Efficacy and safety of low-dose interleukin-2 in combination with methotrexate in patients with active rheumatoid arthritis: a randomized, double-blind, placebo-controlled phase 2 trial

Impact of disease duration on systemic clinical profile in Sjogren's syndrome

BACKGROUND

Primary Sjogren's Syndrome (pSS) is a systemic autoimmune disorder characterized by lymphocyte infiltration of the exocrine glands. Disease duration plays a pivotal role in evaluating the development of SS. In this study, we aimed to clarify the clinical manifestations of pSS across various stages of its progression, thereby offering critical insights for early diagnosis and targeted management strategies for Sjogren's Syndrome.

METHODS

We conducted a retrospective analysis involving 3,978 patients with primary Sjogren's Syndrome (mean [SD] age: 53.1[24] years) from Peking University People's Hospital between January 2015 and December 2022. We classified patients into five distinct groups based on the duration of the syndrome: T0 (≤ 1 year), T1 (> 1 year, ≤ 5 years), T2 (> 5 years, ≤ 10 years), T3 (> 10 years, ≤ 20 years), and T4 (> 20 years).

RESULTS

We observed a statistically significant increase in the percentage of pSS patients with white blood cell (WBC) decrease, specifically: T0 (9.23%), T1 (15.40%), T2 (22.62%), T3 (20.22%), T4 (26.45%). The decreases in hemoglobin (HGB) and platelet (PLT) were also robustly associated with extended disease duration (p < 0.0001). Simultaneously, systemic involvements aggravated with disease progression as incidence rates of skin, joint, lung, and nervous system were strikingly increased in each group. The findings also indicated that patients with long-term pSS exhibit a higher likelihood of developing comorbid conditions, such as diabetes and tumors. In summary, disease duration serves as a crucial determinant for the prognosis of patients with pSS.

CONCLUSIONS

Therefore, early identification of symptoms and initiation of therapies are imperative for mitigating the risk of significant complications in pSS patients.

The 'Treg paradox' in inflammatory arthritis

Classic regulatory T (Treg) cells expressing CD4 and the hallmark transcription factor FOXP3 are integral to the prevention of multi-system autoimmunity. However, immune-mediated arthritis is often associated with increased numbers of Treg cells in the inflamed joints. To understand these seemingly conflicting observations, which we collectively describe as 'the Treg paradox', we provide an overview of Treg cell biology with a focus on Treg cell heterogeneity, function and dysfunction in arthritis. We discuss how the inflamed environment constrains the immunosuppressive activity of Treg cells while also promoting the differentiation of TH17-like Treg cell, exTreg cell (effector T cells that were formerly Treg cells), and osteoclastogenic Treg cell subsets that mediate tissue injury. We present a new framework to understand Treg cells in joint inflammation and define potential strategies for Treg cell-directed interventions in human inflammatory arthritis.

Correlation of fecal microbiome dysregulation to synovial transcriptome in an equine model of obesity associated osteoarthritis

Background

Osteoarthritis (OA) is increasingly thought to be a multifactorial disease in which sustained gut inflammation serves as a continued source of inflammatory mediators driving degenerative processes at distant sites such as joints. The objective of this study was to use the equine model of naturally occurring obesity associated OA to compare the fecal microbiome in OA and health and correlate those findings to differential gene expression synovial fluid (SF) cells, circulating leukocytes and cytokine levels (plasma, SF) towards improved understanding of the interplay between microbiome and immune transcriptome in OA pathophysiology.

Methods

Feces, peripheral blood mononuclear cells (PBMCs), and SF cells were isolated from healthy skeletally mature horses (n=12; 6 males, 6 females) and those with OA (n=6, 2 females, 4 males). Horses were determined to have OA via lameness evaluation, response to intra-articular (IA) diagnostic analgesia, and radiographic and arthroscopic evidence. Horses were excluded who had received medications or joint injections within 2 months. Cytokine analyses of plasma and SF were performed via multiplex immunoassay. Fecal bacterial microbial 16s DNA sequencing was performed and correlated to bulk RNA sequencing of SF cells and PBMC performed using an Illumina based platform.

Results

Horses with OA had higher body condition scores (P=0.009). Cytokines were elevated in plasma [interleukin (IL)-2, IL-6, IL-18, interferon gamma (IFN-γ), interferon gamma inducible protein 10 (CXCL10 or IP-10), granulocyte colony-stimulating factor (G-CSF)] and SF (IL-1β, IL-6, IL-17A, IL-18, IP-10, G-CSF) in OA. Microbial principal coordinate analysis (PCoA) using Bray-Curtis dissimilarity for β-diversity demonstrated distinct grouping of samples from OA versus healthy horses (P=0.003). Faith alpha diversity was reduced in OA (P=0.02). Analysis of microbiome composition showed differential relative abundance of taxa on multiple levels in OA. Specific phyla (Firmicutes, Verrucomicrobia, Tenericutes, Fibrobacteres), correlated to transcriptomic differences related to cell structure, extracellular matrix, collagen, laminin, migration, and motility, or immune response to inflammation in OA.

Conclusions

These findings provide compelling evidence for a link between obesity, gut microbiome dysbiosis and differential gene expression in distant joint sites associated with development of OA in a relevant large animal model, establishing a connection here that provides a platform from which development of therapeutic interventions targeting the gut microbiome can build.

Metabolic impact of low dose IL-2 therapy for primary Sjögren's Syndrome in a double-blind, randomized clinical trial

OBJECTIVES

Low-dose interleukin 2 (Ld-IL2) is increasingly being explored as an immune-modulating treatment for autoimmune diseases which mainly affect T cell subsets. This study investigates the metabolic effects of Ld-IL2 therapy in patients with primary Sjögren's syndrome (pSS).

METHOD

A total of 60 patients were recruited to conduct a double-blind, randomized clinical trial. Of these patients, 50% (30/60) received Ld-IL2 therapy along with standard treatment for 12 weeks, followed by 12 weeks of follow-up. The effectiveness was evaluated by Sjögren's Tool for Assessing Response (STAR). An untargeted analysis was performed to profile hydrophilic metabolites.

RESULTS

Metabolic profiling revealed significant alterations post-treatment, notably in metabolites like acetyl-CoA, ascorbic acid, and glutathione, which are beneficial in managing autoimmune diseases. In addition, the levels of metabolite accumulation were correlated with variations in immune cell subsets (p < 0.05), particularly Tregs. Moreover, patients exhibiting a specific metabolic profile, including lower serum levels of isoleucine, ADP, Thymidine 5'-triphosphate, and other metabolites, had a high response rate (91.7%-98.6%), as indicated by the receiver operating characteristic (ROC) curve.

