Endothelial Response to Type I Interferon Contributes to Vasculopathy and Fibrosis and Predicts Disease Progression of Systemic Sclerosis.

OBJECTIVE: Interferon (IFN)-1 signatures are a hallmark of patients with systemic sclerosis (SSc). However, its significance in clinical stratification and contribution to deterioration still need to be better understood. METHODS: For hypothesis generation, we performed single-cell RNA sequencing (scRNA-seq) on skin biopsies (four patients with SSc and two controls) using the BD Rhapsody platform. Two publicly available data sets of skin scRNA-seq were used for validation (GSE138669: 12 patients with diffuse cutaneous SSc [dcSSc] and 10 controls; GSE195452: 52 patients with dcSSc and 41 patients with limited cutaneous SSc [lcSSc] and 54 controls). The IFN-1 signature was mapped, functionally investigated in a bleomycin plus IFNα-2 adenovirus-associated virus (AAV)-induced model and verified in an SSc cohort (n = 61). RESULTS: The discovery and validation data sets showed similar findings. Endothelial cells (ECs) had the most prominent IFN-1 signature among dermal nonimmune cells. The EC IFN-1 signature was increased both in patients with SSc versus controls and in patients with dcSSc versus those with lcSSc. Among EC subclusters, the IFN-1 signature was statistically higher in the capillary ECs of patients with dcSSc, which was higher than those in patients with lcSSc, which in turn was higher than those in healthy controls (HCs). Endothelial-to-mesenchymal transition (EndoMT) scores increased in parallel. Deteriorated bleomycin-induced dermal fibrosis, EndoMT, and perivascular fibrosis and caused blood vessel loss with EC apoptosis. Vascular myxovirus resistance (MX) 1, an IFN-1 response protein, was significantly increased both in total SSc versus HC skin and in dcSSc versus lcSSc skin. Baseline vascular MX1 performed similarly to skin score in predicting disease progression over 6 to 34 months in total SSc and was superior in the dcSSc subpopulation. CONCLUSION: The EC IFN-1 signature distinguished SSc skin subtypes and disease progression and may contribute to vasculopathy and fibrosis.

Iguratimod attenuated fibrosis in systemic sclerosis via targeting early growth response 1 expression.

BACKGROUND: The early growth response 1 (EGR1) is a central transcription factor involved in systemic sclerosis (SSc) pathogenesis. Iguratimod is a synthesized anti-rheumatic disease-modifying drug, which shows drastic inhibition to EGR1 expression in B cells. This study is aiming to investigate the anti-fibrotic effect of iguratimod in SSc. METHODS: EGR1 was detected by immunofluorescence staining real-time PCR or western blot. Iguratimod was applied in EGR1 overexpressed or knockdown human dermal fibroblast, bleomycin pre-treated mice, tight skin 1 mice, and SSc skin xenografts. RNA sequencing was performed in cultured fibroblast and xenografts to identify the iguratimod regulated genes. RESULTS: EGR1 overexpressed predominantly in non-immune cells of SSc patients. Iguratimod reduced EGR1 expression in fibroblasts and neutralized changes of EGR1 response genes regulated by TGFß. The extracellular matrix (ECM) production and activation of fibroblasts were attenuated by iguratimod while EGR1 overexpression reversed this effect of iguratimod. Iguratimod ameliorated the skin fibrosis induced by bleomycin and hypodermal fibrosis in TSK-1 mice. Decreasing in the collagen content as well as the density of EGR1 or TGFß positive fibroblasts of skin xenografts from naïve SSc patients was observed after local treatment of iguratimod. CONCLUSION: Targeting EGR1 expression is a probable underlying mechanism for the anti-fibrotic effect of iguratimod.

Iguratimod as an alternative therapy for systemic sclerosis and prevention of the occurrence of ischemic digital ulcer.

