High levels of proinflammatory cytokines IL-6 and IL-8 are associated with a poor clinical outcome in sickle cell anemia

Controversies in the pathophysiology of leg ulcers in sickle cell disease

Patients with sickle cell disease (SCD) often experience painful vaso-occlusive crises and chronic haemolytic anaemia, as well as various acute and chronic complications, such as leg ulcers. Leg ulcers are characterized by their unpredictability, debilitating pain and prolonged healing process. The pathophysiology of SCD leg ulcers is not well defined. Known risk factors include male gender, poor social conditions, malnutrition and a lack of compression therapy when oedema occurs. Leg ulcers typically start with spontaneous pain, followed by induration, hyperpigmentation, blister formation and destruction of the epidermis. SCD is characterized by chronic haemolysis, increased oxidative stress and decreased nitric oxide bioavailability, which promote ischaemia and inflammation and consequently impair vascular function in the skin. This cutaneous vasculopathy, coupled with venostasis around the ankle, creates an ideal environment for local vaso-occlusive crises, which can result in the development of leg ulcers that resemble arterial ulcers. Following the development of the ulcer, healing is hindered as a result of factors commonly observed in venous ulceration, including venous insufficiency, oedema and impaired angiogenesis. All of these factors are modulated by genetic factors. However, our current understanding of these genetic factors remains limited and does not yet enable us to accurately predict ulceration susceptibility.

Lipid and hemolysis parameters predicting acute chest syndrome in adulthood with sickle cell disease

Sickle cell disease (SCD) is a lifelong blood disorder affecting approximately 100,000 people in the United States and is one of the most common monogenic diseases. A serious complication of SCD is acute chest syndrome (ACS). ACS is a condition with a high rate of morbidity and mortality. The aim of the study was to assess hemolysis and lipid parameters in a cohort of confirmed SCD patients to predict ACS development in the following year.Standard lipid were performed (triglycerides, total cholesterol, high-density cholesterol, low-density cholesterol) panel to calculate of non-HDL-C, large buoyant LDL cholesterol (lbLDL-C) and small dense LDL cholesterol (sdLDL-C) with Sampson equation. Hemolysis and hematologic parameters were also evaluated.Among 91 patients included between September 2018 and June 2021, thirty-seven patients had history of ACS and 6 patients developed ACS during following year. In unadjusted logistic regression, total bilirubin was associated with ACS occurrence (RR: 1.2 [1.05-1.51] p = 0.013). Concerning lipid profile, non-HDL-C (RR: 0.87 [0.0.67-0.99] p = 0.04) and sdLDL-C (RR: 0.78 [0.49-0.96] p = 0.03) were associated with ACS occurrence decrease. C-reactive protein was associated with ACS occurrence (RR: 1.27 [1.065-1.85] p = 0.011).Based on these findings, this study demonstrated that several biomarker easily available can be used at steady state to predict ACS in the following year. The validation of these results are required to ensure the reproducibility of the findings.

Hemolysis-driven IFNα production impairs erythropoiesis by negatively regulating EPO signaling in sickle cell disease

ABSTRACT

Disordered erythropoiesis is a feature of many hematologic diseases, including sickle cell disease (SCD). However, very little is known about erythropoiesis in SCD. Here, we show that although bone marrow (BM) erythroid progenitors and erythroblasts in Hbbth3/+ thalassemia mice were increased more than twofold, they were expanded by only ∼40% in Townes sickle mice (SS). We further show that the colony-forming ability of SS erythroid progenitors was decreased and erythropoietin (EPO)/EPO receptor (EPOR) signaling was impaired in SS erythroid cells. Furthermore, SS mice exhibited reduced responses to EPO. Injection of mice with red cell lysates or hemin, mimicking hemolysis in SCD, led to suppression of erythropoiesis and reduced EPO/EPOR signaling, indicating hemolysis, a hallmark of SCD, and could contribute to the impaired erythropoiesis in SCD. In vitro hemin treatment did not affect Stat5 phosphorylation, suggesting that hemin-induced erythropoiesis suppression in vivo is via an indirect mechanism. Treatment with interferon α (IFNα), which is upregulated by hemolysis and elevated in SCD, led to suppression of mouse BM erythropoiesis in vivo and human erythropoiesis in vitro, along with inhibition of Stat5 phosphorylation. Notably, in sickle erythroid cells, IFN-1 signaling was activated and the expression of cytokine inducible SH2-containing protein (CISH), a negative regulator of EPO/EPOR signaling, was increased. CISH deletion in human erythroblasts partially rescued IFNα-mediated impairment of cell growth and EPOR signaling. Knocking out Ifnar1 in SS mice rescued the defective BM erythropoiesis and improved EPO/EPOR signaling. Our findings identify an unexpected role of hemolysis on the impaired erythropoiesis in SCD through inhibition of EPO/EPOR signaling via a heme-IFNα-CISH axis.

