The prevalence and clinical characteristics of anti-HMGCR (anti-3-hydroxy-3-methyl-glutaryl-coenzyme A reductase) antibodies in idiopathic inflammatory myopathy: an analysis from the MyoCite registry.

This study aimed to determine the prevalence and clinical characteristics of anti-HMGCR antibodies in idiopathic inflammatory myositis (IIM) at a tertiary care centre in northern India. Data (adult and children) were retrieved from the MyoCite dataset, identifying patients with polymyositis, dermatomyositis, and antibody-negative IIM whilst fulfilling the ACR/EULAR criteria. SLE, sarcoidosis, and systemic sclerosis were included for comparison as disease controls. The baseline clinical profile, laboratory tests, and muscle biopsies were retrieved and analysed. Descriptive statistics and non-parametric statistics were used for comparison. Among 128 IIM (112 adults, 16 children, M:F 1:2.8) of age 37 (24-47) years and 6 (3-17) months disease duration, 4 (3.6%) young adults tested positive for anti-HMGCR antibodies. All children and disease control tested negative for the antibody. Anti-HMGCR + IIM exhibited higher muscle enzymes [AST (367 vs 104 IU/L, p = 0.045), ALT (502 vs 78 IU/L, p = 0.004), and CPK (12,242 vs 699 IU/L, p = 0.001] except lactate dehydrogenase with less frequent systemic features such as fatigue than antibody-negative IIM. One young girl presented with a Limb-girdle muscular dystrophy (LGMD) with chronic pattern. None of the patients exhibited rashes, statin exposure, or cancer, though one had anti-Ro52 and mild disease. Our observations depict a younger population while affirming previous literature, including NM-like presentation, and chronic LGMD-like pattern of weakness in one case. Although a small number of children were included, ours is one of the few paediatric studies that evaluated HMGCR antibodies thus far. Further investigations in a larger Indian cohort are warranted to substantiate our findings.

Renal injury, biomarkers, and myositis, an understudied aspect of disease: prospective study in the MyoCite cohort.

Introduction: The mechanisms leading to chronic kidney disease (CKD) in patients with idiopathic inflammatory myopathies (IIMs) are poorly understood. We assessed the prevalence of subclinical renal injury in patients with IIMs, through elevation in biomarker levels of tubular injury and fibrosis (NGAL, KIM1, Activin A, CD163, and Cys-c), and assessed differences between subtypes of IIMs, and the effect of disease activity and duration. Materials and methods: Clinical data, core set measures, sera and urine were prospectively collected from all patients enrolled in the MyoCite cohort from 2017 to 2021. Twenty healthy subjects (HC) and 16 patients with acute kidney injury (AKI) were included as controls. Baseline and follow up data for IIMs were included. Enzyme-linked immunosorbent assay (ELISA) was used to measure urine NGAL (Human Lipocalin-2/NGAL Duoset ELISA, Cat no: DY1757), KIM1 (Human TIM-1/KIM 1/HAVCR Duoset ELISA, Cat.no: DY1750B), Activin A (Human Activin A Duoset ELISA, Cat no: DY338), CD163 (Human CD163 Duoset ELISA,Cat no: DY1607-05), and Cys-c (Human Cystatin C Duoset ELISA, Cat. no.: DY1196) levels, while eGFR (unit mL/min/1.73 m2) was calculated by the Cockcroft-Gault formula and CKD-EPI formula. Results: Analysis of 201 visits of 110 adult patients with IIMs indicated higher normalized biomarker levels compared to HCs, and comparable to patients with AKI, with the exception of NGAL, which was higher in the AKI group. Notably 72 (49%) patients with IIMs had eGFR<90; the levels of the 5 biomarkers were comparable between active and inactive IIMs, and different subtypes of IIMs. Similarly, a poor correlation between urine biomarker levels and core set measures of activity and damage was found. Changes in biomarker levels on follow-up did not correlate with eGFR changes. Discussion: This exploratory analysis of urinary biomarkers identified low eGFR and elevated biomarkers of CKD in nearly half of the patients with IIMs, comparable to patients with AKI and higher than HCs, indicative of potential renal damage in IIMs that may have a lead to complications in other systems.

Peripheral T helper subset profiling in idiopathic inflammatory myositis: Proof of concept.

