The probability of cardiovascular events has been reported lower in rheumatoid arthritis (RA) patients treated with leflunomide. However, the anti-atherosclerotic and cardiovascular protective effects and metabolism of leflunomide are not explored. In this study, we assessed the potential benefits of leflunomide on atherosclerosis and revealed the underlying mechanism. ApoE-/- mice were fed a western diet (WD) alone or supplemented with leflunomide (20 mg/kg, oral gavage, once per day) for 12 weeks. Samples of the aorta, heart, liver, serum, and macrophages were collected. We found that leflunomide significantly reduced lesion size in both en-face aortas and aortic root in WD-fed ApoE-/- mice. Leflunomide also obviously improved dyslipidemia, reduced hepatic lipid content, and improved disorders of glucose and lipid metabolism in vivo. RNA-Seq results showed that leflunomide effectively regulated the genes\' expression involved in the lipid metabolism pathway. Importantly, leflunomide significantly increased the phosphorylation levels of AMPKα and acetyl-CoA carboxylase (ACC) in vivo. Furthermore, leflunomide and its active metabolite teriflunomide suppressed lipid accumulation in free fatty acid (FFA)-induced AML12 cells and improved endothelial dysfunction in palmitic acid (PA)-induced HUVECs through activating AMPK signaling and inhibiting dihydroorotate dehydrogenase (DHODH) signaling pathway. We present evidence that leflunomide and teriflunomide ameliorate atherosclerosis by regulating lipid metabolism and endothelial dysfunction. Our findings suggest a promising use of antirheumatic small-molecule drugs leflunomide and teriflunomide for the treatment of atherosclerosis and related cardiovascular diseases (CVDs).

BACKGROUND: Vascular fibrosis directly causes vascular thickening in Takayasu arteritis (TAK), in which sustained transforming growth factor beta (TGF-β) activation is critical. Understanding TGF-β activation regulation and blocking it might yield a therapeutic effect in TAK. Proprotein convertase subtilisin/kexin type 5 (PCSK5) rs6560480 (T/C) is associated with TAK development. In this study, we assessed the association between the PCSK5 rs6560480 genotype and PCSK5 expression in TAK and explored its molecular role in TGF-β activation and vascular fibrosis development.
METHODS: In TAK patients, PCSK5 and TGF-β expression in plasma and aortic tissue was examined by ELISA and immunohistochemical staining, and PCSK5 rs6560480 was genotyped. The correlation between PCSK5 and extracellular matrix (ECM) expression was examined by Western blotting (WB) and immunohistochemistry staining. Detection by co-immunoprecipitation was performed to detect the interaction between PCSK5 and TGF-β in adventitial fibroblasts (AAFs). Downstream signaling pathways were detected by WB and validated with appropriate inhibitors. Potential immunosuppressive agents to inhibit the effects of PCSK5 were explored in cell culture and TAK patients.
RESULTS: Patients with PCSK5 rs6560480 TT patients had significantly higher PCSK5 levels and more thickened vascular lesions than patients with PCSK5 rs6560480 CT. PCSK5 expression was significantly increased in alpha smooth muscle actin (α-SMA)-positive myofibroblasts in TAK vascular lesions. Overexpressing PCSK5 facilitated TGF-β and downstream SMAD2/3 activation and ECM expression in AAFs and aorta in in-vitro culture. The mechanistic study supported that PCSK5 activated precursor TGF-β (pro-TGF-β) to the mature form by binding the pro-TGF-β cleavage site. Leflunomide inhibited PCSK5 and pro-TGF-β binding, decreasing TGF-β activation and ECM expression, which was also partially validated in leflunomide-treated patients.
CONCLUSIONS: The findings revealed a novel pro-fibrotic mechanism of PCSK5 in TAK vascular fibrosis via TGF-β and downstream SMAD2/3 pathway activation. Leflunomide might be anti-fibrotic by disrupting PCSK5 and pro-TGF-β binding, presenting a new TAK treatment approach.

