Identification Of A Molecular Signature Associated With Acute Chest Syndrome In Patients With Sickle Cell Disease In Steady State

Author(s):  
Tong Zhou ◽  
Wei Zhang ◽  
Shwu-Fan Ma ◽  
Ankit A. Desai ◽  
Michael S. Wade ◽  
...  
2020 ◽  
pp. 004947552097461
Author(s):  
Odayne Steele ◽  
Alfred L Duncan ◽  
Larnelle N Simms ◽  
Shani A Duncan ◽  
Simone E. Dundas Byles ◽  
...  

We reviewed the post-operative morbidity and mortality of open splenectomy undertaken in conjunction with selective blood transfusion in Jamaican children with sickle cell disease. Data were collected on 150 splenectomies performed between November 1994 and October 2017. Selective blood transfusion involved raising haemoglobin levels to approximately 100 g/L in patients with admission haemoglobin ≥10 g/L below steady state. There was no mortality. Mean post-operative stay was 3.2 days with a median of three days. Total morbidity was 19/150 cases (12.7%), with acute chest syndrome accounting for 11/19 (57.9%). Among the non-transfused, acute chest syndrome occurred in 10/117 cases (8.5%), while among transfused, acute chest syndrome occurred in 1/33 cases (2.9%). We recommend this selective blood transfusion protocol for patients with sickle cell disease to surgeons who undertake splenectomies in settings where blood bank reserves are perennially low.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1662-1662
Author(s):  
Charles T. Quinn ◽  
Naveed Ahmad

Abstract Individuals with sickle cell disease (SCD) may have arterial oxygen desaturation during the steady-state that is mainly due to a right shift of the oxyhemoglobin dissociation curve. This right shift has both non-specific causes (increased concentration of 2,3-DPG due to chronic anemia) and SCD-related causes (an effect of the intracellular concentration of hemoglobin (Hgb) S and an enhanced Bohr effect). Another possible cause is chronic cardiopulmonary disease that may be related to past acute chest syndrome (ACS). We aimed to describe the distribution of steady-state peripheral oxygen saturation (SpO2) in a large population of children with SCD and to determine whether any simple laboratory or clinical features were predictive of SpO2. We hypothesized that most of the variation in SpO2 was not explained by steady-state Hgb alone, and that a history of ACS could explain some of this variability. Using our center’s comprehensive database we identified all subjects with sickle cell anemia (SS), sickle-hemoglobin C disease (SC), sickle-β+-thalassemia (Sβ+), or sickle-β0-thalassemia (Sβ0) who had been evaluated within the past 5 years for whom steady-state Hgb concentration, reticulocyte count (retic), and SpO2 were available. All steady-state values are rolling averages calculated at routine well clinic visits. SpO2 was determined by pulse oximetry in room air. Individuals receiving chronic transfusions were excluded. Lifetime rates of ACS were known for a subset of subjects with SS and Sβ0. A standard multiple regression analysis was performed between steady-state SpO2 as the dependent variable, and steady-state Hgb and retic, age, and sex as independent variables. 585 subjects were analyzed (390 SS/Sβ0, 195 SC/ Sβ+; 47% female, 53% male). Mean age was 9.4 years (SD 5.6, range 0.2 – 19.7). Mean SpO2 was 96.3% (SD 3.0) for SS/Sβ0 and 98.7% (SD 1.7) for SC/ Sβ+ subjects. The percentage of subjects with SpO2 <96% and <90% was 33.1 and 2.8 for SS/Sβ0 and 3.6 and 0.5 for SC/ Sβ+. Bivariate analyses showed no correlation between Hgb and SpO2 for SC/ Sβ+ subjects (N=195, Pearson R=0.024, P=0.74) and no correlation between ACS rate and SpO2 in those with SS/Sβ0 (N=183, Pearson R=−0.043, P=0.56). Thus, only the 390 subjects with SS/Sβ0 were included in the multivariate analysis, and ACS rate was not included in the model as an idependent variable. All 4 independent variables (Hgb, retic, age, and sex) contributed significantly to prediction of SpO2. Altogether, about 45% (adjusted 44%) of the variability in SpO2 was explained by the model. Multiple correlation coefficient (R = 0.67) showed a significant linear relationship between independent variables and SpO2 (F = 78.07, p < 0.001). The estimated model can be given as: SpO2 = 94.24 + (0.58 * Hgb) − (0.16 * Age in years) + (0.64 * Female sex) − (0.20 * Retic in %). In summary, steady-state hypoxemia is common among individuals with SS and Sβ0, in whom decreased steady-state SpO2 is related to decreased steady-state Hgb, increased steady-state retic, increased age, and male sex. This relationship was not found for individuals with SC and Sβ+. Only 5% of the variation in SpO2 was explained by Hgb while controlling for other variables, and ACS rate was not associated with SpO2. We conclude that most steady-state hypoxemia in individuals with SCD is explained by factors other than chronic anemia, and that hypoxemia appears to be unrelated to prior episodes of ACS.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3775-3775
Author(s):  
Iheanyi Okpala ◽  
Cynthia C. Ugochukwu ◽  
Panagiotis Pantelidis ◽  
Baba Inusa ◽  
Obike Ibegbulam ◽  
...  

