Neutralizations of IL-17A and IL-21 regulate regulatory T cell/T-helper 17 imbalance via T-helper 17-associated signaling pathway in immune thrombocytopenia

E3 ubiquitin ligase casitas B-lineage lymphoma-b modulates T-cell anergic resistance via phosphoinositide 3-kinase signaling in patients with immune thrombocytopenia

BACKGROUND

The E3 ubiquitin ligase casitas B-lineage lymphoma-b (CBLB) is a newly identified component of the ubiquitin-dependent protein degradation system and is considered an important negative regulator of immune cells. CBLB is essential for establishing a threshold of T-cell activation and regulating peripheral T-cell tolerance through various mechanisms. However, the involvement of CBLB in the pathogenesis of immune thrombocytopenia (ITP) is unknown.

OBJECTIVES

We aimed to investigate the expression and role of CBLB in CD4+ T cells obtained from patients with ITP through quantitative proteomics analyses.

METHODS

CD4+ T cells were transfected with adenoviral vectors overexpressing CBLB to clarify the effect of CBLB on anergic induction of T cells in patients with ITP. DNA methylation levels of the CBLB promoter and 5' untranslated region (UTR) in patient-derived CD4+ T cells were detected via MassARRAY EpiTYPER assay (Agena Bioscience).

RESULTS

CD4+ T cells from patients with ITP showed resistance to anergic induction, highly activated phosphoinositide 3-kinase-protein kinase B (AKT) signaling, decreased CBLB expression, and 5' UTR hypermethylation of CBLB. CBLB overexpression in T cells effectively attenuated the elevated phosphorylated protein kinase B level and resistance to anergy. Low-dose decitabine treatment led to significantly elevated levels of CBLB expression in CD4+ T cells from 7 patients showing a partial or complete response.

CONCLUSION

These results indicate that the 5' UTR hypermethylation of CBLB in CD4+ T cells induces resistance to T-cell anergy in ITP. Thus, the upregulation of CBLB expression by low-dose decitabine treatment may represent a potential therapeutic approach to ITP.

Intrauterine administration of peripheral blood mononuclear cells (PBMCs) improves embryo implantation in mice by regulating local Treg/Th17 cell balance

Immune imbalance of Treg/Th17 cells may contribute to recurrent implantation failure (RIF) during in vitro fertilization and embryo transfer (IVF-ET). In this study, we sought to determine the effect of intrauterine administration of mouse PBMCs prior to embryo implantation on endometrial receptivity and embryo implantation, and examine the underlying mechanism of Treg/Th17 cell balance following intrauterine administration of PBMCs. Pregnant mice were randomly divided into three groups: control group, embryo implantation dysfunction (EID) group, and EID with PBMCs group, and the number of embryo implantation sites was recorded during early pregnancy (Pd7.5). The balance of Treg/Th17 cells in the peripheral blood, spleen, and local implantation sites was detected during the peri-implantation period (Pd4.0) and early pregnancy (Pd7.5). The EID group demonstrated a significant decrease in the number of embryo implantation sites, while the EID with PBMCs group demonstrated higher number of embryo implantation sites compared to the EID group. The balance of Treg/Th17 cells in the peripheral blood and spleen tissues was not significantly different between the aforementioned groups. However, the local uterine ratio of the Treg/Th17 cells increased in the EID with PBMCs group compared to that in the EID group. Collectively, we found that intrauterine administration of PBMCs prior to embryo implantation effectively promotes embryo implantation rates. This may be attributed to the improvement in the local immune balance of Treg and Th17 cells compared with the overall immune balance.

Low-dose decitabine modulates T-cell homeostasis and restores immune tolerance in immune thrombocytopenia

