Hematological effects of atypical and Cameroon beta-globin gene haplotypes in adult sickle cell anemia.

To examine the effects of unusual or atypical beta-globin gene cluster haplotypes on the hematological features and Hb F levels of sickle cell anemia, we studied African Americans who had an atypical or Cameroon haplotype chromosome in association with a typical haplotype. We identified over 20 atypical haplotypes. The distribution of 5' sub-haplotypes of the atypical chromosomes mirrored the distribution of common haplotypes in African Americans with sickle cell anemia. Neither 5' nor 3' subhaplotypes of the atypical chromosomes affected Hb F levels, packed cell volume, or mean corpuscular volume in individuals with a Benin chromosome. That the 5' subhaplotype is unaffected might be a consequence of the small numbers of Senegal 5' subhaplotypes in our sample, the need for linkage of both 5' and 3' subhaplotypes of any haplotype for an effect on Hb F to be present, or the likelihood that a normal beta-globin gene contributed the 5' subhaplotypes of some atypical haplotypes.

Cardiovascular function during rest and exercise in patients with sickle-cell anemia and coexisting alpha thalassemia-2.

Cardiac function was measured at rest and during exercise in 9 patients with sickle-cell anemia (SS) and coexisting homozygous alpha thalassemia-2 (alpha thal-2). Results were compared with 18 sickle cell patients with normal alpha globin genes, who were matched to the study group by age, gender, and size, and to published normal values. SS alpha thal-2 patients were less anemic: 9.9 +/- 1.0 vs 8.2 +/- 1.2 gm/dl for SS alone (P<.05). Left ventricular dimensions were normal in SS alpha thal-2 (4.9 +/- 0.7 cm), but increased in SS (5.4 +/- 0.7, cm P=.05) (normal range, 3.7-5.6 cm). Left ventricular wall thickness was, however, dramatically increased in the SS alpha thal-2 patients (free wall, 1.8 +/- 0.6 cm; septum, 1.6 +/- 0.4 cm), though SS controls had normal wall thickness (free wall, 1.0 +/- 0.2 cm; septum, 1.0 +/- 0.2 cm, P<.001) (normal range, 0.6-1.1 cm). At rest, Doppler indices of systolic function were not significantly different between sickle groups and normal values. SS alpha thal-2 patients did have abnormal diastolic filling at rest, as evidenced by a reduced ratio of early/late diastolic filling, 1.4 +/- 0.3 vs. 2.0 +/- 0.5 for SS controls (P<.01), and 1.8 +/- 0.4 for normals. An analysis of covariance suggested that this abnormality persisted after taking into account the previously demonstrated hypertrophy. During exercise, SS alpha thal-2 patients had higher heart rates and blood pressures than SS controls in spite of performing the same or less work. This resulted in a higher double product (an estimate of oxygen consumption) in SS alpha thal-2 patients (37,470 +/- 2,310 mm Hg-BPM) than in SS controls (33,310 +/- 1,490 mm Hg-BPM, P<.01). Work capacity, peak heart rate, and blood pressure were all abnormally decreased in both sickle-cell groups when compared to normal. Cardiac abnormalities noted at rest and during exercise in SS alpha thal-2 patients suggest a role of microvascular occlusion and a protective effect of decreased hemoglobin.

Gender and haplotype effects upon hematological manifestations of adult sickle cell anemia.

In Africa, the beta-globin gene cluster haplotype may be associated with variation of Hb F levels in subjects with sickle cell anemia (SS). These observations have not yet been conclusively confirmed in SS out of Africa, perhaps because of small sample sizes, the predominance of haplotype heterozygotes, and diverse influences, including gender, upon Hb F levels. We studied 384 adult African-American SS patients (mean age, 31 years) and explored the relationship of gender, beta-globin gene cluster haplotype, and alpha thalassemia to hematological values and Hb F levels. Both haplotype and gender influenced Hb F concentration. In the total sample, Hb F was higher in females than in males (8.2 vs. 6.5%). In 35 males who were either homozygous for the Senegal chromosome or had the Senegal/Benin haplotype, the mean percent Hb F (8.0%) was equivalent to the Hb F level in females with Benin and Bantu haplotypes (approximately 7.5%). Both females and males homozygous for the Senegal haplotype chromosome or with the Senegal/Benin combination had a significant increase in Hb F compared to other groups. In 44 Senegal/Senegal or Senegal/Benin females the Hb F was 10.9%, or 1.0 g/dl, the highest value observed in all primary analysis groups. Preliminary analyses suggested that the presence of a Bantu chromosome blunted the gender-associated difference in Hb F, but Hb F differences between females with the Senegal/Benin haplotype (11.2%) and the Senegal/Bantu haplotype (8.8%) were not statistically significant. Hemoglobin concentrations were higher in males than in females except in subjects with at least one Senegal haplotype chromosome, where hemoglobin levels were equal. As expected, alpha thalassemia reduced the MCV, increased hemoglobin concentration, and lowered reticulocyte counts, regardless of haplotype. Hb F levels were not affected by the presence of alpha thalassemia in any group. We conclude that gender and beta-globin gene cluster haplotype interact significantly in the modulation of Hb F and anemia in adults with SS.