CONCLUSIONS

These findings suggest that Ld-IL2 therapy influences metabolic pathways in pSS, offering insights into the systemic effects of Ld-IL2 therapy beyond immune modulation.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov number, NCT02464319. Key Points • Metabolic alteration in pSS is significantly associated with Ld-IL2 therapy. • Metabolic changes correlate with variations in immune cell subsets, particularly Tregs. • Metabolic profiling could be a valuable tool in guiding Ld-IL2 therapy choices for pSS patients.

Predictive biomarkers for low-dose IL-2 therapy efficacy in systemic lupus erythematosus: a clinical analysis

BACKGROUND

Low-dose IL-2 (Ld-IL2) has shown favorable therapeutic effects in systemic lupus erythematosus (SLE) therapy. However, previous clinical trials reported an SLE Responder Index-4 (SRI-4) response rate of 65.52%-68%, with approximately half failing to achieve the primary endpoint by week 24. Our study aims to determine the real-world use of Ld-IL2 and to identify determinants of its effectiveness in SLE.

METHODS

We pooled data from 342 SLE patients undergoing sequential Ld-IL2 treatment, with 314 persisting for over 3 months were included in effectiveness and prediction analyses. All patients were categorized into responder (n = 136) and non-responder group (n = 178) according to SRI-4. Lupus Low Disease Activity State (LLDAS) was also analyzed to validate our results.

RESULTS

Rash, lower complement 3 (C3), and renal involvement including urine protein, urine occult blood and urine casts emerged as prominent predictors of achieving SRI-4. Adjusting for baseline values using the ratio of change to baseline revealed significant differences in CD4 + T cell immune profiles between responders and non-responders. ROC analysis confirmed a satisfactory performance of rash, renal involvement, percentage change of CD4 + T cells, and C3 in predicting SRI-4, yielding an AUC of 0.933. LLDAS analysis showed that hematological involvements and lower CLA + Treg were potent predictive markers in LLDAS attainment. Conversely, renal involvement failed to have significant association in achieving LLDAS. The analysis of background therapy in SLE patients showed that MMF was more likely to reach the SRI-4 response with the combination of Ld-IL2.

CONCLUSIONS

These findings uncovered the predictors of Ld-IL2 treatment efficacy in SLE patients and provided guidance to physicians for rational utilization.

Systematic literature review on early clinical evidence for immune-resolution therapies and potential benefits to patients and healthcare providers

Introduction

Several current therapies for autoimmune diseases do not provide sustained remission. Therapies that focus on the restoration of homeostasis within the immune system (i.e., immune resolution) could overcome the limitations of current therapies and provide more durable remission. However, there is no established consensus on appropriate clinical trial designs and endpoints to evaluate such therapies. Therefore, we conducted a systematic literature review (SLR) focusing on five index diseases (asthma, atopic dermatitis, rheumatoid arthritis, systemic lupus erythematosus [SLE], and ulcerative colitis) to explore published literature on 1) expert opinion on immune-resolution outcomes that should be measured in clinical trials; and 2) quantification of immune resolution in previous clinical trials.

Methods

The SLR was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Embase and MEDLINE databases were systematically searched (2013-2023) for published English language articles. Conference proceedings (2020-2022) from American Academy of Dermatology, American College of Rheumatology, Digestive Disease Week, European Alliance of Associations for Rheumatology, and European Academy of Dermatology and Venereology were searched to include relevant abstracts. The study protocol was registered in PROSPERO (CRD42023406489).

Results

The SLR included 26 publications on 20 trials and 12 expert opinions. Expert opinions generally lacked specific recommendations on the assessment of immune resolution in clinical trials and instead suggested targets or biomarkers for future therapies. The targets included thymic stromal lymphopoietin (TSLP) in asthma; T helper (Th)2 and Th22 cells and their respective cytokines (interleukin [IL]-4R and IL-22) in atopic dermatitis; inhibitory/regulatory molecules involved in T-cell modulation, and protein tyrosine phosphatase, non-receptor type 22 (PTPN22) in rheumatoid arthritis; low-dose IL-2 therapy in SLE; and pro-resolution mediators in ulcerative colitis and asthma. In the interventional studies, direct biomarker assessments of immune resolution were the number/proportion of regulatory T-cells (Treg) and the ratio Th17/Treg in SLE and rheumatoid arthritis; the number of T follicular helper cells (Tfh), Th1, Th2, Th17, and Th22 in atopic dermatitis, rheumatoid arthritis, and SLE; and mucosal proinflammatory gene signatures (tumor necrosis factor [TNF], interleukin 1 alpha [IL1A], regenerating family member 1 alpha [REG1A], IL8, interleukin 1 beta [IL1B], and leukocyte immunoglobulin-like receptors A [LILRA]) in ulcerative colitis. Several studies reported a statistically significant relationship between clinical remission and immune-resolution biomarkers, suggesting a link between T-cell homeostasis, cytokine production, and disease activity in autoimmune diseases.

Discussion

Existing literature does not offer clear guidance on the evaluation of immune resolution in interventional studies. Further research and consensus are needed to assess a treatment's ability to induce long-term remission or low disease activity.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023406489, identifier CRD42023406489.

Methotrexate treatment hampers induction of vaccine-specific CD4 T cell responses in patients with IMID

OBJECTIVES

Methotrexate (MTX) is one of the most commonly used medications to treat rheumatoid arthritis (RA). However, the effect of MTX treatment on cellular immune responses remains incompletely understood. This raises concerns about the vulnerability of these patients to emerging infections and following vaccination.

METHODS

In the current study, we investigated the impact of MTX treatment in patients with immune-mediated inflammatory disease on B and CD4 T cell SARS-CoV-2 vaccination responses. Eighteen patients with RA and two patients with psoriatic arthritis on MTX monotherapy were included, as well as 10 patients with RA without immunosuppressive treatment, and 29 healthy controls. CD4 T and B cell responses were analysed 7 days and 3-6 months after two SARS-CoV-2 messenger RNA vaccinations. High-dimensional flow cytometry analysis was used to analyse fresh whole blood, an activation-induced marker assay to measure antigen-specific CD4 T cells, and spike probes to study antigen-specific B cells.

RESULTS

Seven days following two SARS-CoV-2 vaccinations, total B and T cell counts were similar between MTX-treated patients and controls. In addition, spike-specific B cell frequencies were unaffected. Remarkably, the frequency of antigen-specific CD4 T cells was reduced in patients using MTX and correlated strongly with anti-RBD IgG antibodies. These results suggest that decreased CD4 T cell activity may result in slower vaccination antibody responses in MTX-treated patients.

CONCLUSION

Taken together, MTX treatment reduces vaccine-induced CD4 T cell activation, which correlates with lower antibody responses.

TRIAL REGISTRATION NUMBER

NL8900.

