Embryo Cryopreservation in a Patient with Sickle Cell Disease Utilizing Letrozole and Enoxaparin: A Case Report.

PURPOSE: To describe a patient with sickle cell disease, a prothrombotic disorder, who underwent successful embryo cryopreservation for the purposes of fertility preservation prior to hematopoietic stem cell transplant. METHODS: To report a successful case of gonadotropin stimulation and embryo cryopreservation using the aromatase inhibitor letrozole to maintain low serum estradiol to minimize thrombotic risk in a patient with sickle cell disease (SCD) and history of retinal artery thrombosis planning hematopoietic stem cell transplant (HSCT). The patient was given letrozole (5 mg daily) as well as prophylactic enoxaparin while undergoing gonadotropin stimulation with an antagonist protocol to preserve fertility prior to HSCT. After the oocyte retrieval, letrozole was continued for one additional week. RESULTS: The patient's peak serum estradiol concentration was 172 pg/mL during gonadotropin stimulation. Ten mature oocytes were retrieved and a total of 10 blastocysts were cryopreserved. The patient required pain medication and intravenous fluids after oocyte retrieval due to pain but had significant improvement at the scheduled post-operative day one follow-up. No embolic events occurred during stimulation or 6 months thereafter. CONCLUSION: The utilization of definitive treatment for SCD with stem cell transplant is increasing. We successfully used letrozole to maintain low serum estradiol during gonadotropin stimulation along with prophylactic enoxaparin in a patient with SCD to minimize her risk of thrombosis. This approach will allow patients planning definitive treatment with stem cell transplant the opportunity to preserve their fertility safely.

Secondary Neoplasms After Hematopoietic Cell Transplant for Sickle Cell Disease.

PURPOSE: To report the incidence and risk factors for secondary neoplasm after transplantation for sickle cell disease. METHODS: Included are 1,096 transplants for sickle cell disease between 1991 and 2016. There were 22 secondary neoplasms. Types included leukemia/myelodysplastic syndrome (MDS; n = 15) and solid tumor (n = 7). Fine-Gray regression models examined for risk factors for leukemia/MDS and any secondary neoplasm. RESULTS: The 10-year incidence of leukemia/MDS was 1.7% (95% CI, 0.90 to 2.9) and of any secondary neoplasm was 2.4% (95% CI, 1.4 to 3.8). After adjusting for other risk factors, risks for leukemia/MDS (hazard ratio, 22.69; 95% CI, 4.34 to 118.66; P = .0002) or any secondary neoplasm (hazard ratio, 7.78; 95% CI, 2.20 to 27.53; P = .0015) were higher with low-intensity (nonmyeloablative) regimens compared with more intense regimens. All low-intensity regimens included total-body irradiation (TBI 300 or 400 cGy with alemtuzumab, TBI 300 or 400 cGy with cyclophosphamide, TBI 200, 300, or 400 cGy with cyclophosphamide and fludarabine, or TBI 200 cGy with fludarabine). None of the patients receiving myeloablative and only 23% of those receiving reduced-intensity regimens received TBI. CONCLUSION: Low-intensity regimens rely on tolerance induction and establishment of mixed-donor chimerism. Persistence of host cells exposed to low-dose radiation triggering myeloid malignancy is one plausible etiology. Pre-existing myeloid mutations and prior inflammation may also contribute but could not be studied using our data source. Choosing conditioning regimens likely to result in full-donor chimerism may in part mitigate the higher risk for leukemia/MDS.

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.

Social and Psychological Factors Associated With Health Care Transition for Young Adults Living With Sickle Cell Disease.

Introduction: Due to advances in disease management, mortality rates in children with sickle cell disease (SCD) have decreased. However, mortality rates for young adults (YA) increased, and understanding of social and psychological factors is critical. The aim of this study was to explore factors associated with health care transition experiences for YA with SCD. Method: This was a qualitative descriptive study. A 45-minute semistructured interview was conducted with 13 YA (M = 21.5 years, SD = 1.73). Results: Results suggest that social and psychological factors and self-management experiences influence health care transition. Eight themes emerged: "need for accessible support"; "early assistance with goal setting"; "incongruence among expectations, experiences, and preparation"; "spiritual distress"; "stigma"; "need for collaboration"; "appreciation for caring providers"; and "feeling isolated." Discussion: Consideration of cultural contexts will guide nurses in supporting health care transition. Designing culturally relevant interventions that address unique needs for YA living with SCD is warranted.

Phase 2 trial of montelukast for prevention of pain in sickle cell disease.

