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

Bone tissue engineering for treating osteonecrosis of the femoral head

Osteonecrosis of the femoral head (ONFH) is a devastating and complicated disease with an unclear etiology. Femoral head-preserving surgeries have been devoted to delaying and hindering the collapse of the femoral head since their introduction in the last century. However, the isolated femoral head-preserving surgeries cannot prevent the natural progression of ONFH, and the combination of autogenous or allogeneic bone grafting often leads to many undesired complications. To tackle this dilemma, bone tissue engineering has been widely developed to compensate for the deficiencies of these surgeries. During the last decades, great progress has been made in ingenious bone tissue engineering for ONFH treatment. Herein, we comprehensively summarize the state-of-the-art progress made in bone tissue engineering for ONFH treatment. The definition, classification, etiology, diagnosis, and current treatments of ONFH are first described. Then, the recent progress in the development of various bone-repairing biomaterials, including bioceramics, natural polymers, synthetic polymers, and metals, for treating ONFH is presented. Thereafter, regenerative therapies for ONFH treatment are also discussed. Finally, we give some personal insights on the current challenges of these therapeutic strategies in the clinic and the future development of bone tissue engineering for ONFH treatment.

Impact of hydroxyurea on lymphocyte subsets in children with sickle cell anemia

BACKGROUND

Hydroxyurea (HU) has beneficial effects in the management of sickle cell anemia (SCA), but there is a paucity of data on the effect of HU on immune cells in SCA. Herein we aimed to evaluate the effect of HU on immune profiles of Egyptian children with SCA.

METHODS

This was a controlled prospective cohort study conducted in 30 children with SCA and 30 healthy age-matched controls. Flow cytometry was used to evaluate lymphocyte profiles, including CD8+ T, CD19+ B, CD3+, CD4+, natural killer (NK), NK T, T helper 1 (Th1), Th2, T cytotoxic (Tc1), and Tc2 cells, prior to and after 1 year of treatment with HU.

RESULTS

HU treatment led to significant increases in hemoglobin (Hb), red blood cell, and hematocrit counts and a significant decrease in the percentage of sickle Hb, with subsequent improvement in SCA complications. Compared with baseline values, CD3+, CD4+, Th1, and CD8+ T cells were significantly increased, while NK, Th2, and Tc2 cells were significantly decreased, with a resulting increase in the Th1/Th2 and Tc1/Tc2 ratios.

CONCLUSIONS

HU has the beneficial effect of restoring the abnormally elevated immune parameters in children with SCA.

IMPACT

Hydroxyurea treatment restores the abnormal immune parameters in children with sickle cell anemia. HU treatment led to significantly increased CD3+, CD4+, Th1, and CD8+ T cells, while NK, Th2, and Tc2 cells were significantly decreased, with a resulting increase in the Th1/Th2 and Tc1/Tc2 ratios. Our study showed the impact of HU therapy on immune parameters in children with SCA.

Blood plasma and bone marrow interstitial fluid metabolomics of sickle cell disease patients with osteonecrosis: An exploratory study to dissect biochemical alterations

Individuals with sickle cell disease (SCD) often experience numerous vaso-occlusive crisis events throughout their lives, which can progress to severe damage of several organs, including avascular necrosis, also known as osteonecrosis (ON). Osteonecrosis is one of the most devastating musculoskeletal clinical manifestations of sickle cell disease, afflicting up to 50% of the SCD patients. Herein, a NMR-based untargeted metabolomics approach was used to assess the metabolome alterations of blood plasma and bone marrow interstitial fluid (BMIF) samples of SCD patients with osteonecrosis. Furthermore, biochemical signatures associated with different osteonecrosis stages were assessed by analysing the metabolome of blood plasma and bone marrow interstitial fluid samples of SCD patients with different stages of the disease based on the Fiat and Arlet classification (FAC). Multivariate statistical analysis allowed a clear discrimination between the studied groups and it provided important insights into the different osteonecrosis stages. Citrate was pointed out as a possible biomarker to differentiate SCD patients with and without osteonecrosis. Acetate, creatinine, histidine, tyrosine, glucose, and NI5 seems to be key metabolites associated to different stages of the disease. Although this is a pioneer exploratory study, we acknowledge that fact that it is limited by the group sizes and absence of a validation cohort. Nevertheless, multivariate statistical analyses indicated that the metabolome of blood plasma and BMIF samples encompasses a complex metabolic regulation system for osteonecrosis.

An overview of pathophysiology and treatment options of osteonecrosis of femoral head in sickle cell disease

Osteonecrosis of the femoral head (ONFH) is the most prevalent musculoskeletal pathologic manifestation of sickle cell disease (SCD) resulting in an osteonecrotic event. This review aimed to summarize mechanisms involved in pathophysiology of ONFH and treatment options available in Saudi Arabia to treat SCD patients with complication of osteonecrotic event. The pathophysiology of ONFH include genetic and micro particles involvement. The progression of osteonecrosis involves reduced levels of bioactive compounds in peripheral blood mononuclear cells and elevated CD4+T circulating levels to stimulate pro-inflammatory cytokines contributing to inflammation at target site. Initial treatment approach is pharmacological agents use to mitigate risk. Further, bone morphogenetic protein stimulation initiate bone formation and treatment can be improved with the use of bone morphogenetic protein, total hip arthroplasty and cell therapies. This review provides baseline information for future studies to be carried out in Saudi Arabia to improve treatment options in SCD patients with ONFH.