Abstract Our previous study showed that patients with sickle cell disease (SCD) and high steady-state expression of the adhesion molecules L-selectin and αMβ2 integrin on leukocytes developed complications [Blood. 2002;100(suppl):11a. Eur J. Haematol. 2002; 69:135–144]. The aim of this study was to find out if L-selectin protein expression by leukocytes and the development of complications in SCD are affected by previously described single nucleotide polymorphisms within the coding regions of the gene. To detect F206L, T49S and P213S polymorphisms we determined the L-selectin genotype in 142 HbSS patients (64M, 78F, age 2 – 62 yr, mean 27 yr ±12); and 102 racially-matched HbAA controls with similar age and sex distribution. The T49S and P213S amino acid changes in L-selectin are respectively associated with increased risk of vasculopathy and nephropathy; important features of SCD. [Hum Genet. 1996; 97:15–20. Am. J. Hum. Genet.2002; 70: 781–786]. All HbSS patients were evaluated for disease complications. Steady-state expression of L-selectin on neutrophils, lymphocytes and monocytes was measured by flow cytometry in 44 HbSS patients. With respect to F206L polymorphism, 100/142 (70%) patients and 73/102 (72%) controls were FF homozygous, 42 patients and 28 controls were heterozygous FL, and 1 control individual was LL homozygous. There was no significant difference in distribution of the polymorphic variants between patients and controls [Chi-squared (X2) = 0.1, p&gt;0.05]. In codon 213, 48 (33.8%) patients and 42 (41.2%) controls were PP homozygous, 91 patients and 55 controls PS heterozygous, 1 patient and 5 controls SS homozygous [X2 =1.9, p&gt;0.05]. With regard to the T49S polymorphism, 100% of the patients and controls were TT homozygous. At least one complication of SCD was observed in 110 SCD patients; 32 had uncomplicated disease. The most common complications observed were avascular joint necrosis (n=39), sickle nephropathy (n=31), stroke (n=25) and acute chest syndrome (n=20). The observed frequencies of FF genotype in codon 206 among patients with complications (74), and without complication (26) were not significantly different from the expected values [X2 = 2.37, p&gt;0.05]. Similarly, none of the other genotypes (FL, PP, PS) was significantly associated with complications of SCD. Of the 44 patients in who leukocyte L-selectin expression was measured, 31 turned out to be FF homozygous in codon 206, and 13 FL. No significant differences were observed between FF and FL patients in the mean levels of L-selectin expression by neutrophils (FF: 4.00+ 4.56 vs FL: 3.24+ 3.4), monocytes (FF: 4.30+ 5.6 vs FL: 2.56+ 3.39) or lymphocytes (FF: 2.61+ 3.02 vs FL: 2.11+ 2.0); p&gt;0.05. Similarly, the P213S polymorphism had no effect on the level of L-selectin expression. The findings suggest that neither F206L nor P213S L-selectin gene polymorphism predisposes to high leukocyte surface expression of this adhesion molecule, or the development of complications in SCD.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1437-1437
Author(s):  
John J. Strouse ◽  
Joshua Field ◽  
Regina D. Crawford ◽  
Sophie Lanzkron

