Report on the International Co-Operative Study of the Effects of L-Selectin Gene Polymorphisms on the Development of Complications in Sickle Cell Disease.

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>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>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>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>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.

Author(s):  
Mohamed Almuqamam ◽  
◽  
Swetha Madhavarapu ◽  
Nataly Apollonsky ◽  
◽  
...  

Sickle Cell Disease (SCD) is an inherited hemoglobinopathy, which results in production of abnormal hemoglobin S. HbSC disease is a variant of SCD, which shares a similar clinical complication profile to HbSS disease, but often thought to be a milder condition. In patients with SCD, Hb S in deoxygenated state undergoes polymerization, leading to hemolysis, vaso-occlusive events, and eventually end-organ damage. Among other complications in patients with SCD is increased risk of complications caused by parvovirus B19. We present a case of a 14-year-old female with HbSC disease who presented to the emergency room with complaint of abdominal pain and found to have splenic sequestration. Splenic sequestration progressed rapidly, Hemoglobin (hb) dropped to 4.6 g/dl and acute chest syndrome (ACS) developed. She was treated following the ACS protocol, received 4 units of Packed Red Blood Cells (PRBC) and subsequently underwent a single volume PRBC exchange transfusion. Considering her unusual presentation, with severe ARDS from alveolar hemorrhage requiring mechanical ventilation and multi-organ injury, several autoimmune and infectious conditions with a cytokine storm component including COVID-19 disease, were considered. Results of viral testing revealed parvovirus B19 IgM antibodies signifying an acute infection. She fully recovered with supportive care and was discharged home. Multisystem involvement simulating connective tissue disorders or malignancies with acute parvovirus B19 infection has been reported and is considered extremely rare. To our knowledge, there were no reports of pediatric patients with SC disease presenting with splenic sequestration and ACS in the setting of parvovirus B19 multisystem disease. Keywords: sickle cell disease; acute respiratory distress syndrome; acute chest syndrome; parvovirus B19.


2021 ◽  
Vol 11 (9) ◽  
pp. 870
Author(s):  
Pia Proske ◽  
Laura Distelmaier ◽  
Carmen Aramayo-Singelmann ◽  
Nikolaos Koliastas ◽  
Antonella Iannaccone ◽  
...  

Background: This monocentric study conducted at the University Hospital of Essen aims to describe maternal and fetal/neonatal outcomes in sickle cell disease (SCD) documented between 1996 to 2021 (N = 53), reflecting the largest monocentric analysis carried out in Germany. Methods/Results: 46 pregnancies in 22 patients were followed. None of the patients died. In total, 35% (11/31) of pregnancies were preterm. 15 pregnancies in eight patients were conceived on hydroxycarbamide (HC), of which nine had a successful outcome and three were terminated prematurely. There was no difference regarding the rate of spontaneous abortions in patients receiving HC compared to HC-naive patients prior to conception. In patients other than HbS/C disease, pregnancies were complicated by vaso-occlusive crises (VOCs)/acute pain crises (APCs) (96%, 23/24); acute chest syndrome (ACS) (13%, 3/24), transfusion demand (79%, 19/24), urinary tract infections (UTIs) (42%, 10/24) and thromboembolic events (8%, 2/24). In HbS/C patients complications included: VOCs/APCs (43%, 3/7; ACS: 14%, 1/7), transfusion demand (14%, 1/7), and UTIs (14%, 1/7). Independent of preterm deliveries, a significant difference with respect to neonatal growth in favor of neonates from HbS/C mothers was observed. Conclusion: Our data support the results of previous studies, highlighting the high rate of maternal and fetal/neonatal complications in pregnant SCD patients.


2019 ◽  
Vol 8 (11) ◽  
pp. 1839
Author(s):  
Madhi ◽  
Kamdem ◽  
Jung ◽  
Carlier-Gonod ◽  
Biscardi ◽  
...  

