In vivo HSC prime editing rescues sickle cell disease in a mouse model.

Sickle cell disease (SCD) is a monogenic disease caused by a nucleotide mutation in the ß-globin gene. Current gene therapy studies are mainly focused on lentiviral vector-mediated gene addition or CRISPR/Cas9-mediated fetal globin reactivation, leaving the root cause unfixed. We developed a vectorized prime editing system that can directly repair the SCD mutation in hematopoietic stem cells (HSCs) in vivo in a SCD mouse model (CD46/Townes mice). Our approach involved a single intravenous injection of a nonintegrating, prime editor-expressing viral vector into mobilized CD46/Townes mice and low-dose drug selection in vivo. This procedure resulted in the correction of ∼40% of ßS alleles in HSCs. On average, 43% of sickle hemoglobin was replaced by adult hemoglobin, thereby greatly mitigating the SCD phenotypes. Transplantation in secondary recipients demonstrated that long-term repopulating HSCs were edited. Highly efficient target site editing was achieved with minimal generation of insertions and deletions and no detectable off-target editing. Because of its simplicity and portability, our in vivo prime editing approach has the potential for application in resource-poor countries where SCD is prevalent.

Introducing a G-Makassar variant in HSCs by in vivo base editing treats sickle cell disease in mice.

Precise repair of the pathogenic mutation in hematopoietic stem cells (HSCs) represents an ideal cure for patients with sickle cell disease (SCD). Here, we demonstrated correction of the SCD phenotype by converting the sickle mutation codon (GTG) into a benign G-Makassar variant (GCG) using in vivo base editing in HSCs. We demonstrated successful production of helper-dependent adenoviral vectors expressing an all-in-one base editor mapping to the sickle mutation site. In HSC-enriched cells from SCD patients, transduction with the base editing vector in vitro resulted in 35% GTG > GCG conversion and phenotypic improvements of derived red blood cells. After ex vivo transduction of HSCs from a SCD mouse model and subsequent transplantation, we achieved an average of 88% editing at the target site in transplanted mice. Importantly, in vivo HSC base editing followed by selection generated 24.5% Makassar variant in long-term repopulating HSCs of SCD mice. The treated animals demonstrated correction of disease hallmarks without showing noticeable side effects. Off-target analyses at top-scored genomic sites revealed no off-target editing. This in vivo approach requires only one non-integrating vector, only intravenous/subcutaneous injections, and minimal in vivo selection. This technically simple approach has the potential for scalable applications in resource-limiting regions where SCD is prevalent.

A Hematoma in the Anterior Abdominal Muscle in a Woman Receiving Venlafaxine: A Literature Review of the Reports on Similar Cases.

INTRODUCTION: Venlafaxine (VEN) is a selective norepinephrine reuptake inhibitor (SNRI) that mainly helps treat major depressive disorder and anxiety and panic disorders. It works by inhibiting the reuptake of serotonin (5-hydroxytryptamine, 5-HT) and noradrenaline (NA) by presynaptic neurons. Additionally, VEN administration has been linked with a bleeding predisposition that may be due to the inhibition of NA and 5-HT uptake by platelets which have their own receptors on their surface and are implicated in platelet aggregation. CASE PRESENTATION: Herein, we report a case of a 54-year-old patient treated with VEN, who presented with a hematoma in the anterior abdominal muscle. We also present the observational studies and case reports highlighting the association of SNRIs use with various hemorrhagic complications ranging from gastrointestinal hemorrhage or vaginal bleeding to bleeding during or after surgery due to either thrombocytopenia or impaired platelet aggregation. CONCLUSION: Given the cases of either reductions in the platelet count or impairment of platelet activity accompanied by bleeding events, every clinician should be aware of these possible adverse effects when prescribing SNRIs.

A New α1-Globin Variant, Hb Ormylia [HBA1:c.63C > G; p.His21Gln]. Report of Eleven Cases in Northern Greece.