Cysteinyl leukotrienes (CysLTs) are lipid mediators of inflammation. In patients with sickle cell disease (SCD), levels of CysLTs are increased compared with controls and associated with a higher rate of hospitalization for pain. We tested the hypothesis that administration of the CysLT receptor antagonist montelukast would improve SCD-related comorbidities, including pain, in adolescents and adults with SCD. In a phase 2 randomized trial, we administered montelukast or placebo for 8 weeks. The primary outcome measure was a >30% reduction in soluble vascular cell adhesion molecule 1 (sVCAM), a marker of vascular injury. Secondary outcome measures were reduction in daily pain, improvement in pulmonary function, and improvement in microvascular blood flow, as measured by laser Doppler velocimetry. Forty-two participants with SCD were randomized to receive montelukast or placebo for 8 weeks. We found no difference between the montelukast and placebo groups with regard to the levels of sVCAM, reported pain, pulmonary function, or microvascular blood flow. Although montelukast is an effective treatment for asthma, we did not find benefit for SCD-related outcomes. This clinical trial was registered at www.clinicaltrials.gov as #NCT01960413.

Contrast-enhanced ultrasound detects changes in microvascular blood flow in adults with sickle cell disease.

In patients with sickle cell disease (SCD), poor outcome measures compromise the potential success of clinical trials. Contrast-enhanced ultrasound (CEUS) is a technique that can non-invasively quantify deep tissue microvascular blood flow. We tested the hypothesis that CEUS of forearm skeletal muscle could be used to: 1) assess microvascular abnormalities that occur during vaso-occlusive crisis; and 2) test new therapies for SCD that are targeted to improving the status of the microcirculation. We performed a prospective study, CEUS perfusion imaging of resting forearm muscle was performed in adults with SCD: 1) during and after a pain episode, and 2) before, during, and after a 24-hour infusion of the investigative agent, regadenoson, an adenosine A2A agonist. CEUS destruction-replenishment time-intensity data were analyzed to measure microvascular blood flow, as well as its components, microvascular blood volume and flux rate. Serial CEUS measurements were obtained in 32 adults with SCD. For the studies during crisis, there was a 30% reduction in microvascular blood flow compared to steady-state (p = 0.031), a reduction that was largely due to microvascular flux rate. For the regadenoson group, a non-significant 25% increase in flux rate and 9% increase in microvascular blood flow compared to baseline were detected during infusion. In a study of adults with SCD, CEUS detected changes in microvascular blood flow associated with vaso-occlusive crises. No changes were found during an infusion of the adenosine A2A agonist, regadenoson. This study provides preliminary evidence that CEUS could detect blood flow changes consistent with SCD physiology.

Induction of antiinflammatory purinergic signaling in activated human iNKT cells.

Invariant natural killer T (iNKT) cells are activated at sites of local tissue injury, or globally during vaso-occlusive episodes of sickle cell disease (SCD). Tissue damage stimulates production of CD1d-restricted lipid antigens that activate iNKT cells to produce Th1- and Th2-type cytokines. Here, we show that circulating iNKT cells in SCD patients express elevated levels of the ectonucleoside triphosphate diphosphosphohydrolase, CD39, as well the adenosine A2A receptor (A2AR). We also investigated the effects of stimulating cultured human iNKT cells on the expression of genes involved in the regulation of purinergic signaling. iNKT cell stimulation caused induction of ADORA2A, P2RX7, CD38, CD39, ENPP1, CD73, PANX1, and ENT1. Transcription of ADA, which degrades adenosine, was reduced. Induction of CD39 mRNA was associated with increased ecto-ATPase activity on iNKT cells that was blocked by POM1. Exposure of iNKT cells to A2AR agonists during stimulation reduced production of IFN-γ and enhanced production of IL-13 and CD39. Based on these findings, we define "purinergic Th2-type cytokine bias" as an antiinflammatory purinergic response to iNKT cell stimulation resulting from changes in the transcription of several genes involved in purine release, extracellular metabolism, and signaling.

A Fatal Case of Immune Hyperhemolysis with Bone Marrow Necrosis in a Patient with Sickle Cell Disease.

In patients with sickle cell disease, hyperhemolysis is a rare but life-threatening complication of transfusion. In this case report, we describe a 61 year-old woman with hemoglobin sickle cell (SC) disease and history of alloimmunization who developed hyperhemolysis associated with a transfusion. She was found to have a warm and a clinically-significant cold autoantibody. Severe anemia (Hb 2.7 g/dL) with reticulocytopenia and thrombocytopenia prompted a bone marrow biopsy, which demonstrated extensive bone marrow necrosis. Despite treatment, the bone marrow failure did not improve and the patient died on hospital day 38. This case illustrates the potential risks of transfusion in a patient with sickle cell disease, especially one with previous hemolytic reactions. While uncommon, hyperhemolysis can cause death, in this case by extensive bone marrow necrosis. In patients with sickle cell disease, judicious use of red cell transfusions with phenotypically-matched units can diminish, but never completely abrogate, the risks associated with transfusion.