Brain Endothelial Cells Activate Neuroinflammatory Pathways in Response to Early Cerebral Small Vessel Disease (CSVD) Patients' Plasma

The pathogenesis of cerebral small vessel disease (CSVD) is largely unknown. Endothelial disfunction has been suggested as the turning point in CSVD development. In this study, we tested the effect of plasma from CSVD patients on human cerebral microvascular endothelial cells with the aim of describing the pattern of endothelial activation. Plasma samples from three groups of young subjects have been tested: PTs (subjects affected by early stage CSVD); CTRLs (control subjects without abnormalities at MRI scanning); BDs (blood donors). Human Brain Endothelial Cells 5i (HBEC5i) were treated with plasma and total RNA was extracted. RNAs were pooled to reduce gene expression-based variability and NGS analysis was performed. Differentially expressed genes were highlighted comparing PTs, CTRLs and BDs with HBEC5i untreated cells. No significantly altered pathway was evaluated in BD-related treatment. Regulation of p38 MAPK cascade (GO:1900744) was the only pathway altered in CTRL-related treatment. Indeed, 36 different biological processes turned out to be deregulated after PT treatment of HBEC5i, i.e., the cytokine-mediated signaling pathway (GO:0019221). Endothelial cells activate inflammatory pathways in response to stimuli from CSVD patients' plasma, suggesting the pathogenetic role of neuroinflammation from the early asymptomatic phases of cerebrovascular disease.

Homozygote drepanocytosis: Ferric status and inflammation in world and Africa: Review article and meta analysis

Background and Aims

Major sickle cell syndromes are subjected to a high frequency of hemolysis, infections, oxidative stress, and vasooclusive crises which promote inflammation and iron balance disorders. We aimed to systematically review and analyze the studies in this patients addressing in general, and Africa in particular.

Methods

The systematic review of published articles in the Pubmed and Google Scholar databases was carried out according to the recommendations of the PRISMA model. The case-control articles have been included. The data extracted from the articles were analyzed using statistical software R. The standardized mean difference (SMD) was used to assess the extent of the disease on the different variables studied.

Results

At the end, 128 articles were obtained; but only 33 were elligible for meta-analysis. A SMD of -1.79 was obtained for hemoglobin between the sickle cell patients and the controls due to the deviation from the overall mean hemoglobin in the cases (8 ± 2 g/dL) and in controls (13 ± 3 g/dL). Sickle cell disease showed a significant extent on ferritin [SMD = 2.61; (95% confidence interval, CI: 2.39-2.83); (p < 0.01)] compared to non-sickle cell patients thus describing a higher risk for sickle cell sufferer to have ferritin disorders. The included studies also described the influence of sickle cell anemia on serum iron [SMD = 1.52; (95% CI: 1.32-1.76); (p < 0.01)] compared to normal subjects. The high risk of inflammation has been described as higher in sickle cell patients [SMD = 0.38; (95% CI: 0.25-0.50)], reflecting the moderate extent of sickle cell disease on inflammation.

Conclusion

Patients with major sickle cell syndrome in inflammation have a higher risk of iron profile disorders compared to the normal population. Further studies are needed to explore mechanisms for preventing the deleterious effects of iron from this hemolysis, for example haptoglobin genotyping.

Evaluation of lung function in a German single center cohort of young patients with sickle cell disease using EIT and standard techniques

Background and objective

Sickle cell disease (SCD) is a very common autosomal recessive hemoglobinopathy leading to multiple pulmonary complications that are closely associated with mortality. The pathophysiology of chronic pulmonary involvement is not yet fully understood and no specific therapies are available.

Methods

The aim of this cross-sectional study was to characterize the lung function of children and young adolescents with SCD in a German single-center cohort and to extend conventional lung function testing by the use of a new imaging method. We performed spirometry and body plethysmography in 35 children and young adults with hemoglobin SS, SC, S/β-thalassemia as well as 50 controls. These data were compared with clinical characteristics and typical laboratory parameters of hemolysis and disease activity in SCD. To identify lung inhomogeneities, for example due to atelectasis, hyperinflation, air trapping or vascular occlusions, we used the promising new method of electrical impedance tomography (EIT) and calculated global inhomogeneity indices.

