Pathological autoantibody internalisation in myositis.

OBJECTIVES: Autoantibodies targeting intracellular proteins are common in various autoimmune diseases. In the context of myositis, the pathologic significance of these autoantibodies has been questioned due to the assumption that autoantibodies cannot enter living muscle cells. This study aims to investigate the validity of this assumption. METHODS: Confocal immunofluorescence microscopy was employed to localise antibodies and other proteins of interest in myositis muscle biopsies. Bulk RNA sequencing was used to examine the transcriptomic profiles of 669 samples, including those from patients with myositis, disease controls and healthy controls. Additionally, antibodies from myositis patients were introduced into cultured myoblasts through electroporation, and their transcriptomic profiles were analysed using RNA sequencing. RESULTS: In patients with myositis autoantibodies, antibodies accumulated inside myofibres in the same subcellular compartment as the autoantigen. Bulk RNA sequencing revealed that muscle biopsies from patients with autoantibodies targeting transcriptional regulators exhibited transcriptomic patterns consistent with dysfunction of the autoantigen. For instance, in muscle biopsies from patients with anti-PM/Scl autoantibodies recognising components of the nuclear RNA exosome complex, an accumulation of divergent transcripts and long non-coding RNAs was observed; these RNA forms are typically degraded by the nuclear RNA exosome complex. Introducing patient antibodies into cultured muscle cells recapitulated the transcriptomic effects observed in human disease. Further supporting evidence suggested that myositis autoantibodies recognising other autoantigens may also disrupt the function of their targets. CONCLUSIONS: This study demonstrates that, in myositis, autoantibodies are internalised into living cells, causing biological effects consistent with the disrupted function of their autoantigen.

Clinico-pathological phenotypes of systemic sclerosis-associated myopathy: analysis of a large multicentre cohort.

OBJECTIVE: The objective of this study was to analyse the clinico-serological and histological phenotypes of patients with SSc with associated myopathy. METHODS: From November 2002 to September 2020, 52 patients with SSc underwent a muscle biopsy for suspected myopathy. We established two subgroups according to the histological findings based on the presence of isolated fibrosis or fibrosis together with significant inflammation. These patterns were designated as fibrosing and inflammatory, respectively. Clinical data, antibody profile, electrophysiologic studies, muscle biopsy findings and data regarding treatment, mortality and survival were compared between the two groups. RESULTS: Fourteen biopsies had a fibrosing pattern, whereas 26 showed an inflammatory pattern that could be classified (according to the predominant pattern) into DM (n = 7), necrotizing myopathy (n = 4) and non-specific myositis (n = 15). Additionally, 12 muscle biopsies were reported as neurogenic atrophy (n = 2), or normal muscle or minimal changes (n = 10). Compared with the inflammatory group, SSc patients with the fibrosing pattern presented a higher prevalence of ischaemic heart disease (38.5% vs 3.8%, P = 0.011), conduction abnormalities or arrhythmias (61.5% vs 26.9%, P = 0.036), anti-topo I antibodies (42.9% vs 11.5%, P = 0.044), greater median ESR (53.5 mm/h vs 32.5 mm/h, P = 0.013), with poor response to treatment and a higher mortality (42.9% vs 3.8%, P = 0.004) and lower cumulative survival (P = 0.035). CONCLUSIONS: Patients with SSc-associated myopathy require a comprehensive approach that encompasses clinical, serological and histopathological aspects, given their outcome predictive capacity. At least two different phenotypes can be drawn, considering clinico-pathological features. Significant differences are delineated between both a fibrotic and an inflammatory phenotype.

Nailfold videocapillaroscopy patterns in systemic sclerosis: implications for cutaneous subsets, disease features and prognostic value for survival.

