Novel susceptibility loci for steroid-associated osteonecrosis of the femoral head in systemic lupus erythematosus.

Osteonecrosis of the femoral head (ONFH) involves necrosis of bone and bone marrow of the femoral head caused by ischemia with unknown etiology. Previous genetic studies on ONFH failed to produce consistent results, presumably because ONFH has various causes with different genetic backgrounds and the underlying diseases confounded the associations. Steroid-associated ONFH (S-ONFH) accounts for one-half of all ONFH, and systemic lupus erythematosus (SLE) is a representative disease underlying S-ONFH. We performed a genome-wide association study (GWAS) to identify genetic risk factors for S-ONFH in patients with SLE. We conducted a two-staged GWAS on 636 SLE patients with S-ONFH and 95 588 non-SLE controls. Among the novel loci identified, we determined S-ONFH-specific loci by comparing allele frequencies between SLE patients without S-ONFH and non-SLE controls. We also used Korean datasets comprising 148 S-ONFH cases and 37 015 controls to assess overall significance. We evaluated the functional annotations of significant variants by in silico analyses. The Japanese GWAS identified 4 significant loci together with 12 known SLE susceptibility loci. The four significant variants showed comparable effect sizes on S-ONFH compared with SLE controls and non-SLE controls. Three of the four loci, MIR4293/MIR1265 [odds ratio (OR) = 1.99, P-value = 1.1 × 10-9)], TRIM49/NAALAD2 (OR = 1.65, P-value = 4.8 × 10-8) and MYO16 (OR = 3.91, P-value = 4.9 × 10-10), showed significant associations in the meta-analysis with Korean datasets. Bioinformatics analyses identified MIR4293, NAALAD2 and MYO16 as candidate causal genes. MIR4293 regulates a PPARG-related adipogenesis pathway relevant to S-ONFH. We identified three novel susceptibility loci for S-ONFH in SLE.

Potential therapies targeting metabolic pathways in systemic lupus erythematosus.

The pathophysiology of systemic lupus erythematosus (SLE) is multifactorial and involves alterations in metabolic pathways, including glycolysis, lipid metabolism, amino acid metabolism, and mitochondrial dysfunction. Increased glycolysis in SLE T cells, which is associated with elevated glucose transporter 1 expression, suggests targeting glucose transporters and hexokinase as potential treatments. Abnormalities in lipid metabolism, particularly in lipid rafts and enzymes, present new therapeutic targets. This review discusses how changes in glutaminolysis and tryptophan metabolism affect T-cell function, suggesting new therapeutic interventions, as well as mitochondrial dysfunction in SLE, which increases reactive oxygen species. The review also emphasizes that modulating metabolic pathways in immune cells is a promising approach for SLE treatment, and can facilitate personalized therapies based on individual metabolic profiles of patients with SLE. The review provides novel insights into strategies for managing SLE.

Itaconate reduces proliferation and migration of fibroblast-like synoviocytes and ameliorates arthritis models.

Fibroblast-like synoviocytes (FLS) play critical roles in rheumatoid arthritis (RA). Itaconate (ITA), an endogenous metabolite derived from the tricarboxylic acid (TCA) cycle, has attracted attention because of its anti-inflammatory, antiviral, and antimicrobial effects. This study evaluated the effect of ITA on FLS and its potential to treat RA. ITA significantly decreased FLS proliferation and migration in vitro, as well as mitochondrial oxidative phosphorylation and glycolysis measured by an extracellular flux analyzer. ITA accumulates metabolites including succinate and citrate in the TCA cycle. In rats with type II collagen-induced arthritis (CIA), intra-articular injection of ITA reduced arthritis and bone erosion. Irg1-deficient mice lacking the ability to produce ITA had more severe arthritis than control mice in the collagen antibody-induced arthritis. ITA ameliorated CIA by inhibiting FLS proliferation and migration. Thus, ITA may be a novel therapeutic agent for RA.

ADAM9 enhances Th17 cell differentiation and autoimmunity by activating TGF-ß1.

