Rates of Strokes in Californians with Sickle Cell Disease in the Post-STOP Era.

Neurovascular complications, including strokes and transient ischemic attacks (TIAs), are common and cause significant morbidity in individuals with sickle cell disease (SCD). The STOP trial (1998) established chronic transfusions as the standard of care for children with SCD at high risk for stroke. Using statewide emergency department and hospitalization data from the California Department of Health Care Access and Innovation (1991-2019), we determined the cumulative incidence and rates for primary and recurrent strokes and TIAs in people with SCD pre- and post-STOP. For the 7,636 patients included in our SCD cohort, cumulative incidence for first ischemic stroke was 2.1% (95% CI: 1.8%, 2.4%) by age 20 years and 13.5% (95% CI: 12.3%, 14.7%) by age 60 years. Cumulative incidence for first intracranial hemorrhage (ICH) was 0.5% (95% CI: 0.4%, 0.7%) by age 20 years and 6.8% (95%CI: 5.9%, 7.7%) by age 60 years. Ischemic stroke rates increased in children (age <18 years, 234.9 vs 165.1 per 100,000PY, P=0.012) and adults (ages 31-50 years, 431.1 vs 303.2 per 100,000PY, P=0.031) in 2010-2019, compared to the preceding decade. There was an increase in rates of ICH in ages 18-30 and TIA in children <18 years from 2010-2019 when compared to the prior decade. Risk factors for stroke and TIA included increasing age, hypertension, and hyperlipidemia. These findings underscore the need for prevention of strokes in adults with SCD and suggest an emphasis on the management of modifiable cerebrovascular risk factors that have been demonstrated to be effective in the general population.

Alendronate preserves bone mineral density in adults with sickle cell disease and osteoporosis.

Low bone mineral density is highly prevalent in sickle cell disease (SCD); whether bisphosphonates can safely preserve or increase bone mass in SCD adults remains unknown. In this study, lumbar spine bone density remained stable with alendronate use, and treatment-related side effects were mostly mild and self-limited. PURPOSE: To describe the effects of alendronate in adults with sickle cell disease (SCD) and osteoporosis. METHODS: We reviewed retrospective clinical data from adults with SCD and osteoporosis treated with alendronate at a single center in Brazil (2009-2019). Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry (DXA) of the lumbar spine, femoral neck, and total hip. We analyzed BMD changes by alendronate treatment duration (months), stratified by sex, skeletal site, and SCD genotype. RESULTS: Sixty-four SCD adults with osteoporosis (69% females, 73% HbSS, mean age ± standard deviation 42.4 ± 10.9 years) received alendronate for a median (interquartile range) of 48 (29, 73) months. Compared with males, females had significantly lower baseline BMD (g/cm2) at the femoral neck (0.72 vs 0.85, p = < 0.001) and total hip (0.79 vs 0.88, p = 0.009). The between-sex differences in BMD changes were insignificant. Mean lumbar spine BMD significantly changed by 0.0357 g/cm2 (p = 0.028) in those on alendronate for > 5 years. Four adults (6.3%) reported mild therapy-related side effects. An atypical femoral diaphysis fracture, attributed to alendronate, was incidentally noted in a 37-year-old man on treatment for 4 years. CONCLUSION: In this retrospective cohort of adults with SCD and osteoporosis on alendronate for a median of 48 months, we found no significant interactions between sex and changes in lumbar spine, femoral neck, or total hip BMD with alendronate. Lumbar spine BMD was stable in those on alendronate for < 5 years. Side effects of alendronate were mild, though one patient developed an atypical femoral fracture.

Cancer-Associated Venous Thromboembolic Disease, Version 2.2024, NCCN Clinical Practice Guidelines in Oncology.

The NCCN Guidelines for Cancer-Associated Venous Thromboembolic Disease provide strategies for the prevention, diagnosis, and treatment of venous thromboembolism (VTE) in adult patients with cancer. VTE is a common and life-threatening condition in patients with cancer, and its management often requires multidisciplinary efforts. The NCCN panel is comprised of specialists spanning various fields, including cardiology, hematology, medical oncology, internal medicine, interventional radiology, and pharmacology. The content featured in this issue specifically addresses the evaluation and recommended treatment options outlined in the NCCN Guidelines for the diverse subtypes of cancer-associated VTE.

Benserazide as a potential novel fetal hemoglobin inducer: an observational study in non-carriers of hemoglobin disorders.