Randomized phase 2 trial of regadenoson for treatment of acute vaso-occlusive crises in sickle cell disease.

Adenosine A2A receptor (A2AR) agonists have been shown to decrease tissue inflammation induced by hypoxia/reoxygenation in mice with sickle cell disease (SCD). The key mediator of the A2AR agonist's anti-inflammatory effects is a minor lymphocyte subset, invariant natural killer T (iNKT) cells. We tested the hypothesis that administration of an A2AR agonist in patients with SCD would decrease iNKT cell activation and dampen the severity of vaso-occlusive (VO) crises. In a phase 2, randomized, placebo-controlled trial, we administered a 48-hour infusion of the A2AR agonist regadenoson (1.44 µg/kg per hour) to patients with SCD during VO crises to produce a plasma concentration of ∼5 nM, a concentration known from prior studies to suppress iNKT cell activation in SCD. The primary outcome measure was a >30% reduction in the percentage of activated iNKT cells. Ninety-two patients with SCD were randomized to receive a 48-hour infusion of regadenoson or placebo, in addition to standard-of-care treatment, during hospital admission for a VO crisis and had analyzable iNKT cell samples. The proportion of subjects who demonstrated a reduction of >30% in activated iNKT cells was not significantly different between the regadenoson and placebo arms (43% vs 23%; P = .07). There were also no differences between regadenoson and placebo groups in length of hospital stay, mean total opioid use, or pain scores. These data demonstrate that a low-dose infusion of regadenoson intended to reduce the activity of iNKT cells is not sufficient to produce a statistically significant reduction in such activation or in measures of clinical efficacy. This trial was registered at www.clinicaltrials.gov as #NCT01788631.

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.

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.

The role of adenosine signaling in sickle cell therapeutics.

Data suggest a role for adenosine signaling in the pathogenesis of sickle cell disease (SCD). Signaling through the adenosine A2A receptor (A2AR) has demonstrated beneficial effects. Activation of A2ARs decreases inflammation with SCD by blocking activation of invariant natural killer T cells. Decreased inflammation may reduce the severity of vasoocclusive crises. Adenosine signaling through the adenosine A2B receptor (A2BR) may be detrimental in SCD. Whether adenosine signaling predominantly occurs through A2ARs or A2BRs may depend on differing levels of adenosine and disease state (steady state versus crisis). There may be opportunities to develop novel therapeutic approaches targeting A2ARs and/or A2BRs for patients with SCD.

NF-κB is activated in CD4+ iNKT cells by sickle cell disease and mediates rapid induction of adenosine A2A receptors.

Reperfusion injury following tissue ischemia occurs as a consequence of vaso-occlusion that is initiated by activation of invariant natural killer T (iNKT) cells. Sickle cell disease (SDC) results in widely disseminated microvascular ischemia and reperfusion injury as a result of vaso-occlusion by rigid and adhesive sickle red blood cells. In mice, iNKT cell activation requires NF-κB signaling and can be inhibited by the activation of anti-inflammatory adenosine A2A receptors (A2ARs). Human iNKT cells are divided into subsets of CD4+ and CD4- cells. In this study we found that human CD4+ iNKT cells, but not CD4- cells undergo rapid NF-κB activation (phosphorylation of NF-κB on p65) and induction of A2ARs (detected with a monoclonal antibody 7F6-G5-A2) during SCD painful vaso-occlusive crises. These findings indicate that SCD primarily activates the CD4+ subset of iNKT cells. Activation of NF-κB and induction of A2ARs is concordant, i.e. only CD4+ iNKT cells with activated NF-κB expressed high levels of A2ARs. iNKT cells that are not activated during pVOC express low levels of A2AR immunoreactivity. These finding suggest that A2AR transcription may be induced in CD4+ iNKT cells as a result of NF-κB activation in SCD. In order to test this hypothesis further we examined cultured human iNKT cells. In cultured cells, blockade of NF-κB with Bay 11-7082 or IKK inhibitor VII prevented rapid induction of A2AR mRNA and protein upon iNKT activation. In conclusion, NF-κB-mediated induction of A2ARs in iNKT cells may serve as a counter-regulatory mechanism to limit the extent and duration of inflammatory immune responses. As activated iNKT cells express high levels of A2ARs following their activation, they may become highly sensitive to inhibition by A2AR agonists.

