Fusobacterium nucleatum Multiple Liver Abscesses in an Adolescent With Hemoglobin SC Disease.

Liver abscesses are poorly known in sickle cell disease. We report here multiple liver abscesses occurring in a 17-year-old patient with hemoglobin SC disease. A Fusobacterium nucleatum was identified on cyst puncture. Such complications have been described in only 11 children and young adults with hemoglobin SS/Sß-thalassemia diseases. Fusobacterium species are the most frequent pathogens reported and require anaerobic culture to be identified.

Impaired cytoadherence of Plasmodium falciparum-infected erythrocytes containing sickle hemoglobin.

Sickle trait, the heterozygous state of normal hemoglobin A (HbA) and sickle hemoglobin S (HbS), confers protection against malaria in Africa. AS children infected with Plasmodium falciparum are less likely than AA children to suffer the symptoms or severe manifestations of malaria, and they often carry lower parasite densities than AA children. The mechanisms by which sickle trait might confer such malaria protection remain unclear. We have compared the cytoadherence properties of parasitized AS and AA erythrocytes, because it is by these properties that parasitized erythrocytes can sequester in postcapillary microvessels of critical tissues such as the brain and cause the life-threatening complications of malaria. Our results show that the binding of parasitized AS erythrocytes to microvascular endothelial cells and blood monocytes is significantly reduced relative to the binding of parasitized AA erythrocytes. Reduced binding correlates with the altered display of P. falciparum erythrocyte membrane protein-1 (PfEMP-1), the parasite's major cytoadherence ligand and virulence factor on the erythrocyte surface. These findings identify a mechanism of protection for HbS that has features in common with that of hemoglobin C (HbC). Coinherited hemoglobin polymorphisms and naturally acquired antibodies to PfEMP-1 may influence the degree of malaria protection in AS children by further weakening cytoadherence interactions.

Clinical and hematological profile in a newborn cohort with hemoglobin SC.

OBJECTIVES: Hemoglobin SC is the second most common variant of sickle-cell disease worldwide, after hemoglobin SS. The objectives of the study were to describe the clinical and laboratory characteristics of hemoglobin SC disease in children from a newborn screening program and treated at a blood center. METHODOLOGY: This study assessed a cohort of 461 infants born between 01/01/1999 and 12/31/2012 and followed-up until 12/31/2014. Clinical events were expressed as rates for 100 patient-years, with 95% confidence intervals. Kaplan-Meier survival curves were created. RESULTS: The median age of patients was 9.2 years; 47.5% were female. Mean values of blood tests were: hemoglobin, 10.5g/dL; reticulocytes, 3.4%; white blood cells, 11.24×109/L; platelets, 337.1×109/L; and fetal hemoglobin, 6.3%. Clinical events: acute splenic sequestration in 14.8%, blood transfusion 23.4%, overt stroke in 0.2%. The incidence of painful vaso-occlusive episodes was 51 (48.9-53.4) per 100 patient-years and that of infections, 62.2 episodes (59.8-64.8) per 100 patient-years. Transcranial Doppler ultrasonography (n=71) was normal given the current reference values for SS patients. Hydroxyurea was given to ten children, all of whom improvement of painful crises. Retinopathy was observed in 20.3% of 59 children who underwent ophthalmoscopy. Avascular necrosis was detected in seven of 12 patients evaluated, predominantly in the left femur. Echocardiogram compatible with pulmonary hypertension was recorded in 4.6% of 130 children, with an estimated average systolic pulmonary artery pressure of 33.5mmHg. The mortality rate from all causes was 4.3%. CONCLUSIONS: Clinical severity is variable in SC hemoglobinopathy. Several children have severe manifestations similar to those with SS disease.

Differences of microparticle patterns between sickle cell anemia and hemoglobin SC patients.

