Elevated expression of PD‑1 on T cells correlates with disease activity in rheumatoid arthritis

Immune-Mediated Inflammatory Diseases and Cancer - a dangerous liaison

Patients with Immune-Mediated Inflammatory Diseases (IMIDs) are known to have an elevated risk of developing cancer, but the exact causative factors remain subject to ongoing debate. This narrative review aims to present the available evidence concerning the intricate relationship between these two conditions. Environmental influences and genetic predisposition lead to a dysregulated immune response resulting in chronic inflammation, which is crucial in the pathogenesis of IMIDs and oncogenic processes. Mechanisms such as the inflammatory microenvironment, aberrant intercellular communication due to abnormal cytokine levels, excessive reparative responses, and pathological angiogenesis are involved. The chronic immunosuppression resulting from IMIDs treatments further adds to the complexity of the pathogenic scenario. In conclusion, this review highlights critical gaps in the current literature, suggesting potential avenues for future research. The intricate interplay between IMIDs and cancer necessitates more investigation to deepen our understanding and improve patient management.

The clinical association of programmed death-1/PD-L1 axis, myeloid derived suppressor cells subsets and regulatory T cells in peripheral blood of stable COPD patients

Background

Myeloid-derived suppressor cells (MDSCs) have crucial immunosuppressive role in T cell dysfunction in various disease processes. However, the role of MDSCs and their impact on Tregs in COPD have not been fully understood. The aim of the present study is to investigate the immunomodulatory role of MDSCs and their potential impact on the expansion and function of Tregs in COPD patients.

Methods

Peripheral blood samples were collected to analyze circulating MDSCs, Tregs, PD-1/PD-L1 expression to assess the immunomodulatory role of MDSC and their potential impact on the expansion and function of Treg in COPD. A total of 54 COPD patients and 24 healthy individuals were enrolled in our study. Flow cytometric analyses were performed to identify granulocytic MDSCs (G-MDSCs), monocytic MDSCs (M-MDSCs), Tregs, and the expression of PD-1/PD-L1(L2) on MDSCs and Tregs in peripheral blood.

Results

Our results revealed a significantly higher percentage of G-MDSCs and M-MDSCs (p < 0.001) in COPD patients compared to the healthy controls. Additionally, a significantly higher proportion of peripheral blood Tregs was observed in COPD patients. Furthermore, an increased expression of cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) on Tregs (p < 0.01) was detected in COPD patients. The expression of PD-1 on CD4+ Tcells and Tregs, but not CD8+Tcells, was found to be increased in patients with COPD compared to controls. Furthermore, an elevated expression of PD-L1 on M-MDSCs (p < 0.01) was also observed in COPD patients. A positive correlation was observed between the accumulation of M-MDSCs and Tregs in COPD patients. Additionally, the percentage of circulating M-MDSCs is positively associated with the level of PD-1 (r = 0.51, p < 0.0001) and CTLA-4 (r = 0.42, p = 0.0014) on Tregs in COPD.

Conclusion

The recruitment of MDSCs, accumulation of Tregs, and up-regulation of CTLA-4 on Treg in COPD, accompanied by an increased level of PD-1/PD-L1, suggest PD-1/PD-L1 axis may be potentially involved in MDSCs-induced the expansion and activation of Treg at least partially in COPD.

Selective blockade of IL-21 by myricetin impedes T follicular helper cell differentiation by negatively regulating the JAK/STAT/Bcl-6 pathway in a rheumatoid arthritis animal model

Interleukin (IL)-21 is a major lineage-defining factor that promotes Tfh cell differentiation. The current study investigated the molecular basis of myricetin, a flavonoid that impedes IL-21-mediated differentiation of Tfh cells in RA. Through high-throughput virtual screening of natural compounds that inhibit IL-21, we found that myricetin binds to IL-21 and hampers its interaction with IL-21 receptor (IL-21R). Our in vivo studies demonstrated that myricetin treatment ameliorated the clinical manifestations in adjuvant-induced arthritis (AIA) mice by reducing paw thickness and cellular infiltration. In addition, myricetin inhibited splenic Tfh cell differentiation and IL-21 production in AIA mice. Myricetin negatively regulates JAK/STAT signaling and the downstream Bcl-6 transcription factor at the molecular level, which arrests Tfh cell differentiation. Our current research proposal to target IL-21 with myricetin inevitably represents a new molecular approach that expedites new alternative drugs for rheumatoid arthritis therapy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03880-w.

Changes and correlations of T-cell coinhibitory molecule programmed death-1 and interferon-γ in pediatric immune thrombocytopenia

BACKGROUND

Immune thrombocytopenia (ITP) is an acquired autoimmune disease characterized by abnormalities of T cells subsets. Programmed death-1 (PD-1) is a co-signaling inhibitory molecule in T cells that is involved in many autoimmune diseases.