Imbalanced T-Cell Subsets May Facilitate the Occurrence of Osteonecrosis of the Femoral Head

Background

Osteonecrosis of the femoral head (ONFH) is a complex disease resulting in degeneration of the hip joint. The pathogenesis of ONFH is largely unknown, but alterations in immunological factors have been proposed to play a role.

Methods

We included 109 patients with ONFH and 109 age-, sex-, and body mass index-matched healthy controls in this study. The percentage of circulating CD3+, CD4+, and CD8+ lymphocytes among the total lymphocytes was identified by flow cytometry and compared between the cases and controls. Subgroup analysis within each etiological group and correlation analysis of T-cell subset levels with disease duration were performed. Furthermore, we compared the expression patterns of CD4, RANKL, and FoxP3 in the femoral head of healthy and glucocorticoid (GC)-treated ONFH rats.

Results

The results showed that CD3+ and CD4+ T-cell counts and the CD4+/CD8+ ratio were significantly higher in patients with ONFH and that CD3+ lymphocyte levels were negatively correlated with disease duration. The CD4+ T-cell levels and CD4+/CD8+ ratios in the GC-ONFH etiological group were lower than those in the idiopathic-, traumatic-, and alcoholic-ONFH groups, while the CD8+ T-cell levels were higher. Furthermore, the CD3+, CD4+, and CD8+ T-cell counts and the CD4+/CD8+ ratio were higher in the GC-ONFH group than in the control group. Finally, we observed diminished levels of FoxP3/CD4 double-positive T regulatory cells and increased RANKL+ T-cell levels in the bone marrow of the femoral head in GC-ONFH rats.

Conclusion

The imbalance of T-cell subsets might be involved in the pathophysiological process of ONFH, and diminished CD4+/FoxP3+ T regulatory cells may be associated with increased RANKL+ T cells in the bone marrow of the femoral head in GC-ONFH, which may facilitate bone resorption and collapse of the femoral head.

Trial Registration

This study was registered in the Chinese Clinical Trial Registry (Registration number: ChiCTR2100042642).

In-Depth Immunological Typization of Children with Sickle Cell Disease: A Preliminary Insight into Its Plausible Correlation with Clinical Course and Hydroxyurea Therapy

Sickle cell disease (SCD) is a condition of functional hypo-/a-splenism in which predisposition to bacterial infections is only a facet of a wide spectrum of immune-dysregulation disorders forming the clinical expression of a peculiar immunophenotype. The objective of this study was to perform an in-depth immunophenotypical characterization of SCD pediatric patients, looking for plausible correlations between immunological biomarkers, the impact of hydroxyurea (HU) treatment and clinical course. This was an observational case−control study including 43 patients. The cohort was divided into two main groups, SCD subjects (19/43) and controls (24/43), differing in the presence/absence of an SCD diagnosis. The SCD group was split up into HU+ (12/19) and HU− (7/19) subgroups, respectively receiving or not a concomitant HU treatment. The principal outcomes measured were differences in the immunophenotyping between SCD patients and controls through chi-squared tests, t-tests, and Pearson’s correlation analysis between clinical and immunological parameters. Leukocyte and neutrophil increase, T-cell depletion with prevalence of memory T-cell compartment, NK and B-naïve subset elevation with memory and CD21low B subset reduction, and IgG expansion, significantly distinguished the SCD HU− subgroup from controls, with naïve T cells, switched-memory B cells and IgG maintaining differences between the SCD HU+ group and controls (p-value of <0.05). The mean CD4+ central-memory T-cell% count was the single independent variable showing a positive correlation with vaso-occlusive crisis score in the SCD group (Pearson’s R = 0.039). We report preliminary data assessing plausible clinical implications of baseline and HU-related SCD immunophenotypical alterations, which need to be validated in larger samples, but potentially affecting hypo-/a-splenism immuno-chemoprophylactic recommendations.

Role of C-X-C motif chemokine ligand 14 promoter region DNA methylation and single nucleotide polymorphism in influenza A severity

OBJECTIVE

The purpose of our experiment is to discuss the function of DNA methylation and single nucleotide polymorphism (SNP) in C-X-C motif chemokine ligand 14 (CXCL14) promoter region in influenza A (H1N1) severity.

METHODS

Clinic data and blood samples from H1N1 patients were collected. Blood routine indexes were measured. Levels of T lymphocytes were assessed. Importantly, CXCL14 expression and methylation in H1N1 patients and A549 cells were detected through functional assays. Additionally, rs2237061, rs2237062 and rs2547 of CXCL14 were genotyped to analyze the relation of CXCL14 SNP and H1N1 severity.

RESULTS

The number of leukocytes, neutrophils and lymphocytes as well as T lymphocytes in H1N1 patients was lower than that in healthy subjects, and that was decreased in severe H1N1 patients compared with the mild H1N1 patients. In HIN1 patients, CXCL14 expression was decreased, while CXCL14 methylation was increased, and CXCL14 expression was further decreased and CXCL14 methylation was further increased in severe H1N1 patients. CXCL14 methylation was negatively correlated with T lymphocytes in H1N1 patients. CXCL14 methylation was elevated in H1N1-infected A549 cells. GA and AA genotypes of rs2547 in CXCL14 were risky genotypes for H1N1, and AA genotype was risky genotype for severe H1N1. Number of T lymphocytes was lower in H1N1 patients carrying AA genotype of rs2547 than that in GA + GG genotype.

CONCLUSION

CXCL14 promoter region DNA methylation and SNP were correlated with H1N1 severity.