Objectives: This study aimed to assess the effectiveness of iguratimod (IGU) as an alternative treatment for systemic sclerosis (SSc), especially in the prevention of ischemic digital ulcers (DUs). Methods: We constructed two cohorts from the Renji SSc registry. In the first cohort, SSc patients receiving IGU were observed prospectively with effectiveness and safety. In the second cohort, we picked up all the DU patients with at least a 3-month follow-up to investigate the prevention of IGU on ischemic DU. Results: From 2017 to 2021, 182 SSc patients were enrolled in our SSc registry. A total of 23 patients received IGU. With a median follow-up of 61 weeks (IQR: 15-82 weeks), the drug persistence was 13/23. In total, 91.3% of the patients (21/23) became free of deterioration in the last visit with IGU. Of note, 10 patients withdrew from the study due to the following reasons: two patients withdrew due to deterioration, three due to incompliance, and five due to mild-to-moderate side effects. All the patients with side effects recovered fully after stopping IGU. Of note, 11 patients had ischemic DU, and 8 out of 11 (72.7%) patients had no new occurrence of DU during the follow-up. In the second cohort of 31 DU patients receiving a combination of vasoactive agents with a median follow-up of 47 weeks (IQR, 16-107 weeks), IGU treatment was protective of new DU occurrence (adjusted risk ratio = 0.25; 95% CI, 0.05-0.94; adjusted odds ratio = 0.07; and 95% CI, 0.01-0.49). Conclusion: Our study for the first time describes the potential of IGU possibly as an alternative treatment for SSc. To our surprise, this study provides a hint that IGU treatment can be used for the prevention of the occurrence of ischemic DU and merits further investigation.

Efficacy and safety of Iguratimod as an add-on therapy for refractory lupus nephritis: A preliminary investigational study.

Objectives: IGU (IGU), a novel immunomodulatory agent for rheumatoid arthritis, has been shown to be effective and safe as monotherapy in a small population with refractory lupus nephritis (LN). The aim of this prospective study was to evaluate the efficacy and safety of IGU as an add-on therapy in patients with refractory LN in the context of clinical practice. Methods: This is a single-arm observational study. We have enrolled LN patients since 2019 at Renji Hospital. All participants should have recurrent or refractory LN with at least one immunosuppressant (IS) and have a baseline urine protein/creatinine ratio (UPCR) >1.0. After enrollment, we added IGU (25 mg twice daily) to one of their previous immunosuppressants (IS) without increasing the dose of steroids. The primary outcome was the complete renal response (CRR) in the 6th month. UPCR decrease of over 50% was defined as partial response (PR). Extended follow-up was performed after the initial 6 months. Results: We enrolled 26 eligible participants. 11/26 patients had chronic kidney disease (CKD) stage 2/3 at the baseline. The IS combined with IGU included mycophenolate mofetil, tacrolimus, and cyclosporin A. No IS change was allowed. 80.7% of patients had baseline steroids less than 0.5mg/kg daily and there was no steroids escalation during the IGU treatment. The CRR rate was 42.3% (11/26) at month 6. With a median follow-up of 52 weeks (range: 23-116 weeks), the CRR rate at the last visit was 50% (13/26) and 73.1% (19/26) of patients had UPCR decrease of over 50%. Six patients withdrew, three for no response and three for renal flare after initial CRR. One patient had an estimated glomerular filtration rate worsening of over 20% and was classified as renal flare. Three mild to moderate adverse events were recorded. Conclusions: Our investigation merits further investigation in IGU as a potentially tolerable component of combination therapy for refractory LN.

Quantitative infrapatellar fat pad signal intensity alteration as an imaging biomarker of knee osteoarthritis progression.

OBJECTIVE: To determine the association of quantitative infrapatellar fat pad (IPFP) signal intensity alteration with knee osteoarthritis (OA) progression. METHOD: This study was performed based on the Foundation for the National Institutes of Health OA Biomarkers Consortium study, a nested case-control study consisting of 600 participants. The IPFP signal intensity alterations were quantitatively measured at baseline, 12 months and 24 months. The associations of baseline and time-integrated values over 12 and 24 months of IPFP signal intensity measures with knee OA progression over 48 months were evaluated with adjustment for baseline confounders. RESULTS: The baseline level of clustering effect of high signal intensity (Clustering factor (H)) was predictive of clinically relevant progression (both radiographic and pain progression) (OR 1.22). The time-integrated values of all IPFP signal intensity measures, except for mean value of IPFP signal intensity (Mean (IPFP)) over 24 months (ORs ranging from 1.23 to 1.39) as well was all except for Mean (IPFP) and mean value of IPFP high signal intensity (Mean (H)) over 12 months (ORs ranging from 1.20 to 1.31), were positively associated with clinically relevant progression. When the associations of quantitative IPFP signal intensity measures with radiographic and pain progression were examined separately, more IPFP signal intensity measures with stronger effect sizes were associated with radiographic progression compared with pain progression. CONCLUSION: The associations of short-term alteration in quantitative IPFP signal intensity measures with long-term knee OA progression suggest that these measures might serve as efficacy of intervention biomarkers of knee OA.