Regulatory T lymphocytes as a treatment method for rheumatoid arthritis - Superiority of allogeneic to autologous cells

Cellular therapies utilizing regulatory T cells (Tregs) have flourished in the autoimmunity space as a new pillar of medicine. These cells have shown a great promise in the treatment of such devastating conditions as type 1 diabetes mellitus (T1DM), systemic lupus erythematosus (SLE) and graft versus host disease (GVHD). Novel treatment protocols, which utilize Tregs-mediated suppressive mechanisms, are based on the two main strategies: administration of immunomodulatory factors affecting Tregs or adoptive cell transfer (ACT). ACT involves extraction, in vitro expansion and subsequent administration of Tregs that could be either of autologous or allogeneic origin. Rheumatoid arthritis (RA) is another autoimmune candidate where this treatment approach is being considered. RA remains an especially challenging adversary since it is one of the most frequent and debilitating conditions among all autoaggressive disorders. Noteworthy, Tregs circulating in RA patients' blood have been proven defective and unable to suppress inflammation and joint destruction. With this knowledge, adoptive transfer of compromised autologous Tregs in the fledgling clinical trials involving RA patients should be reconsidered. In this article we hypothesize that incorporation of healthy donor allogeneic Tregs may provide more lucid and beneficial results.

Maternal Soluble Programmed Death Ligand-1 (sPD-L1) and T-regulatory Cells (Tregs) Alteration in Preeclampsia: A Cross-Sectional Study From Eastern India

Background Studies have shown that aberrant reactions of the immune system play an important role in the pathogenesis of preeclampsia. The immune checkpoint molecules programmed cell death protein 1/programmed death-ligand 1 (PD-1/PD-L1) system and the T-regulatory cells (Tregs) system are decisive in the regulation of immune responses and can be the target molecules in preeclampsia. In this study, an attempt has been made to evaluate the soluble PD-L1 (sPD-L1) in the serum of preeclampsia cases and correlate it with Tregs and inflammatory markers to have an insight into the link between these immunomodulatory molecules in the pathogenesis of preeclampsia. Materials and methods Ten normal fertile women, 20 trimester-matched normal pregnancy cases, and 20 preeclampsia cases were enrolled in the study. Serum sPD-L1, transforming growth factor beta 1 (TGF-β1), and IL-6 were measured by enzyme-linked immunosorbent assay (ELISA). High-sensitive C-reactive protein (hsCRP) was estimated using a clinical biochemistry autoanalyzer. Tregs were evaluated using flow cytometry. Results and discussion The immune checkpoint molecule PD-L1 inversely correlated with Tregs in preeclampsia cases. Associated inflammation was seen by raised IL-6 and hsCRP. The breakdown of immunological tolerance is mainly caused by the dysregulating the Tregs/Th17 balance, which leads to conditions of autoimmunity and chronic inflammatory disorders. PD-L1 can be the link between this immunological misbalance. Conclusion Our study, showing an increase in sPD-L1 and TGF and a decrease in Tregs with an increase in inflammatory markers like IL-6 and hsCRP levels in preeclampsia, has potential implications for early diagnosis and management of the condition. PD-L1 and Tregs can be target molecules for early management of preeclampsia.

Low-dose IL-2 therapy in autoimmune diseases: An update review

Regulatory T (Treg) cells are essential for maintaining self-immune tolerance. Reduced numbers or functions of Treg cells have been involved in the pathogenesis of various autoimmune diseases and allograft rejection. Therefore, the approaches that increase the pool or suppressive function of Treg cells in vivo could be a general strategy to treat different autoimmune diseases and allograft rejection. Interleukin-2 (IL-2) is essential for the development, survival, maintenance, and function of Treg cells, constitutively expressing the high-affinity receptor of IL-2 and sensitive response to IL-2 in vivo. And low-dose IL-2 therapy in vivo could restore the imbalance between autoimmune response and self-tolerance toward self-tolerance via promoting Treg cell expansion and inhibiting follicular helper T (Tfh) and IL-17-producing helper T (Th17) cell differentiation. Currently, low-dose IL-2 treatment is receiving extensive attention in autoimmune disease and transplantation treatment. In this review, we summarize the biology of IL-2/IL-2 receptor, the mechanisms of low-dose IL-2 therapy in autoimmune diseases, the application in the progress of different autoimmune diseases, including Systemic Lupus Erythematosus (SLE), Type 1 Diabetes (T1D), Rheumatoid Arthritis (RA), Autoimmune Hepatitis (AIH), Alopecia Areata (AA), Immune Thrombocytopenia (ITP) and Chronic graft-versus-host-disease (GVHD). We also discuss the future directions to optimize low-dose IL-2 treatments.

Exploring the therapeutic potential of regulatory T cell in rheumatoid arthritis: Insights into subsets, markers, and signaling pathways

Rheumatoid arthritis (RA) is a complex autoimmune inflammatory rheumatic disease characterized by an imbalance between immunological reactivity and immune tolerance. Regulatory T cells (Tregs), which play a crucial role in controlling ongoing autoimmunity and maintaining peripheral tolerance, have shown great potential for the treatment of autoimmune inflammatory rheumatic diseases such as RA. This review aims to provide an updated summary of the latest insights into Treg-targeting techniques in RA. We focus on current therapeutic strategies for targeting Tregs based on discussing their subsets, surface markers, suppressive function, and signaling pathways in RA.

Smoking and osteoimmunology: Understanding the interplay between bone metabolism and immune homeostasis

Smoking continues to pose a global threat to morbidity and mortality in populations. The detrimental impact of smoking on health and disease includes bone destruction and immune disruption in various diseases. Osteoimmunology, which explores the communication between bone metabolism and immune homeostasis, aims to reveal the interaction between the osteoimmune systems in disease development. Smoking impairs the differentiation of mesenchymal stem cells and osteoblasts in bone formation while promoting osteoclast differentiation in bone resorption. Furthermore, smoking stimulates the Th17 response to increase inflammatory and osteoclastogenic cytokines that promote the receptor activator of NF-κB ligand (RANKL) signaling in osteoclasts, thus exacerbating bone destruction in periodontitis and rheumatoid arthritis. The pro-inflammatory role of smoking is also evident in delayed bone fracture healing and osteoarthritis development. The osteoimmunological therapies are promising in treating periodontitis and rheumatoid arthritis, but further research is still required to block the smoking-induced aggravation in these diseases.

Translational potential

This review summarizes the adverse effect of smoking on mesenchymal stem cells, osteoblasts, and osteoclasts and elucidates the smoking-induced exacerbation of periodontitis, rheumatoid arthritis, bone fracture healing, and osteoarthritis from an osteoimmune perspective. We also propose the therapeutic potential of osteoimmunological therapies for bone destruction aggravated by smoking.