This prospective observational study sought to ascertain clinical and laboratory parameters associated with the development of acute chest syndrome (ACS) during vaso-occlusive episodes (VOE) in children with sickle cell disease (SCD). It was performed at the pediatric department of the university Intercommunal Créteil hospital. All children with SCD (all sickle genotypes) consecutively admitted from November 2013 to December 2016 for painful VOEs and no evidence of ACS were included. Clinical and laboratory parameters collected at admission and within 48 h after admission were compared for children in whom ACS developed or not. Variables that were statistically significant on univariate analysis or considered to be clinically relevant were included in a multivariable model to ascertain the risk factors associated with the development of ACS during a VOE. The variables retained in the multivariate model were used to construct a predictive score for ACS. For each included child and during the study period, only data from the first VOE and/or the first ACS were analyzed. Among 191 hospitalizations for painful VOEs, for 176 children with SCD, ACS developed in 35 during hospitalization. Mean hospital stay was longer for children with ACS versus VOEs alone (7.6 (±2.3) vs. 3.3 (±1.8) days, p < 0.0001), and all children with ACS versus 28/156 (17.9%) with VOEs alone received red blood cell transfusion (p < 0.0001). The multivariate model retained pain score (≥9/10), pain localization (abdominal or spinal pain or involving more than two limbs), and high reticulocyte (≥260 × 109/L) and neutrophil (>10 × 109/L) counts, at admission, as independently associated with ACS development. The area under the receiver operating characteristic curve for the ACS predictive score was 0.82 (95% CI: 0.74–0.89), and the negative predictive value was 97.7%. The evolution profiles during the first 48 h differed between children with ACS and VOEs alone, with a more rapid decline of pain score and leucocytosis in children with VOEs. Clinical and laboratory measurements at admission may be simple parameters to identify children with increased risk of ACS development during VOEs and to facilitate early diagnosis of this respiratory complication. Also, the persistent elevation of leukocyte count on day 2 may be considered a sign of evolving ACS.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1540-1540 ◽  
Author(s):  
Latorya A Barber ◽  
Allison E Ashley-Koch ◽  
Melanie E. Garrett ◽  
Karen L Soldano ◽  
Marilyn J. Telen

Abstract Abstract 1540 Poster Board I-563 Tumor necrosis factor alpha (TNFα) is a pro-inflammatory cytokine that stimulates phagocytosis, neutrophil recruitment, and expression of adhesion molecule VCAM-1. Plasma levels of TNFα have been found to be increased in sickle cell disease (SCD), and in vitro studies show that TNFα causes increased adherence of sickle red blood cells to human umbilical vein endothelial cells. A polymorphism in the promoter region of the TNFα gene has previously been associated with stroke in children with SCD (Hoppe et al., 2007). The current study was designed to identify associations of additional TNFα single nucleotide polymorphisms (SNPs) with SCD clinical complications. We analyzed five SNPs in the TNFα gene in 509 DNA samples of SCD patients from Duke University, University of North Carolina at Chapel Hill, and Emory University. In our data set, cerebrovascular events (CVEs), including overt stroke, seizures, and transient ischemic attacks, occurred in 133 out of 509 SCD patients (26.1%). SNP genotyping was performed using Taqman genotyping assays from Applied Biosystems. Due to low minor allele frequencies (<0.05) for all the SNPs examined, genetic associations with SCD clinical complications were examined by using allele tests. After controlling for age, gender, and use of hydroxyurea, two of the five TNFα SNPs, rs2228088 and rs3093665, were significantly associated with CVEs (p=0.013 and 0.029, respectively). The odds that SCD patients with a G allele at rs2228088 suffered from CVEs were 0.485 times that for patients with the T allele, suggesting that the G allele had a protective effect. The odds of having the A allele at rs3093665 and suffering from CVEs was also reduced, at 0.45 compared to the C allele. Neither SNP was found to be in linkage disequilibrium (LD) with any of the other SNPs analyzed (r2≤0.002). There was also strong association of SNP rs2228088 with acute chest syndrome (ACS; p=0.003), occurring in 382 out of 509 SCD patients (75%). However, in this analysis, the G allele was associated with increased risk for ACS (OR=2.313). In addition to the association with CVEs, the SNP rs3093665 was also significantly associated with priapism (p=0.03), reported by 86 of 223 male SCD patients (38.6%). In this analysis, the A allele was protective, as had been observed for CVE (OR=0.188). Additionally, we found no difference in steady state plasma TNFα levels between genotypes for the two SNPs. The functional significance of these SNPs is presently unknown. SNP rs2228088 is a synonymous SNP located in the coding region, and rs3093665 is located in the 3' untranslated region of the TNFα gene. While the G to T change at SNP rs2228088 does not translate to a change in amino acid sequence, the A to C change at SNP rs3093665 may affect mRNA stability due to its location. It is also possible that one or both of these SNPs is in LD with another functionally relevant SNP. Our findings thus support previous data implicating TNFα polymorphisms in risk for central nervous system events. Interestingly, ACS has been previously associated with seizures, stroke and altered mental status in adults and children with SCD (Vinchinsky et al., 2000) and with silent cerebral infarcts and reversible posterior leukoencephalopathy syndrome in children with SCD (Henderson et al., 2003). However, in our dataset, ACS and the occurrence of CVEs were not associated (p=0.24). Further studies are required to elucidate these and other factors that potentially correlate with SCD clinical complications. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4799-4799
Author(s):  
Angela Zanette ◽  
Karla O. Mota ◽  
Marilda Souza Goncalves ◽  
Laise Vilasboas Schettini ◽  
Lais Magalhaes Aguiar ◽  
...  