Mortality in sickle cell disease. Life expectancy and risk factors for early death.

BACKGROUND: Information on life expectancy and risk factors for early death among patients with sickle cell disease (sickle cell anemia, sickle cell-hemoglobin C disease, and the sickle cell-beta-thalassemias) is needed to counsel patients, target therapy, and design clinical trials. METHODS: We followed 3764 patients who ranged from birth to 66 years of age at enrollment to determine the life expectancy and calculate the median age at death. In addition, we investigated the circumstances of death for all 209 adult patients who died during the study, and used proportional-hazards regression analysis to identify risk factors for early death among 964 adults with sickle cell anemia who were followed for at least two years. RESULTS: Among children and adults with sickle cell anemia (homozygous for sickle hemoglobin), the median age at death was 42 years for males and 48 years for females. Among those with sickle cell-hemoglobin C disease, the median age at death was 60 years for males and 68 years for females. Among adults with sickle cell disease, 18 percent of the deaths occurred in patients with overt organ failure, predominantly renal. Thirty-three percent were clinically free of organ failure but died during an acute sickle crisis (78 percent had pain, the chest syndrome, or both; 22 percent had stroke). Modeling revealed that in patients with sickle cell anemia, the acute chest syndrome, renal failure, seizures, a base-line white-cell count above 15,000 cells per cubic millimeter, and a low level of fetal hemoglobin were associated with an increased risk of early death. CONCLUSIONS: Fifty percent of patients with sickle cell anemia survived beyond the fifth decade. A large proportion of those who died had no overt chronic organ failure but died during an acute episode of pain, chest syndrome, or stroke. Early mortality was highest among patients whose disease was symptomatic. A high level of fetal hemoglobin predicted improved survival and is probably a reliable childhood forecaster of adult life expectancy.

Direct demonstration that the A gamma T globin gene is linked to the 4 bp promoter deletion in the beta A chromosome of sickle cell traits.

In beta zero-thalassemia and sickle cell patients, a 4 bp deletion at -222 to -225 of the A gamma globin promoter was associated with low expression of the A gamma T variant (threonine at codon 75 of A gamma), whereas A gamma I (isoleucine at 75) had the normal A gamma promoter and higher expression. However, it has been reported that the beta A chromosomes of sickle cell trait cases have the 4 bp deletion as a common polymorphism unlinked to the A gamma T allele. We now present data demonstrating the association of the A gamma T allele with the 4 bp deletion in beta A chromosomes of sickle cell traits.

Osteonecrosis of the humeral head in sickle cell disease.

The prevalence and incidence of osteonecrosis (ON) of the humeral head in sickle cell disease was determined by a study of 2524 patients who were entered into a prospective study and followed for an average of 5.6 years. At entry, 5.6% had roentgenographic evidence of ON in one or both shoulders. There was little difference in age-adjusted prevalence among genotypes, but there were striking differences in age-specific rates. Observed at ages ranging from five to 24 years, 3.25% of sickle cell anemia (S/S) patients, but only 1.1% of sickle cell disease (S/C) patients, had ON. No S/beta+ thalassemia patients younger than 25 years of age had ON on entry. The highest age-adjusted incidence rate was found in S/S patients with concomitant alpha-thalassemia (4.85 per hundred patient-years), followed by S/beta zero-thalassemia (4.84 per hundred patient-years), S/beta+ thalassemia (2.61 per hundred patient-years), S/S without alpha-thalassemia (2.54 per hundred patient-years), and S/C (1.66 per hundred patient-years). Only 20.9% of patients reported pain or had limited range of movement at the time of diagnosis. Sickle cell disease is a frequent cause of ON of the humeral head, especially in children and young adults.