The a disintegrin and metalloproteinase (ADAM) family of proteinases alter the extracellular environment and are involved in the development of T cells and autoimmunity. The role of ADAM family members in Th17 cell differentiation is unknown. We identified ADAM9 to be specifically expressed and to promote Th17 differentiation. Mechanistically, we found that ADAM9 cleaved the latency-associated peptide to produce bioactive transforming growth factor ß1, which promoted SMAD2/3 phosphorylation and activation. A transcription factor inducible cAMP early repressor was found to bind directly to the ADAM9 promoter and to promote its transcription. Adam9-deficient mice displayed mitigated experimental autoimmune encephalomyelitis, and transfer of Adam9-deficient myelin oligodendrocyte globulin-specific T cells into Rag1-/- mice failed to induce disease. At the translational level, an increased abundance of ADAM9 levels was observed in CD4+ T cells from patients with systemic lupus erythematosus, and ADAM9 gene deletion in lupus primary CD4+ T cells clearly attenuated their ability to differentiate into Th17 cells. These findings revealed that ADAM9 as a proteinase provides Th17 cells with an ability to activate transforming growth factor ß1 and accelerates its differentiation, resulting in aberrant autoimmunity.

Phosphatidylserine-Dependent Anti-prothrombin Antibodies as a Key Predictor for Systemic Lupus Erythematosus in Patients with Primary Antiphospholipid Syndrome: A retrospective longitudinal cohort study.

OBJECTIVES: Primary antiphospholipid syndrome (PAPS) is an autoimmune disorder characterized by thrombosis and pregnancy morbidity. Although PAPS is distinct from systemic lupus erythematosus (SLE), the two conditions share clinical features and susceptibility genes. Progression from PAPS to SLE is well-recognized. However, risk factors for this transition are poorly understood. We aimed to identify predictors of progression to SLE in patients with PAPS. METHODS: A longitudinal single-center study was conducted at Hokkaido University Hospital from 1990 to 2021. Baseline characteristics including clinical features, laboratory data, aPL profiles were compared between patients who progressed to SLE (SLE group) and those who did not (non-SLE group). RESULTS: Among 64 patients diagnosed with PAPS at baseline, nine (13.8%) progressed to SLE over a mean follow-up of 9 years (incidence rate, 1.61 per 100 person-years). At the diagnosis of PAPS, the SLE group had a higher prevalence of anti-phosphatidylserine/prothrombin antibodies (aPS/PT) and anti-dsDNA antibodies compared to the non-SLE group. Other clinical findings, autoantibody profiles, and serum complement levels were similar between the two groups. Multivariate Cox analysis showed that IgG aPS/PT was significantly associated with SLE development (Hazard ratio: 10.3, 95% CI: 1.13-92.6, p=0.04). CONCLUSION: IgG aPS/PT may be a predictive factor for new-onset SLE in patients with PAPS, suggesting its utility in guiding risk stratification and monitoring strategies for these patients.

Relation between hydroxychloroquine dose and continuation rate in patients with systemic lupus erythematosus.

OBJECTIVES: Hydroxychloroquine (HCQ) is recommended at a target dose of 5 mg/kg per actual body weight to reduce the risk of retinopathy in systemic lupus erythematosus (SLE). However, the efficacy of HCQ has been established at doses of 6.5 mg/kg per ideal body weight. This study aimed to clarify the effects of the HCQ dose on the continuation rate in Japanese patients, who generally have a lower body mass index than Western patients. METHODS: This retrospective single-centre observational study enrolled patients with SLE on HCQ therapy. Patients were divided into two groups with a dose per actual body weight [the low-dose (<5 mg/kg) group and the high-dose (≥5 mg/kg) group], and continuation rates were compared. The efficacy of 1-year HCQ therapy was assessed in patients without additional immunosuppressive agents and biologics. RESULTS: Of the 231 patients enrolled, 48 (20.8%) discontinued HCQ. The HCQ dose per actual body weight was identified as an independent risk factor for discontinuation. The low-dose group showed a significantly higher 1-year HCQ continuation rate than the high-dose group (83.2% vs. 72.8%, respectively). Both groups showed reductions in glucocorticoid requirement and serological activity after 1-year HCQ therapy. CONCLUSIONS: HCQ <5 mg/kg per actual body weight may facilitate greater continuation.