The efficacy and safety of short-term and low-dose IL-2 combined with tocilizumab to treat rheumatoid arthritis

Background

Immunotherapy targeting factors related to immune imbalance has been widely employed for RA treatment. This study aimed to evaluate the efficacy and safety of low-dose interleukin (IL)-2 combined with tocilizumab (TCZ), a biologics targeting IL-6, in RA patients.

Methods

Fifty adults with active RA who met the criteria with complete clinical data were recruited, and divided into three groups: control group (n=15), IL-2 group (n=26), and IL-2+TCZ group (n=9). In addition to basic treatment, participants in the IL-2 group received IL-2 (0.5 MIU/day), while participants in the IL-2+TCZ group received IL-2 (0.5 MIU/day) along with one dose of TCZ (8 mg/kg, maximum dose: 800 mg). All subjects underwent condition assessment, laboratory indicators and safety indicators detection, and records before treatment and one week after treatment.

Results

Compared with the baseline, all three groups showed significant improvement in disease conditions, as evidenced by significantly reduced disease activity indicators. The low-dose IL-2 and combination treatment groups demonstrated a violent proliferation of Tregs, while the absolute number of Th1, Th2, and Th17 cells in the latter group showed a decreasing trend. The decrease in the Th17/Treg ratio was more pronounced in the IL-2+TCZ groups. No significant adverse reactions were observed in any of the patients.

Conclusion

Exogenous low doses of IL-2 combined TCZ were found to be safe and effective in reducing effector T cells and appropriately increasing Treg levels in RA patients with high effector T cell levels. This approach helps regulate immune homeostasis and contributes to the prevention of disease deterioration.

Clinical trial registration

https://www.chictr.org.cn/showprojEN.html?proj=13909, identifier ChiCTR-INR-16009546.

Dihydroartemisinin alleviates erosive bone destruction by modifying local Treg cells in inflamed joints: A novel role in the treatment of rheumatoid arthritis

Treg cell-based therapy has exhibited promising efficacy in combatting rheumatoid arthritis (RA). Dihydroartemisinin (DHA) exerts broad immunomodulatory effects across various diseases, with its recent spotlight on T-cell regulation in autoimmune conditions. The modulation of DHA on Treg cells and its therapeutic role in RA has yet to be fully elucidated. This study seeks to unveil the influence of DHA on Treg cells in RA and furnish innovative substantiation for the potential of DHA to ameliorate RA. To this end, we initially scrutinized the impact of DHA-modulated Treg cells on osteoclast (OC) formation in vitro using Treg cell-bone marrow-derived monocyte (BMM) coculture systems. Subsequently, employing the collagen-induced arthritis (CIA) rat model, we validated the efficacy of DHA and probed its influence on Treg cells in the spleen and popliteal lymph nodes (PLN). Finally, leveraging deep proteomic analysis with data-independent acquisition (DIA) and parallel accumulation-serial fragmentation (PASEF) technology, we found the alterations in the Treg cell proteome in PLN by proteomic analysis. Our findings indicate that DHA augmented suppressive Treg cells, thereby impeding OC formation in vitro. Consistently, DHA mitigated erosive joint destruction and osteoclastogenesis by replenishing splenic and joint-draining lymph node Treg cells in CIA rats. Notably, DHA induced alterations in the Treg cell proteome in PLN, manifesting distinct upregulation of alloantigen Col2a1 (Type II collagen alfa 1 chain) and CD8a (T-cell surface glycoprotein CD8 alpha chain) in Treg cells, signifying DHA's targeted modulation of Treg cells, rendering them more adept at sustaining immune tolerance and impeding bone erosion. These results unveil a novel facet of DHA in the treatment of RA.

Th17/Treg balance: the bloom and wane in the pathophysiology of sepsis

Sepsis is a multi-organ dysfunction characterized by an unregulated host response to infection. It is associated with high morbidity, rapid disease progression, and high mortality. Current therapies mainly focus on symptomatic treatment, such as blood volume supplementation and antibiotic use, but their effectiveness is limited. Th17/Treg balance, based on its inflammatory property, plays a crucial role in determining the direction of the inflammatory response and the regression of organ damage in sepsis patients. This review provides a summary of the changes in T-helper (Th) 17 cell and regulatory T (Treg) cell differentiation and function during sepsis, the heterogeneity of Th17/Treg balance in the inflammatory response, and the relationship between Th17/Treg balance and organ damage. Th17/Treg balance exerts significant control over the bloom and wanes in host inflammatory response throughout sepsis.

Comparison of Low-Dose Interleukin 2 Therapy in Conjunction With Standard Therapy in Patients With Systemic Lupus Erythematosus vs Rheumatoid Arthritis: A Systematic Review

This systematic review aims to compare the efficacy and safety of a novel immunotherapy with low-dose interleukin 2 (IL2) across two of the most prevalent autoimmune diseases i.e. systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Contemporary therapeutic practices have not been able to achieve complete remission from these autoimmune disorders. In contrast, low-dose IL2 has shown promise in achieving this therapeutic goal via inducing self-tolerance in patients with autoimmune diseases; however, due to variable irregularities among autoimmune processes of variable diseases, the benefit of low-dose IL2 could not be determined among different autoimmune diseases. Therefore, we conducted a study to compare low-dose IL2 therapy effects on SLE and RA. We systematically screened four databases: PubMed, Medical Literature Analysis and Retrieval System Online (MEDLINE), PubMed Central (PMC), and Google Scholar. Inclusion and exclusion criteria were implemented. Quality appraisal of studies chosen for the review was done using the Cochrane Risk-of-Bias (RoB) assessment tool for randomized controlled trials, and the Newcastle-Ottawa Scale (NOS) and JBI critical appraisal tool for non-randomized clinical trials. Information was gathered from seven articles: three randomized controlled trials and four non-randomized clinical trials. Our review concluded that low-dose IL2 therapy in conjunction with respective standard therapies for SLE and RA has a higher efficacy and safety profile as compared to standard therapy alone and the therapeutic effects were comparable in both SLE and RA patients treated with low-dose IL2; however, this novel intervention does not seem to have a significant corrective effect on the biomarkers of RA as it does for SLE biomarkers.

