Increased bone marrow (BM) plasma level of soluble CD30 and correlations with BM plasma level of interferon (IFN)-γ, CD4/CD8 T-cell ratio and disease severity in aplastic anemia

Expression levels of key immune indicators and immune checkpoints in manganese-exposed rats

Manganese is essential trace elements, to participate in the body a variety of biochemical reactions, has important physiological functions, such as stimulate the immune cell proliferation, strengthen the cellular immunity, etc. However, excessive manganese exposure can cause damage to multiple systems of the body.The immune system is extremely vulnerable to external toxicants, however manganese research on the immune system are inadequate and biomarkers are lacking. Therefore, here we applied a manganese-exposed rat model to make preliminary observations on the immunotoxic effects of manganese. We found that manganese exposure inhibited humoral immune function in rats by decreasing peripheral blood IgG (ImmunoglobulinG, IgG), IgM (ImmunoglobulinM, IgM) and complement C3 levels; It also regulates rat cellular immune activity by influencing peripheral blood, spleen, and thymus T cell numbers and immune organ ICs (Immune Checkpoints, ICs) and cytokine expression. Furthermore, it was revealed that the impact of manganese exposure on the immune function of rats exhibited a correlation with both the dosage and duration of exposure. Notably, prolonged exposure to high doses of manganese had the most pronounced influence on rat immune function, primarily manifesting as immunosuppression.The above findings suggest that manganese exposure leads to impaired immune function and related changes in immune indicators, or may provide clues for the discovery of its biomarkers.

Mesenchymal Stem Cells in Acquired Aplastic Anemia: The Spectrum from Basic to Clinical Utility

Aplastic anemia (AA), a rare but potentially life-threatening disease, is a paradigm of bone marrow failure syndromes characterized by pancytopenia in the peripheral blood and hypocellularity in the bone marrow. The pathophysiology of acquired idiopathic AA is quite complex. Mesenchymal stem cells (MSCs), an important component of the bone marrow, are crucial in providing the specialized microenvironment for hematopoiesis. MSC dysfunction may result in an insufficient bone marrow and may be associated with the development of AA. In this comprehensive review, we summarized the current understanding about the involvement of MSCs in the pathogenesis of acquired idiopathic AA, along with the clinical application of MSCs for patients with the disease. The pathophysiology of AA, the major properties of MSCs, and results of MSC therapy in preclinical animal models of AA are also described. Several important issues regarding the clinical use of MSCs are discussed finally. With evolving knowledge from basic studies and clinical applications, we anticipate that more patients with the disease can benefit from the therapeutic effects of MSCs in the near future.

Alterations of mesenchymal stem cells on regulating Th17 and Treg differentiation in severe aplastic anemia

Immune-mediated hematopoietic destruction is a key factor in idiopathic severe aplastic anemia (SAA). With great immunomodulatory functions, mesenchymal stem cells (MSCs) are important for bone marrow niche. While the underlying etiology of immunologic changes in SAA bone marrow remains unknown, dysfunctional MSCs are implicated as a major cause. To provide evidence for their defects in immunomodulation, alterations of SAA MSCs in regulating T cell differentiation were determined. During differentiation from CD4+ T cells into T helper 17 (Th17) cells under polarization conditions, impaired inhibition on IL-17 and IL-1β production was noted when cocultured with SAA MSCs compared to control MSCs (P < 0.05). After stimulation of Th17 activation, the percentage of IL-17-secreting cells was significantly increased in the SAA group (9.1 ± 1.5% vs 6.6 ± 0.4%, P < 0.01). Under regulatory T (Treg) polarization, a higher percentage of CD4+CD25+FoxP3+ Treg cells was detected when cocultured with SAA MSCs compared to control MSCs (8.1 ± 0.5% vs 5.8 ± 0.8%, P < 0.01). Inconsistently, transforming growth factor-β (TGF-β) concentrations in the culture supernatant were decreased and IL-1β concentrations were elevated in the SAA group. Our data indicated impaired inhibition of SAA MSCs on Th17 activation and aberrant regulation of SAA MSCs on Treg differentiation. Increased IL-17 and IL-1β levels with decreased TGF-β levels in the supernatant suggested the potential of SAA MSCs for triggering a hyperinflammatory environment. Dysfunctional MSCs could contribute to the lack of immunoprotection in the bone marrow, which may be associated with SAA.