Abstract Introduction: The hemoglobinopathies are the most common monogenic disorders known. A mutation in the gene for β globin gave origin to hemoglobin S, an abnormal hemoglobin originated in Africa. Sickle cell disease (SCD) is characterized by the presence of hemoglobin S, which results in vasoocclusion episodes and hemolytic anemia throughout patients life. Vascular occlusion leads to acute events and progressive disabling organ damage. Sickle cell anemia is the homozygous state SS, while hemoglobinopathy SC is a doubly heterozygous state, where hemoglobin S occurs in combination with hemoglobin C. Brazil has a prominent African ancestry and SCD is highly prevalent in some regions of the country. In Bahia State, for example, neonatal screening data have shown that, from every 650 children born alive, one has SCD, mostly homozygous SS. Among other therapeutic measures, packed red blood cells (RBC) play a prominent role in SCD management. In situations such as acute chest syndrome (ACS), primary and secondary prevention of stroke, splenic or hepatic sequestration crisis, severe anemia, complicated pregnancy, isquemic organ damages and others, the transfusions may save lives. Although RBC may contribute to reduce morbidity and improve quality of life in SCD patients, there still are risks. Among other risk categories, alloimmunization may result from transfusions and occurs in 5 % to 50 % of SCD patients. It is still not known whether allosensibilization significantly affects the clinical outcomes in SCD. Objecive: The purpose of this study was to compare the clinical profile of multitransfused adult SCD patients who developed alloantibodies (ALO) to patients with the same disease, coming from the same population who did not become alloimmunized (non-ALO). Methods: This is a cross sectional study where medical records of SCD patients, referred to a reference center of Salvador, the capital of Bahia State, Brazil, were reviewed. Only SCD patients 18 years of age or older were included. They had received at least 3 RBC transfusions from 2004 to 2007, or had any alloantibody identified during this period. Patient characteristics, clinical findings, number of transfusions, frequency and specificity of alloantibodies, laboratory data, and the main clinical outcomes were reviewed. Results: a hundred and eight patients were included: 105 SS and 3 SC. The pre-transfusional RBC matching was done to ABH, D,C,c,E,e and Kell antigens. 56 patients developed alloantibodies (53 SS and 3 SC). Anti-E, anti-K, and anti-C were the most prevalent alloantibodies identified (39,3 %, 21,4 % and 16,1 %, respectively). Among the variables addressed in this study, age (higher in non-ALO, .041) and antiglobulin test positivity, more prevalente in ALO (.0001), depicted statistically significant difference. A few patients developed immune hemolysis, controlled successfully with corticosteroids. Alloimmunization was more prevalent among women, although no statistically significant difference was reached between ALO and non-ALO Other variables such as number of transfusions, hematological profile, biochemical data and complications such as stroke, leg ulcers, osteonecrosis, renal disease, abnormal cardiac features, and pulmonary hypertension did not show significant difference between both groups. Conclusion: his study shows that, although alloimmunization is a potential dangerous consequence of RBC transfusions, it did not modify the clinical profile of SCD alloimmunized patients. The concomitance of allosensibilization and autoantibodies in SCD leads to additional difficulties in the RBC matching for transfusion and may exacerbate hemolysis. In order to address autoimmunity in SCD, prospective studies with larger samples are needed.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 573-573 ◽  
Author(s):  
Claudia R. Morris ◽  
Michael Ansari ◽  
Lisa Lavrisha ◽  
Nancy Sweeters ◽  
Frans A Kuypers ◽  
...  