Results

Lung function of patients with SCD was significantly reduced compared to that of healthy controls. When the result was found to be pathological, the most commonly observed type of breathing disorder was classified as restrictive. Laboratory parameters showed typical features of SCD including decreased levels of hemoglobin and hematocrit and elevated levels of leucocytes, platelets, lactate dehydrogenase and total bilirubin. However, there was no correlation between blood values and reduced lung function. Electrical impedance tomography (EIT) revealed no abnormalities in SCD patients compared to healthy controls. In particular, we were unable to demonstrate any regional inhomogeneities in lung ventilation.

Conclusion

In our study, SCD patients showed impaired lung function, with a relevant percentage of patients suffering from restrictive breathing disorder. Signs of obstruction could not be detected. Electrical impedance tomography (EIT) measurements revealed no unevenness that would suggest air entrapment, blockage of blood vessels, excessive inflation, obstruction, or other forms of lung disease. Additionally, the reduction in lung function observed in SCD patients was not related to the disease severity or laboratory test results.

Challenges in the treatment of melanoma with BRAF and MEK inhibitors in patients with sickle cell disease: case report and review of the literature

Patients with sickle cell disease (SCD) suffer from complications due to anemia, inflammation, and vaso-occlusion. Factors that trigger sickling and/or inflammation may initiate such complications, while treatment with hydroxyurea (HU) reduces their emergence and prolongs survival. On the contrary, inhibition of the BRAF-MEK-ERK pathway with BRAF and MEK inhibitors (BRAF/MEKi) has revolutionized treatment of melanoma but their use has been correlated with inflammatory adverse events. Thus, treatment of patients with SCD with BRAF/MEKi may be quite challenging and pyrexia in those patients should be managed as a medical emergency. In this article, intrigued by the case of a 36-year-old female patient with S/β-thal under HU who was treated with dabrafenib and trametinib for melanoma, we analyze the mechanisms underlying inflammation and vaso-occlusion in SCD, the mechanisms of pyrexia and inflammation induced by BRAF/MEKi, their potential interconnections, the shared role of the inflammasome in these two entities, and the protective effect of HU in SCD. Since SCD is the most common inheritable blood disorder, the administration of BRAF/MEKi for melanoma in patients with SCD may be a rather common challenge. Thus, proper treatment with HU may pave the way for an uneventful management of such patients.

Repercussions of sickle cell disease and sickle cell ulcers for men inserted in the world of work

OBJECTIVE

To analyze the repercussions of sickle cell disease and sickle cell ulcer for men in the world of work and discuss the challenges faced to remain in the work environment.

METHOD

A qualitative study, developed at the dressing clinic and at a stomatherapy clinic. Twenty men with sickle cell disease and sickle cell ulcer participated, applying a semi-structured interview script. The software Interface de R pour les Analyses Multidimensionnelles de Textes et de Questionnaires was used for treatment and lexical data analysis.

RESULTS

The Descending Hierarchical Classification enabled the creation of classes: Man with sickle cell disease and sickle cell ulcer: experiences and repercussions; and Coping measures adopted by men with sickle cell disease and sickle cell ulcer to stay at work.

CONCLUSION

Disease and injury repercussions involve biopsychosocial dimensions, highlighting the need for professional training to assist with competence and humanity. Strategies adopted to maintain work are breaks in the working day, use of analgesics to relieve pain, allocating time during work to apply dressings.

Are IL-1 family cytokines important in management of sickle cell disease in Sub-Saharan Africa patients?

Introduction

Sickle cell disease (SCD) is the most common genetic disease found in Africa and throughout the world. It is responsible for a high rate of hemolysis, systemic inflammation, and modulation of the immune system with the involvement of immunological molecules, such as cytokines. IL-1β is a major inflammatory cytokine. IL-18 and IL-33, members of IL-1 family, also exhibit characteristics of inflammation-related cytokines. Thus, in order to contribute to the evaluation of the severity and prognosis of SCD in Africa, this study aimed to estimate the cytokine response, in particular the levels of cytokines of the IL-1 family, in sickle cell patients living in a Sub-Saharan country.