Decreased bone marrow regulatory innate lymphoid cells show a distinctive miRNA profiling in aplastic anemia

OBJECTIVES

A new regulatory subpopulation of innate lymphoid cells (ILCs), regulatory innate lymphoid cells (ILCregs), has been identified with both innate lymphoid cells and regulatory cells characteristics. The purpose of this study is to explore ILCregs and its associated miRNAs in patients with aplastic anemia (AA) by evaluating ILCregs frequency, associated miRNA quantification, and their significance.

METHODS

Using 4 color combinations of surface and intracellular antibody staining, the CD45+Lin-CD127+IL-10+ ILCregs from 30 healthy donors and 30 patients newly diagnosed with AA were measured by flow cytometry. Bone marrow cells were studied by next-generation sequence miRNAs quantification.

RESULTS

Our results showed that the frequency of ILCregs in bone marrow cells from healthy donors (HD) and AA patients were 0.703 ± 0.941 and 0.171 ± 0.233%, respectively. The frequencies of ILCregs in AA patients were significantly lower than that in HD (p <0.05). miRNA detection results showed different expression patterns in the AA patient group comparing with HD. Comparing with HD, there were 52 miRNAs up-regulated and 130 miRNAs down-regulated from AA patients. Analysis of miRNAs from ILCregs associated genes demonstrated different miRNAs expression patterns between HD and AA patient.

CONCLUSION

The present study demonstrated the deficiency of ILCregs and differential expression pattern of ILCregs gene-related miRNA in patients with AA. Further studies need to be done to explore the clinical significance of ILCregs and related miRNAs in patients with AA with large samples size and clinical follow-up.

High-Dose Aluminum Exposure Further Alerts Immune Phenotype in Aplastic Anemia Patients

This study explored the relationship between immunological status and clinical characteristics of aplastic anemia (AA) patients to plasma aluminum levels, which were increased after constant exposure to high levels of this metal. Sixty-two AA patients (33 cases with high and 29 cases with low or no exposure to aluminum) and 30 healthy controls were selected for this study. Aluminum in human albumin solution was measured by inductivity coupled plasma mass spectrometry. IL-10, IL-12, IL-17, and INF-γ levels were measured by enzyme-linked immunosorbent assay. The distribution of lymphocyte subsets were determined by flow cytometry. The expression levels of immunoglobulins and complement C3 and C4 were also measured. Exposure to high aluminum raised the levels of serum aluminum in AA patients (P < 0.01). The levels of hemoglobin and complement C4 were lower in AA patients with high aluminum exposure (P < 0.05 and < 0.01, respectively). The percentage of CD4+ T cells and the ratio of CD4+/ CD8+T cells in peripheral blood in AA patients with high aluminum exposure were higher compared with control AA patients (P < 0.05 in both cases), while the percentage of CD8+ T cells was significantly lower than that in non-aluminum-exposed AA patients (P < 0.05). Compared with non-aluminum-exposed AA patients, the level of IL-10 in the high aluminum-exposed AA group was significantly higher (P < 0.05 in both cases). The immunological and clinical characteristics of AA patients from regions of high aluminum exposure are different to those in from non-aluminum areas. These results suggest that high aluminum exposure alters the immune system in patients suffering from AA.

The relationship between interferon-gamma (INF-γ) single nucleotide polymorphism +874(T/A) and occurrence risk of aplastic anemia: a meta-analysis

