CD40 mediates downregulation of CD32B on specific memory B cell populations in rheumatoid arthritis

Apoptosis, Autophagy, NETosis, Necroptosis, and Pyroptosis Mediated Programmed Cell Death as Targets for Innovative Therapy in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease that can lead to clinical manifestations of systemic diseases. Its leading features include chronic synovial inflammation and degeneration of the bones and joints. In the past decades, multiple susceptibilities for rheumatoid arthritis have been identified along with the development of a remarkable variety of drugs for its treatment; which include analgesics, glucocorticoids, nonsteroidal anti-inflammatory medications (NSAIDs), disease-modifying anti-rheumatic drugs (DMARDs), and biologic response modifiers (bDMARDs). Despite the existence of many clinical treatment options, the prognosis of some patients remains poor due to complex mechanism of the disease. Programmed cell death (PCD) has been extensively studied and ascertained to be one of the essential pathological mechanisms of RA. Its dysregulation in various associated cell types contributes to the development of RA. In this review, we summarize the role of apoptosis, cell death-associated neutrophil extracellular trap formation, necroptosis, pyroptosis, and autophagy in the pathophysiology of RA to provide a theoretical reference and insightful direction to the discovery and development of novel therapeutic targets for RA.

Aberrant expression of inhibitory receptors on B cells in patients with Graves' disease

The pathophysiological mechanism underlying Graves' disease (GD) remains incompletely understood. Inhibitory receptors on B cells are critical for humoral immunity, which plays a key role in GD pathogenesis. This study aimed to investigate B cell subsets distribution and inhibitory receptor expression on these subsets in GD patients. Peripheral blood was drawn from 41 healthy controls and 46 GD patients (21 patients with moderate GD, 25 patients with severe GD). B cell subset distribution and CD22, CD32b and CD72 expression on B cells were analyzed by flow cytometry. Serum cytokines were examined by enzyme-linked immunosorbent assay (ELISA). Compared with healthy controls, the naïve B cell percentage was increased, while the preswitched memory and conventional memory B cell percentages were decreased. The inhibitory receptors expression, especially CD32b, on B cell subsets was significantly decreased in patients with GD. In addition, the inhibitory receptors expression on B cell subsets from severe GD patients exhibited a decreasing trend compared with those from moderate GD patients. These results suggest that abnormal B cell subset distribution occurs in GD. Impaired inhibitory receptors, in particular CD32b, play a crucial role in GD pathogenesis and might be a therapeutic target to rebuild self-immune tolerance in GD.

FcγRIIb Expression Is Decreased on Naive and Marginal Zone-Like B Cells From Females With Multiple Sclerosis

B cells are critical to the development of multiple sclerosis (MS), but the mechanisms by which they contribute to the disease are poorly defined. We hypothesised that the expression of CD32b (FcγRIIb), a receptor for the Fc region of IgG with inhibitory activities in B cells, is lower on B cell subsets from people with clinically isolated syndrome (CIS) or MS. CD32b expression was highest on post-naive IgM⁺ B cell subsets in healthy controls. For females with MS or CIS, significantly lower CD32b expression was identified on IgM⁺ B cell subsets, including naive and IgM^hi MZ-like B cells, when compared with control females. Lower CD32b expression on these B cell subsets was associated with detectable anti-Epstein Barr Virus viral capsid antigen IgM antibodies, and higher serum levels of B cell activating factor. To investigate the effects of lower CD32b expression, B cells were polyclonally activated in the presence of IgG immune complexes, with or without a CD32b blocking antibody, and the expression of TNF and IL-10 in B cell subsets was assessed. The reduction of TNF but not IL-10 expression in controls mediated by IgG immune complexes was reversed by CD32b blockade in naive and IgM^hi MZ-like B cells only. However, no consequence of lower CD32b expression on these cells from females with CIS or MS was detected. Our findings highlight a potential role for naive and marginal zone-like B cells in the immunopathogenesis of MS in females, which requires further investigation.

