Hypoxic storage of donor red cells preserves deformability after exposure to plasma from adults with sickle cell disease.

BACKGROUND: Red cell (RBC) transfusions are beneficial for patients with sickle cell disease (SCD), but ex vivo studies suggest that inflamed plasma from patients with SCD during crises may damage these RBCs, diminishing their potential efficacy. The hypoxic storage of RBCs may improve transfusion efficacy by minimizing the storage lesion. We tested the hypotheses that (1) The donor RBCs exposed to the plasma of patients in crisis would have lower deformability and higher hemolysis than those exposed to non-crisis plasma, and (2) hypoxic storage, compared to standard storage, of donor RBCs could preserve deformability and reduce hemolysis. STUDY DESIGN AND METHODS: 18 SCD plasma samples from patients who had severe acute-phase symptoms (A-plasma; n = 9) or were at a steady-state (S = plasma; n = 9) were incubated with 16 RBC samples from eight units that were stored either under conventional(CRBC) or hypoxic(HRBC) conditions. Hemolysis and microcapillary deformability assays of these RBCs were analyzed using linear mixed-effect models after each sample was incubated in patient plasma overnight at 37°C RESULTS: Relative deformability was 0.036 higher (p < 0.0001) in HRBC pairs compared to CRBC pairs regardless of plasma type. Mean donor RBC hemolysis was 0.33% higher after incubation with A-plasma compared to S-plasma either with HRBC or CRBC (p = 0.04). HRBCs incubated with steady-state patient plasma demonstrated the highest deformability and lowest hemolysis. CONCLUSION: Hypoxic storage significantly influenced RBC deformability. Patient condition significantly influenced post-incubation hemolysis. Together, HRBCs in steady-state plasma maximized donor red cell ex vivo function and survival.

Branching out: redox strategies towards the synthesis of acyclic α-tertiary ethers.

Acyclic α-tertiary ethers represent a highly prevalent functionality, common to high-value bioactive molecules, such as pharmaceuticals and natural products, and feature as crucial synthetic handles in their construction. As such their synthesis has become an ever-more important goal in synthetic chemistry as the drawbacks of traditional strong base- and acid-mediated etherifications have become more limiting. In recent years, the generation of highly reactive intermediates via redox approaches has facilitated the synthesis of highly sterically-encumbered ethers and accordingly these strategies have been widely applied in α-tertiary ether synthesis. This review summarises and appraises the state-of-the-art in the application of redox strategies enabling acyclic α-tertiary ether synthesis.

Fostamatinib for the treatment of warm antibody autoimmune hemolytic anemia: Phase 2, multicenter, open-label study.

Patients with relapsed warm antibody autoimmune hemolytic anemia (wAIHA) have limited treatment options. Fostamatinib is a potent, orally administered spleen tyrosine kinase inhibitor approved in the United States and Europe for the treatment of adults with chronic immune thrombocytopenia (ITP). This phase 2 study evaluated the response to fostamatinib, administered at 150 mg BID orally with or without food in adults with wAIHA and active hemolysis with hemoglobin (Hgb) <10 g/dL who had failed at least one prior treatment. Hemoglobin levels and safety assessments were performed at visits every 2 weeks. The primary endpoint was Hgb >10 g/dL with an increase of ≥2 g/dL from baseline by week 24 without rescue therapy or red blood cell transfusion. Eleven of 24 (46%) patients achieved the primary endpoint. Increases in median Hgb were detected at week 2 and sustained over time. Median lactate dehydrogenase levels and reticulocyte counts generally declined over time with little change in median haptoglobin levels. The most common adverse events (AEs) were diarrhea (42%), fatigue (42%), hypertension (27%), dizziness (27%), and insomnia (23%). AEs were manageable and consistent with the fostamatinib safety database of over 3900 patients across multiple diseases (rheumatoid arthritis, B-cell lymphoma, COVID-19, and ITP). No new safety signals were detected. Fostamatinib may be a promising therapeutic option for wAIHA. A randomized, double-blind, phase 3 study is nearing completion.

Treatment of Acute Pain in Adults With Sickle Cell Disease in an Infusion Center Versus the Emergency Department : A Multicenter Prospective Cohort Study.