Abstract Primary hemorrhagic stroke is an uncommon but serious complication of sickle cell disease (SCD) with mortality from 20 to 65%. Proposed risk factors include previous ischemic stroke, aneurysms, low steady-state hemoglobin, high steady-state leukocyte count, acute chest syndrome, and transfusion. We performed a retrospective case-control study to evaluate risk factors for primary hemorrhagic stroke in adults (age &gt;18 years) with SCD from Johns Hopkins and Barnes- Jewish Hospitals and Duke University Medical Center from January 1989 to April 2008. Cases had SCD and intraparenchymal (IPH), subarachnoid (SAH), or intraventricular (IVH) hemorrhage confirmed by neuroimaging or analysis of cerebrospinal fluid; traumatic hemorrhages and hemorrhagic conversion of ischemic strokes were excluded. Controls had SCD and ischemic stroke (focal neurological deficits with corresponding cerebral infarcts by neuroimaging). Both were identified by searching the hospital discharge database using ICD-9 codes for acute stroke and SCD and reviewing divisional records. We compared continuous variables by Student’s t-test and calculated odds ratios with exact methods. We identified 19 cases (mean age 29 years, range 18 – 66, 42% male) and 18 controls (mean age 34 years, range 19 – 61, 39% male). Most cases (14/18) had sickle cell anemia (HbSS) and 22% had a prior overt stroke; controls had HbSS (9/17), HbSB0thalassemia (1), or HbSC (7) and 41% had a history of overt stroke. Cases presented with headache (89%) and seizure (37%) and less frequently hemiparesis (27%). Controls presented with hemiparesis (78%), headache (57%), and rarely seizure (11%). Twelve cases had IPH including those with extension to the ventricles (1), subarachnoid (2) or both (2); six had SAH including ventricular extension (1). Potential causes of hemorrhagic stroke included moyamoya (4), aneurysms (3), anticoagulation (1) and ateriovenous malformation (1). Four cases (21%) and no controls died during the initial hospitalization. More cases (82%) than controls (44%, P&lt;0.05) had elevated systolic blood pressure at the time of stroke. At steady-state, cases had lower hemoglobin (mean ± SEM 8.5 ± 0.6 g/dl vs. 9.7 ± 0.6 g/dl), lower blood pressures (systolic 121 ± 4 vs. 127 ± 6 mm Hg, diastolic 71 ± 4 vs. 72 ± 9 mm Hg) and higher platelet counts (399,231 ± 74,024/ul vs. 362,200/ul ± 39,927/ul) than controls, but these differences were not statistically significant. Mean hemoglobin concentration at the time of stroke increased 1.3 g/dl (19%) from steady-state in cases and 0.01 g/dl (2%) in controls (p&lt;0.05). Seven cases had simple transfusions (between 1 and 11 days before their primary hemorrhagic stroke) in preparation for surgery (3), and for aplastic crisis (1), bacteremia (1), acute renal failure (1), or suspected acute chest syndrome (1). Only 1 control was transfused; and 1 with HbSS had a hemoglobin of 14.5 g/dl at the time of stroke (from excessive erythropoietin administration). In this group of adults with SCD, primary hemorrhagic stroke was associated with antecedent transfusion. Identifiable causes include moyamoya from obstructive cerebral vasculopathy, aneurysms and other vascular malformations, and rarely coagulopathy. Mortality was similar to that previously described. The association of recent transfusion and cerebral vasculopathy with hemorrhagic stroke suggests caution in the use of simple transfusion in adults with SCD and moyamoya or cerebral aneurysms. Table 1: Associations with Primary Hemorrhagic Stroke Variable Odds Ratio (95% CI) P-value Genotype (HbSS vs. other) 3 (0.6 – 17) NS Moyamoya 5 (0.4 – 260) NS Transfusion in the last 14 days 13 (1.3 – 630) &lt;0.02 NSAID in the last 14 days 2.9 (0.3 – 36) NS


Blood ◽  
1996 ◽  
Vol 87 (6) ◽  
pp. 2573-2578 ◽  
Author(s):  
LA Styles ◽  
CG Schalkwijk ◽  
AJ Aarsman ◽  
EP Vichinsky ◽  
BH Lubin ◽  
...  