Abstract Abstract 573 BACKGROUND: Vaso-occlusion is the principal factor in the morbidity of sickle cell disease (SCD). Vaso-occlusive painful episodes (VOE) are common, debilitating, and the leading cause of hospitalizations, emergency room visits, and are associated with an increased mortality rate. There is no effective therapy that targets the underlying mechanisms of VOE. Symptomatic relief with analgesics is the only availabel treatment. Nitric oxide (NO) is a potent vasodilator that contributes to a variety of vaso-occlusive events in SCD. We have found that an arginine deficiency and low NO bioavailability occurs during VOE in SCD. Since arginine is the obligate substrate for NO production, and an acute deficiency is associated with VOE, we hypothesized that arginine supplementation may be a safe and beneficial treatment for sickle cell pain. PATIENTS AND METHODS: Hospitalized SCD patients > 3 years diagnosed within 24 hours with VOE and without associated complications were eligible; written informed consent was obtained. A total of 56 patients completed randomization in this double-blinded, placebo controlled trial. A standardized treatment and monitoring program for VOE was followed. Average age was 13.9 ± 4 years (range 3.6-19 years), and 52% were female. Patients received intravenous (IV) or oral arginine (0.1 gram/kg TID, n=28) or placebo (n=28) for 5 days or until discharge from the hospital. Narcotic records for 2 patients (randomized to placebo arm) were incomplete and were not included in the narcotic use analysis. An intention to treat analysis was performed for narcotic use applying an unpaired t-test with Welch's correction to adjust for unequal variance. RESULTS: Age was equally distributed between treatment and placebo groups. 57% of the arginine treatment group and 46% of the placebo group were female. A significant reduction in narcotic use (defined as total morphine use over the course of the hospital stay in mg/kg) by 56% was observed in the treatment arm receiving IV or oral arginine compared to placebo (mean ± SEM: 1.8 ± 0.4 mg/kg; n=28 vs. 4.1 ± 0.8mg/kg; n=26, p=0.01). Average length of hospitalization was 4.5 ± 0.4 days, and there was no significant difference between the 2 groups (4.1 ± 0.3 vs. 4.8 ± 0.5 days, p = 0.27; arginine vs. placebo arm). Four episodes of acute chest syndrome (ACS) developed during the study, three in the treatment arm and one in the placebo arm. There was one patient who experienced clinical deterioration associated with ACS requiring emergent transfusion and a transfer to the pediatric intensive care unit (PICU) in the placebo arm. No clinical deterioration or PICU transfers occurred in the arginine arm. Five in the treatment arm received transfusion vs. four in the placebo arm. No drug-related adverse events were observed. No significant differences were observed between pre and post therapy liver or renal function, or hematological parameters in the arginine treatment group vs. placebo. Two patients admitted for pain management ultimately did not receive IV narcotics. Both had been randomized into the arginine-treatment arm and received arginine therapy per protocol throughout their hospital stay and required only oral narcotics and non-steroidal analgesia. Reduction in narcotic use in the treatment arm remained significant even when these 2 patients were excluded from the analysis (p=0.02). CONCLUSIONS: IV arginine therapy represents a novel nutritional intervention for the treatment of pain in hospitalized patients with SCD. Use of IV arginine should also be considered in the treatment of VOE in the emergency department setting prior to hospitalization, although further investigation is warranted. A reduction of narcotic use by over 50% observed in this study is remarkable, as this is the first successful intervention for sickle cell-related pain that targets the underlying mechanism of vaso-occlusion through a promising NO-based therapy. Arginine is a safe and inexpensive intervention with narcotic-sparing effects that should be considered as an adjunct to standard therapy for VOE requiring hospitalization. Disclosures: Off Label Use: Arginine for treatment of sickle cell vaso-occlusive pain episodes.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4767-4767
Author(s):  
Giovanna Graziadei ◽  
Alessia Marcon ◽  
Martina Soldarini ◽  
Ilaria Gandolfi ◽  
Luisa Ronzoni ◽  
...  