Oral IRAK4 inhibitor BAY-1834845 prevents acute respiratory distress syndrome.

Acute respiratory distress syndrome (ARDS) is a lethal clinical entity that has become an emergency event with the outbreak of COVID-19. However, to date, there are no well-proven pharmacotherapies except dexamethasone. This study is aimed to evaluate IRAK4 inhibitors as a potential treatment for ARDS-cytokine release syndrome (CRS). We applied two IRAK4 inhibitors, BAY-1834845 and PF-06650833 to an inhaled lipopolysaccharide (LPS)-induced ARDS mouse model with control of high dose dexamethasone (10 mg/kg). Unexpectedly, although both compounds had excellent IC50 on IRAK4 kinase activity, only BAY-1834845 but not PF-06650833 or high dose dexamethasone could significantly prevent lung injury according to a blinded pathology scoring. Further, only BAY-1834845 and BAY-1834845 combined with dexamethasone could effectively improve the injury score of pre-existed ARDS. Compared with PF-06650833 and high dose dexamethasone, BAY-1834845 remarkably decreased inflammatory cells infiltrating lung tissue and neutrophil count in BALF. BAY-1834845, DEX, and the combination of the two agents could decrease BALF total T cells, monocyte, and macrophages. In further cell type enrichment analysis based on lung tissue RNA-seq, both BAY-1834845 and dexamethasone decreased signatures of inflammatory cells and effector lymphocytes. Interestingly, unlike the dexamethasone group, BAY-1834845 largely preserved the signatures of naïve lymphocytes and stromal cells such as endothelial cells, chondrocytes, and smooth muscle cells. Differential gene enrichment suggested that BAY-1834845 downregulated genes more efficiently than dexamethasone, especially TNF, IL-17, interferon, and Toll-like receptor signaling.

Longitudinal association of infrapatellar fat pad signal intensity alteration with biochemical biomarkers in knee osteoarthritis.

OBJECTIVE: To explore the longitudinal association of quantitative infrapatellar fat pad (IPFP) signal intensity alteration with OA-related biomarkers. METHODS: Eighteen OA-related biochemical biomarkers of 600 knee OA participants in the Foundation for the National Institutes of Health OA Biomarkers Consortium (FNIH) study were extracted. The quantitative IPFP signal intensity measures were acquired based on magnetic resonance imaging, including mean value [Mean (IPFP)] and standard deviation [sDev (IPFP)] of the whole IPFP signal intensity, median value [Median (H)] and upper quartile value [UQ (H)] of high signal intensity, the ratio of volume of high signal intensity to volume of whole IPFP signal intensity [Percentage (H)] and Clustering factor (H). The linear mixed-effect model was applied to determine the longitudinal associations between IPFP signal intensity alteration and biochemical biomarkers over 2 years. RESULTS: All IPFP measures except for Clustering factor (H) were positively associated with urine collagenase-cleaved type II collagen neoepitope (uC2C), urine C-terminal cross-linked telopeptide of type II collagen (uCTX-II), urine C-terminal cross-linked telopeptide of type I collagen-α (uCTX-Iα) and urine N-terminal cross-linked telopeptide of type I collagen (uNTX-I). Mean (IPFP), Median (H) and Percentage (H) were positively associated with the nitrated form of an epitope located in the triple helix of type II collagen (Coll2-1 NO2). Mean (IPFP), Median (H) and UQ (H) were positively associated with sCTX-I and uCTX-Iß. Positive associations between sDev (IPFP), Percentage (H) and serum hyaluronic acid (sHA) were found. CONCLUSION: Our results suggest a role of IPFP signal intensity alteration in joint tissue remodelling on a molecular level.