Our previous clinical study showed that low-dose decitabine exhibited sustained responses in nearly half of patients with refractory immune thrombocytopenia (ITP). The long-term efficacy of decitabine in ITP is not likely due to its simple role in increasing platelet production. Whether decitabine has the potential to restore immune tolerance in ITP is unknown. In this study, we analyzed the effect of decitabine on T-cell subpopulations in ITP in vitro and in vivo. We found that low-dose decitabine promoted the generation and differentiation of regulatory T (Treg) cells and augmented their immunosuppressive function. Splenocytes from CD61 knockout mice immunized with CD61+ platelets were transferred into severe combined immunodeficient mouse recipients to induce a murine model of ITP. Low-dose decitabine alleviated thrombocytopenia and restored the balance between Treg and helper T (Th) cells in active ITP mice. Treg deletion and depletion offset the effect of decitabine in restoring CD4+ T-cell subpopulations in ITP mice. For patients who received low-dose decitabine, the quantity and function of Treg cells were substantially improved, whereas Th1 and Th17 cells were suppressed compared with the pretreatment levels. Next-generation RNA-sequencing and cytokine analysis showed that low-dose decitabine rebalanced T-cell homeostasis, decreased proinflammatory cytokines, and downregulated phosphorylated STAT3 in patients with ITP. STAT3 inhibition analysis suggested that low-dose decitabine might restore Treg cells by inhibiting STAT3 activation. In conclusion, our data indicate that the immunomodulatory effect of decitabine provides one possible mechanistic explanation for the sustained response achieved by low-dose decitabine in ITP.

Autoimmune hemolytic anemia: current knowledge and perspectives

Autoimmune hemolytic anemia (AIHA) is an acquired, heterogeneous group of diseases which includes warm AIHA, cold agglutinin disease (CAD), mixed AIHA, paroxysmal cold hemoglobinuria and atypical AIHA. Currently CAD is defined as a chronic, clonal lymphoproliferative disorder, while the presence of cold agglutinins underlying other diseases is known as cold agglutinin syndrome. AIHA is mediated by autoantibodies directed against red blood cells (RBCs) causing premature erythrocyte destruction. The pathogenesis of AIHA is complex and still not fully understood. Recent studies indicate the involvement of T and B cell dysregulation, reduced CD4+ and CD25+ Tregs, increased clonal expansions of CD8 + T cells, imbalance of Th17/Tregs and Tfh/Tfr, and impaired lymphocyte apoptosis. Changes in some RBC membrane structures, under the influence of mechanical stimuli or oxidative stress, may promote autohemolysis. The clinical presentation and treatment of AIHA are influenced by many factors, including the type of AIHA, degree of hemolysis, underlying diseases, presence of concomitant comorbidities, bone marrow compensatory abilities and the presence of fibrosis and dyserthropoiesis. The main treatment for AIHA is based on the inhibition of autoantibody production by mono- or combination therapy using GKS and/or rituximab and, rarely, immunosuppressive drugs or immunomodulators. Reduction of erythrocyte destruction via splenectomy is currently the third line of treatment for warm AIHA. Supportive treatment including vitamin supplementation, recombinant erythropoietin, thrombosis prophylaxis and the prevention and treatment of infections is essential. New groups of drugs that inhibit immune responses at various levels are being developed intensively, including inhibition of antibody-mediated RBCs phagocytosis, inhibition of B cell and plasma cell frequency and activity, inhibition of IgG recycling, immunomodulation of T lymphocytes function, and complement cascade inhibition. Recent studies have brought about changes in classification and progress in understanding the pathogenesis and treatment of AIHA, although there are still many issues to be resolved, particularly concerning the impact of age-associated changes to immunity.

miR-106b-5p induces immune imbalance of Treg/Th17 in immune thrombocytopenic purpura through NR4A3/Foxp3 pathway

BACKGROUND

Immune imbalance of regulatory T cells (Treg)/T helper 17 cells (Th17) contributes to the development of immune thrombocytopenic purpura (ITP). The dysregulation of miRNAs is important in the development of ITP. However, the role of miR-106b-5p in Treg/Th17 imbalance remains unknown in ITP.

MATERIALS AND METHODS

Peripheral blood was collected from patients with ITP and healthy controls, and CD4 + T cells were further isolated. miR-106b-5p, nuclear receptor subfamily 4 group A member 3 (NR4A3), forkhead box protein 3 (Foxp3), IL-17A, and TGF-β expressions were detected by qRT-PCR, western blot, or ELISA. The effect of miR-106b-5p on NR4A3 was detected by dual-luciferase reporter gene assay.

RESULTS

Compared with healthy controls, miR-106b-5p was elevated in peripheral blood of patients with ITP, and NR4A3 expression was decreased. sh-NR4A3 significantly decreased Foxp3 and TGF-β expressions, indicating that NR4A3 may regulate Treg differentiation via Foxp3. Additionally, NR4A3 was identified to be a target of miR-106b-5p, and miR-106b-5p was able to negatively modulate NR4A3 expression. Moreover, we found miR-106b-5p induced immune imbalance of Treg/Th17 through NR4A3. In vivo experiments revealed that silencing miR-106b-5p promoted Treg differentiation and increased the number of platelets, suggesting the relief of ITP.