Beneficial effects of nintedanib on cardiomyopathy in patients with systemic sclerosis: a pilot study.

OBJECTIVES: Nintedanib is an inhibitor of tyrosine kinases that has been shown to slow the progression of interstitial lung disease (ILD), including ILD associated with SSc. The aim of this study was to explore the effect of nintedanib on cardiomyopathy associated with systemic sclerosis (SSc). METHODS: Twenty consecutively hospitalized patients with SSc-ILD were enrolled and prospectively followed. The rate of change at 6 months in cardiac magnetic resonance (CMR) parametric mapping, including myocardial extracellular volume, was primarily evaluated. Other endpoints included changes in CMR functional parameters, echocardiographic parameters, modified Rodnan skin score, serum biomarkers and pulmonary function test. RESULTS: Nintedanib was administered in 10 patients, whereas the other 10 were treated without nintedanib or watched, according to ILD severity and progression. Baseline values of CMR parametric mapping were not different between the two groups. The rate of change at 6 months in myocardial extracellular volume was highly different, almost divergent, between the nintedanib group and the control group (-1.62% vs +2.00%, P = 0.0001). Among other endpoints, the change in right ventricular ejection fraction was significantly different between the two groups (P = 0.02), with a preferential change in the nintedanib group. CONCLUSION: Our data indicate beneficial signals of nintedanib on cardiomyopathy associated with SSc. The anti-fibrotic effect of nintedanib might not be limited to the lung.

The chest CT signs for pulmonary veno-occlusive disease correlate with pulmonary haemodynamics in systemic sclerosis.

OBJECTIVE: Pulmonary arterial hypertension associated with systemic sclerosis (PAH-SSc) sometimes accompanies pulmonary veno-occlusive disease (PVOD). We aimed to reveal the relation between clinical signs of PVOD and severing of pulmonary vasculopathy in SSc. METHODS: This study comprised 52 consecutive SSc patients who had pulmonary haemodynamic abnormalities (mPAP > 20 mmHg, PVR > 2 W.U. or PAWP > 15 mmHg). The chest CT scan was evaluated in all patients. Patients were divided into two groups, the 0-1 group and the 2-3 group, according to the number of chest CT signs for PVOD, including 1) mediastinal lymph node enlargement, 2) thickened interlobular septal wall, and 3) ground glass opacity. Pulmonary haemodynamics, echocardiography and MRI-based cardiac function, pulmonary function, and serum biomarkers were compared between the two groups. RESULTS: Mediastinal lymph node enlargement, thickened interlobular septal wall, and ground glass opacity were observed in 11 (21%), 32 (62%), and 11 (21%) patients, respectively. The 2-3 group (n = 15) had higher mPAP (p= 0.02) while lower DLco/VA (p= 0.02) compared with the 0-1 group (n = 37). Other parameters, including PAWP, cardiac output, left ventricular ejection fraction, left atrial diameter, forced vital capacity, brain natriuretic peptide, and Krebs von den Lunge-6 were not different between the two groups. CONCLUSION: The CT signs for PVOD had positive correlation with mPAP but negative correlation with DLco in SSc patients, indicating that PAH-SSc may reflect a spectrum of pulmonary vascular disease that ranges from the pulmonary artery to the vein.

Incidence and risk of antiresorptive agent-related osteonecrosis of the jaw (ARONJ) after tooth extraction in patients with autoimmune disease.

INTRODUCTION: Antiresorptive agent-related osteonecrosis of the jaw (ARONJ) is a rare but serious complication in patients receiving antiresorprtive agents (AR). However, the incidence of ARONJ after tooth extraction in patients with autoimmune disease (AID) remains unclear. The present study aimed to clarify the high-risk population of ARONJ in patients with AID. MATERIALS AND METHODS: The study population comprised 232 patients treated with AR, AID or non-AID, who had undergone dental extraction from January 2011 to September 2017. The incidence and risk factors of ARONJ were analysed retrospectively. Additionally, the relationship between ARONJ and osteoporotic fracture (OF) and AR discontinuation during dental procedures was investigated. RESULTS: Of 232 patients, 10 developed ARONJ within 1 year of dental extraction. The incidence of ARONJ in patients with AID was higher than that in non-AID patients (2.0/100 person-year vs 0.5/100 person-year; p = 0.03). Among the AID patients, RA patients had strikingly high incidence of ARONJ (3.6/100 person-year). The incidence of neither ARONJ nor OF significantly differed between patients who continued and discontinued AR in the perioperative period. CONCLUSION: Patients with AID who undergo dental extraction are at high risk of ARONJ. Discontinuation of AR would not significantly contribute to reduce the incidence of ARONJ in those patients.