Induction of fetal hemoglobin production with hydroxyurea is an effective strategy in sickle cell disease and beta thalassemias, but up to 20% of patients do not respond to or cannot tolerate it. Benserazide is used in the treatment of Parkinson's disease and was noticed to induce gamma globin in preclinical models. We hypothesized that chronic treatment with benserazide-containing medication may be associated with increase in HbF production and in circulating F-cells. Blood samples were collected from 50 subjects including 35 patients on benserazide for Parkinson's disease, 10 healthy controls, and 5 patients with sickle cell anemia as positive controls for high fetal hemoglobin. We found a strong correlation between HbF and circulating F-cells in the entire population, but we found no significant increase in HbF and F-cell percentage in patients taking benserazide up to 700 mg daily. No hematologic abnormalities attributable to benserazide use after up to 22 years were detected. Our data support long-term safety and tolerability of benserazide at doses ten times higher than used in preclinical models to induce fetal hemoglobin. Further clinical trials enrolling patients with sickle cell disease and thalassemia are warranted to provide insight into its efficacy to treat those populations.

Cancer-Associated Venous Thromboembolic Disease, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology.

NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Cancer-Associated Venous Thromboembolic Disease focus on the prevention, diagnosis, and treatment of patients with cancer who have developed or who are at risk for developing venous thromboembolism (VTE). VTE is a significant concern among cancer patients, who are at heightened risks for developing as well as dying from the disease. The management of patients with cancer with VTE often requires multidisciplinary efforts at treating institutions. The NCCN panel comprises specialists from various fields: cardiology, hematology/hematologic oncology, internal medicine, interventional radiology, medical oncology, pharmacology/pharmacy, and surgery/surgical oncology. This article focuses on VTE prophylaxis for medical and surgical oncology inpatients and outpatients, and discusses risk factors for VTE development, risk assessment tools, as well as management methods, including pharmacological and mechanical prophylactics. Contraindications to therapeutic interventions and special dosing, when required, are also discussed.

Blood use and transfusion needs at a large health care system in Washington state during the SARS-CoV-2 pandemic.

BACKGROUND: This report evaluates hospital blood use trends during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, and identifies factors associated with the need for transfusion and risk of death in patients with coronavirus 2019 (COVID-19). METHODS: Overall hospital blood use and medical records of adult patients with COVID-19 were extracted for two institutions. Multivariate logistic regression models were conducted to estimate associations between the outcomes transfusion and mortality and patient factors. RESULTS: Daily blood use decreased compared to pre-COVID-19 levels; the effect was more significant for platelets (29% and 34%) compared to red blood cells (25% and 20%) at the two institutions, respectively. Surgical and oncologic services had a decrease in average daily use of platelets of 52% and 30%, and red blood cells of 39% and 25%, respectively. A total of 128 patients with COVID-19 were hospitalized, and 13 (10%) received at least one transfusion due to anemia secondary to chronic illness (n = 7), recent surgery (n = 3), and extracorporeal membrane oxygenation (n = 3). Lower baseline platelet count and admission to the intensive care unit were associated with increased risk of transfusion. The blood group distribution in patients with COVID-19 was 37% group O, 40% group A, 18% group B, and 5% group AB. Non-type O was not associated with increased risk of mortality. CONCLUSION: The response to the SARS-CoV-2 pandemic included changes in routine hospital operations that allowed for the provision of a sufficient level of care for patients with and without COVID-19. Although blood type may play a role in COVID-19 susceptibility, it did not seem to be associated with patient mortality.

Genetic and Clinical Heterogeneity in Thirteen New Cases with Aceruloplasminemia. Atypical Anemia as a Clue for an Early Diagnosis.

Aceruloplasminemia is a rare autosomal recessive genetic disease characterized by mild microcytic anemia, diabetes, retinopathy, liver disease, and progressive neurological symptoms due to iron accumulation in pancreas, retina, liver, and brain. The disease is caused by mutations in the Ceruloplasmin (CP) gene that produce a strong reduction or absence of ceruloplasmin ferroxidase activity, leading to an impairment of iron metabolism. Most patients described so far are from Japan. Prompt diagnosis and therapy are crucial to prevent neurological complications since, once established, they are usually irreversible. Here, we describe the largest series of non-Japanese patients with aceruloplasminemia published so far, including 13 individuals from 11 families carrying 13 mutations in the CP gene (7 missense, 3 frameshifts, and 3 splicing mutations), 10 of which are novel. All missense mutations were studied by computational modeling. Clinical manifestations were heterogeneous, but anemia, often but not necessarily microcytic, was frequently the earliest one. This study confirms the clinical and genetic heterogeneity of aceruloplasminemia, a disease expected to be increasingly diagnosed in the Next-Generation Sequencing (NGS) era. Unexplained anemia with low transferrin saturation and high ferritin levels without inflammation should prompt the suspicion of aceruloplasminemia, which can be easily confirmed by low serum ceruloplasmin levels. Collaborative joint efforts are needed to better understand the pathophysiology of this potentially disabling disease.