Objective: This meta-analysis was designed to investigate the association between interferon-gamma (IFN-γ) polymorphisms and occurrence risk of aplastic anemia.Methods: Literature search was conducted in PubMed, Embase and Cochrane Library up to April 2018. The pooled odds ratios (ORs) and 95% confidence interval (CI) were calculated by R 3.12.Results: Total five studies with 304 aplastic anemia patients and 588 controls were included. The statistically significant results were found in the following models: allele genetic model (T vs A: OR = 2.1749, 95% CI = 1.6825-2.8114, P < 0.01), additive genetic model (TA vs AA: OR = 2.1071, 95% CI = 1.3962-3.1799, P < 0.01; TT vs AA: OR = 4.5788, 95% CI = 2.6606-7.8797, P < 0.01), recessive genetic model (TT vs AA + TA: OR = 2.5579, 95% = 1.6680-3.9226, P < 0.01), dominant genetic model (TT + TA vs AA: OR = 2.5599, 95% = 1.7424-3.7611, P < 0.01), the results suggested that the increased occurrence risk of aplastic anemia is significantly associated with the IFN-γ polymorphism.Conclusions: Patients with IFN-γ genotype carrying allele T have higher occurrence risk of aplastic anemia.

T-lymphocyte subsets and Th1/Th2 cytokines in convalescent patients with Epstein-Barr virus-associated aplastic anemia

Objective: The aim of this study was to analyze T-lymphocyte subsets and Th1/Th2 cytokines in convalescent patients with Epstein-Barr virus (EBV)-associated aplastic anemia (AA).Methods: Sixty AA patients were enrolled, who were in remission following immunosuppressive therapy, including 34 EBV-negative cases and 26 EBV-positive cases. Their complete blood count (CBC), T-lymphocyte subsets, Th1/Th2 cytokines were analyzed. The correlation between EBV-DNA and T-lymphocyte subsets was evaluated, as well as the relationship between EBV-DNA and Th1/Th2 cytokines. The presence of EBV-DNA in peripheral blood mononuclear cells (PBMCs) was also assessed in 60 normal controls.Results: EBV-DNA was detected in 26/60 (43.33%) patients and 21/60 (35.00%) controls. EBV-DNA copy number in AA patients was higher than in controls (Z = -2.138, P = 0.033). The percentage of CD3⁺CD4⁺ T-lymphocytes and the ratio of CD4⁺/CD8⁺ T-lymphocytes in the EBV-negative group were higher than in the EBV-positive group (P = 0.001 and 0.001, respectively). EBV was positively correlated with CD3⁺CD8⁺ T-lymphocyte percentages (Pearson R: 0.496, P = 0.009). Moreover, EBV was positively correlated with IL-10 and IFN-γ levels (Pearson R: 0.559, P = 0.002 and Pearson R: 0.621, P = 0.001, respectively).Conclusions: EBV-DNA copy number in AA patients was higher than in normal controls. Both AA and EBV infection may cause changes in the levels of T-lymphocyte subsets. We recommend monitoring the changes in the immune function and EBV infection simultaneously in AA patients, especially following immunosuppressive therapy.

Increased CD8+CD27+perforin+ T cells and decreased CD8+CD70+ T cells may be immune biomarkers for aplastic anemia severity

OBJECTIVES

Aplastic anemia (AA) is T cell immune-mediated autoimmune disease. Aberrant T cell activation involves an imbalance in T cell homeostasis in AA. However, whether the T cell activation molecule CD27 and its ligand CD70 participate in the immune pathogenesis of AA remains ill defined.

METHODS

The frequencies of CD27/CD70 and perforin/granzyme B in different T cell subsets were detected in AA patients and healthy individuals by flow cytometry.

RESULTS

We first time demonstrate a significantly elevated proportion of CD27⁺ and significantly decreased CD70⁺ T cells from AA. Changed frequency of CD27⁺ and CD70⁺ in different T cell subsets appeared to be associated with AA severity. In very severe aplastic anemia (VSAA) and severe aplastic anemia (SAA), increased CD8⁺CD27⁺ T cells present with a cytotoxic effector phenotype by elevating perforin proportion.

CONCLUSIONS

Elevated proportion of CD27 in T cells may contribute to distinct immune pathogenesis for different severities of AA. The CD8⁺CD27⁺perforin⁺ T cells combined with CD8⁺CD70⁺ T cells may serve as an immune biomarker for AA severity estimation.

