, P greater than 0.6). This study demonstrates that it is possible, with carefully controlled technics and properly calibrated instruments, to use electrophoresis with densitometry as a reliable means of identifying abnormal Hb A2 levels.