Hypocholesterolemia and dysregulated production of angiopoietin-like proteins in sickle cell anemia patients.

Angiopoietin-like proteins (ANGPTL) are responsible for inhibiting lipoprotein lipase activity, and ANGPTL3 and ANGPTL4 deficiencies have been shown to lower lipoprotein levels in animal models and in humans carrying loss-of-function mutations. Sickle cell anemia (SCA) is a hereditary hemolytic anemia characterized by vaso-occlusive crises and end-organ damage, which is curiously associated with hypocholesterolemia and a low incidence of atherosclerosis, whose underlying mechanisms are unclear. We hypothesized that ANGPTL3 and ANGPTL4 dysregulation is responsible for the hypolipidemic phenotype in SCA. We measured circulating concentrations of ANGPTL3 and ANGPTL4 and correlated them with hemolytic biomarkers and lipoproteins in 40 patients with SCA and 30 control individuals. The association between hemolysis and low cholesterol levels in SCA was confirmed along with surprisingly higher levels of ANGPTL3 and ANGPTL4 in SCA patients than in controls. ANGPTL3 correlated with hemolysis markers LDH and reticulocyte counts, while ANGPTL4 did not. Our data show a paradoxical increase in production of ANGPTL3 and ANGPTL4 in SCA, which would be expected to cause hyperlipidemia, due to increased inhibition of lipoprotein lipase. ANGPTL3, exclusively produced by the liver, correlated with hemolysis markers, suggesting a possible hepatic response to hemolysis. Further functional studies and replication in larger cohorts are warranted to investigate the dysregulation of lipid metabolism in SCA.

Red blood cells microparticles are associated with hemolysis markers and may contribute to clinical events among sickle cell disease patients.

Microparticles are sub-micron vesicles possessing protein and other materials derived from the plasma membrane of their parent cells, and literature suggests that they may have a role in the pathophysiology and downstream manifestations of sickle cell disease (SCD). The contributions of red blood cells microparticles (RMP) to the pathogenic mechanisms and clinical phenotypes of SCD are largely unknown. There is a controversy as to whether the proportions of intravascular hemolysis (approximately ≤ 30% of total hemolysis) would be enough to explain some complications seen in patients with SCD. We investigated RMP among 138 SCD patients and 39 HbAA individuals. Plasma RMPs were quantified by flow cytometry, plasma hemoglobin and heme by colorimetric assays, and haptoglobin and hemopexin by ELISA. The patients had higher RMP, plasma hemoglobin, and heme compared to the controls. On the contrary, haptoglobin and hemopexin were depleted in the patients. The RMP correlated positively with heme, lactate dehydrogenase, plasma hemoglobin, serum bilirubin, reticulocyte counts, and tricuspid regurgitant jet velocity of the patients. Contrarily, it correlated negatively with HbF, hemopexin, red blood cells counts, hemoglobin concentration, and haptoglobin. Although patients treated with hydroxyurea had lower RMP, this did not attain statistical significance. Patients with sickle leg ulcer and elevated tricuspid regurgitant jet velocity had higher levels of RMP. In conclusion, these data suggest that RMPs are associated with hemolysis and may have important roles in the pathophysiology and downstream complications of SCD.

Clinical relevance of heterozygosis for aceruloplasminemia.