The Pathophysiology of Acquired Aplastic Anemia: Current Concepts Revisited

Idiopathic acquired aplastic anemia is a rare, life-threatening bone marrow failure syndrome characterized by cytopenias and hypocellular bone marrow. The pathophysiology is unknown; the most favored model is of a dysregulated immune system leading to autoreactive T-cell destruction of hematopoietic stem and progenitor cells in a genetically susceptible host. The authors review the literature and propose that the major driver of acquired aplastic anemia is a combination of hematopoietic stem and progenitor cells intrinsic defects and an inappropriately activated immune response in the setting of a viral infection. Alterations in bone marrow microenvironment may also contribute to the disease process.

Aplastic anemia during pregnancy: a review of obstetric and anesthetic considerations

Aplastic anemia is a hematologic condition occasionally presenting during pregnancy. This pathological process is associated with significant maternal and neonatal morbidity and mortality. Obstetric and anesthetic management is challenging, and treatment requires a coordinated effort by an interdisciplinary team, in order to provide safe care to these patients. In this review, we describe the current state of the literature as it applies to the complexity of aplastic anemia in pregnancy, focusing on pathophysiologic aspects of the disease in pregnancy, as well as relevant obstetric and anesthetic considerations necessary to treat this challenging problem. A multidisciplinary-team approach to the management of aplastic anemia in pregnancy is necessary to coordinate prenatal care, optimize maternofetal outcomes, and plan peripartum interventions. Conservative transfusion management is critical to prevent alloimmunization. Although a safe threshold-platelet count for neuraxial anesthesia has not been established, selection of anesthetic technique must be evaluated on a case-to-case basis.

Comparison of T lymphocyte subsets in aplastic anemia and hypoplastic myelodysplastic syndromes

AIMS

This study aims to compare the proportion of peripheral blood T lymphocyte subsets and related blood cell and bone marrow cytology indexes between patients with aplastic anemia (AA) and hypoplastic myelodysplastic syndrome (hypo-MDS), and investigate the clinical identification significance.

MATERIALS AND METHODS

A total of 41 patients with AA and 46 patients with hypo-MDS were collected, and the proportions of peripheral blood T lymphocyte subsets, CD3^-CD16/CD56⁺NK cells, CD3⁺CD57⁺T-LGL cells and CD19⁺B lymphocytes were detected by flow cytometry.

KEY FINDINGS

The CD4⁺/CD8⁺ ratio decreased in the AA and hypo-MDS groups, and the difference was statistically significant when compared with that in the control group (P<0.05). However, there was no significant difference between AA and hypo-MDS groups (P>0.05). The proportions of CD3^-CD16/CD56⁺NK cells and CD3⁺CD57⁺T-LGL cells in the hypo-MDS group were distinctly higher than those in the AA group (P<0.05). However, the proportion of CD19⁺B lymphocyte was obviously lower than that in the AA group (P<0.05). Furthermore, the proportions of reticulocytes, bone marrow progenitor cells and immature red blood cells in the hypo-MDS group were significantly more than those in the AA group (P<0.05), and the proportion of mature lymphocytes in the hypo-MDS group was distinctly lower than that in the AA group (P<0.05).

SIGNIFICANCE

Changes of T lymphocyte subsets and the proportions of large granular lymphocytes and B lymphocytes can be utilized as indexes in the differential diagnosis between AA and hypo-MDS.

CD8+ T cells drive autoimmune hematopoietic stem cell dysfunction and bone marrow failure

Bone marrow (BM) failure syndrome encompasses a group of disorders characterized by BM stem cell dysfunction, resulting in varying degrees of hypoplasia and blood pancytopenia, and in many patients is autoimmune and inflammatory in nature. The important role of T helper 1 (Th1) polarized CD4⁺ T cells in driving BM failure has been clearly established in several models. However, animal model data demonstrating a functional role for CD8⁺ T cells in BM dysfunction is largely lacking and our objective was to test the hypothesis that CD8⁺ T cells play a non-redundant role in driving BM failure. Clinical evidence implicates a detrimental role for CD8⁺ T cells in BM failure and a beneficial role for Foxp3⁺ regulatory T cells (Tregs) in maintaining immune tolerance in the BM. We demonstrate that IL-2-deficient mice, which have a deficit in functional Tregs, develop spontaneous BM failure. Furthermore, we demonstrate a critical role for CD8⁺ T cells in the development of BM failure, which is dependent on the cytokine, IFNγ. CD8⁺ T cells promote hematopoietic stem cell dysfunction and depletion of myeloid lineage progenitor cells, resulting in anemia. Adoptive transfer experiments demonstrate that CD8⁺ T cells dramatically expedite disease progression and promote CD4⁺ T cell accumulation in the BM. Thus, BM dysregulation in IL-2-deficient mice is mediated by a Th1 and IFNγ-producing CD8⁺ T cell (Tc1) response.