Duration biased distribution of clinical and immunological phenotypes in active SLE.

Introduction: This study is aimed to map the clinical and immunological features of active lupus patients with different disease duration. Methods: For clinical phenotype analysis, we enriched eligible medical records with active SLE (SLEDAI-2k≥8) from the Renji Lupus registry, a single-center database of hospitalized SLE patients with standard care, which covered national-wide patients. Patients with repeated hospitalization records in this enrichment were analyzed longitudinally as validation for the cross-sectional study above. Results: We enriched a total of 1313 eligible records on active SLE (SLEDAI-2k≥8) for cross-sectional analysis. Stratified into four groups by a 5-year interval of disease duration, these active SLE patients showed a significantly shifting clinical phenotype along with the duration (ascending nephritis, pulmonary hypertension and descending fever, cutaneous symptoms, arthritis, and neuropsychiatric manifestations), especially in stratifications with disease onset age ≤ 45 years old. A longitudinal analysis of 55 patients with repeated hospitalizations for active lupus showed a similar trend. In the cross-sectional study of 222 records with full information on serology and lymphocyte subsets, peripheral B cell proportion, anti-dsDNA antibody, and serum IgG/IgM negatively correlated with duration, while CD8+ T cell proportion was positively correlated (P values, 0.029-4.8×10-17), which were supported by the sensitivity analysis in patient subgroups according to disease onset age and recent treatment. Multivariate linear regression identified duration as the only significant associator with both B cell and CD8+ T cell proportion (P values, 8.9×10-8 and 7.6×10-5, respectively). These duration biased immune phenotypes were highly consistent with the longitudinal observation in 14 patients with repeated hospitalizations. Conclusions: Both clinical and immunological features of active SLE are significantly duration biased distributed, which merits further investigations in the evolution of SLE pathogenesis.

Association of Cytomegalovirus Infection With Anti-MDA5 Antibody-Positive Dermatomyositis: A Prospective Cohort Study.

Objectives: To investigate whether cytomegalovirus (CMV) infection plays a role in the pathogenesis and prognosis of idiopathic inflammatory myopathy (IIM), particularly in anti-MDA5 antibody-positive (anti-MDA5+) dermatomyositis (DM). Methods: A prospective cohort of 204 newly diagnosed IIM patients and 50 healthy individuals were enrolled in the study. CMV-IgM and CMV-IgG antibody concentrations and lymphocyte counts were analyzed. Differences in categorical data were compared using Fisher's exact test and the chi-square test. One-year survival rates were analyzed in MDA5+ DM patients with and without CMV infection. Results: In IIM patients, the median CMV-IgM level was significantly higher than in healthy controls (6 U/mL vs. 0 U/mL, p < 0.05) as was the median CMV-IgG level (114 U/mL vs. 105 U/mL, p < 0.05). The percentage of recent CMV infections in the MDA5+ DM group was much higher than it was in the MDA5- IIM group (19.1% vs. 7.0%, p = 0.009). MDA5+ DM patients with CMV DNA-emia had poorer 1 year survival than the CMV-DNA- group (33.3% vs. 86.3%, p = 0.010). CMV-IgM-positive (CMV-IgM+) MDA5+ DM patients had lower CD4+ T cell counts (245.7 cells/µL vs. 420.5 cells/µL, p < 0.05) and CD19+ B cell counts (97.3 cells/µL vs. 240.6 cells/µL, p < 0.05). Conclusion: The number of CMV infections was significantly higher in IIM patients, particularly in MDA5+ DM patients. Lower CD4+ T cells and CD19+ B cells were observed in CMV-IgM+ MDA5+ DM patients. CMV infection may have an important role in the pathogenesis and prognosis of MDA5+ DM by disrupting immunity.

High incidence and mortality of Pneumocystis jirovecii infection in anti-MDA5-antibody-positive dermatomyositis: experience from a single center.