Aceruloplasminemia is a rare form of brain iron overload of autosomal recessive inheritance that results from mutations in the CP gene, encoding the iron oxidase ceruloplasmin. Homozygous aceruloplasminemia causes progressive neurodegenerative disease, anemia, and diabetes, and is usually diagnosed late in life upon investigation of anemia, high ferritin, or movement disorders, but its heterozygous state is less characterized and believed to be silent. Here we report two heterozygotes for new mutations causing aceruloplasminemia from whom peripheral blood samples were collected for complete blood counts, iron studies, and genotyping by automated sequencing. We then performed a systematic review of preview reports of heterozygotes with data on genotype and clinical findings. Heterozygosity for aceruloplasminemia invariably causes reduced ceruloplasmin levels, and similarly to previews reports in the literature, our cases did not present with anemia. Mild hyperferritinemia was found only in two reports. Nevertheless, 5 out of 11 variants have been associated with significant neurological symptoms despite the presence of one wild-type alelle. This review contributes to better genetic counseling of heterozygotes for CP gene variants and supports that measuring ceruloplasmin levels may be useful when investigating patients with movement disorders or rare cases of unexplained high ferritin.

Impairment of Nitric Oxide Pathway by Intravascular Hemolysis Plays a Major Role in Mice Esophageal Hypercontractility: Reversion by Soluble Guanylyl Cyclase Stimulator.

Paroxysmal nocturnal hemoglobinuria (PNH) patients display exaggerated intravascular hemolysis and esophageal disorders. Since excess hemoglobin in the plasma causes reduced nitric oxide (NO) bioavailability and oxidative stress, we hypothesized that esophageal contraction may be impaired by intravascular hemolysis. This study aimed to analyze the alterations of the esophagus contractile mechanisms in a murine model of exaggerated intravascular hemolysis induced by phenylhydrazine (PHZ). For comparative purposes, sickle cell disease (SCD) mice were also studied, a less severe intravascular hemolysis model. Esophagus rings were dissected free and placed in organ baths. Plasma hemoglobin was higher in PHZ compared with SCD mice, as expected. The contractile responses produced by carbachol (CCh), KCl, and electrical-field stimulation (EFS) were superior in PHZ esophagi compared with control but remained unchanged in SCD mice. Preincubation with the NO-independent soluble guanylate cyclase stimulator 3-(4-amino-5-cyclopropylpyrimidin-2-yl)-1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine (BAY 41-2272; 1 µM) completely reversed the increased contractile responses to CCh, KCl, and EFS in PHZ mice, but responses remained unchanged with prior treatment with NO donor sodium nitroprusside (300 µM). Protein expression of 3-nitrotyrosine and 4-hydroxynonenal increased in esophagi from PHZ mice, suggesting a state of oxidative stress. In endothelial nitric oxide synthase gene-deficient mice, the contractile responses elicited by KCl and CCh were increased in the esophagus but remained unchanged with the intravascular hemolysis induced by PHZ. In conclusion, our results show that esophagus hypercontractile state occurs in association with lower NO bioavailability due to exaggerated hemolysis intravascular and oxidative stress. Moreover, our study supports the hypothesis that esophageal disorders in PNH patients are secondary to intravascular hemolysis affecting the NO-cGMP pathway.

A randomized trial of amlodipine in addition to standard chelation therapy in patients with thalassemia major.

Cardiovascular disease resulting from iron accumulation is still a major cause of death in patients with thalassemia major (TM). Voltage-gated calcium-channel blockade prevents iron entry into cardiomyocytes and may provide an adjuvant treatment to chelation, reducing myocardial iron uptake. We evaluated whether addition of amlodipine to chelation strategies would reduce myocardial iron overload in TM patients compared with placebo. In a multicenter, double-blind, randomized, placebo-controlled trial, 62 patients were allocated to receive oral amlodipine 5 mg/day or placebo in addition to their current chelation regimen. The main outcome was change in myocardial iron concentration (MIC) determined by magnetic resonance imaging at 12 months, with patients stratified into reduction or prevention groups according to their initial T2* below or above the normal human threshold of 35 ms (MIC, 0.59 mg/g dry weight). At 12 months, patients in the reduction group receiving amlodipine (n = 15) had a significant decrease in MIC compared with patients receiving placebo (n = 15) with a median of -0.26 mg/g (95% confidence interval, -1.02 to -0.01) vs 0.01 mg/g (95% confidence interval, -0.13 to 0.23), P = .02. No significant changes were observed in the prevention group (treatment-effect interaction with P = .005). The same findings were observed in the subgroup of patients with T2* <20 ms. Amlodipine treatment did not cause any serious adverse events. Thus, in TM patients with cardiac siderosis, amlodipine combined with chelation therapy reduced cardiac iron more effectively than chelation therapy alone. Because this conclusion is based on subgroup analyses, it needs to be confirmed in ad hoc clinical trials. This trial was registered at www.clinicaltrials.gov identifier as #NCT01395199.