Persistently activated, proliferative memory autoreactive B cells promote inflammation in rheumatoid arthritis

Autoreactive B cells mediate autoimmune pathology, but exactly how remains unknown. A hallmark of rheumatoid arthritis (RA), a common autoimmune disease, is the presence of disease-specific anticitrullinated protein antibodies (ACPAs). Here, we showed that ACPA-positive B cells in patients with RA strongly expressed T cell-stimulating ligands, produced abundant proinflammatory cytokines, and were proliferative while escaping inhibitory signals. This activated state was found at different degrees in different stages of disease: highest in patients with recent-onset RA, moderate in patients with established RA, and far less pronounced in ACPA-positive individuals "at risk" for developing disease. The activated autoreactive B cell response persisted in patients who achieved clinical remission with conventional treatment. ACPA-positive B cells in blood and synovial fluid secreted increased amounts of the chemoattractant interleukin-8, which attracted neutrophils, the most abundant immune cell in arthritic joints. Tetanus toxoid-specific B cells from the same patients exhibited properties of memory B cells without the activation and proliferation phenotype, but these cells transiently acquired a similar proliferative phenotype upon booster vaccination. Together, these data indicated that continuous antigenic triggering of autoreactive B cells occurs in human autoimmune disease and support the emerging concept of immunological activity that persists under treatment even in clinical remission, which may revise our current concept of treatment targets for future therapeutic interventions. In addition, our data pointed to a pathogenic role of ACPA-positive B cells in the inflammatory disease process underlying RA and favor approaches that aim at their antigen-specific inactivation or depletion.

Epstein-Barr Virus- (EBV-) Immortalized Lymphoblastoid Cell Lines (LCLs) Express High Level of CD23 but Low CD27 to Support Their Growth

Epstein-Barr virus (EBV) is one of the common human herpesvirus types in the world. EBV is known to infect more than 95% of adults in the world. The virus mainly infects B lymphocytes and could immortalize and transform the cells into EBV-bearing lymphoblastoid cell lines (LCLs). Limited studies have been focused on characterizing the surface marker expression of the immortalized LCLs. This study demonstrates the generation of 15 LCLs from sixteen rheumatoid arthritis (RA) patients and a healthy volunteer using B95-8 marmoset-derived EBV. The success rate of LCL generation was 88.23%. All CD19+ LCLs expressed CD23 (16.94-58.9%) and CD27 (15.74-80.89%) on cell surface. Our data demonstrated two distinct categories of LCLs (fast- and slow-growing) (p<0.05) based on their doubling time. The slow-growing LCLs showed lower CD23 level (35.28%) compared to fast-growing LCLs (42.39%). In contrast, the slow-growing LCLs showed higher percentage in both CD27 alone and CD23+CD27+ in combination. Overall, these findings may suggest the correlations of cellular CD23 and CD27 expression with the proliferation rate of the generated LCLs. Increase expression of CD23 may play a role in EBV immortalization of B-cells and the growth and maintenance of the EBV-transformed LCLs while CD27 expression might have inhibitory effects on LCL proliferation. Further investigations are warranted to these speculations.

A recombinant human IgG1 Fc multimer designed to mimic the active fraction of IVIG in autoimmunity

The antiinflammatory effects of i.v. Ig (IVIG) in the treatment of autoimmune disease are due, in part, to the Fc fragments of Ig aggregates. In order to capitalize on the known antiinflammatory and tolerogenic properties of Ig Fc aggregates, we created a recombinant human IgG1 Fc multimer, GL-2045. In vitro, GL-2045 demonstrated high-avidity binding to Fc receptors, blocked the binding of circulating immune complexes from patients with rheumatoid arthritis to human Fcγ receptors (FcγRs), and inhibited antibody-mediated phagocytosis at log order-lower concentrations than IVIG. In vivo, administration of GL-2045 conferred partial protection against antibody-mediated platelet loss in a murine immune thrombocytopenic purpura (ITP) model. GL-2045 also suppressed disease activity in a therapeutic model of murine collagen-induced arthritis (CIA), which was associated with reduced circulating levels of IL-6. Furthermore, GL-2045 administration to nonhuman primates (NHPs) transiently increased systemic levels of the antiinflammatory cytokines IL-10 and IL-1RA, reduced the proinflammatory cytokine IL-8, and decreased surface expression of CD14 and HLA-DR on monocytes. These findings demonstrate the immunomodulatory properties of GL-2045 and suggest that it has potential as a treatment for autoimmune and inflammatory diseases, as a recombinant alternative to IVIG.