Abstract Abstract 4767 Background. Sickle-Cell Disease (SCD) is one of the most common severe monogenic inherited disorders worldwide, due to hemoglobin S (HbS), with reduced affinity for the oxygen. HbS polymerization, leading to erythrocyte rigidity, vaso-occlusion and hemolytic anemia, is central in the pathophysiology and crucial for the clinical outcome. The term SCD refers to Sickle Cell Anemia (SCA) due to homozygosis for βS allele, HbS/β-thalassemia (T-SCD) due to compound of β-thal and βS allele, and HbSC disease, owing to the coinheritance of βS and βcalleles. SCD is a multiorgan disease characterized by recurrent acute events and progressive organ damage, worsening during the life. Aims. This is a retrospective monocentric study aimed to assess and compare the clinical complications among 59 adult SCD patients, followed at the Hereditary Anemia Centre of the Foundation IRCCS “Ca Granda” Ospedale Maggiore Policlinico, in Milan, Italy. Methods. Mutation analysis of the b globin gene was established by direct DNA sequencing on the ABI Prism 310 genetic analyzer. Clinical and hematological features were evaluated by routine tests and physical examination, with special attention to the erythropoiesis stress parameters as LDH values and extramedullary erythropoietic (EE) masses. Results. Fifty-nine adult SCD patients, 16 SCA and 43 T-SCD, were evaluated. In T-SCD patients detected b-mutations were severe (b°) in 69.8%, and moderate or mild (b+-b++) in 30.2%. The mean age of SCA patients was 36±9 and 41±11 years for T-SCD patients. For both groups the mean follow-up was 20±6 years, while the mean age at the presentation in our Centre was 32±8 years in SCA patients and 31±10 years in T-SCD ones. Five out of 16 (31.2%) SCA patients and 16/43 (37.2%) T-SCD patients were male. HbF mean levels were 6.9±5.1% and 10.1±7.2%, respectively in SCA and T-SCD group; surprisingly Hb mean levels were lower in SCA (9.3±1.3 g/dl) than in T-SCD (9.9±1.4 g/dl) patients. Comparing SCA and T-SCD, there was statistically significant difference in splenic features: splenectomy was performed in 2/16 (12.5%) SCA patients vs 21/43 (48.8%) T-SCD patients (p-value < 0.01). Splenomegaly was absent in SCA, while was detected in 11/22 (50%) T-SCD (p-value < 0.0001); all SCA patients had functional asplenia, not observed in T-SCD patients; splenic infarctions were absent in SCA patients and were detected in 7/22 (31.8%) T-SCD patients, of whom 5 had splenomegaly and 2 had normal spleen size (pvalue <0.001). On the other side, there was not statistically significant difference in the prevalence of stroke, acute chest syndrome (ACS), bone pain crisis, sepsis, leg ulcers and priapism. However, we observed some clinical differences, even if not statistically significant. Cholecistectomy was performed in 4/16 (25%) SCA patients vs 17/43 (39.5%) T-SCD patients, and gallstones were detected respectively in 5/12 (41.7%) and in 14/26 (53.8%) of SCA and T-SCD patients. Thrombotic events were absent in SCA patients, compared to 4/43 (9.3%) T-SCD patients. Furthermore, we detected EE in 3/16 (18.6%) SCA and in 3/43 (7%) T-SCD, all carrying b° thal mutations. We underlie that Hb levels and LDH values were higher in SCA than in T-SCD patients (823±295 vs 689±209 U/L). About the treatment, 14/16 (87.5%) SCA and 31/43 (72%) T-SCD underwent to top-up transfusion; 5/43 (11.6%) T-SCD were regularly transfused. Seven out of 16 (43.8%) SCA and 18/43 (41.8%) T-SCD patients were treated with Hydroxycarbamide (HU). Criteria for transfusion therapy were: painful crisis not responsive to HU, major clinical complications, such as stroke or ACS, extramedullary erythropoietic masses associated with high LDH levels and low Hb values. Conclusions. These data suggest that SCA and T-SCD patients have similar clinical course. Splenomegaly is present only in T-SCD patients, probably due to the increased amount of extravascular hemolysis. Surprisingly, SCA patients showed EE and lower Hb levels with higher LDH values compared to T-SCD ones. This could be related to the prevalence of intravascular hemolysis, that can lead to erythropoietic stress in SCA, even if tissues are better oxygenated in these patients because of biochemical characteristic of HbS in terms of decreased oxygen affinity. These observations could be important to evaluate transfusion and HU treatment. Disclosures: Cappellini: Novartis: Research Funding.