UNASSIGNED: Among patients with rheumatoid arthritis (RA) who had an inadequate response to methotrexate, a treatment sequence initiated with biosimilar disease-modifying antirheumatic drugs (DMARDs) provides better clinical efficacy compared with conventional synthetic DMARDs recommended by current treatment guidelines; but its cost-effectiveness evidence remains unclear.
UNASSIGNED: To evaluate the cost-effectiveness of the treatment sequence initiated with biosimilar DMARDs after failure with methotrexate vs leflunomide and inform formulary listing decisions.
UNASSIGNED: This economic evaluation\'s cost-effectiveness analysis was performed at a Hong Kong public institution using the Markov disease transition model to simulate the lifetime disease progression and cost for patients with RA, using monetary value in 2022. Scenario and sensitivity analyses were performed to test the internal validity of the modeling conclusion. Participants included patients diagnosed with RA from 2000 to 2021 who were retrieved retrospectively from local electronic medical records to generate model input parameters. Statistical analysis was performed from January 2023 to March 2024.
UNASSIGNED: The model assesses 3 competing treatment sequences initiated with biosimilar infliximab (CT-P13), biosimilar adalimumab (ABP-501), and leflunomide; all used in combination with methotrexate.
UNASSIGNED: Lifetime health care cost and quality-adjusted life-years (QALYs) of the simulated cohort.
UNASSIGNED: In total, 25 099 patients with RA were identified (mean [SD] age, 56 [17] years; 19 469 [72.7%] women). In the base-case analysis, the lifetime health care cost and QALYs for the treatment sequence initiated with leflunomide were US $154 632 and 14.82 QALYs, respectively; for biosimilar infliximab, they were US $152 326 and 15.35 QALYs, respectively; and for biosimilar adalimumab, they were US $145 419 and 15.55 QALYs, respectively. Both biosimilar sequences presented lower costs and greater QALYs than the leflunomide sequence. In the deterministic sensitivity analysis, the incremental cost-effectiveness ratio (US$/QALY) comparing biosimilar infliximab sequence vs leflunomide sequence and biosimilar adalimumab sequence vs leflunomide sequence ranged from -15 797 to -8615 and -9088 to 10 238, respectively, all below the predefined willingness-to-pay threshold (US $48 555/QALY gain). In the probabilistic sensitivity analysis, the probability of treatment sequence initiated with leflunomide, biosimilar infliximab, and biosmilar adalimumab being cost-effective out of 10 000 iterations was 0%, 9%, and 91%, respectively.
UNASSIGNED: In this economic evaluation study, the treatment sequences initiated with biosimilar DMARDs were cost-effective compared with the treatment sequence initiated with leflunomide in managing patients with RA who experienced failure with the initial methotrexate treatment. These results suggest the need to update clinical treatment guidelines for initiating biosimilars immediately after the failure of methotrexate for patients with RA.

This study examines the association of standard-of-care systemic lupus erythematosus (SLE) medications with key outcomes such as low disease activity attainment, flares, damage accrual, and steroid-sparing, for which there is current paucity of data.
The Asia Pacific Lupus Collaboration (APLC) prospectively collects data across numerous sites regarding demographic and disease characteristics, medication use, and lupus outcomes. Using propensity score methods and panel logistic regression models, we determined the association between lupus medications and outcomes.
Among 1707 patients followed over 12,689 visits for a median of 2.19 years, 1332 (78.03%) patients achieved the Lupus Low Disease Activity State (LLDAS), 976 (57.18%) experienced flares, and on most visits patients were taking an anti-malarial (69.86%) or immunosuppressive drug (76.37%). Prednisolone, hydroxychloroquine and azathioprine were utilised with similar frequency across all organ domains; methotrexate for musculoskeletal activity. There were differences in medication utilisation between countries, with hydroxychloroquine less frequently, and calcineurin inhibitors more frequently, used in Japan. More patients taking leflunomide, methotrexate, chloroquine/hydroxychloroquine, azathioprine, and mycophenolate mofetil/mycophenolic acid were taking ≤ 7.5 mg/day of prednisolone (compared to > 7.5 mg/day) suggesting a steroid-sparing effect. Patients taking tacrolimus were more likely (Odds Ratio [95% Confidence Interval] 13.58 [2.23-82.78], p = 0.005) to attain LLDAS. Patients taking azathioprine (OR 0.67 [0.53-0.86], p = 0.001) and methotrexate (OR 0.68 [0.47-0.98], p = 0.038) were less likely to attain LLDAS. Patients taking mycophenolate mofetil were less likely to experience a flare (OR 0.79 [0.64-0.97], p = 0.025). None of the drugs was associated with a reduction in damage accrual.
This study suggests a steroid-sparing benefit for most commonly used standard of care immunosuppressants used in SLE treatment, some of which were associated with an increased likelihood of attaining LLDAS, or reduced incidence of flares. It also highlights the unmet need for effective treatments in lupus.