OBJECTIVES: To assess the associations and prognostic value of scleroderma patterns by nailfold videocapillaroscopy (NVC) in patients with systemic sclerosis (SSc) and cutaneous subsets. METHODS: At baseline, 1356 SSc patients from the RESCLE registry were compared according to the scleroderma pattern as Late pattern and non-Late pattern, which included Early and Active patterns. Patient characteristics, disease features, survival time and causes of death were analysed. RESULTS: Late pattern was identified in 540 (39.8%), and non-Late pattern in 816 (60.2%) patients (88% women; 987 lcSSc/251 dcSSc). Late pattern was associated to dcSSc (OR=1.96; p<0.001), interstitial lung disease (ILD) (OR=1.29; p=0.031), and scleroderma renal crisis (OR=3.46; p<0.001). Once the cutaneous subset was disregarded in an alternative analysis, both digital ulcers (DU) (OR=1.29; p<0.037) and anti-topoisomerase I antibodies (OR=1.39; p< 0.036) emerged associated with the Late pattern. By cutaneous subsets, associations with Late pattern were: (1) in dcSSc, acro-osteolysis (OR=2.13; p=0.022), and systolic pulmonary artery pressure >40 mmHg by Doppler echocardiogram (OR=2.24; p<0.001); and (2) in lcSSc, ILD (OR=1.38; p=0.028). Survival was reduced in dcSSc with Late pattern compared to non-Late pattern (p=0.049). Risk factors for SSc mortality in multivariate regression Cox analysis were age at diagnosis (HR=1.03; p<0.001), dcSSc (HR=2.48; p<0.001), DU (HR=1.38; p=0.046), ILD (HR=2.81; p<0.001), and pulmonary arterial hypertension (HR=1.99; p<0.001). CONCLUSIONS: SSc patients with Late pattern more frequently present dcSSc and develop more fibrotic and vascular manifestations. Advanced microangiopathy by NVC identifies dcSSc patients at risk of reduced survival due to SSc-related causes.

External clinical validation of automated software to identify structural abnormalities and microhaemorrhages in nailfold videocapillaroscopy images.

OBJECTIVES: Automated systems to analyse nailfold videocapillaroscopy (NVC) images are needed to promptly and comprehensively characterise patients with systemic sclerosis (SSc) or Raynaud's phenomenon (RP). We previously developed, and validated in-house, a deep convolutional neural network-based algorithm to classify NVC-captured images according to the presence/absence of structural abnormalities and/or microhaemorrhages. We present its external clinical validation. METHODS: A total of 1,164 NVC images of RP patients were annotated by 5 trained capillaroscopists according to the following categories: normal capillary; dilation; giant capillary; abnormal shape; tortuosity; microhaemorrhage. The images were also presented to the algorithm. Matches and discrepancies between algorithm predictions and those annotations obtained by consensus of ≥3 or ≥4 interobservers were analysed. RESULTS: Consensus among ≥3 capillaroscopists was achieved in 86.9% of images, 75.8% of which were correctly predicted by the algorithm. Consensus among ≥4 experts occurred in 52.0% of cases, in which 87.1% of the algorithm's results matched with those of the expert panel. The algorithm's positive predictive value was >80% for microhaemorrhages and unaltered, giant or abnormal capillaries. Sensitivity was >75% for dilations and tortuosities. Negative predictive value and specificity were >89% for all categories. CONCLUSIONS: This external clinical validation suggests that this algorithm is useful to assist in the diagnosis and follow-up of SSc or RP patients in a timely manner. It may also be helpful in the management of patients with any pathology presenting with microvascular changes, as the algorithm has been designed to also be useful for research aiming at extending the usage of nailfold capillaroscopy to more conditions.

The challenge of comprehensive nailfold videocapillaroscopy practice: a further contribution.

OBJECTIVES: Although classification systems and scores for capillaroscopy interpretation have been published, there is a lack of homogenization for the procedure, especially in the way and place the images are taken, the counting of the capillaries and the measuring of their size. Our objective is to provide a deep learning-based software to obtain objective and exhaustive data for the whole nailfold without increasing the time or effort needed to do the examination, or requiring expensive equipment. METHODS: An automated software to count nailfold capillaries has been designed, through an exploratory image dataset of 2,713 images with 18,000 measurements of 3 different types. Subsequently, application rules have been created to detect the morphology of nailfold videocapillaroscopy images, through a training set of images. The software reliability has been evaluated with standard metrics used in the machine learning field for object detection tasks, comparing automatic and manual counting on the same NVC images. RESULTS: A mean average precision (mAP) of 0.473 is achieved for detecting and classifying capillaries and haemorrhages by their shape, and a mAP of 0.515 is achieved for detecting and classifying capillaries by their size. A precision of 83.84% and a recall of 92.44% in the identification of capillaries was estimated. CONCLUSIONS: Deep learning is a useful tool in nailfold videocapillaroscopy that allows to analyse objectively and homogeneously images taken with multiple devices. It should make the assessment of the capillary morphology in nailfold video capillaroscopy easier, quicker, more complete and accessible to everyone.

Anti-Polymyositis/Scl Antibodies in Systemic Sclerosis: Clinical Associations in a Multicentric Spanish Cohort and Review of the Literature.