Calcineurin inhibitors for adult-onset Still's disease: a multicentre retrospective cohort study.

OBJECTIVES: To clarify the efficacy and safety of calcineurin inhibitors (CNI) for treating adult-onset Still's disease (AOSD). METHODS: This multicentre historical cohort study enrolled the consecutive patients with AOSD according to Yamaguchi classification criteria. The endpoints were set as the time from the initiation of treatment to events, the persistency rate of CNI and safety. Based on the recurrent event data analysis, these endpoints were evaluated for each event. We divided the events into two groups according to the treatment that included CNI or conventional therapy without CNI. RESULTS: One hundred seventy-eight patients with 247 events were analysed. CNI were predominantly used in 72 events with a recurrent history, typical skin rash, high ferritin levels, and/or severe complications such as macrophage activation syndrome, disseminated intravascular coagulation, serositis, meningitis. CNI led to a significantly longer event-free survival (hazard ratio: 0.57, 95% confidential interval: 0.32-0.99) after adjustment of concomitant medications. Subgroup analysis showed that CNI were effective for AOSD patients with high ALT level (hazard ratio: 0.11, 95% confidential interval: 0.02-0.59) and severe complications (hazard ratio: 0.11, 95% confidential interval: 0.01-0.94). The persistency rate of CNI was 71% at 5th year. Adverse events occurred more frequently in the CNI group (18% versus 8%, p=0.02); however, CNI did not involve in increased risk of adverse events, including nephrotoxicity, after adjustment (p=0.23). CONCLUSIONS: Our retrospective analysis suggested that CNI could be an effective and safe option for treating AOSD.

Anti-cyclic citrullinated peptide antibody titers decrease in rheumatoid arthritis patients treated with tocilizumab: A pilot study.

Objectives: To analyze the effects of tocilizumab on peripheral B-cell subpopulation and its ability to produce anti-cyclic citrullinated peptide (CCP) antibody in patients with rheumatoid arthritis (RA).Methods: Thirteen consecutive RA patients initiated with tocilizumab were enrolled in our prospective study. Anti-CCP antibody titers and clinical parameters were evaluated during treatment. Peripheral blood B-cell subsets were analyzed using flow cytometry according to the Human Immunology Project.Results: Disease activity was significantly improved and anti-CCP antibody titers significantly decreased at week 24 compared to baseline. The percentages of post-switch memory B cells in CD19+ cells transiently increased at week 12, but there was no significant difference in any of the investigated B-cell subpopulations at week 24 compared to baseline. The ratios of post-switch memory to naïve B cells (post-switch/naïve) correlated negatively with anti-CCP antibody titers regardless of the time-points.Conclusion: Our study indicated that tocilizumab has a potential to reduce anti-CCP antibody production presumably by affecting post-switch/naïve ratio, and that anti-CCP antibody titers reflect B-cell distribution/subpopulation. As anti-CCP antibodies are produced in lymph nodes or ectopic lymphoid structures in synovial tissues, not in circulation, transient increment of post-switch memory B cells after tocilizumab treatment may reflect the altered balance of B-cell distribution between circulation and arthritic joints, resulting in suppressed production of anti-CCP antibody in situ.

Pathogenic roles of anti-C1q antibodies in recurrent pregnancy loss.