Molecular Engineering of Interleukin-2 for Enhanced Therapeutic Activity in Autoimmune Diseases

The interleukin-2 (IL-2) cytokine plays a crucial role in regulating immune responses and maintaining immune homeostasis. Its immunosuppressive effects have been harnessed therapeutically via administration of low cytokine doses. Low-dose IL-2 has shown promise in the treatment of various autoimmune and inflammatory diseases; however, the clinical use of IL-2 is complicated by its toxicity, its pleiotropic effects on both immunostimulatory and immunosuppressive cell subsets, and its short serum half-life, which collectively limit the therapeutic window. As a result, there remains a considerable need for IL-2-based autoimmune disease therapies that can selectively target regulatory T cells with minimal off-target binding to immune effector cells in order to prevent cytokine-mediated toxicities and optimize therapeutic efficacy. In this review, we discuss exciting advances in IL-2 engineering that are empowering the development of novel therapies to treat autoimmune conditions. We describe the structural mechanisms of IL-2 signaling, explore current applications of IL-2-based compounds as immunoregulatory interventions, and detail the progress and challenges associated with clinical adoption of IL-2 therapies. In particular, we focus on protein engineering approaches that have been employed to optimize the regulatory T-cell bias of IL-2, including structure-guided or computational design of cytokine mutants, conjugation to polyethylene glycol, and the development of IL-2 fusion proteins. We also consider future research directions for enhancing the translational potential of engineered IL-2-based therapies. Overall, this review highlights the immense potential to leverage the immunoregulatory properties of IL-2 for targeted treatment of autoimmune and inflammatory diseases.

A humanized IL-2 mutein expands Tregs and prolongs transplant survival in preclinical models

Long-term organ transplant survival remains suboptimal, and life-long immunosuppression predisposes transplant recipients to an increased risk of infection, malignancy, and kidney toxicity. Promoting the regulatory arm of the immune system by expanding Tregs may allow immunosuppression minimization and improve long-term graft outcomes. While low-dose IL-2 treatment can expand Tregs, it has a short half-life and off-target expansion of NK and effector T cells, limiting its clinical applicability. Here, we designed a humanized mutein IL-2 with high Treg selectivity and a prolonged half-life due to the fusion of an Fc domain, which we termed mIL-2. We showed selective and sustainable Treg expansion by mIL-2 in 2 murine models of skin transplantation. This expansion led to donor-specific tolerance through robust increases in polyclonal and antigen-specific Tregs, along with enhanced Treg-suppressive function. We also showed that Treg expansion by mIL-2 could overcome the failure of calcineurin inhibitors or costimulation blockade to prolong the survival of major-mismatched skin grafts. Validating its translational potential, mIL-2 induced a selective and sustainable in vivo Treg expansion in cynomolgus monkeys and showed selectivity for human Tregs in vitro and in a humanized mouse model. This work demonstrated that mIL-2 can enhance immune regulation and promote long-term allograft survival, potentially minimizing immunosuppression.

The effects of low-dose IL-2 on Th17/Treg cell imbalance in primary biliary cholangitis mouse models

BACKGROUND/AIMS

Primary biliary cholangitis (PBC) is a chronic cholestatic liver disease. The imbalance of Th17/Treg cells has been reported in PBC patients. Low-dose IL-2 can alleviate disease severity through modulating CD4 + T cell subsets in patients with autoimmune diseases. Hence, the present study aimed to examine the effects and mechanism of low-dose IL-2 in PBC mouse models.

METHODS

PBC models were induced in female C57BL/6 mice by two immunizations with 2OA-BSA at two-week intervals, and poly I: C every three days. PBC mouse models were divided into the IL-2 treated and untreated groups and low-dose IL-2 was injected at three different time points. Th17 and Tregs were analyzed by flow cytometry, and the related cytokines were analyzed by ELISA. Liver histopathology was examined by H&E and immunohistochemical staining.

RESULTS

Twelve weeks after modeling, the serum AMA was positive and the ALP was significantly increased in PBC mouse models (P<0.05). The pathology showed lymphocyte infiltration in the portal area, damage, and reactive proliferation of the small bile duct (P<0.05). The flow cytometric showed the imbalance of Th17/Treg cells in the liver of PBC mouse models, with decreased Treg cells, increased Th17 cells, and Th17/Treg ratio (P < 0.05). After the low-dose IL-2 intervention, biochemical index and liver pathologies showed improvement at 12 weeks. Besides, the imbalance of Th17 and Treg cells recovered. Public database mining showed that Th17 cell differentiation may contribute to poor response in PBC patients.

CONCLUSION

Low-dose IL-2 can significantly improve liver biochemistry and pathology by reversing the imbalance of Th17 and Treg cells, suggesting that it may be a potential therapeutic target for PBC.

Targeting kinase ITK treats autoimmune arthritis via orchestrating T cell differentiation and function

IL-2 inducible T cell kinase (ITK) is critical in T helper subset differentiation and its inhibition has been suggested for the treatment of T cell-mediated inflammatory diseases. T follicular helper (Tfh), Th17 and regulatory T cells (Treg) also play important roles in the development of rheumatoid arthritis (RA), while the role of ITK in the development of RA and the intricate balance between effector T and regulatory T cells remains unclear. Here, we found that CD4+ T cells from RA patients presented with an elevated ITK activation. ITK inhibitor alleviated existing collagen-induced arthritis (CIA) and reduced antigen specific antibody production. Blocking ITK kinase activity interferes Tfh cell generation. Moreover, ITK inhibitor effectively rebalances Th17 and Treg cells by regulating Foxo1 translocation. Furthermore, we identified dihydroartemisinin (DHA) as a potential ITK inhibitor, which could inhibit PLC-γ1 phosphorylation and the progression of CIA by rebalancing Th17 and Treg cells. Out data imply that ITK activation is upregulated in RA patients, and therefore blocking ITK signal may provide an effective strategy to treat RA patients and highlight the role of ITK on the Tfh induction and RA progression.

Low-dose Interleukin-2 For Psoriasis Therapy Based on the Regulation of Th17/Treg Cell Balance in Peripheral Blood

The imbalance between regulatory T (Treg) cells and efficient T cells plays an important role in psoriasis. Low-dose interleukin (IL)-2 can preferentially activate Treg cells and ameliorate the imbalance of Treg/efficient T cells. This study focused on the status of circulating CD4+ T subsets and the clinical efficacy of low-dose IL-2 therapies in psoriasis. This retrospective study included peripheral blood samples obtained from 45 psoriatic patients and 40 healthy controls. The 45 psoriatic patients received three cycles of subcutaneous low-dose IL-2 treatment (0.5 million IU/day for 2 weeks) combined with conventional therapies. Inflammatory indices, CD4+ T-lymphocyte subsets, and cytokines were measured in all patients before and after treatment. The percentage of Treg cells was dramatically decreased in the psoriasis group compared to the healthy group, and the percentage of Treg cells negatively correlated with the disease indices and the Psoriasis Area and Severity Index (PASI) (P < 0.001). The Th17/Treg ratio was significantly increased in the psoriasis group compared to the healthy group, and the Th17/Treg ratio positively correlated with disease indices and PASI (P < 0.001). Low-dose IL-2 treatment significantly amplified the percentage of Treg cells and restored the Th17 and Treg immune balance in psoriasis (P < 0.001). Low-dose IL-2 combination therapy effectively improved the clinical manifestations of psoriasis but decreased the inflammatory indicators of the disease activity, with no apparent side effects. Thus, low-dose IL-2 provides a new strategy for the treatment of psoriasis.