The first identification of a novel α1-Globin variant, Hb Ormylia in 11 Greeks originating from a small village, Ormylia, Chalkidiki, Greece is reported. The new genetic variant leads to the production of a hemoglobin variant that can be identified and quantified by High-Performance Liquid Chromatography. Capillary and classic electrophoresis were not informative. Direct DNA sequencing revealed a new mutation C > G mutation at codon 21 of α1 gene (His > Gln). The new variant has been named Hb Ormylia and this is the first description of this genetic variant of α1 gene in the literature.

Predisposing factors for advanced liver fibrosis in patients with sickle cell disease.

Sickle cell disease (SCD) is one of the most common monogenic disorders worldwide and liver complications are common in this group of patients. Our study aims to highlight the prevalence of chronic liver complications and the main predisposing factors for advanced liver fibrosis in SCD patients. For this purpose, 219 patients from eight Thalassemia and Sickle Cell Units across Greece enrolled in our study and history of liver related disease complications was recorded, as well as a full laboratory and imaging analysis concerning their liver function. 13.6% of the patients had advanced liver fibrosis. The presence of liver fibrosis was significantly correlated with advanced age, male gender, cholelithiasis and higher LDH, γ-GT, INR, direct and indirect bilirubin levels. These patients had exhibited significantly more episodes of liver crises and acute intrahepatic cholestasis. No correlation was observed with right heart failure or previous viral hepatitis. Patients with advanced liver fibrosis were receiving a more intensive transfusion therapy for a longer period of time and had higher Liver Iron Concentration levels. Our study shows that liver complications and cirrhosis is a significant cause of morbidity in patients with SCD and it is primarily associated with intravascular hemolysis and vaso-occlusive phenomena and secondarily with iron overload.

A Phase 3 Trial of Luspatercept in Patients with Transfusion-Dependent ß-Thalassemia.

BACKGROUND: Patients with transfusion-dependent ß-thalassemia need regular red-cell transfusions. Luspatercept, a recombinant fusion protein that binds to select transforming growth factor ß superfamily ligands, may enhance erythroid maturation and reduce the transfusion burden (the total number of red-cell units transfused) in such patients. METHODS: In this randomized, double-blind, phase 3 trial, we assigned, in a 2:1 ratio, adults with transfusion-dependent ß-thalassemia to receive best supportive care plus luspatercept (at a dose of 1.00 to 1.25 mg per kilogram of body weight) or placebo for at least 48 weeks. The primary end point was the percentage of patients who had a reduction in the transfusion burden of at least 33% from baseline during weeks 13 through 24 plus a reduction of at least 2 red-cell units over this 12-week interval. Other efficacy end points included reductions in the transfusion burden during any 12-week interval and results of iron studies. RESULTS: A total of 224 patients were assigned to the luspatercept group and 112 to the placebo group. Luspatercept or placebo was administered for a median of approximately 64 weeks in both groups. The percentage of patients who had a reduction in the transfusion burden of at least 33% from baseline during weeks 13 through 24 plus a reduction of at least 2 red-cell units over this 12-week interval was significantly greater in the luspatercept group than in the placebo group (21.4% vs. 4.5%, P<0.001). During any 12-week interval, the percentage of patients who had a reduction in transfusion burden of at least 33% was greater in the luspatercept group than in the placebo group (70.5% vs. 29.5%), as was the percentage of those who had a reduction of at least 50% (40.2% vs. 6.3%). The least-squares mean difference between the groups in serum ferritin levels at week 48 was -348 µg per liter (95% confidence interval, -517 to -179) in favor of luspatercept. Adverse events of transient bone pain, arthralgia, dizziness, hypertension, and hyperuricemia were more common with luspatercept than placebo. CONCLUSIONS: The percentage of patients with transfusion-dependent ß-thalassemia who had a reduction in transfusion burden was significantly greater in the luspatercept group than in the placebo group, and few adverse events led to the discontinuation of treatment. (Funded by Celgene and Acceleron Pharma; BELIEVE ClinicalTrials.gov number, NCT02604433; EudraCT number, 2015-003224-31.).