Methods

Ninety patients with a diagnosis of SCD were recruited with different hemoglobin types. Samples were assessed for cytokine levels using the Human Inflammation Panel assay from BioLegend. The assay allows the simultaneous quantification of 13 human inflammatory cytokines/chemokines, i.e., IL-1β, IFN-α2, IFN-γ, TNFα, MCP-1 (CCL2), IL-6, IL-8 (CXCL8), IL-10, IL-12p70, IL-17A, IL-18, IL-23, and IL-33.

Results and discussion

the assessment of plasma cytokines in SCD patients revealed significantly increased levels of IL-1 family cytokines in crisis compared to steady state, suggesting a substantial involvement of these cytokines in clinical exacerbation. This suggests the possibility of a causal effect in the SCD pathology and can open the way to define better care, pointing toward new therapeutic avenues for sickle disease in Sub-Saharan Africa.

Contributions of von Willebrand factor to clinical severity of sickle cell disease: a systematic review and metanalysis

AIM

To evaluate the contributions of VWF to the clinical manifestation and severity of SCD.

DESIGN

A systematic review of peer-reviewed articles published in English. The review was carried out in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist.

METHODS

The data sources for the review included MEDLINE, PubMed, CINAHL, and Academic Search Complete. Articles that applied a quantitative approach to the investigation of the relationship of vWF with clinical manifestations and severity indices were included. The risk of bias assessment was carried out with a mixed-method appraisal tool. We computed I ² to estimate the degree of heterogeneity.

RESULT

There was a significantly higher level of VWF in SCD than in the control (d = 2.7, Z = 4.865, P < 0.001, I ² = 96.41%). Significant positive correlations were obtained for the relationship of VWF with vasoocclusive crisis (r= 0.277, Z= 5.077, P < 0.001, 1 ² =15.62), rate of hemolysis (r=0.441; Z= 4.440, I ² = <1%), extracellular haemoglobin (r=-0.397, Z=-4.155, I ² =<1%) and CRP (r = 0.331, Z = 4.566, P < 0.001, I ² < 1%).The VWF is important in determining the clinical severity of sickle cell disease, which constitutes a putative therapeutic target. More work is required to understand the causal direction underlying the association between VWF levels and the clinical severity of sickle cell disease and the potential role that VWF plays in the clinical manifestations of sickle cell disease.

PROTOCOL REGISTRATION

The protocol was registered with PROSPERO (CRD42021262625).

COVID-19 infection and pain in adolescents with sickle cell disease: A case series

Adolescents with sickle cell disease (SCD) have been shown to have pain-related sequelae following COVID-19 infection. In this case series, we discuss five adolescents with SCD and SARS-CoV-2 infection who subsequently developed complex pain circumstances manifested as: (1) increased frequency of acute care visits or admissions for pain; (2) new onset chronic pain; (3) new onset neuropathic pain; (4) escalation in the complexity of pharmacologic therapies; (5) increased use of nonpharmacologic interventions. While more research is needed to fully understand the implications of COVID-19 infection on pain in adolescents with SCD, these cases suggest the presence of a complex relationship.

CXCL8, CCL2, and CMV Seropositivity as New Prognostic Factors for a Severe COVID-19 Course

The exact pathophysiology of severe COVID-19 is not entirely elucidated, but it has been established that hyperinflammatory responses and cytokine storms play important roles. The aim of this study was to examine CMV status, select chemokines, and complement components in COVID-19, and how concentrations of given molecules differ over time at both molecular and proteomic levels. A total of 210 COVID-19 patients (50 ICU and 160 non-ICU patients) and 80 healthy controls were enrolled in this study. Concentrations of select chemokines (CXCL8, CXCL10, CCL2, CCL3, CCR1) and complement factors (C2, C9, CFD, C4BPA, C5AR1, CR1) were examined at mRNA and protein levels with regard to a COVID-19 course (ICU vs. non-ICU group) and CMV status at different time intervals. We detected several significant differences in chemokines and complement profiles between ICU and non-ICU groups. Pro-inflammatory chemokines and the complement system appeared to greatly contribute to the pathogenesis and development of severe COVID-19. Higher concentrations of CXCL8 and CCL2 in the plasma, with reduced mRNA expression presumably through negative feedback mechanisms, as well as CMV-positive status, correlated with more severe courses of COVID-19. Therefore, CXCL8, CCL2, and CMV seropositivity should be considered as new prognostic factors for severe COVID-19 courses. However, more in-depth research is needed.