Advances in psoriasis and gut microorganisms with co-metabolites

This review summarizes the potential role of gut microbes and their metabolites as novel mediators of psoriasis, including their composition and function in disease pathogenesis, progression, and management. Gut microbiota network analysis, colony construction, and in vivo large-scale interaction experiments showed that different degrees of damage and repair in psoriasis, both in animals and humans, involve cross-border homeostasis of the microbial community. Which gut microbiota interactions are present in psoriasis and how they collaborate with immune cells and influence psoriasis development via the gut-skin axis remain incompletely elucidated. In this article, we review the latest information on the unique patterns of gut microbiota and co-metabolites involved in the pathogenesis of psoriasis and attempt to explore microbial-based therapeutic targets derived from mono-and polymicrobial probiotics, fecal microbiota transplantation, pharmacomicrobiomics, and dietary interventions as diagnostic or therapeutic approaches promising to provide new options and long-term management for psoriasis.

Knowledge, Attitudes, and Practices Related to Cervical Cancer Prevention and Screening among Female Pharmacy Students at a Public University in a Southern Region of Saudi Arabia

Despite the availability of human papillomavirus (HPV) vaccines and screening facilities at various health centers in Saudi Arabia, the annual death rate due to cervical cancer is high. Therefore, knowledge and awareness are essential for self-care and educating others, particularly among healthcare students. The present descriptive, cross-sectional study explored female pharmacy students' knowledge, attitudes, and practices related to cervical cancer. A total of 140 students participated in the survey. The survey was conducted for the period between April 2022 to September 2023. We observed a good knowledge score and positive attitudes among 8.5% and 93.5% of participants, respectively. A total of 10% of the study participants reported good practice scores. Most participants had never been screened for cervical cancer (94.3%). Among the non-screened subjects, feeling healthy and lacking information were the participants' significant reasons for not screening for cervical cancer. A positive history of cancer related to smoking significantly impacted the knowledge score (p = 0.050). The current study reveals that healthcare awareness programs for cervical cancer and HPV vaccination are necessary at the level of educational institutions to improve public health.

Inflammation across tissues: can shared cell biology help design smarter trials?

Immune-mediated inflammatory diseases (IMIDs) are responsible for substantial global disease burden and associated health-care costs. Traditional models of research and service delivery silo their management within organ-based medical disciplines. Very often patients with disease in one organ have comorbid involvement in another, suggesting shared pathogenic pathways. Moreover, different IMIDs are often treated with the same drugs (including glucocorticoids, immunoregulators and biologics). Unlocking the cellular basis of these diseases remains a major challenge, leading us to ask why, if these diseases have so much in common, they are not investigated in a common manner. A tissue-based, cellular understanding of inflammation might pave the way for cross-disease, cross-discipline basket trials (testing one drug across two or more diseases) to reduce the risk of failure of early-phase drug development in IMIDs. This new approach will enable rapid assessment of the efficacy of new therapeutic agents in cross-disease translational research in humans.

Role of IL-2/IL-2 receptor in pathogenesis of autoimmune disorders: Genetic and therapeutic aspects

Interleukin-2 (IL-2) is an important cytokine that plays a key role in the immune response. The IL-2 receptor (IL-2R) is composed of three subunits, alpha, beta, and gamma, with the alpha subunit having the highest affinity for IL-2. Several studies reported that immune dysregulation of IL-2 may cause tissue injury as well as damage leading to the pathogenesis of various autoimmune diseases such as acute necrotizing vasculitis in systemic lupus erythematosus (SLE), inflammatory synovitis in rheumatoid arthritis (RA), salivary and lacrimal gland dys-function in Sjogren syndrome (SS), obliterative vasculopathy fibrosis in systemic sclerosis (SSc), and inflammatory demyelination in multiple sclerosis (MS). The aim of this review paper was to examine the role of IL-2/IL-2R in various autoimmune disorders, taking into account recent advancements and discoveries, gaps in the current literature, ongoing debates, and potential avenues for future research. The focus of this review is on systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis, sjogren syndrome, and multiple sclerosis, which are all linked to the malfunctioning of IL-2/IL-2R. In genetic studies, gene polymorphisms of IL-2 such as IL-2 330/T, IL-2 330/G, and rs2069763 are involved in increasing the risk of SLE. Furthermore, genetic associations of IL-2/IL-2R such as rs791588, rs2281089, rs2104286, rs11594656, and rs35285258 are significantly associated with RA susceptibility. The IL-2 polymorphism including rs2069762A, rs6822844T, rs6835457G, and rs907715T are significant connections with systemic sclerosis. In addition, rs2104286 (IL-2), rs11594656 (IL-2RA), rs35285258 (IL-2RB) gene polymorphism significant increases the risk of multiple sclerosis. In therapeutic approaches, low-dose IL-2 therapy could regulate Tfr and Tfh cells, resulting in a reduction in disease activity in the SLE patients. In addition, elevated sIL-2R levels in the peripheral blood of SLE patients could be linked to an immunoregulatory imbalance, which may contribute to the onset and progression of SLE. Consequently, sIL-2R could potentially be a target for future SLE therapy. Moreover, Low dose-IL2 was well-tolerated, and low levels of Treg and high levels of IL-21 were associated with positive responses to Ld-IL2 suggested to be a safe and effective treatment for RA. Additionally, low-dose IL-2 treatment improves the exocrine glands' ability to secrete saliva in SS-affected mice. Whereas, Basiliximab targets the alpha chain of the IL-2 receptor suggested as a potential treatment for SSc. Also, pre-and post-treatment with Tregs, MDSCs, and IL-2 may have the potential to prevent EAE induction in patients with MS. It is suggested that further studies should be conducted on IL-2 polymorphism in Sjogren syndrome.

Mechanisms regulating the loss of Tregs in HUPO mice that develop spontaneous inflammatory arthritis

T regulatory cells (Tregs) are a potential therapeutic target in many autoimmune diseases including rheumatoid arthritis (RA). The mechanisms responsible for the maintenance of Tregs in chronic inflammatory conditions such as RA are poorly understood. We employed our mouse model of RA in which, the following deletion of Flice-like inhibitory protein in CD11c+ cells, CD11c-FLIP-KO (HUPO) mice develop spontaneous, progressive, erosive arthritis, with reduced Tregs, and the adoptive transfer of Tregs ameliorates the arthritis. HUPO thymic Treg development was normal, but peripheral of Treg Foxp3 was diminished mediated by reduction of dendritic cells and interleukin-2 (IL-2). During chronic inflammatory arthritis Tregs fail to maintain Foxp3, leading to non-apoptotic cell death and conversion to CD4+CD25+Foxp3- cells. Treatment with IL-2 increased Tregs and ameliorated the arthritis. In summary, reduced dendritic cells and IL-2 in the milieu of chronic inflammation, contribute to Treg instability, promoting HUPO arthritis progression, and suggesting a therapeutic approach in RA.