Development of a Thalassemia International Prognostic Scoring System (TIPSS).

A prognostic scoring system that can differentiate ß-thalassemia patients based on mortality risk is lacking. We analysed data from 3145 ß-thalassemia patients followed through a retrospective cohort design for the outcome of death. An a priori list of prognostic variables was collected. ß Coefficients from a multivariate cox regression model were used from a development dataset (n = 2516) to construct a formula for a Thalassemia International Prognostic Scoring System (TIPSS) which was subsequently applied to a validation dataset (n = 629). The median duration of observation was 10.0 years. The TIPSS score formula was constructed as exp (1.4 × heart disease + 0.9 × liver disease + 0.9 × diabetes + 0.9 × sepsis + 0.6 × alanine aminotransferase ≥42 IU/L + 0.6 × hemoglobin ≤9 g/dL + 0.4 × serum ferritin ≥1850 ng/mL). TIPSS score thresholds of greatest differentiation were assigned as <2.0 (low-risk), 2.0 to <5.0 (intermediate-risk), and ≥5.0 (high-risk). The TIPSS score was a good predictor for the outcome of death in the validation dataset (AUC: 0.722, 95%CI: 0.641-0.804) and survival was significantly different between patients in the three risk categories (P < 0.001). Compared to low-risk patients, the hazard ratio for death was 2.778 (95%CI: 1.335-5.780) in patients with intermediate-risk and 6.431 (95%CI: 3.151-13.128) in patients with high-risk. This study provides a novel tool to support mortality risk categorization for patients with ß-thalassemia that could help management and research decisions.

Endocrinopathies in Hemoglobinopathies: What Is the Role of Iron?

Hemoglobinopathies, including ß-thalassemia and sickle cell disease (SCD), are common genetic blood disorders. Endocrine disorders are frequent manifestations of organ damage observed mainly in patients with ß-thalassemia and rarely in SCD. Iron overload, oxidative stress-induced cellular damage, chronic anemia, and HCV infection contribute to the development of endocrinopathies in ß-thalassemia. The above factors, combined with vaso-occlusive events and microcirculation defects, are crucial for endocrine dysfunction in SCD patients. These endocrinopathies include diabetes mellitus, hypothyroidism, parathyroid dysfunction, gonadal and growth failure, osteoporosis, and adrenal insufficiency, affecting the quality of life of these patients. Thus, we aim to provide current knowledge and data about the epidemiology, pathogenesis, diagnosis, and management of endocrine disorders in ß-thalassemia and SCD. We conducted a comprehensive review of the literature and examined the available data, mostly using the PubMed and Medline search engines for original articles. In the era of precision medicine, more studies investigating the potential role of genetic modifiers in the development of endocrinopathies in hemoglobinopathies are essential.

Primary HBB gene mutation severity and long-term outcomes in a global cohort of ß-thalassaemia.

In ß-thalassaemia, the severity of inherited ß-globin gene mutations determines the severity of the clinical phenotype at presentation and subsequent transfusion requirements. However, data on associated long-term outcomes remain limited. We analysed data from 2109 ß-thalassaemia patients with available genotypes in a global database. Genotype severity was grouped as ß0 /ß0 , ß0 /ß+ , ß+ /ß+ , ß0 /ß++ , ß+ /ß++ , and ß++ /ß++ . Patients were followed from birth until death or loss to follow-up. The median follow-up time was 34·1 years. Mortality and multiple morbidity outcomes were analyzed through five different stratification models of genotype severity groups. Interestingly, ß0 and ß+ mutations showed similar risk profiles. Upon adjustment for demographics and receipt of conventional therapy, patients with ß0 /ß0 , ß0 /ß+ , or ß+ /ß+ had a 2·104-increased risk of death [95% confidence interval (CI): 1·176-3·763, P = 0·011] and 2·956-increased odds of multiple morbidity (95% CI: 2·310-3·784, P < 0·001) compared to patients in lower genotype severity groups. Cumulative survival estimates by age 65 years were 36·8% for this subgroup compared with 90·2% for patients in lower genotype severity groups (P < 0·001). Our study identified mortality and morbidity risk estimates across various genotype severity groups in patients with ß-thalassaemia and suggests inclusion of both ß+ and ß0 mutations in strata of greatest severity.