PURPOSE

Here we aimed to measure changes in PD-1 expression and serum interferon-γ (IFN-γ) levels before and 1 month after treatment in pediatric patients with newly diagnosed ITP.

METHODS

We measured PD-1+ CD4+ T cells percentages using flow cytometry and the serum IFN-γ levels by enzyme-linked immunosorbent assay in 40 pediatric patients with ITP and 20 healthy controls.

RESULTS

Compared with healthy controls, the PD-1+ CD4+ T cells percentages and serum IFN-γ levels were significantly higher in ITP patients before and 1 month after therapy. A correlation study revealed that PD-1+ CD4+ T cells percentage was negatively associated with platelet count and positively associated with IFN-γ level in patients with ITP. Furthermore, serum IFN-γ levels were significantly decreased in patients after treatment, but no significant change was detected in the percentage of PD-1+ CD4+ T cells before or 1 month after therapy.

CONCLUSION

PD-1+ CD4+ T cells expression and IFN-γ levels were increased in patients with ITP. These preliminary data suggest a potential role of PD-1+ CD4+ T cells as mediators of ITP. We also found a correlation between PD-1+ CD4+ T cells and both platelet counts and IFN-γ levels. These findings suggest a potential role of PD-1+ CD4+ T cells and IFN-γ in the pathogenesis of ITP. Further studies investigating PD-1 expression in different T-cell subsets, serum IFN-γ concentrations, and antiplatelet antibodies levels over a longer duration after therapy initiation could delineate the precise role of PD-1 in ITP pathogenesis. Consequently, novel nontraditional therapeutic strategies for ITP patients may become available.

Leveraging whole blood based functional flow cytometry assays to open new perspectives for rheumatoid arthritis translational research

Despite introduction of biological disease modifying anti-rheumatic drugs (DMARDs) for Rheumatoid arthritis (RA) treatment, therapeutic strategies do not always lead to disease control and remission. Hence, a more efficient patient stratification and monitoring biomarkers and tools are needed to enable a more personalized medicine. We used a whole blood based functional flow cytometry assay to characterize immune cells from RA patients (treated or not), healthy donors and psoriatic arthritis (PsA) patients according to their responses to LPS and/or anti-TNFα (infliximab, IFX). Activation marker expression was measured using a 10-color flow cytometry panel following a no-wash protocol. Naïve-to-treatment RA patients had a stronger inflammatory profile in comparison to healthy donors at basal level. Higher expression of activation markers (CD69 and/or CD11b) on NK, B cells and granulocytes and lower expression of the adhesion molecule CD62L were measured on monocytes, granulocytes and B cells. After LPS, naïve RA patients' cells were less capable of regulating CD69, CD11b, CD16 or CD62L showing impaired activation capabilities. Upon LPS and IFX co-incubation, hierarchical clustering analysis showed different profiles between cohorts. We believe that this whole blood-based approach should further be assessed for RA patient characterization as it provides new perspectives for stratification and/or monitoring.

Programmed Cell Death Protein-1 Upregulation in Response to SARS-CoV-2 in Juvenile Idiopathic Arthritis: A Case-Control Study

Currently, data regarding the impact of COVID-19 disease (caused by SARS-CoV-2) on patients with childhood rheumatic diseases are significantly limited. To assess the possible connection, we measured levels of IgA and IgG anti-SARS-CoV-2 antibodies in children with juvenile idiopathic arthritis (JIA) and a control group during the pandemic, prior to the introduction of anti-COVID-19 vaccination. We assessed levels of PD-1 suppressive molecule and inflammatory markers in patients and correlated those results with serological response to SARS-CoV-2. In JIA patients, the activity of the disease was assessed using the Juvenile Arthritis Disease Activity Score 71 (JADAS 71) scale. The study consisted of 96 children, 65 diagnosed with JIA, treated with antirheumatic drugs, and 31 healthy volunteers. In patients with JIA, significantly higher levels of SARS-CoV-2 antibodies in the IgA and IgG were demonstrated compared to the control group. We also found significantly higher serum PD-1 levels in JIA patients and control volunteers who were seropositive for SARS-CoV-2 IgA or IgG antibodies compared to those who were seronegative. The humoral immune response to SARS-CoV-2 infection is associated with the persistent upregulation of PD-1 expression in both JIA patients and healthy children. The clinical significance of the detected disorder requires further careful observation.