Exercise Capacity and Biomarkers Among Children and Adolescents With Sickle Cell Disease

BACKGROUND

Sickle cell disease is the most common genetic hemoglobinopathy globally and systemically affects body functioning, decreasing exercise capacity.

OBJECTIVE

To assess exercise capacity through the 6-minute walk test (6MWT) and biomarkers in children and adolescents with sickle cell disease.

MATERIALS AND METHODS

Cross-sectional study involving 20 children and adolescents from Brazil. Demographic and socioeconomic data were obtained. Baseline measurements included biomarkers (red blood cells, hemoglobin, hematocrit, white blood cells, platelets, reticulocytes, lactate dehydrogenase, creatine phosphokinase, C-reactive protein, interleukin 6, and fetal hemoglobin). The following data were obtained before, during, and after the 6MWT: heart rate, blood pressure, and peripheral oxygen saturation.

RESULTS

Eighteen children and adolescents ages 5-14 years old were analyzed, 61.1% boys, 100% black or brown, and 61.1% in primary education, with low household income. The average distance walked in 6MWT was 463.8 (137.7) m, significantly less than the predicted value (P < .001). The distance of 6MWT was associated positively with age (P = .042) and inversely with reticulocyte count (P = .42) and interleukin 6 (P = .00). Age modified the effect of interleukin 6 in younger children (P = .038).

CONCLUSION

Our findings suggest increased baseline levels of biomarkers of hemolysis and inflammation impact on 6MWT performance.

Differentially Expressed Genes Reveal the Biomarkers and Molecular Mechanism of Osteonecrosis

Osteonecrosis is one of the most refractory orthopedic diseases, which seriously threatens the health of old patients. High-throughput sequencing (HTS) and microarray analysis have confirmed as an effective way for investigating the pathological mechanism of disease. In this study, GSE7716, GSE74089, and GSE123568 were obtained from Gene Expression Omnibus (GEO) database and used to identify differentially expressed genes (DEGs) by R language. Subsequently, the DEGs were analyzed with Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. Moreover, the protein-protein interaction (PPI) network of DEGs was analyzed by STRING database and Cytoscape. The results showed that 318 downregulated genes and 58 upregulated genes were observed in GSE7116; 690 downregulated genes and 1148 upregulated genes were screened from 34183 genes in GSE74089. The DEGs involved in progression of osteonecrosis involved inflammation, immunological rejection, and bacterial infection-related pathways. The GO enrichment showed that osteonecrosis was related with extracellular matrix, external encapsulating structure organization, skeletal system development, immune response activity, cell apoptosis, mononuclear cell differentiation, and serine/threonine kinase activity. Moreover, PPI network showed that the progression of osteonecrosis of the femoral head was related with CCND1, CDH1, ESR1, SPP1, LOX, JUN, ITGA, ABL1, and VEGF, and osteonecrosis of the jaw is related with ACTB, CXCR4, PTPRC, IL1B, CXCL8, TNF, JUN, PTGS2, FOS, and RHOA. In conclusion, this study identified the hub factors and pathways which might play important roles in progression of osteonecrosis and could be used as potential biomarkers for diagnosis and treatment of osteonecrosis.

Anti-inflammatory cytokines in sickle cell disease

Sickle cell disease (SCD) is a well-studied monogenetic disease with an established chronic inflammatory component. The paradigm shift towards inflammation has made the pathophysiology of SCD even more complex. Studies have shown that an imbalance between the pro-inflammatory and anti-inflammatory cytokines in SCD exists; however, the reports are skewed toward the pro-inflammatory mediators. We enumerate recent in vitro and in vivo studies on anti-inflammatory cytokines in SCD patients, and discuss the biology of anti-inflammatory cytokines including the already reported IL-2, TGF-β, and IL-10 as well as the recently discovered IL-27, IL-35 and IL-37. This review will improve the understanding of the pathophysiology of SCD and aid in the search of new therapeutic options for patients with SCD.

Association between inflammatory molecules, nitric oxide metabolites and leg ulcers in individuals with sickle cell anemia

Introduction

Leg ulcers (LUs) are relatively common in patients with sickle cell anemia (SCA). The role of inflammation and nitric oxide (NO) pathways in the pathophysiology of the LU is not understood.

Objective

The aim of this study was to verify the association between inflammatory molecules and nitric oxide metabolites (NOx) and the occurrence of the LU in patients with SCA.