Molecular Advances in Preeclampsia and HELLP Syndrome.

Preeclampsia (PE) constitutes one of the principal reasons for maternal and perinatal morbidity and mortality worldwide. The circumstance typically implicates formerly healthful normotensive women, after 20 weeks of gestation, typically withinside the third trimester, without regarded threat elements or past deliveries. PE can be further complicated with hemolysis and thrombocytopenia, leading to the emergence of HELLP syndrome (Hemolysis, Elevated Liver enzymes, Low platelets). Both conditions are classified as hypertensive diseases of pregnancy (HDP), and their pathogenesis has been linked to an excessive maternal inflammatory response, accompanied by enhanced endothelial activation. Several studies have found that in pregnancies affected by PE/HELLP, von Willebrand factor (vWF) antigen levels (vWF:Ag) are significantly elevated, while its cleaving protease (ADAMTS-13, A Disintegrin-like and Metalloprotease with Thrombospondin type 1 motif, member 13) activity is normal to decreased. Furthermore, the higher urine excretion of the terminal complement complex C5b-9, as well as its greater deposition in the placental surface in preeclamptic women, imply that the utero-placental unit's distinctive deficits are intimately tied to disproportionate complement activation. The goal of this updated evaluation is to provide the most up-to-date molecular advances in the pathophysiology of PE/HELLP syndromes. Recent medical data on vWF:Ag levels in patients with PE, ADAMTS-13, and dysregulation of the complement system, are highlighted and evaluated. Furthermore, we discuss the relationship between those entities and the progression of the disease, as well as their significance in the diagnostic process. Finally, considering the difficulties in analyzing and controlling those symptoms in pregnant women, we can provide a current diagnostic and therapeutic algorithm.

Total Annual Economic Burden of Patients with Sickle Cell Disease in Steady State in Greece.

Sickle cell disease includes a group of congenital hemolytic anemias, all characterized by the predominance of Hb S (HBB: c.20A>T). The population movement due to economic migration or escape from conflict zones will further affect the health systems of countries by either increasing the number of patients or forcing countries to create care units for sickle cell disease patients. This will probably also increase the incidence of the disease in areas where their incidence and prevalence were previously low. In the present study, an attempt has been made to estimate the total annual cost of the treatment of sickle cell disease in Greece. This was the first attempt to calculate the total annual cost of treating sickle cell disease patients in a steady state. The annual cost of sickle cell disease was estimated to be €21,152,340.00 (US$25,219,300.41), without calculating the cost of hospitalization for severe complications. Since 2013, in Greece, a pharmaceutical expenditure limit (decreasing with the years) has been budgeted at €1,945,000,000.00 (US$2,318,965,150.00), annually. It is therefore calculated that approximately 1.0% of the budget allocated to pharmaceutical spending is used to treat patients with sickle cell disease.

Coinheritance of Triplicated Alpha-Globin Gene and Beta-Thalassemia Mutations in Adulthood: Ten Years of Referrals in Northern Greece.

Greece is a country of ~11 million people, where hemoglobinopathies are the most common genetic diseases. The reported data describe the clinical phenotype of cases with coinheritance of triplicated α-globin (anti-α3.7 kb) and ß-globin gene mutations in Northern Greece, that were referred within the last 10 years, in The Adult Thalassemia Unit of "Hippokration" Hospital, Thessaloniki, Northern Greece. The description of specific genotypes of the ß-globin gene mutations in coinheritance with the triplicated α-globin gene (anti-α3.7 kb) and correlation with the hematologic and clinical data in adulthood may be useful in the evaluation of pediatric patients' prognosis and in genetic counseling of couples at risk.

