Cytokine mRNA Profile of Alveolar T Lymphocytes and Macrophages in Patients with Systemic Sclerosis Suggests a Local Tr1 Response

The role of iTr35 cells in the inflammatory response and fibrosis progression of systemic sclerosis

OBJECTIVE

To evaluate the role of induced immunosuppressive T regulatory (iTr) 35 cells in SSc-related inflammation and fibrosis.

METHODS

Sixty-eight SSc patients were enrolled in this study. Subsets of iTr35 and Tr1 were measured by flow cytometry. IL-35 and IL-10 levels were measured using ELISA. Expressions of iTr35, Tr1, fibrosis-related genes and proteins associated with signalling pathways were determined using immunofluorescence, western blot and immunohistochemistry assays.

RESULTS

In peripheral blood, the proportions of the iTr35 cells were higher and Tr1 cells were lower than the control group. Similarly, IL-35 expression was increased, while IL-10 levels were decreased. In fibroblasts from skin tissue, the expression levels of EBI3, IL-12Ap35, Foxp3 and IL-10 were decreased, but collagen I, TGF-β, alpha smooth muscle actin (α-SMA) and fibronectin levels were increased. Phosphorylated STAT3/6 were increased, but iTr35 and Tr1 cell levels were significantly decreased. When CD4+ cells were incubated with both recombinant human (rh)IL-35 and rhIL-10, the cell numbers of iTr35 and Tr1 were greater than the same type of cells treated with rhIL-35 or rhIL-10 alone. However, the viability of conventional CD4+ T cells was decreased by gradually increasing iTr35 cells. Moreover, iTr35 cells affected α-SMA expression through the STAT3/6 signalling pathway.

CONCLUSION

Both iTr35 and Tr1 cells are involved in SSc-related inflammation and fibrosis. IL-35 can induce iTr35 cells, showing a synergistic effect with IL-10. We also found that iTr35 cells can inhibit T cell proliferation and differentiation via the STAT3/6 signalling pathway, thereby causing fibrosis.

Cellular and Molecular Diversity in Scleroderma

With the increasing armamentarium of high-throughput tools available at manageable cost, it is attractive and informative to determine the molecular underpinnings of patient heterogeneity in systemic sclerosis (SSc). Given the highly variable clinical outcomes of patients labelled with the same diagnosis, unravelling the cellular and molecular basis of disease heterogeneity will be crucial to predicting disease risk, stratifying management and ultimately informing a patient-centered precision medicine approach. Herein, we summarise the findings of the past several years in the fields of genomics, transcriptomics, and proteomics that contribute to unraveling the cellular and molecular heterogeneity of SSc. Expansion of these findings and their routine integration with quantitative analysis of histopathology and imaging studies into clinical care promise to inform a scientifically driven patient-centred personalized medicine approach to SSc in the near future.

Elevated serum levels of interleukin-1β and interleukin-33 in patients with systemic sclerosis in Chinese population

PURPOSE OF THE STUDY

Systemic sclerosis (SSc) is a multisystem autoimmune disease. Although the pathogenesis of the disease remains incompletely understood, some cytokines or growth factors which regulate SSc induction may be involved in the injury of endothelial cells and the modulation of leukocyte function. We aimed to perform this case-control study to determine serum levels of interleukin (IL)-1α, IL-1β, IL-18 and IL-33 and their associations with clinical manifestations in SSc patients.

MATERIALS AND METHODS

There were 56 patients with SSc and 56 healthy individuals who were recruited from local hospital between 2012 and 2014. Serum IL-1α, IL-1β, IL-18 and IL-33 levels were measured with specific enzyme-linked immunosorbent assay kits.

RESULTS

Univariate analysis revealed that serum IL-1β, IL-18 and IL-33 levels in SSc patients were significantly higher than that in healthy controls. After adjusting possible confounding factors (sex, age, smoking and drinking) by multivariable analyses, serum IL-1β levels (OR = 1.082; 95 % CI: 1.013-1.155) and serum IL-33 levels (OR = 1.100; 95 %CI: 1.022-1.185) were still related factors. There were interrelationships among the serum levels of IL-1α, IL-1β, IL-18 and IL-33 and these associations were not consistent in SSc patients and controls. No associations of serum IL-1α, IL-1β, IL-18 and IL-33 levels with clinical parameters were found.

CONCLUSION

IL-1β and IL-33 may contribute to the development of SSc. While there were no direct associations between these cytokines and disease manifestations, they still could be considered as serum markers of development of SSc. Further studies are required to validate this incipient data.

Higher levels of serum interleukin-35 are associated with the severity of pulmonary fibrosis and Th2 responses in patients with systemic sclerosis