Acute chest syndrome (ACS) is associated with significant morbidity and is the leading cause of death in patients with sickle cell disease (SCD). Recent reports suggest that bone marrow fat embolism can be detected in many cases of severe ACS. Secretory phospholipase A2 (sPLA2) is an important inflammatory mediator and liberates free fatty acids, which are felt to be responsible for the acute lung injury of the fat embolism syndrome. We measured SPLA2 levels in 35 SCD patients during 20 admissions for ACS, 10 admissions for vaso-occlusive crisis, and during 12 clinic visits when patients were at the steady state. Eleven non-SCD patients with pneumonia were also evaluated. To determine if there was a relationship between sPLA2 and the severity of ACS we correlated SPLA2 levels with the clinical course of the patient. In comparison with normal controls (mean = 3.1 +/- 1.1 ng/mL), the non- SCD patients with pneumonia (mean = 68.6 +/- 82.9 ng/mL) and all three SCD patient groups had an elevation of SPLA2 (steady state mean = 10.0 +/- 8.4 ng/mL; vaso-occlusive crisis mean = 23.7 +/- 40.5 ng/mL; ACS mean = 336 +/- 209 ng/mL). In patients with ACS sPLA2 levels were 100- fold greater than normal control values, 35 times greater than values in SCD patients at baseline, and five times greater than non-SCD patients with pneumonia. The degree of SPLA2 elevation in ACS correlated with three different measures of clinical severity and, in patients followed sequentially, the rise in SPLA2 coincided with the onset of ACS. The dramatic elevation of SPLA2 in patients with ACS but not in patients with vaso-occlusive crisis or non-SCD patients with pneumonia and the correlation between levels of SPLA2 and clinical severity suggest a role for SPLA2 in the diagnosis and, perhaps, in the pathophysiology of patients with ACS.


Blood ◽  
1994 ◽  
Vol 84 (2) ◽  
pp. 643-649 ◽  
Author(s):  
O Castro ◽  
DJ Brambilla ◽  
B Thorington ◽  
CA Reindorf ◽  
RB Scott ◽  
...  

Abstract The acute chest syndrome (ACS), a pneumonia-like illness in sickle cell patients, is one of the most frequent causes of their morbidity and hospitalizations. Repeated ACS events may predict the development of chronic lung disease. ACS is reported as a frequent cause of death in these patients. We examine here the incidence and risk factors of ACS in 3,751 patients with sickle cell disease who were observed prospectively for at least 2 years (19,867 patient-years [pt-yrs]) as part of a multicenter national study group. The ACS, defined by a new pulmonary infiltrate on x-ray, occurred at least once in 1,085 patients (2,100 events). ACS incidence was higher in patients with homozygous sickle cell disease (SS; 12.8/100 pt-yrs) and in patients with sickle cell-beta(0) -thalassemic (9.4/100 pt-yrs), and lower in patients with hemoglobin (Hb) SC disease (5.2/100 pt-yrs) and patients with sickle cell-beta(+) thalassemia (3.9/100 pt-yrs). alpha-Thalassemia did not affect the rate of ACS incidence in SS patients. Within each Hb type the incidence was strongly but inversely related to age, being highest in children 2 to 4 years of age (25.3/100 pt-yrs in SS) and decreasing gradually to its lowest value in adults (8.8/100 pt-yrs in SS). In SS children (< 10 years of age), we documented an age-related within- person reduction in ACS attack rates. Adults with a higher ACS rate had a higher rate of mortality (from all causes) than those with low ACS rates. This increased rate of mortality might also have contributed to the decline in ACS rate with age. In multivariate analysis, other factors affecting incidence in SS patients were degree of anemia (lower ACS rates in patients with lower steady-state Hb levels) and fetal Hb (lower rates in patients with high fetal Hb). There was also a positive association between ACS rate and steady-state leukocyte count. The relationship of ACS rate to higher steady-state Hb levels in SS patients is unexplained but might be caused by increased blood viscosity.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3562-3562
Author(s):  
Patrick C. Hines ◽  
Ahmar Urooj Zaidi ◽  
Xiufeng Gao ◽  
Ke Liu ◽  
Muhammad O. Shareef ◽  
...  