INTRODUCTION: There is a dearth of biomarkers in Idiopathic Inflammatory Myopathies (IIM) to recognize ongoing muscle inflammation and distinguish damage from activity. Since IIM is an autoantibody-mediated disease with tertiary lymphoid organogenesis reported in the diseased muscles, we aimed to study the peripheral blood T helper (Th) subset profiling as a plausible reflection of ongoing muscle inflammation. METHODS: Fifty-six patients of IIM were compared with 21 healthy controls (HC) and 18 patients with sarcoidosis. Th1, Th17, Th17.1, and Treg cells were identified after stimulation assays (BD Biosciences). Myositis autoantibodies were tested by line immunoassay (Euroimmune, Germany). RESULTS: All Th subsets were elevated in IIM as compared with HC. As compared to HC, PM had elevated Th1 and Treg while Th17 and Th17.1 populations were higher in OM. Patients with sarcoidosis had higher Th1 and Treg but lower Th17 population as compared to IIM {Th1(69.1% vs 49.65%, p<0.0001), {Treg (12.05% vs 6.2%, p<0.0001), {Th17 (2.49% vs 4.4%, p<0.0001)}. Similar results were obtained when sarcoidosis ILD was compared with IIM ILD with a higher Th1 and Treg population but lower Th17 population in the former. No difference in T cell profile was observed after stratification for MSA positivity, type of MSA, clinical features of IIM and disease activity. CONCLUSION: Th subsets in IIM are distinct from sarcoidosis and HC with a TH17 predominant paradigm, creating a case of exploring Th17 pathway and IL-17 blockers for the treatment of IIM. However, cell profiling cannot distinguish active from inactive disease limiting its predictive potential as a biomarker of activity in IIM.

Anti-mitochondrial antibodies in Indian patients with idiopathic inflammatory myopathies.

AIMS: Anti-mitochondrial antibodies (AMAs) are associated with distinct clinical phenotypes including cardiac and hepatic manifestations in idiopathic inflammatory myopathies (IIMs). This article studies the prevalence, clinical characteristics and outcomes of AMA in Indian patients with IIM. METHODS: Patients (97: 81 adult, 16 juvenile) clinically diagnosed with polymyositis or antibody-negative IIM were retrieved from the MyoCite bio-archive. They were tested for myositis-specific autoantibodies / myositis autoantibodies (MSAs/MAAs) using line immunoassay and antinuclear antibodies and AMAs using immunofluorescence assay (IFA). Patients were also screened for cardiac biomarkers (cardiac troponin I [c-TnI] and N terminal-pro brain natriuretic peptide [NT-pro-BNP] using immunometric immunoassay technique and enhanced chemiluminescence assay testing respectively) and hepatic manifestations using AMA testing. Results were formulated after carrying out analytical tests. RESULTS: Of the cohort, 5 adults (6.2%) (M:F 0:1) with a median age and disease duration of 37 years and 2 months respectively, tested AMA+ while the children tested negative. Dermatomyositis was the commonest phenotype, with amyopathic forms being common, often with MSA positivity. Cancer-associated myositis and polymyositis were also seen. AMA positivity is associated with Gottron's sign and calcinosis. Comparable levels of C-TnI and NT-pro-BNP and AMA testing in patients help to rule out subclinical cardiac and hepatic involvement respectively. CONCLUSION: Anti-mitochondrial antibodies are rare (6.2%) in different subtypes of IIM in the Indian population, and often coexist with MSAs. Their negative association with cardiac and hepatic involvement and probable association with Gottron's sign and calcinosis merit further investigation and long-term follow-up to understand the entire spectrum of the disease.

Retinal changes in patients with idiopathic inflammatory myopathies: A case-control study in the MyoCite cohort.

Background: Retinal changes are the window to systemic vasculature. Therefore, we explored retinal changes in patients with Idiopathic inflammatory myopathies (IIM) as a surrogate for vascular health. Methods: Adult and Juvenile IIM patients (2017 ACR/EULAR criteria), visiting a tertiary care center in 2021 were enrolled for detailed ophthalmic examination in comparison with healthy controls (HC). Patients with conditions that precluded thorough posterior chamber examination were excluded. Scale variables are expressed as median (IQR). Multivariate analysis (binary logistic regression-BLR) was conducted, adjusting for age, gender, and comorbidities besides factors significant in univariate analysis. Results: 43 patients with IIM [31 females; age 36 (23-45) years; disease duration 5.5 (2-12) months] were enrolled for participation. DM (44%) was the most common diagnosis. IIM patients exhibited frequent attenuation of retinal vessels (32.6 vs. 4.3%, p < 0.001), AV nicking (14 vs. 2.2%, p = 0.053), and vascular tortuosity (18.6 vs. 2.2%, p = 0.012), besides decreased visual acuity (53.5 vs. 10.9%, p<0.001) and immature cataracts (34.9 vs. 2.2%, p < 0.001). Attenuation of vessels [OR 10.9 (1.7-71), p = 0.004] emerged as significantly different from HC after adjusting for covariates in BLR. Notably, adults with IIM were more predisposed to retinal abnormalities [21 (57%) vs. 1 (16%), p = 0.068], especially attenuation of vessels [14(38%) vs. 0(0), p = 0.067] than jIIM. However, no difference was found in retinal features amongst the subtypes of adult IIM, nor did they correlate with MDAAT, MDI, or HAQ-DI. Conclusion: Retinal microvasculopathy and diminution of vision occur in nearly one-thirds to half of the patients with IIM. Microvasculopathy occurs across subtypes of IIM, and more so in adults, calling for further investigation as a surrogate for damage assessment and potentially even systemic vascular health.