First Report of a Coincidental Discovery of Hb Antibes-Juan-Les-Pins (HBB: c.349_350insGTGTGCTGGCCC) in a Greek Woman.

The rare Hb Antibes-Juan-Les-Pins (HBB: c.349_350insGTGTGCTGGCCC) was first reported in France. Hb Antibes-Juan-Les-Pins seems to be an innocuous variant and few published data are available. Heterozygous carriers have mild clinical or hematological findings. The abnormal hemoglobin (Hb) is detected by high performance liquid chromatography (HPLC) or capillary zone electrophoresis (CZE), but confirmation of the variant requires molecular analysis. This is the first description of Hb Antibes-Juan-Les-Pins heterozygosity in a woman of Greek origin.

Necrobiosis Lipoidica in a Patient with ß-Thalassemia Major: A Case Report and Review of the Literature.

Necrobiosis lipoidica (NL) is a rare granulomatous disease that predominantly affects middle-aged women and is often associated with diabetes mellitus (DM), rheumatoid arthritis (RA) and other metabolic disorders. Thalassemias are the most common hereditary hemoglobin (Hb) disorders worldwide. A few studies investigated dermatologic problems that coexist with ß-thalassemia major (ß-TM). The most common skin disorders in patients with ß-TM are xerosis, urticaria, pseudoxanthoma, hyperpigmentation, leg ulcers and small-vessel vasculitis. Necrobiosis lipoidica has only been occasionally reported in patients with ß-TM. Herein, we present a female with ß-TM and NL. Furthermore, a brief review of the literature was performed.

Impact of ZBTB7A hypomethylation and expression patterns on treatment response to hydroxyurea.

BACKGROUND: We aimed to clarify the emerging epigenetic landscape in a group of genes classified as "modifier genes" of the ß-type globin genes (HBB cluster), known to operate in trans to accomplish the two natural developmental switches in globin expression, from embryonic to fetal during the first trimester of conception and from fetal to adult around the time of birth. The epigenetic alterations were determined in adult sickle cell anemia (SCA) homozygotes and SCA/ß-thalassemia compound heterozygotes of Greek origin, who are under hydroxyurea (HU) treatment. Patients were distinguished in HU responders and HU non-responders (those not benefited from the HU) and both, and in vivo and in vitro approaches were implemented. RESULTS: We examined the CpG islands' DNA methylation profile of BCL11A, KLF1, MYB, MAP3K5, SIN3A, ZBTB7A, and GATA2, along with γ-globin and LRF/ZBTB7A expression levels. In vitro treatment of hematopoietic stem cells (HSCs) with HU induced a significant DNA hypomethylation pattern in ZBTB7A (p*, 0.04) and GATA2 (p*, 0.03) CpGs exclusively in the HU non-responders. Also, this group of patients exhibited significantly elevated baseline methylation patterns in ZBTB7A, before the HU treatment, compared to HU responders (p*, 0.019) and to control group of healthy individuals (p*, 0.021), which resembles a potential epigenetic barrier for the γ-globin expression. γ-Globin expression in vitro matched with detected HbF levels during patients' monitoring tests (in vivo) under HU treatment, implying a good reproducibility of the in vitro HU epigenetic effect. LRF/ZBTB7A expression was elevated only in the HU non-responders under the influence of HU. CONCLUSIONS: This is one of the very first pharmacoepigenomic studies indicating that the hypomethylation of ZBTB7A during HU treatment enhances the LRF expression, which by its turn suppresses the HbF resumption in the HU non-responders. Its role as an epigenetic regulator of hemoglobin switching is also supported by the wide distribution of ZBTB7A-binding sites within the 5' CpG sequences of all studied human HBB cluster "modifier genes." Also, the baseline methylation level of selective CpGs in ZBTB7A and GATA2 could be an indicator of the negative HU response among the ß-type hemoglobinopathy patients.