BACKGROUND: Patients with sickle cell disease (SCD) have vaso-occlusive crises (VOCs). Infusion centers (ICs) are alternatives to emergency department (ED) care and may improve patient outcomes. OBJECTIVE: To assess whether care in ICs or EDs leads to better outcomes for the treatment of uncomplicated VOCs. DESIGN: Prospective cohort. (ClinicalTrials.gov: NCT02411396). SETTING: 4 U.S. sites, with recruitment between April 2015 and December 2016. PARTICIPANTS: Adults with SCD living within 60 miles of a study site. MEASUREMENTS: Participants were followed for 18 months after enrollment. Outcomes of interest were time to first dose of parenteral pain medication, whether pain reassessment was completed within 30 minutes after the first dose, and patient disposition on discharge from the acute care visit. Treatment effects for ICs versus EDs were estimated using a time-varying propensity score adjustment. RESULTS: Researchers enrolled 483 participants; the 269 who had acute care visits on weekdays are included in this report. With inverse probability of treatment-weighted adjustment, the mean time to first dose was 62 minutes in ICs and 132 minutes in EDs; the difference was 70 minutes (95% CI, 54 to 98 minutes; E-value, 2.8). The probability of pain reassessment within 30 minutes of the first dose of parenteral pain medication was 3.8 times greater (CI, 2.63 to 5.64 times greater; E-value, 4.7) in the IC than the ED. The probability that a participant's visit would end in admission to the hospital was smaller by a factor of 4 (0.25 [CI, 0.18 to 0.33]) with treatment in an IC versus an ED. LIMITATION: The study was restricted to participants with uncomplicated VOCs. CONCLUSION: In adults with SCD having a VOC, treatment in an IC is associated with substantially better outcomes than treatment in an ED. PRIMARY FUNDING SOURCE: Patient-Centered Outcomes Research Institute.

Chronic Pain Does Not Impact Baseline Circulating Cytokine Levels in Adults with Sickle Cell Disease.

Chronic pain affects 50% of adults with sickle cell disease (SCD). Although inflammation is thought to contribute to the pathogenesis of chronic pain, no studies have examined the differences in circulating cytokines between patients with SCD with and without chronic pain. We performed an observational cohort study using blood and urine samples from adults with SCD with and without chronic pain at their usual state of health. We tested the hypothesis that, compared to those without chronic pain, those with chronic pain would have significantly higher baseline circulating proinflammatory cytokines. A total of 61 adults with SCD, 40 with chronic pain and 21 without chronic pain were tested. When SCD patients with chronic pain were compared to those without chronic pain, no significant differences in cytokine levels were noted. The variables most associated with the diagnosis of chronic pain in this population were opioid dose and subject age.

The controversial role of red cell transfusions for sickle cell pain.

PURPOSE OF REVIEW: Red cell transfusions are one of the most common and important therapies used for patients with sickle cell disease (SCD). For prevention of strokes, there is abundant evidence that transfusions are efficacious, whereas for other indications, such as prevention of pain, there are less data. Nonetheless, with few therapeutic options, the use of transfusion for prevention of acute pain has increased in children and adults with SCD without a clear understanding of its benefits. RECENT FINDINGS: Although it makes conceptual sense that red cell transfusions would prevent pain that arises from vaso-occlusion, we now know that the mechanism of pain is more complex than vaso-occlusion alone. Recent taxonomies recognize a chronic pain syndrome that is both common in adults with SCD and affects the presentation of acute pain. It is not known if acute pain on the background of chronic pain responds differently to sickle cell therapies, such as hydroxyurea and blood transfusion. SUMMARY: In this review, we will examine the studies that have investigated whether red cell transfusions are efficacious for preventing pain. In the absence of high-quality data that specifically addresses this question, we will outline our approach, which might soon change with new drugs and curative therapies on the horizon.

Chronic pain persists in adults with sickle cell disease despite regular red cell transfusions.