Recurrent pregnancy loss (RPL) is often considered idiopathic, however excessive complement activation has been observed in pregnancy related manifestations. Anti-C1q antibodies (anti-C1q) are associated with the activation of complement pathway in lupus patients, while it remains unclear in RPL. Firstly, we showed that both the prevalence and titre of anti-C1q were significantly higher in unexplained RPL than in healthy parous individuals. Secondly, we established the murine model of anti-C1q induced pregnancy loss using a monoclonal anti-mouse C1q antibody, JL-1. In mice treated with JL-1, high ratio of pregnancy loss and fetal growth restriction were frequently observed and complement activation occurred. C5a receptor (C5aR) blockade cancelled these pathogenic changes in mice treated with JL-1. In conclusion, our study reveals an association between the prevalence of anti-C1q and RPL. Additionally, our murine model has indicated that anti-C1q can induce reproductive failure, which might be ameliorated by therapy targeting the C5-C5aR axis.

Antiphospholipid score is a novel risk factor for idiopathic osteonecrosis of the femoral head in patients with systemic lupus erythematosus.

OBJECTIVE: Idiopathic osteonecrosis of the femoral head (ION) is a common complication of SLE associated with CS therapy. Although the pathogenesis of ION involves local bone ischaemia favoured by thrombophilia, the involvement of aPL in lupus ION remains to be elucidated. We have previously reported the aPL score (aPL-S) as a quantitative marker of aPL and the development of thrombotic events in autoimmune diseases. The aim of this study was to identify the impact of aPL on the development of ION using aPL-S. METHODS: This was a single-centre retrospective study comprising 88 consecutive SLE patients who underwent MRI of the hip joints from January 2000 to March 2017. Baseline characteristics, pharmacotherapy and total hip arthroplasty performed during follow-up were evaluated. RESULTS: The presence of ION was confirmed by MRI scan in 38 patients (43.1%). Male gender, positivity of any aPL, aPL-S, high aPL-S (≥30) and high dose of CS were identified as risk factors for ION by univariate analysis. Multivariate analysis revealed high aPL-S (odds ratio 5.12, 95% CI 1.18-29.79) and use of high-dose CS (odds ratio 10.25, 95% CI 3.00-48.38) as independent variables. Kaplan-Meier analysis showed that patients with high aPL-S received total hip arthroplasty more frequently than those without aPL (P = 0.010). CONCLUSIONS: We newly identified high aPL-S as an important risk factor for ION development in SLE, suggesting the involvement of aPL-induced coagulopathy in the pathophysiology of lupus ION.

Efficacy of dual antiplatelet therapy for preventing recurrence of arterial thrombosis in patients with antiphospholipid syndrome.

OBJECTIVE: Warfarin is regarded as the standard treatment for preventing thrombotic events in APS, but the recurrence rate is still high. Dual antiplatelet therapy (DAPT) has been shown to be effective for the prevention of acute coronary syndrome or stroke. The objective of this study was to evaluate the efficacy of DAPT for the prevention of thrombosis recurrence in APS patients with history of arterial thrombosis. METHODS: This retrospective cohort study of APS patients was conducted at Hokkaido University Hospital between 1990 and 2016. The secondary prophylactic effects and safety of warfarin monotherapy (Wf), antiplatelet monotherapy (AP), warfarin and antiplatelet combination therapy (Wf + AP) and DAPT were evaluated. The primary endpoints were set as thrombosis-free and adverse events-free survival period. Adverse events were defined as severe bleeding and death. RESULTS: A total of 90 APS patients were enrolled. Thrombotic recurrence was found in 40 patients (35 arterial and 5 venous thromboses) and serious adverse events in 20 patients (9 severe bleeding events and 14 deaths). Kaplan-Meier analysis demonstrated a 10-year recurrence-free survival rate of 62%. The recurrence rate per 100 patient-years was as follows: Wf: 11.6, AP: 5.5, Wf: + AP: 3.7, DAPT: 1.8. We demonstrated that DAPT significantly reduced the rate of recurrence compared with Wf (log-rank P = 0.001). There were no significant differences in the rate of serious adverse events among the groups. CONCLUSION: DAPT might be considered as an effective and safe option for the prophylaxis of recurrent arterial thrombosis in APS.

Clinical significance of plasma presepsin levels in patients with systemic lupus erythematosus.