Sickle cell disease (SCD) is a complex, multi-organ system condition characterized by frequent and unpredictable vaso-occlusive episodes (VOEs) and significant phenotypic variability. Red blood cell (RBC) adhesion contributes to vaso-occlusive pathology, thus we have developed and validated a standardized clinical whole blood flow adhesion assay to VCAM-1 (FA-WB-VCAM) to serve as a clinical biomarker of RBC health in sickle cell disease and other conditions1-4. Blood for the FA-WB-VCAM assay is drawn in sodium citrate tubes and can be stored at 4oC for up to 48hrs. Whole blood samples are perfused through VCAM-1-coated channels and adherent blood cells are quantified manually to generate a clinical adhesion index (cells/mm2). We previously reported longitudinal steady-state FA-WB-VCAM adhesion indices established from every 3 weeks blood sampling over 6 months (mean=368.3 ±198.4 cells/mm2, range=83.50 - 917.0), and the correlation of steady state adhesion indices to a lifetime historical SCD severity index (SCDI) (r=0.5851, p=0.0003) 5,6. The lifetime historical SCDSI was calculated by quantifying the total number of objectively, documentable, vaso-occlusive end-organ events (VEEs), including acute chest syndrome/pneumonia, stroke, priapism, splenic sequestration, hepatic sequestration, and cholelithiasis, indexed over the total years of life (# VEEs/age; range=0.0 to 0.38 in ELIPSIS). The objective of this study was to determine if the FA-WB-VCAM could predict clinical SCD severity prospectively using various metrics of disease severity, including the SCDI over a 2-year period post ELIPSIS. First, we classified study subjects as "severe" or "mild/moderate" adhesion phenotypes defined by mean steady state adhesion indices acquired from every 3 week sampling over 6 months of the ELIPSIS study (severe adhesion phenotype: &gt; 75th percentile, 455.9 cells/mm2; mild/moderate adhesion phenotype: &lt; 75thpercentile). VEEs were verified by retrospective review of medical records, and a SCDSI over the 2-year period following the ELIPSIS study was established. Our data show that individuals with severe adhesive SCD phenotypes experienced significantly more VEEs compared to individuals with low/moderate severe adhesive SCD phenotypes (mean=55.67 ±69.78 compared to mean=17.04 ±20.58 respectively; p=0.01). SCD patients with severe adhesive phenotypes also had more hospital admissions (mean=5.67 ±2.29 compared to mean=2.88 ±3.41, p=0.001), ER visits (mean=36.00 ±63.42 compared to mean=9.20 ±15.65, p=0.02), transfusions (mean=4.33 ±3.74 compared to mean=1.60 ±2.55, p=0.01), acute chest syndrome/pneumonia (mean=1.56 ±0.73 compared to mean=0.20 ±0.65, p&lt;0.001), and priapism (mean=2.56 ±5.57 compared to mean=0.00 ±0.00, p=0.003) when compared to low/moderate adhesive phenotypes. These data suggest that the FA-WB-VCAM assay may serve as a predictive biomarker for impending VEEs, and a monitoring biomarker to assess response to SCD-modifying therapies. Additional studies in a larger prospective cohort are required to definitively establish the clinical utility of the FA-WB-VCAM assay. Disclosures Hines: Functional Fluidics: Equity Ownership. Gao:Functional Fluidics: Equity Ownership. Liu:Functional Fluidics: Employment. White:Functional Fluidics: Equity Ownership.


Blood ◽  
1994 ◽  
Vol 84 (2) ◽  
pp. 643-649 ◽  
Author(s):  
O Castro ◽  
DJ Brambilla ◽  
B Thorington ◽  
CA Reindorf ◽  
RB Scott ◽  
...  