BACKGROUND: Idiopathic inflammatory myopathies (IIM) are associated with a significantly higher risk of opportunistic infections including Pneumocystis jirovecii pneumonia (PJP), a potentially fatal opportunistic infection. However, no prior studies have evaluated PJP infection in subtypes of IIM. OBJECTIVES: To investigate the prevalence and mortality rate of PJP infection in subgroups of IIM patients stratified according to myopathy-specific antibodies. METHODS: In the first part of the study, 463 consecutive patients with IIM were prospectively followed for a period of at least 1 year to analyze the incidence of PJP. In the second part of the study, we enrolled 30 consecutive PJP patients with any rheumatic disease in order to identify the mortality rate and risk factors by Cox regression analysis. The Kaplan-Meier method with log-rank testing was used to assess differences in survival. RESULTS: The prevalence of PJP in IIM patients was found to be 3.0/100 person-years, while in MDA5+ DM patients it was 7.5/100 person-years and in MDA5- IIM patients 0.7/100 person-years (P < 0.05). PJP typically occurred in the first 2 months in the case of MDA5+ DM patients who had a significant decrease in their CD4+ T cell counts and lymphocyte counts (P < 0.05). In PJP patients, 3-month mortality was higher for MDA5+ DM patients than in those with other rheumatic diseases (83.3% vs 38.9%, P < 0.05). Alarmingly, MDA5+ DM patients seemed not to benefit from prompt anti-PJP treatment, unlike patients with other rheumatic diseases whose survival improved when anti-PJP treatment was started within 6 days (P < 0.05). CONCLUSION: PJP has an alarming high incidence and mortality in MDA5+ DM patients. Timely treatment for PJP seems not to improve the prognosis of patients with this particular subtype. Hence, there remains a crucial unmet need to develop PJP prophylaxis for MDA5+ DM patients.

Comparison of iguratimod and conventional cyclophosphamide with sequential azathioprine as treatment of active lupus nephritis: study protocol for a multi-center, randomized, controlled clinical trial (iGeLU study).

BACKGROUND: Systemic lupus erythematosus (SLE) is an autoimmune disease that can involve multiple organs or systems. Lupus nephritis (LN) is associated with high mortality and morbidity. However, plenty of patients do not respond to present treatment or relapse. Iguratimod (IGU) is a new small molecular, anti-rheumatic drug and has shown the potential for drug repurposing from rheumatoid arthritis (RA) to LN treatment. It has been approved for treating RA in northeast Asia. Beyond expectation in a recent observational study, over 90% of thirteen refractory LN patients responded to iguratimod monotherapy in 24 weeks, with no steroids dose increasing or any other medication add-on during the entire follow-up. METHODS/DESIGN: This study is a multi-center, randomized, 52-week parallel positive drug-controlled study. The study was designed as a head-to-head comparison between the iguratimod and present first-line therapy on LN patients. A total of 120 patients (60 patients each group) is in the enrolling plan. All enrolled patients are assigned randomly into trial and control groups. The patients will be selected from six study sites in China and will all have biopsy-proven active lupus nephritis. In the first 24 weeks of the trial, IGU is compared with cyclophosphamide as an induction therapy, and in the second 24 weeks, IGU is compared with azathioprine as a maintenance therapy. The primary outcome is renal remission rate including both complete remission and partial remission at week 52, which will be analyzed using a non-inferiority hypothesis test. DISCUSSION: Most patients diagnosed with SLE will develop LN within 5 years and LN remains a major cause of morbidity and death for SLE patients. Although some medications are proven effective for the treatment of this condition, at least 20-35% LN patients have to suffer from relapse or ineffective treatment and medication intolerance is also frequent. This trial is designed to demonstrate whether iguratimod can be used as an alternative induction or maintenance therapy in subjects who have lupus nephritis. Data from this study will provide an evidence on whether or not iguratimod should be recommended to active LN patients. TRIAL REGISTRATION: ClinicalTrials.gov NCT02936375 . Registered on October 18, 2016.

Dihydroartemisinin alleviates skin fibrosis and endothelial dysfunction in bleomycin-induced skin fibrosis models.