OBJECTIVES: Presepsin (PSEP: soluble CD14 subtype) is produced from bacteria-stimulated monocytes or neutrophils, thus recognized as a biomarker of sepsis. Aberrant functions in monocyte or neutrophils are increasingly recognized in systemic lupus erythematosus (SLE). We investigated whether plasma PSEP reflects disease activity in patients with SLE. METHODS: This retrospective study comprised 35 patients with SLE and 72 with non-SLE autoimmune diseases who visited our facility during the period from August 2012 to September 2015. Plasma PSEP levels and laboratory data were compared between SLE and non-SLE. Clinical markers of SLE disease activity, including SLE disease activity index 2000 (SLEDAI-2K), serum complement concentrations and serum anti-ds-DNA antibodies were assessed in correlation with plasma PSEP levels. RESULTS: Plasma PSEP levels in SLE were higher than those in non-SLE. This phenomenon holds true when comparing SLE and non-SLE patients in the absence of infection (p = .0008). Plasma PSEP levels in SLE patients negatively correlated with C3 (r = -0.4454, p = .0430), CH50 (r = -0.4502, p = .0406) and positively with SLEDAI-2K (r = 0.4801, p = .0237). CONCLUSION: Elevated plasma PSEP levels were correlated with disease activity of SLE, suggesting inappropriate monocyte or neutrophil activation in the pathophysiology of SLE exacerbation.

Autoantibodies against a complement component 1 q subcomponent contribute to complement activation and recurrent thrombosis/pregnancy morbidity in anti-phospholipid syndrome.

OBJECTIVE: To investigate the prevalence and significance of the autoantibodies against complement component 1 q subcomponent (C1q) in patients with APS. METHODS: In all, 40 consecutive primary APS patients, 42 patients with non-SLE CTDs and 20 SLE patients negative for aPL were enrolled in this retrospective analysis. Refractory APS was defined as a clinical status of recurring thrombosis or pregnancy morbidity during adequate secondary prophylaxis. An ELISA was used to measure serum levels of anti-C1q antibodies and anaphylatoxins (C3a, C4a). RESULTS: Anti-C1q antibodies were found in 36% (15/42) and 2.5% (1/40) of primary APS patients and controls, respectively. Among primary APS patients, anti-C1q antibody titres were significantly correlated with serum C4a levels (P = 0.013). Neither the prevalence nor the titre of anti-C1q antibodies was associated with any specific clinical manifestations of APS, nor titres of aPL. Refractory APS patients (n = 10) had a higher prevalence of anti-C1q antibodies (9/10 vs 6/32, P = 0.01) than APS patients without recurrence (n = 32). CONCLUSION: Anti-C1q antibodies are associated with complement activation in APS and may contribute to the pathogenesis, particularly in refractory cases.

Significantly Delayed Development of Polyarthritis with Active Tenosynovitis after Possible Temporary Neutropenic Immune-Related Adverse Events Caused by Atezolizumab Treatment: A Novel Case Report.

Immune checkpoint inhibitors have drastically improved cancer treatment. However, they may induce immune-related adverse events (irAEs). Here, we report a case of significantly delayed rheumatic irAEs (Rh-irAEs) with prior possible temporary neutropenic irAEs in a patient with atezolizumab-treated non-small-cell lung cancer and its management. A man in his sixties received atezolizumab monotherapy as the sixth-line treatment. He experienced an infusion-related reaction (fever) during the first cycle. On day 22 of cycle 2, grade 4 neutropenia suddenly appeared, but it disappeared on the next day. Cycle 3 was initiated after seven days; the patient did not exhibit any symptoms for approximately 500 days. However, on day 534 (day 1 of cycle 21), the patient complained of pain in the shoulders, back, and wrists. On day 644, the shoulder and back pain worsened with obvious swelling of the fingers. We thus suspended treatment and consulted a rheumatologist. A diagnosis of polyarthritis with active tenosynovitis was made based on joint ultrasound and laboratory tests. Prednisolone 15 mg attenuated the symptoms, allowing suspension of analgesics; however, dose reduction from 15 mg/day was difficult because of symptom flares. Finally, iguratimod 25 mg twice daily was initiated on day 764; prednisolone was reduced to 10 mg without flares, and its dosage was slowly reduced to 5 mg/day. Although irAEs exhibit multisystem features, delayed development of polyarthritis with active tenosynovitis after possible temporary neutropenic irAEs is rare. Thus, irAEs need to be monitored for a long time in patients with suspected irAE development even if it appears transiently.