Sickle cell anemia (SCA) and hemoglobin SC (HbSC) disease are the two most common forms of sickle cell disease (SCD), a frequent hemoglobinopathy which exhibits a highly variable clinical course. Although high levels of microparticles (MPs) have been consistently reported in SCA and evidence of their harmful impact on the SCA complication occurrences have been provided, no data on MP pattern in HbSC patients has been reported so far. In this study, we determined and compared the MP patterns of 84 HbSC and 96 SCA children, all at steady-state, using flow cytometry. Most of circulating MPs were derived from platelets (PLTs) and red blood cells (RBCs) in the two SCD syndromes. Moreover, we showed that HbSC patients exhibited lower blood concentration of total MPs compared to SCA patients, resulting mainly from a decrease of MP levels originated from RBCs and to a lesser extent from PLTs. We did not detect any association between blood MP concentrations and the occurrence of painful vaso-occlusive crises, acute chest syndrome and pulmonary hypertension in both patient groups. We also demonstrated for the first time, that whatever the considered genotype, RBC-derived MPs exhibited higher externalized phosphatidylserine level and were larger than PLT-derived MPs.

Optical characterization of red blood cells from individuals with sickle cell trait and disease in Tanzania using quantitative phase imaging.

Sickle cell disease (SCD) is common across Sub-Saharan Africa. However, the investigation of SCD in this area has been significantly limited mainly due to the lack of research facilities and skilled personnel. Here, we present optical measurements of individual red blood cells from healthy individuals and individuals with SCD and sickle cell trait in Tanzania using the quantitative phase imaging technique. By employing a quantitative phase imaging unit, an existing microscope in a clinic is transformed into a powerful quantitative phase microscope providing measurements on the morphological, biochemical, and biomechanical properties of individual cells. The present approach will open up new opportunities for cost-effective investigation and diagnosis of several diseases in low resource environments.

Liver involvement in sickle cell disease.

In an effort to clarify the features of hepatic dysfunction in sickle cell disease, we obtained serial tests of liver function in 100 consecutive patients with sickle cell anemia and in 30 consecutive patients with hemoglobinopathy SC during a five-year period. There were 32 patients with chronic abnormalities in tests of liver function. These abnormal tests were explained by a variety of lesions in 30 cases, and the liver disease remained unexplained in only 2 patients who declined liver biopsy. The diagnoses in these 30 patients included hepatitis, chronic passive congestion, common duct obstruction, alcoholic liver disease, pregnancy, collagen-vascular disease, and sarcoidosis. Evidence for hepatitis B infection was present in 19 of those with sickle cell anemia and in 6 of those with hemoglobinopathy SC. The bilirubin levels in sickle cell anemia appeared to have a trimodal distribution, with six patients exhibiting markedly elevated levels of indirect bilirubin suggesting a difference in bilirubin metabolism. There was no evidence of liver disease in 72 patients with sickle cell anemia, nor in 24 patients with hemoglobinopathy SC, as these patients exhibited only mild elevation of their serum indirect bilirubin levels owing to chronic hemolysis. Intrasinusoidal sickling and Kupffer cell erythrophagocytosis were nearly universal findings at liver biopsy, irrespective of the clinical disorder, and were not related to the degree of liver test abnormalities. Liver and biliary tract dysfunction in sickle cell disease have been attributed to anoxia secondary to sinusoidal obstruction by sickled erythrocytes and Kupffer cell erythrophagocytosis. However, some causes of liver disease in sickle cell patients can be explained by clinical disorders other than the hemoglobinopathy alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute splenic sequestration crises in adults with sickle cell disease.

Reports of acute splenic sequestration crises in adults with sickle cell hemoglobin C disease or sickle cell thalassemia are rare, although an enlarged and distensible spleen persists in half of these patients. Seven episodes of acute splenic sequestration crises in four adults, two with sickle C disease and two with sickle thalassemia, are described. The crises were life-threatening and recurrent in all, but there were no fatalities. One patient had mild steady-state thrombocytopenia suggesting hypersplenism. Technetium 99m/sulfur colloid scanning of the spleen during the acute splenic sequestration crises in three patients showed almost total lack of splenic uptake or decreased uptake with intrasplenic filling defects thought to be splenic infarcts or hematomas on follow-up computed tomographic scanning. The scanning abnormalities resolved following recovery from the crises. Acute splenic sequestration crises probably are common in adults with sickle C disease and sickle thalassemia but may be underdiagnosed or misdiagnosed as splenic infarctions. The hematologic and splenic findings during acute splenic sequestration crises resemble those following splenic vein ligation in animals.