Environmental tobacco smoke and airway obstruction in children with sickle cell anemia.

BACKGROUND: The contribution of environmental tobacco smoke (ETS) exposure to pulmonary morbidity in children with sickle cell anemia (SCA) is poorly understood. We tested the hypothesis that children with SCA and ETS exposure would have an increased prevalence of obstructive lung disease and respiratory symptoms compared with children with SCA and no ETS exposure. METHODS: Parent reports of ETS and respiratory symptom frequency were obtained for 245 children with SCA as part of a multicenter prospective cohort study. One hundred ninety-six children completed pulmonary function testing. Multivariable regression models were used to evaluate the associations between ETS exposure at different time points (prenatal, infant [birth to 2 years], preschool [2 years to first grade], and current) and lung function and respiratory symptoms. RESULTS: Among the 245 participants, a high prevalence of prior (44%) and current (29%) ETS exposure was reported. Of the 196 children who completed pulmonary function testing, those with parent-reported infant and current ETS exposure were more likely to have airway obstruction (defined as an FEV1/FVC ratio below the lower limit normal) compared with unexposed children (22.0% vs 3.1%, P < .001). Those with ETS exposure also had a lower forced expiratory flow, midexpiratory phase/FVC ratio (0.82 vs 0.97, P = .001) and were more likely to have evidence of bronchodilator responsiveness (23% vs 11%, P = .03). Current and prior ETS exposure and in utero smoke exposure were associated with increased frequency of respiratory symptoms. CONCLUSIONS: ETS exposure is associated with evidence of lower airway obstruction and increased respiratory symptoms in SCA.

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.

Elevated circulating fibrocyte levels in patients with hypertensive heart disease.

OBJECTIVE: Autopsy and biopsy studies have shown that there is significantly more fibrosis in hearts of patients with hypertensive heart disease compared to normal hearts. Fibrocytes, a population of circulating bone marrow-derived cells, have been shown to home to tissues and promote scar formation in several diseases, but their role in human hypertensive heart disease has not been investigated to date. Our objective was to determine whether fibrocyte levels are elevated in individuals with hypertensive heart disease. METHODS: We measured peripheral blood fibrocyte levels and their activated phenotypes in 12 individuals with hypertensive heart disease as determined by increased left ventricular mass on noninvasive imaging and compared them to fibrocyte levels from 19 healthy normal controls and correlated them to cardiac MRI findings. RESULTS: Compared to normal controls, individuals with hypertensive heart disease had significantly higher circulating levels of total fibrocytes [median (interquartile range); 149000 (62200-220000) vs. 564500 (321000-1.2900e(+006)), P < 0.0001, respectively] as well as activated fibrocytes [15700 (6380-19800) vs. 478500 (116500-1.2360e(+006)) P < 0.0001]. Moreover, the fibrocyte subsets expressing the chemokine markers CXCR4 (P < 0.0001), CCR2 (P < 0.0001), CCR7 (P < 0.0001) and coexpression of both CXCR4 and CCR2 (P < 0.0001) were significantly elevated in patients with hypertensive heart disease compared to controls. Lastly, in patients with hypertensive heart disease there was a strong correlation between left ventricular mass index and total fibrocytes (r = 0.65, P = 0.037) and activated fibrocytes (r = 0.70, P = 0.016). CONCLUSION: Our data suggest that bone marrow-derived circulating fibrocytes are associated with the presence and extent of left ventricular hypertrophy in patients with hypertensive heart disease.

Targeting iNKT cells for the treatment of sickle cell disease.

Sickle cell disease (SCD) causes widely disseminated vaso-occlusive episodes. Building on evidence implicating invariant NKT (iNKT) cells in the pathogenesis of ischemia/reperfusion injury, recent studies demonstrate that blockade of iNKT cell activation in mice with SCD reduces pulmonary inflammation and injury. In patients with SCD, iNKT cells in blood are increased in absolute number and activated in comparison to healthy controls. iNKT cell activation is reduced by agonists of adenosine 2A receptors (A(2A)Rs) such as the clinically approved coronary vasodilator, regadenoson. An ongoing multi-center, dose-finding and safety trial of infused regadenoson, has been initiated and is providing preliminary data about its safety and efficacy to treat SCD. Very high accumulation of adenosine may have deleterious effects in SCD through activation of adenosine 2B receptors that are insensitive to regadenoson. Future possible therapeutic approaches for treating SCD include selective A(2B)R antagonists and antibodies that deplete iNKT cells.