The acute chest syndrome (ACS), a pneumonia-like illness in sickle cell patients, is one of the most frequent causes of their morbidity and hospitalizations. Repeated ACS events may predict the development of chronic lung disease. ACS is reported as a frequent cause of death in these patients. We examine here the incidence and risk factors of ACS in 3,751 patients with sickle cell disease who were observed prospectively for at least 2 years (19,867 patient-years [pt-yrs]) as part of a multicenter national study group. The ACS, defined by a new pulmonary infiltrate on x-ray, occurred at least once in 1,085 patients (2,100 events). ACS incidence was higher in patients with homozygous sickle cell disease (SS; 12.8/100 pt-yrs) and in patients with sickle cell-beta(0) -thalassemic (9.4/100 pt-yrs), and lower in patients with hemoglobin (Hb) SC disease (5.2/100 pt-yrs) and patients with sickle cell-beta(+) thalassemia (3.9/100 pt-yrs). alpha-Thalassemia did not affect the rate of ACS incidence in SS patients. Within each Hb type the incidence was strongly but inversely related to age, being highest in children 2 to 4 years of age (25.3/100 pt-yrs in SS) and decreasing gradually to its lowest value in adults (8.8/100 pt-yrs in SS). In SS children (< 10 years of age), we documented an age-related within- person reduction in ACS attack rates. Adults with a higher ACS rate had a higher rate of mortality (from all causes) than those with low ACS rates. This increased rate of mortality might also have contributed to the decline in ACS rate with age. In multivariate analysis, other factors affecting incidence in SS patients were degree of anemia (lower ACS rates in patients with lower steady-state Hb levels) and fetal Hb (lower rates in patients with high fetal Hb). There was also a positive association between ACS rate and steady-state leukocyte count. The relationship of ACS rate to higher steady-state Hb levels in SS patients is unexplained but might be caused by increased blood viscosity.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3388-3388
Author(s):  
Andrew D. Campbell ◽  
Caterina Minniti ◽  
Craig Sable ◽  
Greg Ensing ◽  
Niti Dham ◽  
...  

Abstract Background: Echocardiography (ECHO)-determined tricuspid regurgitation jet velocity (TRV) ≥2.5 m/s occurs in about 30% of adults with sickle cell disease(SCD)and is associated with increased mortality. The frequency and significance of high TRV in children is not known. We determined the prevalence and risk factors of elevated estimated systolic pulmonary artery pressures in 228 patients with SCD and 39 controls. Methods: Patients with SCD (Hb SS, SC, SB thalassemia or other major sickling phenotypes) aged 3 to 20 years were evaluated clinically and with ECHO and six minute walk tests at their steady state. Healthy, non-SCD controls, matched for ethnicity, sex and age, were also evaluated. Results: A comparison of patients and controls is summarized in Table 1. 184 patients (81%) had hemoglobin SS phenotype and 28 (12%) had hemoglobin SC. TRV was measurable in 214 (94%) of the patients and 34 (87%) of the controls. In a multivariate logistic regression model, each 10 mm Hg increase in systolic blood pressure was associated with an estimated 2.0-fold increase in the odds of TRV≥2.5 m/sec (P = 0.002) and a 10-fold increase in LDH with a 25-fold increase in the odds (P = 0.015). Conclusion: This study of children with SCD who have limited iron overload and limited renal dysfunction compared with the aging SCD population provides a unique window into the early pathogenesis of PH in SCD. TRV and LVMI are significantly higher in children and adolescents with SCD at steady state than age-matched control participants. Among children with SCD, TRV elevation is independently associated with systolic BP and LDH concentration. In this analysis we find a strong association with hemolysis and systemic hypertension and surprisingly no associations with vaso-occlusive events or biomarkers (VOC, ACS, HU use, WBC and platelet counts). Table I. Comparison of SCD and control subjects. Results in mean (SD) unless otherwise stated. SCD(n=228) Control (n=39) p Age in years 12 (5) 12 (5) 0.7 Female (%) 48% 46% 0.8 Systolic BP (mm Hg) 112 (11) 116 (15) 0.1 Diastolic BP (mm Hg) 64 (9) 68 (10) 0.040 Six minute walk in meters 454 (76) 498 (84) 0.006 TRV in m/sec 2.3 (0.3) 2.1 (0.3) 0.003 TRV 2.5 m/sec (%) 21% 3% 0.012 LV intern. diastolic diam Z-score 1.2(1.4) −0.3(1.2) <0.001 LV mass index 88 (25) 59 (13) <0.001 Table II. Comparison of SCD patients according to TRV category. Results in mean (SD) unless otherwise stated. Variables TRV <2.5 (n= 169) TRV ≥2.5 (n=45) p History of acute chest syndrome (%) 20% 40% 0.034 Hydroxyurea therapy 42% 44% 0.8 Hemoglobin in g/dl 9.3 (1.8) 8.9 (1.7) 0.071 LDH in U/L 393 (163) 474 (170) 0.009 Total Bilirubin in mg/dL 2.7 (1.9) 3.8 (2.2) 0.004