Increased Expression of TLR10 in B Cell Subsets Correlates with Disease Activity in Rheumatoid Arthritis

Toll-like receptor (TLR) 10, mainly expressed on B cells, has emerged as a modulatory receptor in inflammation. Nonetheless, the clinical significance of TLR10 in rheumatoid arthritis (RA) remains unclear. In this study, we explored the expression of TLR10 in B cells and B cell subsets in RA subjects and healthy controls (HCs) and determined its relevance to disease activity and inflammatory biomarkers. TLR10 levels in B cells and B cell subsets (CD19⁺CD27⁺, CD19⁺CD27⁻, CD27⁺IgD⁻, CD27⁺IgD⁺, CD27⁻IgD⁺, D27⁻IgD⁻, CD19⁺CD5⁺, and CD19⁺CD5⁻) and inflammatory biomarker concentrations in peripheral blood (PB) obtained from RA subjects and HCs were detected by flow cytometry and enzyme-linked immunosorbent assay (ELISA), respectively. The correlations of TLR10 expression with disease activity and inflammatory biomarkers were then analysed. Similar levels of TLR10 in all CD19⁺ B cells were observed in the RA subjects and HCs. Compared to that in the HCs, TLR10 was elevated significantly in the CD19⁺CD27⁻IgD⁻ and CD19⁺CD5⁺ subsets in the RA subjects. In addition, almost all subsets expressing TLR10 were increased with disease activity. The present study reveals that enhanced TLR10 in B cell subsets is positively correlated with disease activity in RA subjects.

Synovial IL-9 facilitates neutrophil survival, function and differentiation of Th17 cells in rheumatoid arthritis

Background

Role of Th9 cells and interleukin-9 (IL-9) in human autoimmune diseases such as psoriasis and ulcerative colitis has been explored only very recently. However, their involvement in human rheumatoid arthritis (RA) is not conclusive. Pathogenesis of RA is complex and involves various T cell subsets and neutrophils. Here, we aimed at understanding the impact of IL-9 on infiltrating immune cells and their eventual role in synovial inflammation in RA.

Methods

In vitro stimulation of T cells was performed by engagement of anti-CD3 and anti-CD28 monoclonal antibodies. Flow cytometry was employed for measuring intracellular cytokine, RORγt in T cells, evaluating apoptosis of neutrophils. ELISA was used for measuring soluble cytokine, Western blot analysis and confocal microscopy were used for STAT3 phosphorylation and nuclear translocation.

Results

We demonstrated synovial enrichment of Th9 cells and their positive correlation with disease activity (DAS28-ESR) in RA. Synovial IL-9 prolonged the survival of neutrophils, increased their matrix metalloprotienase-9 production and facilitated Th17 cell differentiation evidenced by induction of transcription factor RORγt and STAT3 phosphorylation. IL-9 also augmented the function of IFN-γ + and TNF-α + synovial T cells.

Conclusions

We provide evidences for critical role of IL-9 in disease pathogenesis and propose that targeting IL-9 may be an effective strategy to ameliorate synovial inflammation in RA. Inhibiting IL-9 may have wider impact on the production of pathogenic cytokines involved in autoimmune diseases including RA and may offer better control over the disease.

Electronic supplementary material

The online version of this article (10.1186/s13075-017-1505-8) contains supplementary material, which is available to authorized users.