Role of the PD-1/PD-L1 Signaling in Multiple Sclerosis and Experimental Autoimmune Encephalomyelitis: Recent Insights and Future Directions

Multiple sclerosis (MS) is an autoimmunity-related chronic demyelination disease of the central nervous system (CNS), causing young disability. Currently, highly specific immunotherapies for MS are still lacking. Programmed cell death 1 (PD-1) is an immunosuppressive co-stimulatory molecule, which is expressed on activated T lymphocytes, B lymphocytes, natural killer cells, and other immune cells. PD-L1, the ligand of PD-1, is expressed on T lymphocytes, B lymphocytes, dendritic cells, and macrophages. PD-1/PD-L1 delivers negative regulatory signals to immune cells, maintaining immune tolerance and inhibiting autoimmunity. This review comprehensively summarizes current insights into the role of PD-1/PD-L1 signaling in MS and its animal model experimental autoimmune encephalomyelitis (EAE). The potentiality of PD-1/PD-L1 as biomarkers or therapeutic targets for MS will also be discussed.

The PD-1:PD-L1 axis in Inflammatory Arthritis

The activation of antigen specific T cells during an immune response is a tightly regulated process at the level of both costimulatory and coinhibitory receptors. One such coinhibitory receptor or checkpoint inhibitor which has received much attention in the field of oncology is the programmed cell death protein 1 (PD-1). Blockade of PD-1 or its ligand PD-L1 has proven successful in the treatment of a wide variety of cancers, therefore highlighting an important role for this pathway in anti-tumour immune responses. However, a caveat of PD-1 therapy and boosting anti-tumour immune responses is the development of self-reactive T cells which can lead to the induction of various autoimmune or inflammatory diseases, referred to as immune- related adverse events (irAEs). The emergence of rheumatological irAEs such as Inflammatory Arthritis (IA) in recent years has highlighted the importance of PD-1 in maintaining self-tolerance. Furthermore, the emergence of rheumatology related irAEs raises an important question as to how defects in this pathway can contribute to spontaneous rheumatological disease. In this review, we describe the biological distribution, function and regulation of the PD-1 pathway, its potential role in IA and irAE related IA.

On Research Progress of Western and Chinese Medicine Treatment on Pre-Rheumatoid Arthritis

Pre-rheumatoid arthritis is the inevitable phase before the actual onset of rheumatoid arthritis and has the crucial clinical significance of early controlling and preventing disease progression. Full understanding, from both Western medicine (WM) and Chinese medicine (CM), could offer new ideas for decision making in clinical and mechanism research. This paper reviews the novel studies of WM and CM to discuss the advantages and potential mechanisms working behind.

Analysis of PD-1 and Tim-3 expression on CD4+ T cells of patients with rheumatoid arthritis; negative association with DAS28

Expression of T cell immunoglobulin and mucin-domain containing-3 (Tim-3) and programmed cell death-1 (PD-1) was studied on CD4⁺ T cells of patients with rheumatoid arthritis (RA). Association of Tim-3 and PD-1 expression with disease activity of RA patients was also addressed. A total of 37 RA patients and 31 sex- and age-matched healthy controls were included in this study. Disease activity of RA patients was determined by Disease Activity Score of 28 joints scoring system (DAS28). A three-color flow cytometry method was applied to determine the frequency of Tim-3⁺/PD-1⁺/CD4⁺ T cells. To measure the cytokine production, peripheral blood mononuclear cells (PBMCs) were stimulated with PMA/ionomycin. Concentrations of IL-17, IL-10, IFN-γ, and TNF-α were measured in culture supernatants by ELISA. The frequency of PD-1⁺/CD4⁺ and Tim-3⁺/PD-1⁺/CD4⁺ T cells was significantly higher in patients with RA compared to that in controls (p = 0.0013 and p = 0.050, respectively). The percentage of Tim-3⁺/CD4⁺ T cells was similar in patients and controls (p = 0.4498). The RA patients have produced significant higher levels of TNF-α, IL-17, and IFN-γ than those of healthy controls (p = 0.0121, p = 0.0417, and p = 0.0478, respectively). Interestingly, an inverse correlation was found between the frequency of Tim-3⁺/CD4⁺ cells and DAS28 of RA patients (r = - 0.4696, p = 0.0493). Similarly, the percentage of Tim-3⁺/PD-1⁺/CD4⁺ T cells was also revealed an inverse correlation with DAS28 (r = - 0.5268, p = 0.0493). Moreover, significant positive correlations were detected between the concentrations of TNF-α (r = 0.6418, p = 0.0023) and IL-17 (r = 0.4683, p = 0.0373) with disease activity of RA patients. Our results indicate that Tim-3 and PD-1 are involved in immune dysregulation mechanisms of rheumatoid arthritis and could be considered as useful biomarkers for determination of disease activity and progression.