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2235-2235 ◽  
Author(s):  
Olufolake Adisa ◽  
Benjamin Yaw Owusu ◽  
Yijuan Hu ◽  
Samit Ghosh ◽  
Fang Tan ◽  
...  

Abstract Inflammation is a cardinal component of the pathogenesis of sickle cell disease (SCD). Increased plasma concentration of the inflammatory agonist hemin increases the odds of acute chest syndrome (ACS) in children with SCD (Adisa et al., Br. J Haematol, 2013). In addition, free hemin promotes the development of a lethal ACS-like disease in transgenic sickle mice (Ghosh et al., J Clin Invest, 2013). Hemin degradation is controlled by the rate-limiting enzyme heme oxygenase-1 (HO-1). Polymorphism of a (GT)n dinucleotide repeat in the HO-1 promoter, which enhances expression of the gene, is associated with lower rates of hospitalization for ACS in children. Over-expression of HO-1 reduces stasis in a mouse model of SCD vaso-occlusion. However, the role of plasma HO-1 in SCD patients is entirely unknown. In this study, we measured steady-state plasma HO-1 in two cohorts of patients. Cohort 1 in Atlanta (n=98) consisted of children with a mean age of 10.07±0.42 years (range 2-19 years) and cohort 2 from Accra (n=80) consisted of older patients (mean age 25.30±1.0 years, range 13-58 years). The mean plasma HO-1 of both cohorts was significantly higher compared to the mean value of age- and ethnic-matched individuals with normal adult Hb; Atlanta: 10.19±5.80 vs. 2.08± 1.16, p<0.0001 and Accra: 13.7±8.14 vs. 2.57± 0.82, p<0.0001. Plasma HO-1 varied by 25-fold in both cohorts and it correlated with the white blood cell count (Atlanta: r=0.3361, p<0.0001, Accra: r=0.25, p=0.02). Fifty-four percent (n=53) of subjects in the Atlanta cohort were on hydroxyurea. The mean plasma HO-1 of this subgroup was lower (8.1 ± 4.5) compared to the hydroxyurea naïve Accra cohort (p=<0.0001). Further studies of the Accra cohort revealed significant correlations between HO-1 and multiple markers of vascular inflammation; sICAM-1(r=0.2794, p=0.03, n=60), sE-selectin (r= 0.4209, p=0.0017, n=58) and sP-selectin (r=0.3855, p=0.0028, n=58). The number of the (GT)n dinucleotide in the HO-1 promoter ranged 17 to 45; the distribution was trimodal with peaks at 23, 30 and 41 repeats. The overwhelming majority of patients had medium and large size alleles that are generally hypo-response to induction. Plasma HO-1 level correlated with the length of the (GT)n dinucleotide repeat (p=0.003, n=80). In a multivariable regression model, WBC, sICAM-1, sE-selectin and sP-selectin accounted for 13.4% of the total variance of plasma HO-1 level, and the (GT)n polymorphism accounted for 9.8%. In conclusion, the concentration of plasma HO-1 is generally raised among SCD patients at steady-state. However, a large proportion of patients have a relatively modest level that is probably inadequate to counter the severity of inflammation typical of SCD, due in part to a hypo-responsive HO-1 promoter. Therapeutic strategies that complement induction of the endogenous HO-1 gene may be critical to ameliorate inflammation in SCD. Disclosures: No relevant conflicts of interest to declare.


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