Elevated Serum Levels of Soluble CD30 in Ankylosing Spondylitis Patients and Its Association with Disease Severity-Related Parameters

Soluble CD30 (sCD30), a transmembrane glycoprotein that belongs to the tumor necrosis factor receptor (TNFR) superfamily, has been shown to be associated with various pathological conditions. This study was designed to measure the levels of serum sCD30 in patients with ankylosing spondylitis (AS) and to evaluate the relationships between serum sCD30 levels and other disease severity-related indexes, including bath ankylosing spondylitis disease activity index (BASDAI), ankylosing spondylitis disease activity score (ASDAS), and bath ankylosing spondylitis functional index (BASFI). Our results demonstrated significantly elevated sCD30 levels in AS patients compared to healthy controls (HCs) with mean values of 32.0 ± 12.2 and 24.9 ± 8.0 ng/mL, respectively (P^** = 0.007), suggesting a potential role of sCD30 in the pathogenesis of AS. However, no significant correlations of sCD30 with BASDAI, ASDAS, or BASFI were detected in our study (P > 0.05). Therefore, sCD30 cannot be used as a reliable marker for reflecting disease activity and functional ability of AS patients.

Preeclampsia is Characterized by Fetal NK Cell Activation and a Reduction in Regulatory T Cells

Problem

Preeclampsia affects 3–17% of pregnancies worldwide and has serious consequences for both the mother and the fetus. As maternal–fetal immune tolerance is bidirectional, fetal immunopathology may play a significant role in the pathogenesis of pregnancy disorders. Nevertheless, the impact of preeclampsia on the fetal immune system is unclear.

Method of study

In this case–control study, we examined the phenotype of innate and adaptive immune cells from the cord blood of 3rd trimester babies born to healthy mothers and compared them to cord blood from 3rd trimester babies born to mothers with symptomatic preeclampsia.

Results

The ratio of CD56hi CD16− non‐activated/regulatory NK cells to CD56lo CD16+ activated/effector NK cells as well as the proportion of CD4+ T cells was significantly decreased in the cord blood of babies born to preeclamptic mothers. The percentage of FoxP3+ Treg, especially the FoxP3lo populations (resting Treg and cytokine Treg), were significantly reduced. Importantly, this reduction in FoxP3+ Treg affected the ratio of CD8+ effector T cells per FoxP3+ Treg in the cord blood of babies born to preeclamptic mothers.

Conclusion

These observations indicate that there are significant fetal immune system derangements during preeclampsia.

The complex pathophysiology of acquired aplastic anaemia

Immune-mediated destruction of haematopoietic stem/progenitor cells (HSPCs) plays a central role in the pathophysiology of acquired aplastic anaemia (aAA). Dysregulated CD8(+) cytotoxic T cells, CD4(+) T cells including T helper type 1 (Th1), Th2, regulatory T cells and Th17 cells, natural killer (NK) cells and NK T cells, along with the abnormal production of cytokines including interferon (IFN)-γ, tumour necrosis factor (TNF)-α and transforming growth factor (TGF)-β, induce apoptosis of HSPCs, constituting a consistent and defining feature of severe aAA. Alterations in the polymorphisms of TGF-β, IFN-γ and TNF-α genes, as well as certain human leucocyte antigen (HLA) alleles, may account for the propensity to immune-mediated killing of HSPCs and/or ineffective haematopoiesis. Although the inciting autoantigens remain elusive, autoantibodies are often detected in the serum. In addition, recent studies provide genetic and molecular evidence that intrinsic and/or secondary deficits in HSPCs and bone marrow mesenchymal stem cells may underlie the development of bone marrow failure.