Morphological features of the human umbilical vein in normal, sickle cell trait, and sickle cell disease pregnancies.

Pathological changes often occur in the placenta of women with sickle cell disease (SCD). These alterations are caused by sickling of erythrocytes and vasoocclusion in the placental circulation, leading to regional hypoxia. However, the morphological status of the umbilical cord, which is in close physical association with the placenta, is not documented under such conditions. To explore this, the umbilical vein structure in healthy, sickle cell trait (the heterozygous state), and SCD pregnancies was studied using scanning (SEM) and transmission electron microscopy (TEM). Interestingly, the sickle cell trait umbilical vein architecture was morphologically similar to that in control veins, whereas numerous alterations were seen in the SCD umbilical vein wall. In SEM, the SCD umbilical vein endothelial cells showed atypical morphologies. TEM analysis of the tunica media showed (1) smooth muscle cell proliferation and increase in the thickness of the basement membrane underlying the cells; (2) areas of necrosis; (3) reduplication of the inner elastic lamina. Such features were often seen in sickle patients vasculature at autopsy. Our findings could have importance because tissue hypoxemia is an integral part of vasoocclusion. We conclude that the SCD umbilical vein may be an additional tool for studying vasoocclusion in sickle cell disease.

Foveal avascular zone diameter and sickle cell disease.

Patients with sickle cell disease can have a distinct retinopathy in which the posterior pole shows abnormalities, including perifoveolar vascular abnormalities. The foveal avascular zone (FAZ) was examined using fluorescein angiography in patients with sickle cell disease and in healthy normal controls. The longest FAZ diameters of 38 patients (51 eyes) with sickle cell disease were compared with those of the 48 patients (60 eyes) in the control group. The average of the longest FAZ diameter in the patients with sickle cell disease was 1.00 mm compared with 0.61 mm for the controls. This difference was statistically significant (P less than .00001). Within the sickle cell group, there were no significant differences in the FAZ diameters with respect to degree of retinopathy, type of sickle hemoglobinopathy, or visual acuity. Thus, an enlarged FAZ diameter in patients with sickle cell disease is confirmed.

Localization of vascular endothelial growth factor in human retina and choroid.

OBJECTIVE: To examine the distribution and relative levels of vascular endothelial growth factor (VEGF) in the nondiabetic and preproliferative diabetic human retina and choroid. METHODS: Immunohistochemical localization was performed on frozen sections from cryopreserved postmortem human tissue using a polyclonal antibody against VEGF and a streptavidin peroxidase system. Eyes from 5 subjects without diabetes and 8 subjects with diabetes were examined and analyzed using a 7-point immunohistochemical grading system. RESULTS: In subjects without diabetes, weak or no VEGF immunoreactivity was associated with retinal blood vessels. In subjects with diabetes, we found significantly increased immunoreactivity in the retinal vascular endothelium and blood vessel walls. Vascular endothelial growth factor immunoreactivity was also associated with intravascular leukocytes in subjects with and without diabetes. In the choroid of subjects without diabetes, immunoreactivity was almost exclusively associated with intravascular leukocytes, whereas in diabetic subjects, immunoreactivity was localized within choriocapillaris endothelium, choroidal neovascular endothelium, and migrating retinal pigment epithelium cells. CONCLUSIONS: The observed increase in VEGF immunoreactivity in the diabetic retina and choroid suggests that VEGF may contribute to 2 well-documented events during retinopathy: increased vascular permeability and angiogenesis.

New classification of peripheral retinal vascular changes in sickle cell disease.