BACKGROUND: Pain affects over 50% of adults with sickle cell disease (SCD), and this pain is largely managed outside of the hospital. While chronic transfusion therapy is used to decrease the rate of acute pain events in patients with SCD, less is known about its impact on the day-to-day experience of pain. To address this knowledge gap, we provided pain diaries to patients with SCD receiving chronic transfusion. PATIENTS AND METHODS: A convenience sample of chronically-transfused adults with SCD successfully completed a diary over the course of at least 2 transfusion events. Patients receiving simple transfusions and red cell exchanges were included. Pain was rated on a scale of 0 to 10 each day, and patient laboratory values, co-morbidities, and hospital utilization were also obtained using the electronic medical record. The mean pain scores pre- and post-transfusion were evaluated using both a random effects-expectation maximization regression tree analysis and a generalized linear mixed regression model. RESULTS: Ten subjects (63%) in this cohort were defined as having chronic pain, while the remaining four (27%) subjects had episodic pain. Despite chronic transfusion and a suppressed HbS% (22.5% (16.5-25.9)), 10 patients (63%) continued to report nearly daily pain, and on almost 70% of diary days, the pain was significant (≥5/10). When the relationship between HbS% and reported pain intensity was examined, no association was found. DISCUSSION: These results suggest that, even with regular transfusions and a low HbS%, daily pain persists in many adults with SCD.

The clinical impact of glucose-6-phosphate dehydrogenase deficiency in patients with sickle cell disease.

PURPOSE OF REVIEW: Glucose-6-phosphate dehydrogenase (G6PD) deficiency and sickle cell disease (SCD) cause hemolysis, often occurring in individuals of African descent. These disorders co-occur frequently, and possibly interact, altering clinical outcomes in SCD. However, epidemiological investigations of SCD with G6PD deficiency have produced variable results. This contribution reviews the available data about the interaction of G6PD deficiency and SCD. RECENT FINDINGS: Overall, G6PD deficiency contributes few, if any, effects to laboratory values and clinical outcomes in SCD patients, but may impact transfusion efficacy. This observation is most likely because of the relatively increased G6PD activity in the young red blood cell (RBC) population seen in SCD patients with or without G6PD deficiency. In addition, G6PD deficiency possibly interacts with other genetic modifiers, such as α thalassemia, hemoglobin F levels and SCD haplotype. SUMMARY: Although G6PD deficiency is relatively common, it does not appear to clinically impact patients with SCD. Nonetheless, it is important to evaluate G6PD status in patients with SCD to avoid the use of medications that may cause hemolysis. Future studies evaluating the clinical impact of transfusions from G6PD-deficient RBC donors would be of the greatest benefit to the current literature.

Augmentation of Muscle Blood Flow by Ultrasound Cavitation Is Mediated by ATP and Purinergic Signaling.

BACKGROUND: Augmentation of tissue blood flow by therapeutic ultrasound is thought to rely on convective shear. Microbubble contrast agents that undergo ultrasound-mediated cavitation markedly amplify these effects. We hypothesized that purinergic signaling is responsible for shear-dependent increases in muscle perfusion during therapeutic cavitation. METHODS: Unilateral exposure of the proximal hindlimb of mice (with or without ischemia produced by iliac ligation) to therapeutic ultrasound (1.3 MHz, mechanical index 1.3) was performed for 10 minutes after intravenous injection of 2×108 lipid microbubbles. Microvascular perfusion was evaluated by low-power contrast ultrasound perfusion imaging. In vivo muscle ATP release and in vitro ATP release from endothelial cells or erythrocytes were assessed by a luciferin-luciferase assay. Purinergic signaling pathways were assessed by studying interventions that (1) accelerated ATP degradation; (2) inhibited P2Y receptors, adenosine receptors, or KATP channels; or (3) inhibited downstream signaling pathways involving endothelial nitric oxide synthase or prostanoid production (indomethacin). Augmentation in muscle perfusion by ultrasound cavitation was assessed in a proof-of-concept clinical trial in 12 subjects with stable sickle cell disease. RESULTS: Therapeutic ultrasound cavitation increased muscle perfusion by 7-fold in normal mice, reversed tissue ischemia for up to 24 hours in the murine model of peripheral artery disease, and doubled muscle perfusion in patients with sickle cell disease. Augmentation in flow extended well beyond the region of ultrasound exposure. Ultrasound cavitation produced an ≈40-fold focal and sustained increase in ATP, the source of which included both endothelial cells and erythrocytes. Inhibitory studies indicated that ATP was a critical mediator of flow augmentation that acts primarily through either P2Y receptors or adenosine produced by ectonucleotidase activity. Combined indomethacin and inhibition of endothelial nitric oxide synthase abolished the effects of therapeutic ultrasound, indicating downstream signaling through both nitric oxide and prostaglandins. CONCLUSIONS: Therapeutic ultrasound using microbubble cavitation to increase muscle perfusion relies on shear-dependent increases in ATP, which can act through a diverse portfolio of purinergic signaling pathways. These events can reverse hindlimb ischemia in mice for >24 hours and increase muscle blood flow in patients with sickle cell disease. CLINICAL TRIAL REGISTRATION: URL: http://clinicaltrials.gov. Unique identifier: NCT01566890.