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by abnormal activation of CD4+ T cells and an imbalance of T helper 17 (Th17) and regulatory T (Treg) cells. Tolerogenic therapy via administration of self-antigens is a promising strategy for RA treatment, but delivery of autoantigens alone may exacerbate disease conditions. Current studies indicated that codelivery of autoantigens with immunomodulators can lead to a more tolerogenic immune response. Here, we constructed an autoantigen type II collagen peptide (CII250-270)- and immunomodulator leflunomide (LEF)-coloaded phosphatidylserine liposome vaccine (CII250-270-LEF-PSL) for RA treatment via induction of tolerant dendritic cells (tolDC) for further activation of Treg cells. The in vivo results showed that CII250-270-LEF-PSL can effectively induce tolDC, regulate the balance of Th1/Th2 and Th17/Treg, and reduce the secretion of pro-inflammatory cytokines (IFN-γ, IL-1β, and IL-17A) and IgG antibodies to inhibit synovial inflammation and bone erosion. Furthermore, our study also suggested that LEF regulated Th1 cell differentiation by inhibiting the activation of the JAK1/STAT1 signaling pathway, further alleviating RA. Overall, this work proved that the combination of autoantigenic peptides and immunomodulators was a promising modality for RA treatment by reestablishing antigen-specific immune tolerance, which also inspired additional insights into the development of combination therapies for the tolerability of RA.

OBJECTIVE: The effectiveness of immunosuppressive and corticosteroid treatments for Immunoglobulin A (IgA) nephropathy (IgAN) remains thoroughly evaluated. We undertook a meta-analysis to investigate the efficacy and safety of low-dose corticosteroids plus leflunomide for progressive IgA nephropathy.
METHODS: Eligible studies were obtained from PubMed, Embase, and Cochrane Library databases. We also searched the references of the included studies. Our protocol followed the preferred reporting items for systematic reviews and meta-analyses (PRISMA) checklist. Eligibility criteria were defined using a PICOS framework.
RESULTS: Our study included three articles presenting 342 patient cases. Findings revealed that low-dose corticosteroids combined with the leflunomide group were effective in relieving urine protein excretion (UPE) [mean difference (MD) = -0.35, 95% confidence interval (CI): -0.41 to -0.30, P < 0.00001] compared with the full-dose corticosteroids group. Regarding serum creatinine (SCr), estimated glomerular filtration rate (eGFR), complete remission rate, and overall response rate, there was no difference between the groups (p > 0.05). Regarding safety, low-dose corticosteroids combined with leflunomide significantly reduced the risk of serious adverse events [odds ratio (OR): 0.11, 95% CI: 0.01 to 0.91, P = 0.04]. Besides, no significant differences were observed between the two groups in the incidence of respiratory infection, abnormal liver function, diarrhea, herpes zoster, alopecia, pruritus, insomnia, pneumonia, diabetes, and urinary tract infection (P > 0.05).
CONCLUSIONS: Low-dose corticosteroids combined with leflunomide are a safe and effective treatment for progressive IgA nephropathy.
BACKGROUND: The PROSPERO registration number is CRD42022361883.

BACKGROUND: Rheumatoid arthritis (RA) is a chronic autoimmune disease with complex pathogenesis, including alterations in the gut microbiota. Gui Zhi Shao Yao Zhi Mu Decoction (GSZD), a traditional Chinese herbal formula, has shown efficacy in RA treatment, but its impact on intestinal microflora remains unclear. This study aimed to investigate the effects of GSZD combined with leflunomide on the gut microbiota of RA patients.
METHODS: The study enrolled 48 RA patients who were randomly assigned to either a control group receiving leflunomide or a treatment group receiving GSZD combined with leflunomide for 12 weeks. Gut microbiota composition was analyzed pre- and post-intervention using 16S rDNA sequencing. Changes in microbial diversity, abundance, and metabolic functions were assessed.
RESULTS: Post-treatment, both groups exhibited significant alterations in gut microbiota composition. GSZD combined with leflunomide led to an increased Bacteroidetes/Firmicutes ratio and a reduction in Actinobacteria compared to leflunomide alone. This was associated with beneficial shifts in microbial genera and metabolic pathways, suggesting improved gut health and systemic immune modulation.
CONCLUSIONS: GSZD combined with leflunomide significantly modulates the gut microbiota in RA patients. This study provides insights into the mechanisms underlying the therapeutic effects of GSZD and highlights the potential of integrating traditional Chinese medicine with conventional treatments in managing RA.