Hydroxyurea: effects on hemoglobin F production in patients with sickle cell anemia.

Patients with sickle cell anemia were treated with daily doses of hydroxyurea, to assess pharmacokinetics, toxicity, and increase in fetal hemoglobin (Hb) production in response to the drug. Plasma hydroxyurea clearances were not a useful guide to maximum tolerated doses of the drug. The mean daily single oral dose that could be maintained for at least 16 weeks was 21 mg/kg (range, 10 to 35 mg/kg). Among 32 patients, last HbF levels were 1.9% to 26.3% (mean, 14.9%) with increases in HbF over initial values of 1.4% to 20.2% (mean, 11.2%). The most significant predictors of last HbF were last plasma hydroxyurea level, initial white blood count and initial HbF concentration. Last HbF was not related to beta globin haplotype or alpha globin gene number. No serious toxicity was encountered. Clinically significant bone marrow depression was avoided, and chromosome abnormalities after 2 years of treatment were no greater than those observed before treatment. The period of observation has been too short to evaluate the risk of carcinogenesis. Patient's red cells developed striking macrocytosis. Median red cell Hb concentrations did not change. Hb concentrations increased, on average 1.2 g/dL, but serum erythropoietin levels increased. Patients' body weights increased, and some returned to work or school, but no conclusions regarding therapeutic efficacy could be drawn from this uncontrolled open-label study.

Sickle cell disease as a cause of osteonecrosis of the femoral head.

BACKGROUND AND METHODS: Osteonecrosis of the femoral head is an important complication of sickle cell disease. We studied 2590 patients who were over 5 years of age at entry and followed them for an average of 5.6 years. Patients were examined twice a year, and radiographs of the hips were taken at least twice: at study entry and approximately three years later. RESULTS: At study entry, 9.8 percent of patients were found to have osteonecrosis of one or both femoral heads. On follow-up, patients with the hemoglobin SS genotype and alpha-thalassemia were at the greatest risk for osteonecrosis (age-adjusted incidence rate, 4.5 cases per 100 patient-years, as compared with 2.4 in patients with the hemoglobin SS genotype without alpha-thalassemia and 1.9 in those with the hemoglobin SC genotype). Although the rate of osteonecrosis in patients with the hemoglobin SC genotype did not differ significantly from that in patients with the hemoglobin SS genotype without alpha-thalassemia, osteonecrosis tended to develop in these patients later in life. Intermediate rates of osteonecrosis were observed among patients with the hemoglobin S-beta zero-thalassemia and the hemoglobin S-beta(+)-thalassemia genotypes (3.6 and 3.3 cases per 100 patient-years, respectively). Osteonecrosis was found in patients as young as five years old (1.8 cases per 100 patient-years for all genotypes). The frequency of painful crises and the hematocrit were positively associated with osteonecrosis. The mean corpuscular volume and serum aspartate aminotransferase level were negatively associated. Twenty-seven patients had hip arthroplasty during the study; 10 were under 25 years of age. Five of the 27 required reoperation 11 to 53 months after the initial operation. CONCLUSIONS: Osteonecrosis of the femoral head is common in patients with sickle cell disease, with an incidence ranging from about 2 to 4.5 cases per 100 patient-years. Patients with the hemoglobin SS genotype and alpha-thalassemia and those with frequent painful crises are at highest risk. The overall prevalence is about 10 percent. The results of hip arthroplasty are poor.

Pain in sickle cell disease. Rates and risk factors.