Reduced rate of sickle-related complications in Brazilian patients carrying HbF-promoting alleles at the BCL11A and HMIP-2 loci.

The presence of high levels of fetal haemoglobin (HbF) provides well-validated clinical benefits to patients with sickle cell anaemia (SCA). Nevertheless it has been difficult to show clear direct effects of the known genetic HbF modifiers, such as the enhancer polymorphisms for haematopoietic transcription factors BCL11A and MYB, on SCA severity. Investigating SCA patients from Brazil, with a high degree of European genetic admixture, we have detected strong effects of these variants on HbF levels. Critically, we have shown, for the first time, that the presence of such HbF-promoting variants leads to a reduced rate of SCA complications, especially stroke.

Abnormal expression of inflammatory genes in placentas of women with sickle cell anemia and sickle hemoglobin C disease.

Sickle cell disease (SCD) is a complex disease that is characterized by the polymerization of deoxyhemoglobin S, altered red blood cell membrane biology, endothelial activation, hemolysis, a procoagulant state, acute and chronic inflammation, and vaso-occlusion. Among the physiological changes that occur during pregnancy, oxygen is consumed by fetal growth, and pregnant women with SCD are more frequently exposed to low oxygen levels. This might lead to red blood cells sickling, and, consequently, to vaso-occlusion. The mechanisms by which SCD affects placental physiology are largely unknown, and chronic inflammation might be involved in this process. This study aimed to evaluate the gene expression profile of inflammatory response mediators in the placentas of pregnant women with sickle cell cell anemia (HbSS) and hemoglobinopathy SC (HbSC). Our results show differences in a number of these genes. For the HbSS group, when compared to the control group, the following genes showed differential expression: IL1RAP (2.76-fold), BCL6 (4.49-fold), CXCL10 (-2.12-fold), CXCR1 (-3.66-fold), and C3 (-2.0-fold). On the other hand, the HbSC group presented differential expressions of the following genes, when compared to the control group: IL1RAP (4.33-fold), CXCL1 (3.05-fold), BCL6 (4.13-fold), CXCL10 (-3.32-fold), C3 (-2.0-fold), and TLR3 (2.38-fold). Taken together, these data strongly suggest a differential expression of several inflammatory genes in both SCD (HbSS and HbSC), indicating that the placenta might become an environment with hypoxia, and increased inflammation, which could lead to improper placental development.

Hydroxycarbamide reduces eosinophil adhesion and degranulation in sickle cell anaemia patients.

Inflammation, leucocyte and red cell adhesion to the endothelium contribute to the pathogenesis of sickle cell anaemia. Neutrophils appear to be important for vaso-occlusion, however, eosinophils may also participate in this phenomenon. The role of eosinophils in the pathophysiology of sickle cell anaemia (SCA) and the effect of hydroxycarbamide (HC) therapy on the functional properties of these cells are not understood. Patients with SCA and those on HC therapy (SCAHC) were included in the study. SCAHC individuals presented significantly lower absolute numbers of eosinophils than SCA. Furthermore, SCAHC eosinophils demonstrated significantly lower adhesive properties, compared to SCA eosinophils. SCA and SCAHC eosinophils presented greater spontaneous migration when compared with control eosinophils. Baseline eosinophil peroxidase and reactive oxygen species release was higher for SCA individuals than for control individuals, as were plasma levels of eosinophil derived neurotoxin. SCAHC eosinophil degranulation was lower than that of SCA eosinophil degranulation. Eotaxin-1 and RANTES levels were higher in the plasma of SCA and SCAHC individuals, when compared with controls. These data suggest that eosinophils exist in an activated state in SCA and indicate that these cells play a role in the vaso-occlusive process. The exact mechanism by which HC may alter SCA eosinophil properties is not clear.

Influence of the ßs haplotype and α-thalassemia on stroke development in a Brazilian population with sickle cell anaemia.