Clinical significance of costimulatory molecules CD40/CD40L and CD134/CD134L in coronary heart disease: A case-control study

The aim of the study was to evaluate the potential role of CD40/CD40 ligand (CD40L) and CD134/CD134 ligand (CD134L) in the development of coronary heart disease (CHD) via the performance of a case-control study.The research objects were 234 cases of CHD patients and 120 cases of well-matched normal controls. Following the separation of peripheral blood mononuclear cells (PBMCs), real-time quantitative PCR (qRT-PCR), Western blot, immunohistochemistry, and flow cytometry were applied for the detection of mRNA levels and expression levels of CD40/CD40L and CD134/CD134L; meanwhile, intercellular adhesion molecule-1 (ICAM-1) and Fas protein mRNA levels were detected using qRT-PCR.There was no statistical difference in the comparison of baseline characteristics between groups, indicating comparability between groups. qRT-PCR and Western blot analysis indicated that CD40/CD40L and CD134/CD134L mRNA and protein expression levels were all increased in the CHD group than those in the control group. Flow cytometry further confirmed the similar tendency. Meanwhile, ICAM-1 and Fas protein mRNA levels were elevated in the CHD group and positively correlated with the above parameters. Furthermore, CD40/CD40L expression rates were negatively correlated with gender and different types of CHD. Meanwhile, CD134/CD134L expressions were also higher in male patients, in patients with family history, previous history of hypertension, diabetes, and cerebrovascular diseases.CD40/CD40L and CD134/CD134L are increased and may have potential correlation with clinical pathological features of patients with CHD. Further in-depth exploration of costimulatory molecules for CHD guidance as well as intrinsic mechanisms are needed combined with in vivo and in vitro experiments.

CD32b expression is down-regulated on double-negative memory B cells in patients with Hashimoto's thyroiditis

Inhibitory CD32b receptors on B cells are critical for humoral immunity. The humoral response plays a role in the pathogenesis of Hashimoto's thyroiditis (HT). This study aimed to investigate B cell subset distribution and CD32b expression within these subsets in HT patients. B cell subset distribution and CD32b expression were analyzed in 60 HT patients and 21 healthy donors. Subset distribution and CD32b expression following stimulation with α-Ig and α-CD40 were also assessed. The percentage of double-negative (DN) memory cells was increased in the HT patients, while the expression level of CD32b on DN memory cells was decreased. Redistribution of B cell subsets was detected in response to stimulation with α-Ig. In addition, the expression level of CD32b was reduced following α-CD40 stimulation. These results suggest that abnormal B cell subset distribution and decreased CD32b expression on DN memory cells might be involved in the pathogenesis of HT.

Immunomodulation of inflammatory leukocyte markers during intravenous immunoglobulin treatment associated with clinical efficacy in chronic inflammatory demyelinating polyradiculoneuropathy

OBJECTIVE

The objective of the study was to profile leukocyte markers modulated during intravenous immunoglobulin (IVIg) treatment, and to identify markers and immune pathways associated with clinical efficacy of IVIg for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) with potential for monitoring treatment efficacy.

METHODS

Response to IVIg treatment in newly diagnosed IVIg-naïve and established IVIg-experienced patients was assessed by changes in expression of inflammatory leukocyte markers by flow cytometry. The adjusted INCAT disability and Medical Research Council sum scores defined clinical response.

RESULTS

Intravenous immunoglobulin modulated immunopathogenic pathways associated with inflammatory disease in CIDP. Leukocyte markers of clinical efficacy included reduced CD185⁺ follicular helper T cells, increased regulatory markers (CD23 and CD72) on B cells, and reduction in the circulating inflammatory CD16⁺ myeloid dendritic cell (mDC) population and concomitant increase in CD62L and CD195 defining a less inflammatory lymphoid homing mDC phenotype. A decline in inflammatory CD16⁺ dendritic cells was associated with clinical improvement or stability, and correlated with magnitude of improvement in neurological assessment scores, but did not predict relapse. IVIg also induced a nonspecific improvement in regulatory and reduced inflammatory markers not associated with clinical response.

CONCLUSIONS

Clinically effective IVIg modulated inflammatory and regulatory pathways associated with ongoing control or resolution of CIDP disease. Some of these markers have potential for monitoring outcome.