Older red cell units are associated with an increased incidence of infection in chronically transfused adults with sickle cell disease.

BACKGROUND: In adults with sickle cell disease (SCD), the effects of the red cell storage lesion are not well defined. The objectives of this study were to: (1) describe the distribution of storage ages provided to adults with SCD, and (2) evaluate clinical outcomes associated with storage age. PATIENTS AND METHODS: We performed a retrospective cohort study of adults with SCD managed with prophylactic simple transfusion regimens. Units were universally pre-storage leukocyte reduced and CEK-matched. Age of the unit was 42 days minus the difference between the expiration and transfusion dates. A mixed effects model, which accounts for a subject's contribution to repeated transfusion encounters, was used to investigate the association between storage age and the incidence of hospital encounters for infection and pain crises prior to the next red cell transfusion. RESULTS: Over the study interval, twenty-eight steady-state adults with SCD received 627 units via simple transfusion over 281 outpatient encounters. Overall median unit storage age was 22 days (range: 2-42 days). Receipt of older units was associated with an increased incidence of emergency department or hospital admission for infection prior to the next transfusion (p=0.04). There was no association between unit storage age and admission for pain (p=0.4). DISCUSSION: In a cohort of chronically transfused adults with SCD, we provide evidence that receipt of older units is associated with a higher rate of admission for infection. Prospective studies will need to validate these data and explore potential mechanisms by which these older units promote infection.

Maternal opioid dose is associated with neonatal abstinence syndrome in children born to women with sickle cell disease.

The objective of this study was to test the hypothesis that higher daily opioid dose is associated with the presence and severity of neonatal abstinence syndrome (NAS) in pregnant women with sickle cell disease (SCD). This was a retrospective study of pregnant women with SCD who required opioids. NAS was evaluated using the Finnegan scoring system and classified as none, mild, and severe. Severe NAS was defined as a Finnegan score ≥ 8 on 3 consecutive tests. Thirty-four pregnancies were examined in 30 women with SCD. Higher daily morphine dose was associated with a higher percentage of days in the hospital during pregnancy (P < 0.001). Hospital days contributed disproportionately to daily morphine dose as larger amounts of opioids were administered in the hospital compared to home (P = 0.002). Median maternal oral morphine dose was 416 mg for infants with severe NAS compared with 139 mg for those with mild NAS (P = 0.04). For infants with no NAS, median maternal morphine was 4 mg, significantly less than those with mild NAS (P < 0.001). Infants born to women who used on average >200 mg/day of oral morphine equivalent in the last month of pregnancy had a 13-fold increased risk of severe NAS compared with those who used <200 mg/day. These data demonstrate that higher median daily opioid dose is associated with progressively more severe NAS in pregnant women with SCD. Strategies to decrease pain and avoid hospitalizations are needed to reduce opioid use and NAS.

Red cell storage age policy for patients with sickle cell disease: A survey of transfusion service directors in the United States.

In patients with sickle cell disease (SCD), the effects of the red cell storage lesion are not well defined. The objective of this study was to determine the prevalence of transfusion services that limit red cell units by storage age for patients with SCD. We developed a 22 question survey of transfusion service director opinions and their corresponding blood bank policies. Target subjects were systematically identified on the AABB website. Responses were recorded in SurveyMonkey and summarized using standard statistical techniques. Ninety transfusion service directors responded to the survey. Response rate was 22%. Only 23% of respondents had storage age policies in place for patients with SCD, even though 36% of respondents consider older units to be potentially harmful in this patient population. Of those with a policy, a less-than 15 day storage age requirement was most often used (75%), but practices varied, and most respondents (65%) agreed that evidence-based guidelines regarding storage age are needed for patients with SCD. Policies, practices and opinions about the risks of older units for patients with SCD vary. As patients with SCD may have unique susceptibilities to features of the red cell storage lesion, prospective studies in this population are needed to determine best practice.

NHLBI state of the science symposium in therapeutic apheresis: Knowledge gaps and research opportunities in the area of hematology-oncology.