National registry of hemoglobinopathies in Greece: updated demographics, current trends in affected births, and causes of mortality.

National registries constitute an invaluable source of information and contribute to the improvement of hemoglobinopathy management. Herein, we present the second updated report of the National Registry for Haemoglobinopathies in Greece (NRHG) and critically discuss the time trends in demographics, affected births, and causes of mortality. Thirty-eight Greek hemoglobinopathy units reported data from diagnosis to the last follow-up or death by retrospectively completing an electronic form. Four thousand thirty-two patients were eligible for inclusion; more than half of them had thalassaemia major. Compared to the previous report, a reduction in the total number of all hemoglobinopathies except for hemoglobinopathy "Η" was evident. The total number of affected births was also reduced; most of them were attributable to diagnostic errors and lack of awareness. Importantly, data on iron overload are reported for the first time; although most patients had low or moderate liver iron concentration (LIC) values, a non-negligible proportion of patients had high LIC. The burden due to heart iron overload was less prominent. Cardiac- and liver-related complications are the major causes of morbidity and mortality. From 2000 to 2015, a decrease in heart-related deaths along with an increase in liver-associated fatalities was observed. The Hellenic Prevention Program along with advances in chelation regimens and iron status monitoring have resulted in improved patient outcomes. The NRHG gives insight into the effectiveness of prevention programs, the therapeutic management of hemoglobinopathies and associated outcomes. NRHG may contribute to the formulation of a roadmap for hemoglobinopathies in Europe and promote the implementation of effective public health policies.

Role of Genomic Biomarkers in Increasing Fetal Hemoglobin Levels Upon Hydroxyurea Therapy and in ß-Thalassemia Intermedia: A Validation Cohort Study.

Hemoglobinopathies exhibit a remarkable phenotypic diversity in terms of disease severity, while individual genetic background plays a key role in differential response to drug treatment. In the last decade, genomic variants in genes located within, as well as outside the human ß-globin cluster have been shown to be significantly associated with Hb F increase, in relation to hydroxyurea (HU) therapy in patients with these diseases. Here, we aim to determine the effect of genomic variants located in genes, such as MAP3K5, ASS1, NOS2A, TOX, PDE7B, NOS1, FLT1 and ARG2, previously shown to modulate fetal hemoglobin (Hb F) levels in patients with ß type hemoglobinopathies and reflecting disease severity and response to HU therapy in an independent cohort of Greek patients with these diseases. We recruited and genotyped 45 ß-thalassemia patients (ß-thal), either transfusion-dependent (TDT) or non transfusion-dependent (NTDT), 42 Hb S (HBB: c.20A>T)-ß-thal compound heterozygotes, who were treated with HU, as well as 53 healthy individuals, all of Hellenic origin. Our study showed that genomic variants of the MAP3K5, NOS2A and ARG2 gene are associated with HU therapy efficacy in Hb S-ß-thal compound heterozygotes. We have also shown that FLT1 and ARG2 genomic variants are associated with the mild phenotype of NTDT patients. Our findings provide evidence that MAP3K5, NOS2A, ARG2 and FLT1 genomic variants could be considered as genomic biomarkers to predict HU therapy efficacy in Hb S-ß-thal compound heterozygotes and also to describe disease severity in patients with ß type hemoglobinopathies.

Production and Transduction of a Human Recombinant ß-Globin Chain into Proerythroid K-562 Cells To Replace Missing Endogenous ß-Globin.