The aim of the study is to investigate the levels of serum interleukin-35 (IL-35) before and after treatment and its relationship with clinical parameters as well as the frequency of different subsets of CD4⁺ T cells in patients with systemic sclerosis (SSc) to explore the role of IL-35 in the pathogenesis of SSc. The levels of serum IL-35, interferon-γ (IFN-γ), IL-4, IL-17A, and IL-10 in 49 patients with SSc and 50 age- and gender-matched healthy subjects were measured by enzyme-linked immunosorbent assay (ELISA). The percentages of peripheral blood Th1, Th2, Th17 cells and Tregs in 49 SSc patients and 20 healthy controls were characterized by flow cytometry. The relationship between the levels of serum IL-35 and the percentages of different subsets of CD4+ T cells, disease duration, the values of forced vital capacity (FVC), modified Rodnan skin scores (MRSS) or high-resolution computed tomography (HRCT) scores was analyzed in patients with SSc. The levels of serum IL-35 in SSc patients were significantly higher than that of healthy controls (P < 0.001), but significantly reduced after treatment for 3 months (P = 0.001). The levels of serum IL-35 were positively correlated with the HRCT scores in SSc patients (P = 0.014) and with disease duration in patients with diffuse cutaneous SSc (P = 0.03), but negatively correlated with the FVC values in SSc patients (P = 0.034). In comparison with that in the healthy controls, significantly decreased percentages of Th1, but increased Th2 and Th17 cells were detected in patients, leading to reduced ratios of Th1/Th2 and increased ratios of Th17/Tregs (P < 0.001). The levels of serum IL-35 were positively correlated with IL-4 (P = 0.036) and tended to be positively associated with the frequency of Tregs in SSc patients (P = 0.054). Higher levels of serum IL-35 may be associated with the development of SSc and severity of pulmonary fibrosis in SSc patients.

RGC32 Promotes Bleomycin-Induced Systemic Sclerosis in a Murine Disease Model by Modulating Classically Activated Macrophage Function

Systemic sclerosis (SSc) is a multisystem autoimmune disorder that is characterized by inflammation and fibrosis in the skin and internal organs. Previous studies indicate that inflammatory cells and cytokines play essential roles in the pathogenesis of SSc; however, the mechanisms that underlie the inflammation-driven development of SSc are not fully understood. In this study, we show that response gene to complement 32 (RGC32) is abundantly expressed in mouse macrophages in the early stage of bleomycin-induced SSc. Importantly, RGC32 is required to induce the inflammatory response during the onset of SSc, because RGC32 deficiency in mice significantly ameliorates skin and lung sclerosis and inhibits the expression of inflammatory mediators inducible NO synthase (iNOS) and IL-1β in macrophages. RGC32 appears to be a novel regulator for the differentiation of classically activated macrophages (M1 macrophages). IFN-γ and LPS stimulation induces RGC32 expression in primary peritoneal macrophages and bone marrow-derived macrophages. RGC32 deficiency impairs the polarization of M1 macrophages and attenuates iNOS and IL-1β production. Mechanistically, RGC32 interacts with NF-κB proteins and promotes iNOS and IL-1β expression by binding to their promoters. Collectively, our data reveal that RGC32 promotes the onset of SSc by regulating the inflammatory response of M1 macrophages, and it may serve as a promising therapeutic target for treating SSc.

Lymphocyte profile and cytokine mRNA expression in peripheral blood mononuclear cells of patients with recurrent respiratory papillomatosis suggest dysregulated cytokine mRNA response and impaired cytotoxic capacity

Objectives

Recurrent respiratory papillomatosis (RRP) is a relatively rare, chronic disease caused by Human Papilloma Virus (HPV) 6 and 11, and characterized by wart‐like lesions in the airway affecting voice and respiratory function. The majority of HPV infections are asymptomatic and resolve spontaneously, however, some individuals are afflicted with persistent HPV infections. Failure to eliminate HPV 6 and 11 due to a defect immune responsiveness to these specific genotypes is proposed to play a major role in the development of RRP.

Methods

We performed a phenotypic characterization of peripheral blood mononuclear cells (PBMC) collected from 16 RRP patients and 12 age‐matched healthy controls, using immunoflow cytometry, and monoclonal antibodies against differentiation and activation markers. The cytokine mRNA profile of monocytes, T helper‐, T cytotoxic‐, and NK cells was assessed using RT‐qPCR cytokine analysis, differentiating between Th1‐, Th2‐, Th3/regulatory‐, and inflammatory immune responses.

Results

We found a dominance of cytotoxic T cells, activated NK cells, and high numbers of stressed MIC A/B expressing lymphocytes. There was an overall suppression of cytokine mRNA production and an aberrant cytokine mRNA profile in the activated NK cells.

Conclusion

These findings demonstrate an immune dysregulation with inverted CD4⁺/CD8⁺ ratio and aberrant cytokine mRNA production in RRP patients, compared to healthy controls.

Paget's disease of bone: an osteoimmunological disorder?

Osteoimmunology represents a large area of research resulting from the cross talk between bone and immune systems. Many cytokines and signaling cascades are involved in the field of osteoimmunology, originating from various cell types. The RANK/receptor activator of nuclear factor Kappa-B ligand (RANKL)/osteoprotegerin (OPG) signaling has a pivotal role in osteoimmunology, in addition to proinflammatory cytokines such as tumor necrosis factor-α, interleukin (IL)-1, IL-6, and IL-17. Clinically, osteoimmunological disorders, such as rheumatoid arthritis, osteoporosis, and periodontitis, should be classified according to their pattern of osteoimmunological serum biomarkers. Paget’s disease of bone is a common metabolic bone disorder, resulting from an excessively increased bone resorption coupled with aberrant bone formation. With the exception of the cellular responses to measles virus nucleocapsid protein and the interferon-gamma signature, the exact role of the immune system in Paget’s disease of bone is not well understood. The cytokine profiles, such as the increased levels of IL-6 and the interferon-gamma signature observed in this disease, are also very similar to those observed in other osteoimmunological disorders. As a potential osteoimmunological disorder, the treatment of Paget’s disease of bone may also benefit from progress made in targeted therapies, in particular for receptor activator of nuclear factor Kappa-B ligand and IL-6 signaling inhibition.