The systemic complications of homozygous sickle cell disease (SS) are more severe than in sickle cell haemoglobin C (SC) disease, and yet visual loss due to proliferative retinopathy is more common in the latter. This anomaly is unexplained. It is believed that proliferative disease occurs in response to closure of the peripheral retinal vasculature, yet a systematic longitudinal survey of the peripheral retinal vascular bed has not been undertaken. In the Jamaica Sickle Cohort study all subjects are scheduled to receive annual ocular examination and fluorescein angiography. The results have now been analysed in subjects with SS and SC disease using a new classification system based on a comparison of the peripheral retinal vascular bed with that recorded in the cohort with normal haemoglobin (AA) genotype. The vascular patterns could be classified as qualitatively normal (type I) or abnormal (type II). An abnormal vascular pattern was identified more commonly with age, in a significantly larger proportion of subjects with SC than SS disease, and was associated with the development of proliferative disease. In order to establish the dynamics of change, the angiograms were analysed in the 18 subjects (24 eyes) who developed proliferative disease. It is shown that a qualitatively normal vascular pattern may be retained despite loss of capillary bed and posterior displacement of the vascular border. A border which is qualitatively abnormal does not revert to normal, and once abnormal, continuous evolution may occur before development of proliferative lesions. The peripheral border of the retinal vasculature was too peripheral to photographed in 13 of the 24 eyes before it becoming qualitatively abnormal. It is concluded that a normal border, if posterior, results from gradual modification of the capillary bed and indicates low risk of proliferative disease. A qualitatively abnormal vascular border occurs as a radical alteration of retinal perfusion in subjects in whom little modification of the vascular bed occurred before the event, and signals risk of proliferative disease. This classification system is useful in identifying the likelihood of threat to vision in young Jamaicans with sickle cell disease, and the higher frequency of proliferative retinopathy in SC can be explained by the higher prevalence of a qualitatively abnormal peripheral retinal vasculature.

Selected vascular lesions of the placenta.

The double circulation of the placenta results in great diversity in the morphologic expression of vascular lesions. Although the etiology and pathogenesis of many of these lesions are not completely understood, it is clear that some have potentially serious implications for fetal well-being. This article focuses on the diagnostic criteria and clinical significance of selected placental vascular lesions.

Renal length in sickle cell disease: observations from a cohort study.

Renal length has been measured by ultrasound in 237 subjects with homozygous sickle cell (SS) disease, 147 with sickle cell-hemoglobin C (SC) disease, and in 78 age-matched controls with a normal hemoglobin (AA) genotype. As expected, renal length increased with age in all genotypes but mean length was significantly greater in SS disease compared with SC disease (mean difference 4.3 mm after adjustment for height) and significantly greater in both genotypes than in AA controls (SS/AA difference 9.2 mm, SC/AA difference 5.0 mm after adjustment for height). Examination of relationships between renal length and some hematological indices (hemoglobin, fetal hemoglobin, reticulocyte counts, alpha thalassemia status) in SS or SC disease showed only a significant negative correlation with hemoglobin and positive correlation with reticulocyte count in SS disease. Further analysis suggested that the stronger relationship was between renal length and high reticulocyte count. The mechanism of renal enlargement is unknown although glomerular hypertrophy and increased renal blood volume are likely contributors.

Postmortem diagnosis of hemoglobin SC disease complicated by fat embolism.

A case is reported of a previously healthy 52-year-old African American male who presented with acute onset of abdominal pain. Progressive increase in his abdominal symptoms led to an exploratory laparotomy; however, no pathology was discovered. Postoperatively, the patient became hypoxemic which progressed to diffuse infiltrates on chest x-ray, suggestive of adult respiratory distress syndrome. He had a rapidly fatal course. Autopsy showed bone marrow infarction, fat embolism, splenomegaly, and widespread congestion with sickle erythrocytes. Hemoglobin electrophoresis done postmortem showed hemoglobin (Hb) SC disease that was undiagnosed antemortem. To the best of our knowledge, it is unusual for Hb SC to be diagnosed postmortem in adults. This case suggests that sickle cell disorders should be ruled out in patients at risk for hemoglobinopathy in the presence of signs and symptoms compatible with the disease, irrespective of age.