BACKGROUND AND METHODS: Acute episodes of pain are the principal symptom of sickle cell disease, but little is known about the epidemiologic features of these episodes or risk factors for them, nor is it known whether patients with high rates of such episodes die prematurely. We prospectively studied the natural history of sickle cell disease in 3578 patients ranging from newborns to persons up to 66 years old who were followed at clinical centers across the United States. RESULTS: There were 12,290 episodes of pain in 18,356 patient-years. The average rate was 0.8 episode per patient-year in sickle cell anemia, 1.0 episode per patient-year in sickle beta 0-thalassemia, and 0.4 episode per patient-year in hemoglobin SC disease and sickle beta(+)-thalassemia. The rate varied widely within each of these four groups--e.g., 39 percent of patients with sickle cell anemia had no episodes of pain, and 1 percent had more than six episodes per year. The 5.2 percent of patients with 3 to 10 episodes per year had 32.9 percent of all episodes. Among patients with sickle cell anemia who were more than 20 years old, those with high rates of pain episodes tended to die earlier than those with low rates. High rates were associated with a high hematocrit and low fetal hemoglobin levels. alpha-Thalassemia had no effect on pain apart from its association with an increased hematocrit. CONCLUSIONS: The "pain rate" (episodes per year) is a measure of clinical severity and correlates with early death in patients with sickle cell anemia over the age of 20. Even when the fetal hemoglobin level is low, one can predict that small increments in the level may have an ameliorating effect on the pain rate and may ultimately improve survival. This outcome is particularly encouraging to investigators studying hydroxyurea and other treatments designed to increase the fetal hemoglobin level.

G gamma and A gamma globin genes are identical from -471 of the promoter midway through gamma IVSII in a Benin beta s haplotype associated with elevated fetal hemoglobin.

In seven kindreds in which sickle cell (SS) patients had elevated (greater than 12%) fetal hemoglobin (Hb F), Milner and colleagues reported that a determinant for elevated Hb F and elevated F cells was linked to the beta s gene. Independently, the Senegal (SEN) beta s haplotype has been found in association with elevated Hb F in SS and beta-thalassemia patients. We have used the kindreds of Milner and colleagues to characterize further the association of haplotype and gamma gene DNA sequence variation with Hb F expression. For the largest kindred, Wi, all four SS had high (greater than 14%) Hb F and both SEN and Benin (BEN) haplotypes. Two AS cases carrying SEN had low Hb F and low F cells, while three AS and one CS carrying BEN had elevated Hb F and elevated F cells; only one AS carrying BEN had low Hb F and low F cells. In order to look for genetic alterations that could account for the elevated Hb F of kindred Wi, we sequenced both the G gamma and A gamma genes of the Wi BEN haplotype. The data showed largely identical G gamma and A gamma genes which may have been generated by two gene conversions: the A gamma promoter was like that of G gamma 3' to -471, while the G gamma IVSII was like that of A gamma in its 5' half. In addition, three new mutations were found in gamma IVSII.(ABSTRACT TRUNCATED AT 250 WORDS)

Histopathologic features of liver biopsy specimens in sickle cell disease.

Liver biopsy results and clinical records from 13 patients with sickle cell anemia were reviewed to assess the relative importance of local ischemia or of factors unrelated to sickling as a cause of their liver disease. Two of the biopsy specimens were normal and one showed cirrhosis. Nine patients had received multiple blood transfusions and nine had cholelithiasis, of whom two also had choledocholithiasis. Seven had both risk factors. Five had lobular cholestasis and four had acute or chronic hepatitis. One biopsy specimen showed changes of the Budd-Chiari syndrome. Another showed clear portal tract changes of large bile duct obstruction but no mechanical blockage of the biliary system; this suggests the thickened bile as postulated by Muirhead. Otherwise the changes observed were those to be expected in a heavily transfused population with a high prevalence of gallstones.

Incidence of ocular abnormalities in patients with sickle hemoglobinopathies.

We examined 110 consecutive unselected patients with SS, SC, or Sthal sickle hemoglobinopathies to determine the prevalence of various retinal lesions within each group. The most prevalent retinal abnormality was the black sunburst, occurring in 46% of SS patients, 63% of SC patients, and 37% of Sthal patients. Our data also suggest that retinal lesions become more prevalent up to the fifth decade of life. Included in our series was an eight-year-old SS hemoglobin patient who presented with a dense vitreous hemorrhage secondary to a large salmon patch that had bled into the vitreous, reducing her vision to 20/200.

The effect of Hb F and alpha-thalassemia on the red cell indices in sickle cell anemia.