Automated clustering reveals CD4+ T cell subset imbalances in rheumatoid arthritis

Background

Despite the report of an imbalance between CD4+ T helper (Th) cell subsets in rheumatoid arthritis (RA), patient stratification for precision medicine has been hindered by the discovery of ever more Th cell subsets, as well as contradictory association results.

Objectives

To capture previously reported Th imbalance in RA with deep immunophenotyping techniques; to compare hypothesis-free unsupervised automated clustering with hypothesis-driven conventional biaxial gating and explore if Th cell heterogeneity accounts for conflicting association results.

Methods

Unstimulated and stimulated peripheral blood mononuclear cells from 10 patients with RA and 10 controls were immunophenotyped with a 37-marker panel by mass cytometry (chemokine receptors, intra-cellular cytokines, intra-nuclear transcription factors). First, conventional biaxial gating and standard definitions of Th cell subsets were applied to compare subset frequencies between cases and controls. Second, unsupervised clustering was performed with FlowSOM and analysed using mixed-effects modelling of Associations of Single Cells (MASC).

Results

Conventional analytical techniques fail to identify classical Th subset imbalance, while unsupervised automated clustering, by allowing for unusual marker combinations, identified an imbalance between pro- and anti-inflammatory subsets. For example, a pro-inflammatory Th1-like (IL-2+ T-bet+) subset and an unconventional but pro-inflammatory IL-17+ T-bet+ subset were significantly enriched in RA (odds ratio=5.7, p=2.2 x 10-3; odds ratio=9.7, p=1.5x10-3, respectively). In contrast, a FoxP3+ IL-2+ HLA-DR+ Treg-like subset was reduced in RA (odds ratio=0.1, p=7.7x10-7).

Conclusion

Taking an unbiased approach to large dataset analysis using automated clustering algorithms captures non-canonical CD4+ T cell subset imbalances in RA blood.

Efficacy and safety of tofacitinib combined with methotrexate in the treatment of rheumatoid arthritis: A systematic review and meta-analysis

Objective

To evaluate the efficacy and safety of tofacitinib in combination with methotrexate (MTX) versus MTX monotherapy in patients with active rheumatoid arthritis (RA).

Methods

Trials were identified from four electronic databases: PubMed, Web of science, Cochrane Library and EMBASE from inception to April 2022. Two independent reviewers evaluated each database to scan the title, abstract and keywords of each record retrieved. Full articles were further assessed when the information suggested that the study was a randomized clinical trial (RCT) comparing tofacitinib combined with MTX vs. MTX monotherapy in patients with active RA. Data were extracted from the literature, and the methodological quality of the included literature were evaluated and screened by two reviewers independently. The results were analyzed using RevMan5.3 software. The full text of the studies and extracted data were reviewed independently according to PRISMA guidelines. The outcome indicators were ACR 20, ACR 50, ACR 70, Disease activity score 28 (DAS28), erythrocyte sedimentation Rate (ESR) and adverse events (AEs).

Results

Of 1152 studies yielded by the search, 4 were retained, totaling 1782 patients (1345 treated with tofacitinib combined with MTX vs 437 received MTX. In the trial of insufficient response to MTX treatment, tofacitinib combined with MTX had significant advantages compared with MTX monotherapy. Numerically higher ACR20, ACR50 and ACR70 response rates were observed in the tofacitinib combined with MTX groups versus MTX monotherapy. ACR20 (odds ratio (OR), 3.62; 95% CI, 2.84-4.61; P < 0.001), ACR50 (OR, 5.17; 95% CI, 3.62-7.38; P < 0.001), and ACR70 (OR, 8.44; 95% CI, 4.34-16.41; P < 0.001), DAS28 (ESR) < 2.6 (OR, 4.71, 95% CI, 2.06-10.77; P < 0.001). The probability of adverse events of tofacitinib combined with MTX was lower than that of MTX monotherapy (OR, 1.42; 95% CI, 1.08-1.88; P = 0.01). The number of cases discontinued due to lack of efficacy or adverse events was similar in both groups (OR, 0.93; 95% CI, 0.52-1.68). The probability of abnormal liver enzymes in the treatment of tofacitinib combined with MTX was significantly lower than that of MTX monotherapy (OR, 1.86; 95% CI, 1.35-2.56). However, there was no significant difference between the two groups in severe adverse reactions, neutropenia, anemia and cardiovascular disease.

Conclusions

In terms of ACR20/50/70 and DAS28 (ESR), tofacitinib combined with MTX demonstrated superiority to MTX monotherapy in the treatment of patients with refractory RA. Considering the hepatoprotective and observably therapeutic efficacy, tofacitinib combined with MTX could be effective in treating refractory RA. However, in terms of hepatoprotective, it requires further large-scale and high-quality clinical trials to confirm.

Enhancing Regulatory T Cells to Treat Inflammatory and Autoimmune Diseases

Regulatory T cells (Tregs) control immune responses and are essential to maintain immune homeostasis and self-tolerance. Hence, it is no coincidence that autoimmune and chronic inflammatory disorders are associated with defects in Tregs. These diseases have currently no cure and are treated with palliative drugs such as immunosuppressant and immunomodulatory agents. Thereby, there is a great interest in developing medical interventions against these diseases based on enhancing Treg cell function and numbers. Here, we give an overview of Treg cell ontogeny and function, paying particular attention to mucosal Tregs. We review some notable approaches to enhance immunomodulation by Tregs with therapeutic purposes including adoptive Treg cell transfer therapy and discuss relevant clinical trials for inflammatory bowel disease. We next introduce ways to expand mucosal Tregs in vivo using microbiota and dietary products that have been the focus of clinical trials in various autoimmune and chronic-inflammatory diseases.

Impact of Siglecs on autoimmune diseases

Autoimmune diseases affect tens of millions of people just in the United States alone. Most of the available treatment options are aimed at reducing symptoms but do not lead to cures. Individuals affected with autoimmune diseases suffer from the imbalance between tolerogenic and immunogenic functions of their immune system. Often pathogenesis is mediated by autoreactive B and T cells that escape central tolerance and react against self-antigens attacking healthy tissues in the body. In recent years Siglecs, sialic-acid-binding immunoglobulin (Ig)-like lectins, have gained attention as immune checkpoints for therapeutic interventions to dampen excessive immune responses and to restore immune tolerance in autoimmune diseases. Many Siglecs function as inhibitory receptors suppressing activation signals in various immune cells through binding to sialic acid ligands as signatures of self. In this review, we highlight potential of Siglecs in suppressing immune responses causing autoimmune diseases. In particular, we cover the roles of CD22 and Siglec-G/Siglec-10 in regulating autoreactive B cell responses. We discuss several functions of Siglec-10 in the immune modulation of other immune cells, and the potential of therapeutic strategies for restoring immune tolerance by targeting Siglecs and expanding regulatory T cells. Finally, we briefly review efforts evaluating Siglec-based biomarkers to monitor autoimmune diseases.