The National Heart Lung and Blood Institute (NHLBI) hosted a two-day state of the science symposium on therapeutic apheresis in Bethesda, MD on November 28th-29th, 2012. The purpose of the symposium was multifaceted, and included the following aims: (a) To discuss this state of research and key scientific questions in apheresis medicine; (b) To identify gaps in knowledge for relevant cardiovascular diseases, hematological and oncological diseases, infectious diseases and sepsis, renal diseases, and neurological diseases where there may be strong therapeutic rationale for the application of apheresis treatments; (c) To explore ways of coordinating therapeutic apheresis with other medical disciplines and treatment modalities; (d) To identify and prioritize the most important research questions to be answered in apheresis medicine; and (e) To offer NHLBI suggestions on how a structured research approach can be applied to the therapeutic apheresis research agenda in future years. The following document summarizes three such key proposals presented at the meeting for evaluating apheresis therapy for the treatment of pain in sickle cell disease, heparin induced thrombocytopenia, and leukostasis from acute myeloid leukemia. The challenges and limitations regarding apheresis therapy for each disease are discussed, and avenues for future investigation for each disease are outlined.

Erythropoietic drive is the strongest predictor of hepcidin level in adults with sickle cell disease.

Levels of hepcidin, a key modulator of iron metabolism, are influenced by erythropoiesis, iron, and inflammation, all of which may be increased in patients with sickle cell disease (SCD). The objectives of this study were to determine: 1) the variation in hepcidin level, and 2) the relative contribution of erythropoietic drive, iron, and inflammation to differences in hepcidin level in an adult cohort with SCD. In a prospective study, cross-sectional measurements of hepcidin, reticulocyte percentage, erythropoietin, ferritin, and high-sensitivity CRP were obtained. A regression tree analysis was used to measure the association between these interacting factors and hepcidin level. The cohort was comprised of 40 adults with SCD. Median age was 26years, 68% were female, and all had HbSS. Hepcidin values ranged from 30ng/ml to 326ng/ml, with a median of 87ng/ml. Regression tree analysis demonstrated that reticulocyte percentage, erythropoietin, ferritin and hs-CRP all were associated with hepcidin. The highest hepcidin values were found in subjects with low reticulocyte percentage and erythropoietin. In conclusion, erythropoietic drive, iron status, and inflammation all contribute to variation in hepcidin level. The strongest contributor is erythropoietic drive. Future studies could determine whether suppression of erythropoiesis with chronic transfusion influences hepcidin level.

Sickle cell vaso-occlusion causes activation of iNKT cells that is decreased by the adenosine A2A receptor agonist regadenoson.

Adenosine A2A receptor (A2AR) agonists reduce invariant natural killer T (iNKT) cell activation and decrease inflammation in sickle cell disease (SCD) mice. We conducted a phase 1 trial of the A2AR agonist regadenoson in adults with SCD. The target dose was 1.44 µg/kg/h. iNKT cell activation was evaluated using antibodies targeting the p65 subunit of nuclear factor-κB (phospho-NF-κB p65), interferon-γ (IFN-γ), and A2AR. Regadenoson was administered to 27 adults with SCD. We examined 21 patients at steady state and 6 during painful vaso-occlusive crises (pVOC). iNKT cell activation was also measured in 14 African-American controls. During pVOC, the fraction of iNKT cells demonstrating increased phospho-NF-κB p65 and A2AR expression was significantly higher compared with controls (P < .01) and steady-state patients (P < .05). IFN-γ expression was also significantly higher compared with controls (P = .02). After a 24-hour infusion of regadenoson during pVOC, phospho-NF-κB p65 activation in iNKT cells decreased compared to baseline by a median of 48% (P = .03) to levels similar to controls and steady-state SCD. No toxicities were identified. Infusional regadenoson administered to adults with SCD at 1.44 µg/kg/h during pVOC decreases activation of iNKT cells without toxicity.

Barriers to using molecularly typed minority red blood cell donors in support of chronically transfused adult patients with sickle cell disease.