CONCLUSION

miR-106b-5p regulated immune imbalance of Treg/Th17 in ITP through the NR4A3/Foxp3 pathway.

Autoimmune Cytopenias in Chronic Lymphocytic Leukemia: Focus on Molecular Aspects

Autoimmune cytopenias, particularly autoimmune hemolytic anemia (AIHA) and immune thrombocytopenia (ITP), complicate up to 25% of chronic lymphocytic leukemia (CLL) cases. Their occurrence correlates with a more aggressive disease with unmutated VHIG status and unfavorable cytogenetics (17p and 11q deletions). CLL lymphocytes are thought to be responsible of a number of pathogenic mechanisms, including aberrant antigen presentation and cytokine production. Moreover, pathogenic B-cell lymphocytes may induce T-cell subsets imbalance that favors the emergence of autoreactive B-cells producing anti-red blood cells and anti-platelets autoantibodies. In the last 15 years, molecular insights into the pathogenesis of both primary and secondary AIHA/ITP has shown that autoreactive B-cells often display stereotyped B-cell receptor and that the autoantibodies themselves have restricted phenotypes. Moreover, a skewed T-cell repertoire and clonal T cells (mainly CD8+) may be present. In addition, an imbalance of T regulatory-/T helper 17-cells ratio has been involved in AIHA and ITP development, and correlates with various cytokine genes polymorphisms. Finally, altered miRNA and lnRNA profiles have been found in autoimmune cytopenias and seem to correlate with disease phase. Genomic studies are limited in these forms, except for recurrent mutations of KMT2D and CARD11 in cold agglutinin disease, which is considered a clonal B-cell lymphoproliferative disorder resulting in AIHA. In this manuscript, we review the most recent literature on AIHA and ITP secondary to CLL, focusing on available molecular evidences of pathogenic, clinical, and prognostic relevance.

Effect of IL-21 on the Balance of Th17 Cells/Treg Cells in the Pathogenesis of Graves' Disease

Graves' disease (GD) is a common organ-specific autoimmune disease, and its pathogenesis is still unclear. The aim of this study is to investigate the role of interleukin (IL)-21 in the regulation of Th17/Treg cells in GD. We recruited 28 newly diagnosed GD patients, 27 GD patients in remission (eGD), and 24 normal controls (NC). Thyroid function and autoantibodies were evaluated by electrochemical luminescence. Peripheral blood mononuclear cells (PBMCs) were isolated and cultured with or without recombinant human interleukin-21 (rhIL-21), and mRNA and protein levels were quantified by real-time PCR and ELISA, respectively. Compared with those in the eGD and control groups, the thyroid function indexes and autoantibodies levels were significantly different in the GD group (P < 0.05). Without rhIL-21 stimulation, the expression levels of retinoid-related orphan gamma t (RORγt), IL-17, IL-22, forkhead box protein P3 (Foxp3) and IL-10 mRNA and the IL-10 and IL-22 proteins were significantly higher in the GD group than those in the eGD and control groups (P < 0.05). rhIL-21 stimulation increased the RORγt, IL-17, and IL-22 mRNA levels and IL-22 protein levels and decreased the Foxp3 and IL-10 mRNA levels and IL-10 protein levels (P < 0.05) in the GD group. In conclusion, our analyses demonstrated that IL-21 might induce the differentiation of CD4⁺ T cells to Th17 cells and reduce Treg cell differentiation, which could contribute to activation of the downstream immune response and the pathogenesis of GD.

Vitamin D supplementation for the prevention or depletion of side effects of therapy with alemtuzumab in multiple sclerosis

PURPOSE OF REVIEW

Not only the multiple sclerosis specialist but also the general neurologist and primary care practitioner are increasingly aware of possible adverse events (AEs) by treatment with alemtuzumab (over 47% risk of secondary autoimmune-mediated diseases). Vitamin D supplementation's effect (VDS) to reduce these autoimmune AEs is poorly performed in routine practice. This article seeks to justify why this simple, inexpensive, patient-friendly therapy should be seriously discussed.