Blood ◽  
2001 ◽  
Vol 97 (11) ◽  
pp. 3628-3632 ◽  
Author(s):  
Alina Ferster ◽  
Parvine Tahriri ◽  
Christiane Vermylen ◽  
Geneviève Sturbois ◽  
Francis Corazza ◽  
...  

The short-term beneficial effect of hydroxyurea (HU) in sickle cell disease (SCD) has been proven by randomized studies in children and adults. The Belgian registry of HU-treated SCD patients was created to evaluate its long-term efficacy and toxicity. The median follow-up of the 93 patients registered is 3.5 years; clinical and laboratory data have been obtained for 82 patients at 1 year, 61 at 2 years, 44 at 3 years, 33 at 4 years, and 22 after 5 years. On HU, the number of hospitalizations and days hospitalized dropped significantly. Analysis of the 22 patients with a minimum of 5 years of follow-up confirm a significant difference in the number of hospitalizations (P = .0002) and days in the hospital (P &lt; .01), throughout the treatment when compared to prior to HU therapy. The probabilities of not experiencing any event or any vaso-occlusive crisis requiring hospitalization during the 5 years of treatment were, respectively, 47% and 55%. On HU, the rate per 100 patient-years of severe events was estimated to be 3.5% for acute chest syndrome, 1.2% for aplastic crisis, 0.4% for splenic sequestration; it was 0% for the 9 patients with a history of stroke or transient ischemic attack followed for an average of 4 years. No important adverse effect occurred. Long-term chronic treatment with HU for patients with SCD appears feasible, effective, and devoid of any major toxicity; in patients with a history of stroke, HU may be a valid alternative to chronic transfusion support.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1063-1063 ◽  
Author(s):  
Xu Zhang ◽  
Wei Zhang ◽  
Santosh L. Saraf ◽  
Sergei Nekhai ◽  
Mark T Gladwin ◽  
...  