A chinese medicine formula (kunbixiao granule) for female rheumatoid arthritis: Study protocol for a double-blind, randomized, placebo-controlled trial

Introduction: Rheumatoid arthritis (RA) is a chronic autoimmune disease affecting females more than males. Clinical symptoms, disease activity and comorbidities are more severe in females. Moreover, the choice of treatment for females is limited during childbearing age due to the side effects of current drugs. Therefore, developing novel and safer drugs for females is urgently needed. Kunbixiao granules (KBXG), a Chinese medicine formula, has been applied to treat female RA patients in our center as a complementary therapy. However, there is insufficient evidence for its effect. Therefore, we aim to conduct a randomized, controlled, double-blind clinical trial to confirm the efficacy and safety of KBXG for the treatment of female RA.

Methods: This study is a single-center, double-blind, randomized, parallel group, placebo-controlled clinical trial. A total of 90 female RA patients with Disease Activity Score for 28 joints (DAS28) > 3.2 will be enrolled. They will be randomly assigned to receive either KBXG or placebo for 12 weeks. The change in DAS28 based on C-reactive protein (DAS28-CRP) and the Clinical Disease Activity Index (CDAI) are the primary outcomes. The secondary outcomes include a rate of achieving 20%, 50% and 70% improvement in the American College Rheumatology criteria (ACR20, ACR50, ACR70), TCM syndrome score, visual analogue scale (VAS), average hands grip strength, the consumption of concomitant medication, Hospital Anxiety and Depression Scale (HADS), lumbar spine bone mineral density (L-BMD) and 7-joint ultrasound score (US7). Any adverse events will also be recorded.

Discussion: This trial will provide evidence of KBXG in reducing disease activity, and improving clinical symptoms and quality of life of female RA patients. The long-term effects of KBXG on female RA patients still needs a further follow-up.

Low-dose IL-2 therapy restores imbalance between Th17 and regulatory T cells in patients with the dermatomyositis combined with EBV/CMV viremia

OBJECTIVE

Dermatomyositis (DM) is closely associated with infection, the levels of peripheral lymphocyte subpopulations are rarely studied in patients with DM combined with Epstein-Barr virus (EBV)/cytomegalovirus (CMV) infection. Here, we aimed to observe the level of lymphocyte subsets, especially Th17, regulatory T (Treg) cells in DM combined with EBV/CMV viremia, and explore the effects of short-term low-dose IL-2.

METHODS

34 DM patients combined with EBV/CMV viremia (DM infection group), 31 DM patients without infection (DM non-infection group) and 20 healthy controls were entrolled in our study. In DM infection group, 13 patients received low-dose IL-2 at 0.50 Million IU/day for a five-day course on the basis of conventional treatment. All subjects had completed the decetion of the absolute numbers of lymphocytes subsets in peripheral blood by flow cytometry.

RESULTS

The infection group had significant decreases levels of total T, total B, NK, CD4 + T cells and CD4 + T subsets (Th1, Th2, Th17, Treg cells). Compare to the healthy controls, Th17 cells was significantly reduced in the infection group, but not in the non-infection group (P < 0.001 vs. P = 0.171). After low-dose IL-2 therapy, the levels of Treg (P = 0.001) cells and Th17 cells were significantly elevated, re-balancing the Th17 and Treg proportions.

CONCLUSIONS

The absolute numbers of Th17 and Treg cells in DM patients with EBV/CMV viremia is further reduced. In addition to Treg cells, a decrease in Th17 cells may be also a crucial feature. Low-dose IL-2 treatment may be beneficial and safe prospect immunomodulatory therapy to restores imbalance between Th17 and Treg cells for these patients. Low-dose IL-2 therapy may be a new prospect field with some challenges such as long-term immunoregulatory utility in various virus infection.

Short-term and low-dose IL-2 therapy increases the reduced Treg cells in patients with microscopic polyangiitis

OBJECTIVE

The breakdown of immune tolerance mediated by the reduced regulatory T (Treg) cell contributes to autoimmune diseases, which can be recovered by the shortterm and low-dose interleukin 2 (IL-2). However, the role of Treg cells in microscopic polyangiitis (MPA) and the efficacy of short-term and low-dose IL-2 for MPA remain unclear. Therefore, we performed a retrospective study to explore the role of Treg cells and evaluate the efficacy of short-term and low-dose IL-2 therapy in MPA.

METHODS

52 MPA were collected as research objects, and 15 of them voluntarily received short-term and low-dose IL-2 subcutaneous injection combined with conventional therapy. 60 volunteers were recruited as health controls (HC) according to the inclusion and exclusion criteria. The number of circulating CD4 + T cell subsets was detected by flow cytometry.

RESULTS

Patients with MPA had reduced circulating Treg cells than HCs (P < 0.001), and the level of Treg cells were reduced in MPA-activity and ANCA-positive group (P = 0.018 and P = 0.008 respectively). The patients with lower Treg cells had the higher incidence of the organ involvement (P = 0.006). The level of Treg cells in MPA was doubled after the short-term and low-dose IL-2 combined with conventional therapy (P = 0.001), and the disease activity indicators such as ESR and CRP were improved (P < 0.05) with no apparent side effects.

CONCLUSION

Patients with MPA had reduced circulating Treg cells, especially in the MPA-activity and ANCA-positive patients. And the patients with lower Treg cells were more likely to exhibit the organ involvement. Short-term and low-dose IL-2 therapy increased the reduced Treg cells and promoted the remission of the disease at a certain extent with well tolerance.

Therapeutic potential of interleukin-2 in autoimmune diseases

Autoimmune diseases are characterized by dysregulation and aberrant activation of cells in the immune system. Therefore, restoration of the immune balance represents a promising therapeutic target in autoimmune diseases. Interleukin-2 (IL-2) can promote the expansion and differentiation of different immune cell subsets dose-dependently. At high doses, IL-2 can promote the differentiation and expansion of effector and memory T cells, whereas at low doses, IL-2 can promote the differentiation, survival, and function of regulatory T (T_reg) cells, a CD4⁺ T cell subset that is essential for the maintenance of immune homeostasis and immune tolerance. Therefore, IL-2 exerts immunostimulatory and immunosuppressive effects in autoimmune diseases. The immunoregulatory role of low-dose IL-2 has sparked excitement for the therapeutic exploration of modulating the IL-2-T_reg axis in the context of autoimmune diseases. In this review, we discuss recent advances in the therapeutic potential of IL-2 or IL-2-derived molecules in the treatment of autoimmune diseases.