Protein replacement therapy (PRT) has been applied to treat severe monogenetic/metabolic disorders characterized by a protein deficiency. In disorders where an intracellular protein is missing, PRT is not easily feasible due to the inability of proteins to cross the cell membrane. Instead, gene therapy has been applied, although still with limited success. ß-Thalassemias are severe congenital hemoglobinopathies, characterized by deficiency or reduced production of the adult ß-globin chain. The resulting imbalance of α-/ß-globin chains of adult hemoglobin (α2ß2) leads to precipitation of unpaired α-globin chains and, eventually, to defective erythropoiesis. Since protein transduction domain (PTD) technology has emerged as a promising therapeutic approach, we produced a human recombinant ß-globin chain in fusion with the TAT peptide and successfully transduced it into human proerythroid K-562 cells, deficient in mature ß-globin chain. Notably, the produced human recombinant ß-globin chain without the TAT peptide, used as internal negative control, failed to be transduced into K-562 cells under similar conditions. In silico studies complemented by SDS-PAGE, Western blotting, co-immunoprecipitation and LC-MS/MS analysis indicated that the transduced recombinant fusion TAT-ß-globin protein interacts with the endogenous native α-like globins to form hemoglobin α2ß2-like tetramers to a limited extent. Our findings provide evidence that recombinant TAT-ß-globin is transmissible into proerythroid K-562 cells and can be potentially considered as an alternative protein therapeutic approach for ß-thalassemias.

Compound Heterozygosity for Silent Cap +1570 (T>C) (HBB: c*96T>C), Codon 39 (C>T) (HBB: c.118C>T) and the Presence of αααanti-3.7/αα in Greece. A Case Presentation.

The rare point mutation Cap +1570 (T>C) (HBB: c*96T>C) has been reported in families of Czech, Greek, Turkish and Italian origin. The mutation contributes to a reduction of the ß-globin chain synthesis, and in heterozygous carriers, it causes a silent phenotype, while in compound heterozygosity with severe ß-thalassemia (ß-thal) mutations, it leads to a non transfusion dependent ß-thal intermedia (ß-TI) state. We report a case of compound heterozygosity for codon 39 (C>T) (HBB: c.118C>T) and Cap +1570, in addition to the presence of αααanti-3.7/αα.

Successful Outcome of Hyperhemolysis in Sickle Cell Disease following Multiple Lines of Treatment: The Role of Complement Inhibition.

Delayed hemolytic transfusion reaction (DHTR) is a life-threatening complication in patients with sickle cell disease, characterized by difficulties in diagnosis and management. Certain reports have suggested successful salvage treatment with the terminal complement inhibitor, eculizumab. We here report evidence of complement activation and successful complement inhibition with one dose of eculizumab in an adult sickle cell disease patient presenting DHTR with hyperhemolysis. A 21-year old female sickle cell disease patient [Hb S (HBB: c.20A>T)/ß-thalassemia (ß-thal)] presented at our Adult Thalassaemia Unit, Hippokration General Hospital of Thessaloniki, Thessaloniki, Greece, with headaches, perioral numbness and pain in both antibrachia. The patient was admitted with the diagnosis of vaso-occlussive crisis (VOC) and treated symptomatically. On her third day of admission, due to hemoglobin (Hb) value of 6.9 g/dL with increase in reticulocytes, the patient was transfused with one unit of compatible leukodepleted red blood cells (RBC). The following day, hemolytic parameters increased, although Coombs, panel antibodies and screening tests were negative. Five days later, she again received a unit of RBCs, resulting in another increase of hemolytic parameters. During the following 2 days, there was a dramatic decrease of Hb levels to 5.4 g/dL with reticulocytes at 6.0%, negative Coombs testing and negative alloantibodies. Based on these findings, we recognized the syndrome of DHTR with hyperhemolysis. Given the lack of immediate access to other treatment, we administered intravenous rituximab, immunoglobulins and corticosteroids. As there was no response, one dose of eculizumab (900 mg) was then administered with ciprofloxacin as prophylaxis. The patient remains well 6 months post treatment.