Method

It was a cross-sectional study on adult participants with SCA followed at Fundação Hemominas, a public blood center in Brazil. Eligible participants were recruited and included in one of two groups: Group 1, comprised of cases with SCA (Hb SS) and at least one LU at the time of inclusion in the study and Group 2, comprised of controls with SCA without a history of LU, matched by sex and age to cases. Participants were interviewed to obtain sociodemographic data and blood samples were collected. Clinical and laboratory data were abstracted from medical records. Nitric oxide metabolites (NOx) and inflammatory molecules were quantified using an immunoassay and Multiplex xMAP® technology, respectively. Eighty-seven individuals were included, ranging in age from 17 to 61 years (mean 40 ± 10.7 years); 30 had LU and 57 were controls without LU.

Results

Participants with LU had significantly higher levels of interleukin 8 (IL-8), IL-10, IL-15, NOx and platelet and white blood cell (WBC) counts, when compared to those without LU. Participants with LU had a significantly higher risk of having a history of osteomyelitis and a higher use of antiseptic soap in bathing, when compared to those without LU.

Conclusion

In conclusion, our results showed that NOx, inflammatory molecules and hematological features were associated with LU in Brazilian adults with SCA.

Hyponatremia in Patients with Hematologic Diseases

Hyponatremia is the most common electrolyte disorder in clinical practice and is associated with increased morbidity and mortality. It is frequently encountered in hematologic patients with either benign or malignant diseases. Several underlying mechanisms, such as hypovolemia, infections, toxins, renal, endocrine, cardiac, and liver disorders, as well as the use of certain drugs appear to be involved in the development or the persistence of hyponatremia. This review describes the pathophysiology of hyponatremia and discusses thoroughly the contributing factors and mechanisms that may be encountered specifically in patients with hematologic disorders. The involvement of the syndrome of inappropriate antidiuretic hormone (SIADH) secretion and renal salt wasting syndrome (RSWS) in the development of hyponatremia in such patients, as well as their differential diagnosis and management, are also presented. Furthermore, the distinction between true hyponatremia and pseudohyponatremia is explained. Finally, a practical algorithm for the evaluation of hyponatremia in hematologic patients, as well as the principles of hyponatremia management, are included in this review.

Leg ulcers in sickle cell disease patients

Leg ulcers are the most common cutaneous complication of sickle cell disease. These lesions occur mainly in homozygous forms, are slow to heal and often relapse, causing negative physical, emotional, and economic impacts. In this paper, we discuss the clinical presentation, diagnosis, and pathophysiology of sickle cell leg ulcers and their implications for treatment.

CD4+ T Cell Profile and Activation Response in Sickle Cell Disease Patients with Osteonecrosis

Recent evidence suggests that abnormalities involving CD4⁺T lymphocytes are associated with the pathophysiology of osteonecrosis (ON); however, few studies have addressed the CD4⁺T cells in ON related to sickle cell disease (SCD/ON). In addition, T cells producing multiple cytokines simultaneously are often present in the inflammatory milieu and may be implicated in the immune response observed in SCD/ON. In the present study, we aimed to characterize the functional status of CD4⁺T cells in SCD by simultaneously determining the frequency of IFN-γ ⁺, IL-4⁺, and IL-17⁺ CD4⁺T in cell cultures under exogenous stimuli. Peripheral blood mononuclear cells (PB-MNCs) from 9 steady-state SCD patients, 15 SCD/ON patients, and 19 healthy controls had functional status of CD4⁺T cells analyzed. Bone marrow mononuclear cells (BM-MNCs) from 24 SCD/ON patients (SCD BM) and 18 patients with ON not related to SCD (non-SCD BM) were also analyzed. We found that PB-MNC of SCD patients with or without ON presented significantly reduced TCD4⁺, TCD8⁺, and TCD4⁺ naïve cell frequencies and increased frequency of circulating CD4⁺T cells able to simultaneously produce IFN-γ ⁺/IL4⁺ and IL-17⁺/IL4⁺ compared to healthy controls. Conversely, the polyclonal stimulation of BM-MNC induced an increased frequency of CD4⁺IFN-γ ⁺ and CD4⁺IL-17⁺ in SCD BM compared to non-SCD BM. The increased proportion of CD4⁺ T cells able to produce a broad spectrum of proinflammatory cytokines after a strong stimulus indicates that the immune system in SCD/ON patients presents an expressive pool of partially differentiated cells ready to take on effector function. It is possible that this increased subpopulation may extend to inflammatory sites of target organs and may contribute to the maintenance of inflammation and the pathophysiology of osteonecrosis in sickle cell disease.