The comparison of cardiovascular disease risk prediction scores and evaluation of subclinical atherosclerosis in rheumatoid arthritis: a cross-sectional study.

OBJECTIVES: Primary objectives estimated prevalence of traditional cardiovascular disease (CVD) risk factors and compared different CVD risk prediction algorithms in an Indian rheumatoid arthritis (RA) population. Secondary objectives evaluated associations between carotid intima-media thickness (CIMT) and subclinical atherosclerosis (SCA) with CVD risk factors and CVD risk scores. METHODS: The presence of CVD risk factors were recorded, and 10-year CVD risk was predicted using Framingham risk scoring (FRS) using lipids (FRS-Lipids), FRS using body mass index (FRS-BMI), QRISK-2, SCORE, and the algorithm recommended by ACC/AHA (ASCVD). CIMT was measured on the far-wall of the common carotid artery. Subclinical atherosclerosis was defined as CIMT > 0.9 mm or the presence of carotid plaque. RESULTS: A total of 332 patents were enrolled, 12% had diabetes mellitus, 21.4% hypertension, and 6.9% were current/past smokers. Proportions of RA with predicted 10-year CVD risk > 10% varied from 16.2 to 41.9% between scores. Highest magnitude of risk was predicted by FRS-BMI. Agreement between scores in predicting risk was moderate in general. Mean CIMT was 0.70 ± 0.15 mm. Age, male sex, and extra-articular manifestations associated with greater CIMT. All risk scores except SCORE moderately correlated with CIMT. About one-seventh had SCA defined as CIMT > 0.9 mm or the presence of carotid plaques, associated with increasing age, male gender, or higher ratio of total cholesterol to high-density lipoprotein cholesterol. ASCVD and QRISK-2 scores had maximum area under curve for distinguishing SCA. CONCLUSION: Individual CVD risk scores predict 10-year CVD risk differently in Indian patients with RA, and require validation for predicting hard end points (CVD events, mortality). Key Points • Diabetes mellitus and hypertension are the most prevalent cardiovascular disease risk factors in Indian patients with RA. • Individual cardiovascular risk prediction scores predict risk differently in Indian patients with RA, highest risk being predicted by the FRS-BMI. • Carotid intima-media thickness in RA associated with increasing age, male sex and extra-articular manifestations. • 14% RA had subclinical atherosclerosis, associated with increasing age, male sex, and higher total cholesterol to HDL-C ratio, best distinguished by ASCVD and QRISK-2 scores.

NMR-based serum and muscle metabolomics for diagnosis and activity assessment in idiopathic inflammatory myopathies.

Objectives: Differentiating smoldering disease activity from weakness due to fatty replacement of atrophied muscle can often be a challenge in the idiopathic inflammatory myositis (IIM). We aimed to identify the metabolic disturbances associated with IIM and if these changes can aid in the assessment of disease activity. Methods: Metabolic profiles of sera (N = 99) and muscle (N = 21) from patients with IIM (ACR-EULAR criteria) were compared with healthy control (HC) samples (N = 75 for serum and N = 12 for muscle tissues) employing 800 MHz NMR (Nuclear Magnetic Resonance) spectroscopy. Metabolic disparity between IIM and HC was established based on Partial Least Squares Discriminant Analysis (PLS-DA) and the discriminatory metabolites were identified based on variable importance in projection (VIP) statistics (P-value < .05, corrected for false discovery rate (FDR)). Results: Serum metabolomics profiles were distinctive in IIM as compared to HC, with a visible shift to anaerobic metabolism (increased lactate, low glucose), oxidative defect (high Phenylalanine/tyrosine), decreased muscle mass (low serum creatinine), increased muscle catabolism (increased branched-chain amino acids), and dyslipidemia (higher lipids, higher very low-density lipoprotein [VLDL]/low-density lipoprotein [LDL] ratio, lower polyunsaturated fatty acid [PUFA]). The sera of active IIM patients were characterized by anaerobic metabolism (low glucose), loss of muscle mass (low creatinine, amino acids), and oxidative defect (high Phenylalanine/tyrosine). Three metabolites (isopropanol, succinate, and glycine) were distinctive in muscle tissue metabolomics. NMR-based serum metabolic disparity was lacking between different clinical subsets of IIM. Conclusion: Serum and muscle tissue metabolomics have the potential to distinguish (a) IIM from HC and (b) active IIM from inactive IIM irrespective of disease subtype.