BACKGROUND: Much effort and resources have been devoted to programs that provide transfusion support for patients with sickle cell disease (SCD). The focus of many donor programs is to prevent alloimmunization by recruiting racially matched African American donors to limit the red blood cell (RBC) antigenic differences that exist between Caucasian donors and patients with SCD. STUDY DESIGN AND METHODS: In this study, we evaluated the RBC antigen characteristics of both the recipient population with SCD and the African American donor population from 2010 to 2013. We evaluated the genotype-derived predicted antigen frequencies of the donors and compared these frequencies with those of the population supported by these units. Specific attention was given to the alloimmunization rate over the 3 years and the number of D- units provided to D+ patients. RESULTS: We recruited 6066 African American donors during the 3-year study period with 77.3% of these donors donating no more than twice. The observed genotype-derived predicted antigen frequencies were similar to the expected frequencies, and the antigen frequencies of a cohort of 54 adult patients with SCD (p > 0.05). Twelve patients (22.2%) with SCD had alloantibodies and five of these patients developed these antibodies while receiving Rh and K antigen-matched blood during the study interval. Finally, we found that 607 (37.1%) D- units were diverted to D+ patients. CONCLUSIONS: New recruitment and prevention strategies are needed to increase the pool of available antigen-matched RBCs and decrease alloimmunization risk for this patient population.

Intensive management of high-utilizing adults with sickle cell disease lowers admissions.

A minority of super-utilizing adults with sickle cell disease (SCD) account for a disproportionate number of emergency department (ED) and hospital admissions. We performed a retrospective cohort study comparing the rate of admission before and after the opening of a clinic for adults with SCD. Unique to this clinic was an intensive management strategy, focusing on super-utilizing adults with 12 or more admissions per year. ED/hospital and 30 days re-admission rates were compared, 1 year pre- and post-intervention, for those adults who established in the clinic. Prior to the intervention, 17 super-utilizers, comprising 15% of the pre-intervention cohort (n = 115), accounted for 58% of the total admissions and had an admission rate of 28 per patient-year. When pre- and post-intervention years were compared, rate of ED/hospital admission per patient-year for super-utilizers decreased from 27.9 to 13.5 (P < 0.001), while there was not a significant reduction for the entire cohort (7.1 vs. 6.1, P = 0.84). Similarly, the decrease in rate of 30 day re-admission was larger for the super-utilizers (13.5 per patient-year to 1.8, P < 0.001), than the whole cohort (2.6 per patient-year to 0.7, P = 0.006). Among the super-utilizers, the reduced rate of admission from the pre- to post-clinic intervention year equated to 252 fewer ED/hospital admissions and 227 fewer 30 day re-admissions. This management strategy focusing on super-utilizing adults with SCD lowered admission and 30 day re-admission rate.

Use of a dual lumen port for automated red cell exchange in adults with sickle cell disease.

Red cell exchange (RCE) is a common procedure in adults with sickle cell disease (SCD). Implantable dual lumen Vortex (DLV) ports can be used for RCE in patients with poor peripheral venous access. We performed a retrospective cohort study of RCE procedures performed in adults with SCD. The main objective of the study was to compare the inlet speed, duration of procedures and rate of complications performed through DLV ports to those performed through temporary central venous and peripheral catheters. Twenty-nine adults with SCD underwent a total of 318 RCE procedures. Twenty adults had DLV ports placed and 218 procedures were performed using DLV ports. Mean length of follow-up after DLV port placement was 397 ± 263 days. Six DLV ports were removed due to infection and 1 for malfunction after a mean of 171 ± 120 days. Compared to temporary central venous and peripheral catheters, DLV port procedures had a greater rate of procedural complications, a longer duration, and a lower inlet speed (all P < 0.01). When accounting for the maximum allowable inlet speed to avoid citrate toxicity, 40% of DLV port procedures were greater than 10% below maximum speed, compared to 7 and 14% of procedures performed through temporary central venous and peripheral catheters (P < 0.0001). In conclusion, DLV ports can be used for RCE in adults with SCD, albeit with more procedural complications and longer duration. The smaller internal diameter and longer catheter of DLV ports compared to temporary central venous catheters likely accounts for the differences noted.

Advances in sickle cell therapies in the hydroxyurea era.

In the hydroxyurea era, insights into mechanisms downstream of erythrocyte sickling have led to new therapeutic approaches for patients with sickle cell disease (SCD). Therapies have been developed that target vascular adhesion, inflammation and hemolysis, including innovative biologics directed against P-selectin and invariant natural killer T cells. Advances in hematopoietic stem cell transplant and gene therapy may also provide more opportunities for cures in the near future. Several clinical studies are underway to determine the safety and efficacy of these new treatments. Novel approaches to treat SCD are desperately needed, since current therapies are limited and rates of morbidity and mortality remain high.