Abstract In sickle cell disease (SCD) polymerization of hemoglobin S under deoxygenated conditions causes vaso-occlusion, which can manifest as acute pain crisis and progressive bone/organ damage. Molecular studies have attributed vaso-occlusion to elevated vascular adhesion and inflammatory responses, whereas the genetic regulation has only recently been assessed. Genomic DNA isolated from peripheral blood mononuclear cells (PBMCs) was hybridized to Illumina Human 610-Quad SNP array for the PUSH and Walk-PHaSST cohorts and to Affrymetrix SNP 6.0 array for the Howard SCD expression cohort. Single nucleotide polymorphisms (SNPs) for 381 PUSH, 525 Walk-PHaSST, and 55 Howard patients were imputed to 1000 genomes project phase 3 data. Messenger RNA from PBMCs was profiled using Affymetrix Human Exon 1.0 ST Array for the Howard expression cohort and Affymetrix Human gene 2.0 ST array for the UIC expression cohort. Patients within the PUSH and Walk-PHaSST cohorts were classified to four groups according to a cumulative pain score, calculated based on pain frequency and questionnaire description of pain intensity. Pain grouping was examined for correlation with other SCD complications using Cochran Armitage test. History of acute chest syndrome (ACS, PUSH P=3.8×10-9, Walk-PHaSST P=2.4×10-5) and avascular necrosis (AVN, PUSH P=4.1×10-4, Walk-PHaSST P=3.7×10-5) were the most significant clinical manifestations that consistently associated with pain in the two cohorts. To investigate the genetic control of vaso-occlusive manifestations with appropriate power, we leveraged genetic association of pain, ACS, and AVN with genetic regulation of disease-specific gene expression. We mapped expression quantitative trait loci (eQTL) in the Howard expression cohort for SNPs<1 Mb away from gene ends per expression trait. At a permutation based false discovery rate of 5%, 1004 independent eQTL (linkage disequilibrium r2 ≤0.3 per trait) were identified for 880 genes. Focusing on 129 genes whose expression was altered in PBMCs in sickle cell anemia by at least 1.5-fold [1], we identified six eQTL for five differential genes (up-regulated: OSBP2, SLC14A1, RNF182, CCRL2; down-regulated: S100B). The six eQTL were assessed for association with pain, ACS, and AVN, using the Walk-PHaSST cohort for discovery and the PUSH cohort for validation. At a significance of Bonferroni corrected P=0.05 (nominal P=0.0083), an eQTL of S100B (rs2154586) significantly associated with AVN in the Walk-PHaSST cohort (OR=1.8, P=0.00061) and the association was replicated in the PUSH cohort (OR=2.7, P=0.0052). The A allele of the eQTL (frequency=0.18) associated with increased risk for AVN and increased expression level of S100B in the Howard expression cohort (β=0.40, P=1.6 ×10-6). In an additional 64 sickle cell anemia patients without hydroxyurea treatment from the UIC expression cohort, expression levels of S100B were significantly elevated in the individuals with AVN (β=0.28, P=0.029). The 24 SNPs in linkage disequilibrium with the eQTL (r2 >0.7) constituted the third most significant peak in a meta-analysis of genome-wide association of AVN in the PUSH and Walk-PHaSST cohorts. To test the hypothesis that genes involved in vaso-occlusion in SCD may affect thrombotic risk in non SCD individuals, we examined the association of the locus with venous thromboembolism (VTE) in the ARIC, JHS and CHS cohorts from dbGaP. The locus was imputed in African Americans and VTE was defined as being told by a doctor to have a blood clot in the leg or lung as answered in questionnaires during medical exams. The SNPs were associated with VTE using logistic linear regression adjusting for age, gender, enrollment site, and the first 15 principal components per cohort. The risk allele of the leading SNP for AVN consistently associated with increased risk of VTE across the cohorts, with a combined P=0.0041 and OR=1.4. S100B encodes a calcium sensor that appears to intervene in a variety of biological functions. S100B can mediate the inflammatory effects of damage-associated molecular pattern molecules (DAMPs) produced by erythrocyte hemolysis [2, 3]. Serum concentration of S100B correlates with LDH and with TCD-determined peak velocity of the left middle cerebral artery in thalassemia patients[4]. Polymorphisms of S100B that lead to increased serum levels are associated with increased risk of ischemic stroke in the Chinese population[5]. Disclosures Nekhai: NIMHD, NIH: Research Funding; NHLBI, NIH: Research Funding; NIAID, NIH: Research Funding.


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