Stroke is a catastrophic complication of sickle cell anaemia (SCA) and is one of the leading causes of death in both adults and children with SCA. Evidence suggests that some genetic polymorphisms could be related to stroke development, but their association remains controversial. Here, we performed genotyping of five published single nucleotide polymorphisms, the α-thalassemia genotype, the G6PD A (-) variant deficiency, and the ß(S) haplotype in a large series of SCA patients with well-defined stroke phenotypes. Of 261 unrelated SCA patients included in the study, 67 (9.5 %) presented a documented, primary stroke event. Markers of haemolysis (red blood cell (RBC) counts, p = 0.023; reticulocyte counts, p = 0.003; haemoglobin (Hb) levels, p < 0.001; indirect bilirubin levels, p = 0.006; lactate dehydrogenase (LDH) levels, p = 0.001) were associated with stroke susceptibility. Genetically, only the ß(S) haplotype (odds ratio (OR) 2.9, 95 % confidence interval (CI) 1.56 to 4.31; p = 0.003) and the α(3.7kb)-thalassemia genotype (OR 0.31, 95 % CI 0.11 to 0. 83; p = 0.02) were associated with increased and decreased stroke risk, respectively. In multivariate analysis, the ß(S) haplotype was independently associated with stroke development (OR 2.26, 95 % CI 1.16 to 4.4; p = 0.016). Our findings suggest that only the ß(S) haplotypes and the α(3.7kb)-thalassemia genotype modulate the prevalence of stroke in our SCA population. Genetic heterogeneity among different populations may account for the irreproducibility amongst different studies.

Imaging flow cytometry for automated detection of hypoxia-induced erythrocyte shape change in sickle cell disease.

In preclinical and early phase pharmacologic trials in sickle cell disease, the percentage of sickled erythrocytes after deoxygenation, an ex vivo functional sickling assay, has been used as a measure of a patient's disease outcome. We developed a new sickle imaging flow cytometry assay (SIFCA) and investigated its application. To perform the SIFCA, peripheral blood was diluted, deoxygenated (2% oxygen) for 2 hr, fixed, and analyzed using imaging flow cytometry. We developed a software algorithm that correctly classified investigator tagged "sickled" and "normal" erythrocyte morphology with a sensitivity of 100% and a specificity of 99.1%. The percentage of sickled cells as measured by SIFCA correlated strongly with the percentage of sickle cell anemia blood in experimentally admixed samples (R = 0.98, P ≤ 0.001), negatively with fetal hemoglobin (HbF) levels (R = -0.558, P = 0.027), negatively with pH (R = -0.688, P = 0.026), negatively with pretreatment with the antisickling agent, Aes-103 (5-hydroxymethyl-2-furfural) (R = -0.766, P = 0.002), and positively with the presence of long intracellular fibers as visualized by transmission electron microscopy (R = 0.799, P = 0.002). This study shows proof of principle that the automated, operator-independent SIFCA is associated with predictable physiologic and clinical parameters and is altered by the putative antisickling agent, Aes-103. SIFCA is a new method that may be useful in sickle cell drug development.

Erythropoiesis-driven regulation of hepcidin in human red cell disorders is better reflected through concentrations of soluble transferrin receptor rather than growth differentiation factor 15.

Growth differentiation factor 15 (GDF-15) is a bone marrow-derived cytokine whose ability to suppress iron regulator hepcidin in vitro and increased concentrations found in patients with ineffective erythropoiesis (IE)suggest that hepcidin deficiency mediated by GDF-15 may be the pathophysiological explanation for nontransfusional iron overload. We aimed to compare GDF-15 production in anemic states with different types of erythropoietic dysfunction. Complete blood counts, biochemical markers of iron status, plasma hepcidin, GDF-15, and known hepcidin regulators [interleukin-6 and erythropoietin (EPO)] were measured in 87 patients with red cell disorders comprising IE and hemolytic states: thalassemia, sickle cell anemia, and cobalamin deficiency. Healthy volunteers were also evaluated for comparison. Neither overall increased EPO,nor variable GDF-15 concentrations correlated with circulating hepcidin concentrations (P = 0.265 and P = 0.872). Relative hepcidin deficiency was found in disorders presenting with concurrent elevation of GDF-15 and soluble transferrin receptor (sTfR), a biomarker of erythropoiesis, and sTfR had the strongest correlation with hepcidin (r(s) = 0.584, P < 0.0001). Our data show that high concentrations of GDF-15 in vivo are not necessarily associated with pathological hepcidin reduction, and hepcidin deficiency was only found when associated with sTfR overproduction. sTfR elevation may be a necessary common denominator of erythropoiesis-driven mechanisms to favor iron absorption in anemic states and appears a suitable target for investigative approaches to iron disorders.