RECENT FINDINGS

Patients who have developed autoimmunity also show a high basal level of IL-21, a cytokine which increases the growth of auto-reactive T-cells. For side effects such as thyroid dysfunction, autoimmune thrombocytopenia, autoimmune hemolytic anemia, autoimmune hepatitis, diabetes mellitus type 1, and alopecia areata/alopecia totalis, VDS may have an impact on the immunological mechanism, in particular lowering levels of IL-17 and IL-21.

SUMMARY

The potential role of vitamin D in influencing autoimmune diseases is evident. If a life-threatening side-effect can be prevented by high-dose VDS, it is ethical to initiate this add-on therapy despite contradictory results in studies on the effectiveness of VDS.

Research Progress on Chinese Medicine Immunomodulatory Intervention for Chronic Primary Immune Thrombocytopenia: Targeting Cellular Immunity

Chronic primary immune thrombocytopenia (CITP) is the most common acquired autoimmune disease that seriously threaten the physical and mental health of patients. Compared with Western medicine treatment, the intervention and treatment of Chinese medicine (CM) has shown certain therapeutic advantages. This paper reviewed the new pathogenesis progress on T cell immune abnormality in CITP, and CM studies on interferes effects of cellular immune regulation of CITP in recent years. Qi deficiency failing to control blood and internal obstruction of blood stasis are the two common types of CM syndromes in CITP patients, the corresponding treatments include invigorating Pi (Spleen), supplementing qi, activating blood, as well as tonifying qi and activating yang, regulating Gan (Liver) to invigorate Pi. The authors also mentioned the problems in the research field of CM for CTIP treatment, and put forward new ideas for the research in the future.

Low mucosal-associated invariant T-cell number in peripheral blood of patients with immune thrombocytopenia and their response to prednisolone

Mucosal-associated invariant T (MAIT) cells help protect against certain infections and are related to some autoimmune diseases. Immune thrombocytopenia (ITP) is a relatively rare hematological autoimmune disease associated with low platelet count. We designed a cross-sectional study wherein we examined peripheral blood samples of patients with ITP for the number of MAIT cells (CD3+TCR-Vα7.2+CD161+IL-18Rα+ lymphocytes) and their CD4/8 subsets (by flow cytometry) and levels of cytokines (by multiplex assays). The study cohort included 18 patients with ITP and 20 healthy controls (HCs). We first compared the number of MAIT cells between HCs and patients with ITP and then performed subgroup analysis in patients with ITP. The number of total MAIT cells in patients with ITP was significantly lower than that in HCs (p < 0.0001), and the CD4-CD8+ subset of MAIT cells showed the same trend. Moreover, patients with ITP refractory to prednisolone exhibited a significantly lower number of total MAIT and CD4-CD8+ MAIT cells than patients sensitive to prednisolone. The number of total MAIT and CD4-CD8+ MAIT cells was not correlated with the response to thrombopoietin receptor agonist treatment or with Helicobacter pylori infection. We found no relation between cytokine levels and response to prednisolone treatment, although the levels of IP-10 and RANTES showed a correlation with the number of total MAIT and CD4-CD8+ MAIT cells. In conclusion, total MAIT and CD4-CD8+ MAIT cells in peripheral blood were decreased in patients with ITP, correlating with their response to prednisolone.

Circulating level of Th17 cells is associated with sensitivity to glucocorticoids in patients with immune thrombocytopenia

Glucocorticoids are a widely recognized first-line therapy for immune thrombocytopenia (ITP). However, some patients are unresponsive to glucocorticoid therapy for reasons that remain unclear. Accumulating evidence suggests that CD4⁺ T-cell abnormalities play a crucial role in the development of ITP. In the present study, we investigated peripheral blood CD4⁺ T cells, Th17-associated cytokines, and the mRNA expression level of Th17 transcription factor-RORγt-in patients with newly-diagnosed ITP before glucocorticoid therapy. The study involved 27 newly-diagnosed patients. Th17-cell levels in the peripheral blood of newly-diagnosed ITP patients were associated with responsiveness to glucocorticoid therapy. Newly-diagnosed ITP patients who were not sensitive to glucocorticoid treatment were found to have lower levels of Th17 cells. Quantifying Th17 cells may allow physicians to predict prognosis of glucocorticoid treatment and stratify therapy for those with ITP. This strategy may provide a new approach to the treatment of glucocorticoid-insensitive patients.