A case of tick-borne Yezo virus infection: Concurrent detection in the patient and tick.

A 76-year-old woman infected with Yezo virus (YEZV) developed liver dysfunction and thrombocytopenia following a tick bite. Despite the severity of her elevated liver enzymes and reduced platelet counts, the patient's condition improved spontaneously without any specific treatment. To our knowledge, this represents the first documented case where the YEZV genome was detected simultaneously in a patient's serum and the tick (Ixodes persulcatus) that bit the patient. This dual detection not only supports the hypothesis that YEZV is a tick-borne pathogen but also underscores the importance of awareness and diagnostic readiness for emerging tick-borne diseases, particularly in regions where these ticks are prevalent.

Hypoxia Promotes the Expression of ADAM9 by Tubular Epithelial Cells, Which Enhances Transforming Growth Factor ß1 Activation and Promotes Tissue Fibrosis in Patients With Lupus Nephritis.

OBJECTIVE: Enhanced expression of transforming growth factor (TGF) ß in the kidneys of patients with lupus nephritis (LN) can lead to progressive fibrosis, resulting in end-organ damage. ADAM9 activates TGFß1 by cleaving the latency-associated peptide (LAP). We hypothesized that ADAM9 in the kidney may accelerate fibrogenesis by activating TGFß1. METHODS: We assessed the expression of ADAM9 in the kidneys of mice and humans who were lupus prone. In vitro experiments were conducted using tubular epithelial cells (TECs) isolated from mice and explored the mechanisms responsible for the up-regulation of ADAM9 and the subsequent activation of TGFß1. To assess the role of ADAM9 in the development of tubular-intestinal fibrosis in individuals with LN, we generated MRL/lpr mice who were Adam9 deficient. RESULTS: ADAM9 was highly expressed in tubules from MRL/lpr mice. The transcription factor hypoxia-inducible factor-1α was found to promote the transcription of ADAM9 in TECs. TECs from mice who were Adam9 deficient and exposed to the hypoxia mimetic agent dimethyloxalylglycine failed to cleave the LAP to produce bioactive TGFß1 from latent TGFß1. Coculture of TECs from mice who were Adam9 deficient with fibroblasts in the presence of dimethyloxalylglycine and latent TGFß1 produced decreased amounts of type I collagen and α-smooth muscle actin (SMA) by fibroblasts. MRL/lpr mice who were Adam9 deficient showed reduced interstitial fibrosis. At the translational level, ADAM9 expression in tissues and urine of patients with LN was found to increase. CONCLUSION: Hypoxia promotes the expression of ADAM9 by TECs, which is responsible for the development of interstitial fibrosis in patients with LN by enhancing the TGFß1 activation, which promotes fibroblasts to produce collagen and α-SMA.

An Antiphospholipid Antibody Profile as a Biomarker for Thrombophilia in Systemic Lupus Erythematosus.

Despite recent advances in treatment and significant improvements in prognosis, thrombosis remains the major cause of death in systemic lupus erythematosus (SLE). Antiphospholipid antibodies (aPL) are the main triggers of thrombosis in patients with SLE, with a frequency of approximately 30-40%. Lupus anticoagulant, anticardiolipin, and anti-ß2-glycoprotein I antibodies, which are included in the criteria for antiphospholipid syndrome, and 'non-criteria' aPL such as anti-phosphatidylserine/prothrombin complex antibodies, are risk factors for thrombosis in patients with SLE. Multiple positivity for aPL is also associated with an increased risk of thrombosis, and scores calculated from aPL profiles can predict the risk of developing thrombosis. Although there is insufficient evidence for treatment, aPL-positive SLE patients should/may be treated with anticoagulants and/or low-dose aspirin as appropriate. This review summarises the evidence on the clinical significance of the aPL profile as a biomarker of thrombophilia in patients with SLE.