A Transmembrane Polymorphism of Fcγ Receptor IIb Is Associated with Kidney Deficiency Syndrome in Rheumatoid Arthritis

Objective. The purpose is to investigate the role of kidney deficiency and the association between kidney deficiency and a polymorphism FcγRIIb 695T>C coding for nonsynonymous substitution IIe232Thr (I232T) in rheumatoid arthritis (RA). Methods. Clinical parameters and autoantibodies were analyzed and genotyping was performed in 159 kidney deficiency and 161 non-kidney-deficiency RA patients. Results. The age of disease onset and disease duration exhibited significant differences between two groups (P < 0.01). Patients with kidney deficiency tend to have higher activity of disease (P < 0.05). Anti-cyclic citrullinated peptides antibodies (ACPA) levels of patients with kidney deficiency were higher than the controls (P = 0.039). 125 (78.6%) kidney deficiency and 114 (70.8%) non-kidney-deficiency patients had both ACPA-positive and RF-positive (P = 0.04, OR = 3.29). FcγRIIb I232TT homozygotes were identified in 10 of 159 (6.3%) kidney deficiency subjects and 1 of 161 (0.6%) controls (P = 0.000, OR = 16.45). Furthermore, in pooled genotype analysis, I232IT and I232TT homozygotes were significantly enriched in kidney deficiency individuals compared with the controls (P = 0.000, OR = 3.79). Frequency of T allele was associated with kidney deficiency RA population (P = 0.000, OR = 3.18). Conclusion. This study confirmed that kidney deficiency was closely associated with disease activity and autoimmune disorder in RA. Kidney deficiency in RA is first to reveal a strong genetic link to FcγRIIb variants.

Immunization associated with erectile dysfunction based on cross-sectional and genetic analyses

Erectile dysfunction (ED) is a global disease affecting a large number of people. Some studies have found a relationship between low-grade inflammation and ED. We hypothesized that the immune system might play a key role in the outcome of ED. Five immune agents (C3, C4, IgA, IgM, and IgG) were collected based on the Fangchenggang Area Male Health and Examination Survey (FAMHES), using methods of a traditional cross-sectional analysis. Our results repeated the significant association between ED and metabolic syndrome, obesity, and so forth. However, there seemed to be no positive relation between the tested indexes and ED risk in the baseline analysis (C3: P = 0.737; C4: P = 0.274; IgA: P = 0.943; IgG: P = 0.069; IgM: P = 0.985). Then, after adjusting for age and multivariate covariates, a potentially significant association between ED and IgG was discovered (P = 0.025 and P = 0.034, respectively). Meanwhile, in order to describe the development of ED on a gene level, SNP-set kernel-machine association test (SKAT) was applied with the known humoral immune genes involved. The outcomes suggested that PTAFR (binary P value: 0.0096; continuous P value: 0.00869), IL27 (0.0029; 0.1954), CD37 (0.0248; 0.5196), CD40 (0.7146; 0.0413), IL7R (0.1223; 0.0222), PSMB9 (0.1237; 0.0212), and CXCR3 (0.0849; 0.0478) might be key genes in ED, especially IL27, when we restricted the family-wise error rate (FWER) to 0.5. Our study shows that IgG and seven genes (PTAFR, CD37, CD40, IL7R, PSMB9, CXCR3, and especially IL27) might be key factors in the pathogenesis of ED, which could pave the way for future gene and immune therapies.

NF-κB and Rheumatoid Arthritis: Will Understanding Genetic Risk Lead to a Therapeutic Reward?

NF-κB has long been known to play an important role in autoimmune diseases such as rheumatoid arthritis (RA). Indeed, as our understanding of how NF-κB is utilized has increased, we have been hard put to find a process not associated with this transcription factor family in some way. However, new data originating, in part, from genome-wide association studies have demonstrated that very specific alterations in components of the NF-κB pathway are sufficient to confer increased risk of developing disease. Here we review the data which have identified specific components of the NF-κB pathway, and consider what is known of their mechanisms of action and how these mechanisms might play into the disease process. In addition, the use of genetic information to predict RA is considered.