This study examines the effect of different levels of fetal hemoglobin (Hb F) and the presence or absence of genes for alpha-thalassemia on the red cell indices and degree of anemia among 102 patients with homozygous sickle cell disease (S/S) between the ages of 15 and 62 years. Patients were divided into those with an average Hb F of less than 10 gm/L ("low" Hb F group) and those with greater than 10 gm/L ("high" Hb F group). alpha-Thalassemia was assessed by restriction enzyme analysis of DNA by the Southern blotting technique. Homozygosity for the beta(s) gene was confirmed by restriction enzyme analysis of DNA using the enzyme Mst II. There were 51 patients with four alpha-globin genes, 28 of whom had "high" and 23 "low" Hb F levels. Fifty-one patients had alpha-thalassemia, 38 of whom were heterozygous and 13 homozygous for the 3.7 kb alpha-thalassemia deletion. Nine had "high" and 31 had "low" Hb F. Irrespective of alpha-globin genotype, patients in the high Hb F group had a higher mean Hb, Hct, MCV, and MCH than those in the low HB F group. In patients without alpha-thalassemia Hb F was positively correlated with MCV and MCH (p less than 0.001), patients with high Hb F levels having macrocytosis confirmed by microhematocrit studies. Patients with alpha-thalassemia had a lower MCHC than patients with four alpha-globin genes and this was not significantly affected by the level of Hb F. The combination of alpha-thalassemia and high levels of Hb F appears to result in a distinctive S/S phenotype that is similar to the type of S/S disease described in Southern India.

Posttransfusion crises in sickle cell anemia: role of delayed hemolytic reactions to transfusion.

We describe ten patients with sickle cell anemia who became acutely ill within a few days after a blood transfusion. Two patients died. In eight cases the posttransfusion detection of alloantibodies suggested that delayed hemolytic reactions to transfusion were involved in precipitating the acute illness. In some cases the illnesses mimicked vaso-occlusive crises, with bone marrow infarction, while in other cases transient biliary obstruction or transient renal insufficiency was documented. Profound anemia mimicked aplastic crises, but we observed a remarkable capacity of the bone marrow to restore the hemoglobin level without further transfusion. In view of the prevalence of delayed hemolytic transfusion reactions in these patients receiving frequent transfusions and whose red cell antigens differ from those of the white population, we suggest that efforts to more closely match recipient and donor red cell antigens would be clinically, technically, and financially advantageous. Moreover, criteria for transfusion in sickle cell anemia should be strictly scrutinized. Quantitation of transfused hemoglobin A has proved useful in confirming delayed hemolytic reactions in sickle cell disease.

A delayed hemolytic transfusion reaction due to anti-Cob.

A delayed hemolytic transfusion reaction precipitated by anti-Cob is described in a multiple transfused primigravida woman with sickle-cell disease. Sixteen days after the prophylactic transfusion of the first of 4 units of red cells, she experienced a fall in hemoglobin concentration accompanied by a newly positive antibody screen and direct antiglobulin test. Anti-Cob was identified both in the patient's serum and in an eluate prepared from her red cells.

Sickle-cell-induced hematuria in pregnancy. The current diagnostic and therapeutic approach.

Hematuria is a rather frequent complication in patients with sickling disorders. However, the occurrence, incidence and management of this complication during pregnancy have not been discussed in the medical literature. We treated three patients with sickle-cell-induced hematuria in pregnancy and developed an approach we find useful for such patients.

Increased HbF in sickle cell anemia is determined by a factor linked to the beta S gene from one parent.

Members of 7 large families, containing 20 patients with sickle cell anemia (SS) characterized by high levels of fetal hemoglobin (HbF), were studied using immunofluorescence to count F cells and a radioimmunoassay to measure small amounts of HbF. In five of these families, one of the sickle cell trait (AS) parents had a much higher HbF and F-cell count than the other; in one family, both parents had a marked increase in HbF and F cells; in the remaining family, HbF and F cells were at borderline values in both parents. Seven of 14 AS siblings, but only 1 of 8 normal hemoglobin (AA) siblings, also had HbF and F-cell counts above the "normal" range. It seems that a factor for increased F cells, linked to the beta S gene of one parent, is segregating in these families and is responsible for the greatly increased HbF and F cells in the SS subjects. HbF per F cell in AS parents and siblings was the same as that of normal AA subjects, whereas in the SS offspring it was greatly increased, suggesting that it was the result of marrow hyperplasia associated with their hemolytic anemia. The similarity of this "increased F-cell gene" to heterocellular hereditary persistence of fetal hemoglobin (HPFH). Swiss type, is discussed, and it is suggested that it may control the persistent synthesis of HbF in sickle cell anemia by its presence in early infancy.