Rheumatoid arthritis (RA), a chronic autoimmune disorder, is characterized by erosive inflammation of bone and cartilage, leading to progressive joint destruction. Pulmonary involvement occurs in approximately 60% of RA patients, manifests most commonly as interstitial lung disease and, less commonly, as rheumatoid lung nodules. Here, we report a 50-year-old woman, non-smoker, with recurrent cough and sputum of 7 years\' duration, accompanied by a chest CT showing multiple cavitary nodules in both lungs. She had been treated empirically at several medical centers and was finally diagnosed with rheumatoid lung nodules. Marked improvement in rheumatoid lung nodules was observed after treatment with tocilizumab in combination with glucocorticoids and leflunomide. The aim of this study was to improve clinicians\' understanding of rheumatoid lung nodules by analyzing the clinical features, diagnosis, and treatment of this case, and reviewing the relevant medical literature.
类风湿关节炎（rheumatoid arthritis，RA）是一种以侵蚀性关节炎症为主要临床表现的自身免疫病，约60%的患者可出现肺部受累，其常见表现类型为间质性肺病，类风湿肺结节少见。本文报道1例50岁女性反复咳嗽、咳痰7年伴胸部CT显示双肺多发结节伴空洞形成，辗转多家医院治疗效果不佳，最终确诊为类风湿肺结节，经托珠单抗联合激素及来氟米特治疗后病情改善。通过分析该病例的临床特点及诊治经过，并复习相关文献，提高临床医生对类风湿肺结节的认识。.

OBJECTIVE: To date, our understanding of IgA nephropathy (IgAN) pathophysiology has remained incomplete; therefore, treatment remains largely empiric, and the efficacy and safety of immunosuppressants remain controversial. We aimed to assess the efficacy and safety of hydroxychloroquine and leflunomide therapy in a retrospective cohort of patients with IgAN.
METHODS: We screened the IgAN registration database in our department, and a total of 159 kidney patients with biopsy-confirmed IgAN were enrolled, with 57 patients receiving hydroxychloroquine plus a renin-angiotensin system inhibitor (hydroxychloroquine group), 52 patients receiving leflunomide plus a renin-angiotensin system inhibitor (leflunomide group), and 50 patients receiving only a renin-angiotensin system inhibitor (renin-angiotensin system inhibitor-only group). Changes in proteinuria, hematuria, and the estimated glomerular filtration rate (eGFR), as well as adverse events, were analyzed during the follow-up period.
RESULTS: At the end of 6-month follow-up, proteinuria significantly decreased by 70.36 (57.54, 79.33)%, 57.29 (46.79, 67.29)% and 41.20 (25.76, 48.94)% in the hydroxychloroquine, leflunomide and renin-angiotensin system inhibitor-only groups, respectively, compared to baseline (all P values < 0.001). Hematuria significantly decreased by 71.07 (56.48, 82.47)% in the leflunomide group (P < 0.001). The eGFR improved by 3.72 ± 2.97%, 3.16 ± 2.00% and 1.91 ± 2.41%, respectively, in the hydroxychloroquine, leflunomide and renin-angiotensin system inhibitor-only groups, but without statistical significance. No serious adverse events occurred during the follow-up period.
CONCLUSIONS: Both hydroxychloroquine combined with a renin-angiotensin system inhibitor and leflunomide combined with a renin-angiotensin system inhibitor were more effective than a renin-angiotensin system inhibitor alone in improving proteinuria in IgAN patients. Hydroxychloroquine was more effective in reducing proteinuria, and leflunomide showed superiority in reducing hematuria. Our results need to be verified in large-scale randomized controlled trials.

UNASSIGNED: This study was to assess the safety and effectiveness of immunosuppressive agents, specifically Voclosporin, when used in conjunction with mycophenolate mofetil (MMF) induction therapy for the management of lupus nephritis (LN).
UNASSIGNED: A systematic review and network meta-analysis (NMA) was conducted on randomized controlled trials investigating the efficacy of immunosuppressant-induced therapy for LN. The random effects model was used in the analysis. I2 was used to evaluate the heterogeneity of the model. Odds ratios (OR) and 95% credible intervals (CrI) were computed to assess and compare the relative effectiveness and safety of various treatment protocols.
UNASSIGNED: The study included a total of 16 randomized controlled trials (RCTs) involving 2444 patients with LN. The analysis results indicated that there was no significant difference in terms of partial remission (PR) between the drugs. However, when considering complete remission (CR), the combination of Voclosporin with MMF showed the highest remission rate, followed by Tacrolimus (TAC). Unfortunately, Voclosporin in combination with MMF had the highest risk of infection and serious infection, indicating a lower safety profile.
UNASSIGNED: Voclosporin in combination with MMF demonstrated the highest efficacy as an induction therapy for LN. However, it should be noted that the risk of infection and serious infection was found to be high with this regimen. On the other hand, TAC not only showed efficacy but also had a lower risk of infection and serious infection, making it a favorable option in terms of safety. This study did\' not include results on other adverse events.