OBJECTIVE: The present study was to investigate whether dihydroartemisinin (DHA), which is a highly effective and safe drug in the treatment of malaria, could be repurposed for the treatment of skin fibrosis and vascular dysfunction in systemic sclerosis (SSc). METHODS: The value of DHA was determined using a bleomycin-induced model of skin fibrosis. mRNA transcriptome analysis was performed, and the targets of DHA on fibroblasts were identified. Immunofluorescence staining was used to identify dermal vessels undergoing endothelial-to-mesenchymal transition (EndoMT). Autophagic flux was detected by western blot and mRFP-GFP-LC3 adenovirus vector transfection. RESULTS: Both systemic and topical administration of DHA decreased dermal thickness and collagen deposition and alleviated EndoMT in bleomycin-induced skin fibrosis mice model. Treatment of human umbilical vein endothelial cells (HUVECs) with TGF-ß1 resulted in the acquisition of the activation marker (α-SMA) and loss of endothelial markers (CD31 and VE-cadherin), a process that was restored by DHA. DHA significantly suppressed skin fibroblast activation and collagen-1 production mainly through regulating PI3K-Akt pathway. DHA also induced fibroblast autophagic flux and that autophagy dependently suppressed collagen-1 production. CONCLUSION: The results of the present study revealed that oral and topical DHA administration ameliorated tissue fibrosis and protected dermal blood vessels from bleomycin-induced EndoMT. Our study has elucidated the value of repurposing DHA for the treatment of SSc. Key Points • Oral or topical usage of DHA alleviated dermal fibrosis and EndoMT in bleomycin-induced skin fibrosis mice models. • DHA autophagy dependently inhibited fibroblast activation and collagen deposition via PI3K-ATK pathway. • DHA inhibited EndoMT of HUVECs induced by TGF-ß1 by the downregulation of α-SMA and the upregulation of CD31 and VE-cadherin.

Understanding Fibrosis in Systemic Sclerosis: Novel and Emerging Treatment Approaches.

PURPOSE OF THE REVIEW: Over the years, our perceptions of fibrogenesis in systemic sclerosis (SSc) have advanced a lot. Herein, we review potential targets for SSc discovered in the past 3 years. RECENT FINDINGS: In recent years, metabolites have come into the limelight of SSc research. Anti-oxidants, promotor of adipogenesis, modulator of fatty acid metabolism, regulator of glucose homeostasis, and adenosine deaminase open a new door for SSc treatment. A mosaic of biolipids, especially cannabinoid receptor 2 agonist, represents a rational therapeutic approach in fibrosis. In terms of immune aspects, targeting chemokines or integrins for cell adhesion may become new approach to inhibiting fibrotic pathways. Epigenetic modulation of immune pathways has been uncovered much recently. Targeting histone modifications and lncRNAs has demonstrated therapeutic potential in SSc animal models. The classical JAK-STAT and interferon pathway drive great attention these years because of the promising potential for the drug repurposing of targeted therapies from arthritis to SSc. In fibrosis-associated developmental pathways, BMP, Hedgehog, and PU.1 are expected to offer new targets to restrain fibrosis. New targets involved in metabolic reprogramming, immunity, epigenetics together with developmental and apoptotic pathways open new avenues for therapeutic modulation in SSc.

Efficacy of Combination Therapy With Pirfenidone and Low-Dose Cyclophosphamide for Refractory Interstitial Lung Disease Associated With Connective Tissue Disease: A Case-Series of Seven Patients.

OBJECTIVES: This study reports a low dose combination therapy of cyclophosphamide (CYC) and pirfenidone (PFD) and the efficiency and safety of the therapy in refractory connective tissue disease associated interstitial lung disease (CTD-ILD) patients. PATIENTS AND METHODS: The study included seven CTD-ILD patients (2 males, 5 females; mean age 48.8 years; range, 32 to 63 years) treated between January 2016 and December 2017 in our clinic. At enrolment, all patients had shown no improvement in their symptoms (dyspnea or cough) after at least one month of high dose steroids treatment. Patients who had received adjusted immunosuppressive agents other than steroids or anti-fibrotic medications within the three months before enrolment were excluded. We changed the treatment to a low dose combination of CYC 0.4 g/m2 monthly and PFD 300 mg twice per day and quickly reduced the steroids. All the patients were followed-up for 12 months. RESULTS: Two patients had anti-synthetase syndrome, two had Sjögren syndrome, two had scleroderma and one had mixed connective tissue disease. The baseline forced vital capacity (FVC) was 39-81% and the six-minute walk distance (6MWD) was 202 m-324 m. Within 12 months follow-up, the median improvement in the FVC was 13.4% (range, 0-35.9%), the median improvement of carbon monoxide diffusing capacity was 6.3% (range, 1.7-16%) and the median improvement of 6MWD was 52.7% (range, 34.4-86.3%). All the patients were self-sufficient, and their dyspnea, chest high- resolution computed tomography scores, and quality of life improved simultaneously. Exceeding our expectations, no adverse events associated with CYC or PFD were observed during the follow-up period. CONCLUSION: Our study provided preliminary while promising clinical evidence for combination therapy of CYC-PFD for CTD-ILD. A low dose combination of CYC and PFD was unexpectedly well tolerated, with satisfactory effects in refractory CTD-ILD patients. Well-designed controlled studies are needed to further establish the safety and efficacy of this approach.

Iguratimod as an alternative induction therapy for refractory lupus nephritis: a preliminary investigational study.

OBJECTIVES: Iguratimod, a novel immunomodulatory agent for rheumatoid arthritis, has been shown to be effective against murine lupus. The aim of this study was to make a preliminary evaluation of the efficacy and safety of iguratimod as salvage therapy in patients with refractory lupus nephritis (LN). METHODS: We enrolled eligible patients with refractory LN, which we defined as having failed or relapsed on at least two immunosuppressant agents. After enrollment, we substituted iguratimod (25 mg twice daily) for their previous immunosuppressant agents without increasing the dose of steroids. The primary outcome was complete/partial remission (PR/CR) at week 24. Patients who achieved remission continued iguratimod as maintenance therapy over an extended follow-up. RESULTS: The study cohort comprised 14 patients with refractory LN, 10 of whom had recent treatment failure and 4 repeated relapses with inadequate initial responses. At enrollment, none of the patients had detectable evidence of extra-renal involvement. The median prednisone dosage was 10 mg/d (IQR 0-10 mg/day). Thirteen patients were eligible for response evaluation, with one patient missed. The renal response rate was 92.3% (12/13) at week 24, with 38.5% (5/13) achieving CR and 53.8% (7/13) achieving PR. We then continued to follow up the responding patients for up to 144 weeks. Twenty-five percent of the patients (3/12) had renal relapse after initial PR. The estimated glomerular filtration rate of all patients maintained stable during follow-up. One patient had a severe adverse reaction (anemia) but recovered fully after stopping iguratimod. CONCLUSIONS: Our study supports the potential of iguratimod for treatment of refractory LN. Iguratimod could be a promising candidate drug for this condition.

Iguratimod represses B cell terminal differentiation linked with the inhibition of PKC/EGR1 axis.

BACKGROUND: This study aimed to explore the molecular mechanism and clinical relevance of iguratimod in the regulation of human B cell terminal differentiation. METHODS: An in vitro human antibody-secreting cell (ASC) differentiation system was established to test the effect of iguratimod. B cell phenotype and key transcription factors (TFs) relevant to ASC differentiation were analyzed through flow cytometry and qPCR. The COX-2 activity was measured by enzyme immunoassay (EIA). RNA sequencing was used to identify potential targets of iguratimod. We enrolled six treatment-naive rheumatoid arthritis (RA) patients whose blood samples were collected for phenotypic and molecular studies along with 12-week iguratimod monotherapy. RESULTS: Iguratimod inhibited human ASC generation without affecting B cell activation and proliferation. Iguratimod showed only weak COX-2 activity. Gene set enrichment analysis (GSEA) identified that protein kinase C (PKC) pathway was targeted by iguratimod which was confirmed by PKC activity detection. Furthermore, early growth response 1 (EGR1), a target of PKC and a non-redundant TF for ASC differentiation, was found to be the most downregulated gene in iguratimod-treated B cells. Lastly, iguratimod monotherapy decreased peripheral ASCs and was associated with improved disease activity. The expression of major ASC-related TFs, including EGR1, was similarly downregulated in patient blood samples. CONCLUSIONS: Iguratimod inhibits ASC differentiation both in vitro and in RA patients. Our study suggests that PKC/EGR1 axis, rather than COX-2, is critically involved in the inhibitory effect by iguratimod on human ASC differentiation. Iguratimod could have a broader application to treat B cell-related autoimmune diseases in clinics.