OBJECTIVES: To assess the clinical profile of patients with anti-polymyositis/Scl (PM/Scl) antibodies in a cohort of Spanish patients with systemic sclerosis. METHODS: From the Spanish Scleroderma Study Group database, we selected patients in whom PM/Scl antibodies had been tested. We compared demographic, clinical, laboratory, and survival data between patients with and without PM/Scl antibodies. RESULTS: Seventy-two of 947 patients (7.6%) tested positive for PM/Scl antibodies. Patients with PM/Scl antibodies presented initially with more puffy fingers and arthralgias but less Raynaud phenomenon. Regarding cumulative manifestations, myositis and arthritis were more prevalent in patients with PM/Scl antibodies, as well as pulmonary fibrosis. On the contrary, patients with PM/Scl antibodies had less pulmonary hypertension. No difference in terms of survival at 5 and 10 years was noticed between the 2 groups. CONCLUSIONS: In systemic sclerosis patients from Spain, PM/Scl antibodies are associated with a distinct clinical profile. However, PM/Scl antibodies did not influence survival.

Comprehensive analysis of the major histocompatibility complex in systemic sclerosis identifies differential HLA associations by clinical and serological subtypes.

OBJECTIVE: The greatest genetic effect reported for systemic sclerosis (SSc) lies in the major histocompatibility complex (MHC) locus. Leveraging the largest SSc genome-wide association study, we aimed to fine-map this region to identify novel human leucocyte antigen (HLA) genetic variants associated with SSc susceptibility and its main clinical and serological subtypes. METHODS: 9095 patients with SSc and 17 584 controls genome-wide genotyped were used to impute and test single-nucleotide polymorphisms (SNPs) across the MHC, classical HLA alleles and their composite amino acid residues. Additionally, patients were stratified according to their clinical and serological status, namely, limited cutaneous systemic sclerosis (lcSSc), diffuse cutaneous systemic sclerosis (dcSSc), anticentromere (ACA), antitopoisomerase (ATA) and anti-RNApolIII autoantibodies (ARA). RESULTS: Sequential conditional analyses showed nine SNPs, nine classical alleles and seven amino acids that modelled the observed associations with SSc. This confirmed previously reported associations with HLA-DRB1*11:04 and HLA-DPB1*13:01, and revealed a novel association of HLA-B*08:01. Stratified analyses showed specific associations of HLA-DQA1*02:01 with lcSSc, and an exclusive association of HLA-DQA1*05:01 with dcSSc. Similarly, private associations were detected in HLA-DRB1*08:01 and confirmed the previously reported association of HLA-DRB1*07:01 with ACA-positive patients, as opposed to the HLA-DPA1*02:01 and HLA-DQB1*03:01 alleles associated with ATA presentation. CONCLUSIONS: This study confirms the contribution of HLA class II and reveals a novel association of HLA class I with SSc, suggesting novel pathways of disease pathogenesis. Furthermore, we describe specific HLA associations with SSc clinical and serological subtypes that could serve as biomarkers of disease severity and progression.

The incidence rate of pulmonary arterial hypertension and scleroderma renal crisis in systemic sclerosis patients with digital ulcers on endothelin antagonist receptors (ERAs) and phosphodiesterase-5 inhibitors (PDE5i).

INTRODUCTION: Endothelin antagonist receptors (ERAs) and phosphodiesterase-5 inhibitors (PDE5i) are beneficial in pulmonary arterial hypertension (PAH) and digital ulcers (DU) and prevent from DU recurrences. Our study aimed to determine the difference in the incidence rate of PAH and scleroderma renal crisis (SRC) in patients with SSc and DU (SSc-DU) under ERAs/PDE5i or without treatment. METHODS: We conducted a retrospective cohort study including SSc-DU patients from the Spanish Scleroderma Registry (RESCLE). The primary outcome was the incidence rate of PAH and SRC in patients under ERAs/PDE5i or not. RESULTS: Some 544 patients out of 1817 (29.9%) in the RESCLE database had DU, 221 (40.6%) under ERAs/PDE5i and 323 (59.4%) not. The incidence rate (95% CI) difference between patients under treatment or not under did not reach statistical significance in PAH [-0.1 (-4.8, 4.69), P = 0.988] or in SRC [0.7 (-2.2, 3.7), P = 0.620]. However, the time from the first DU to the diagnosis of SRC was delayed in treated patients [mean (s.d.) 7.6 (5.8) years vs 2.9 (5.3); P = 0.021]. The dcSSc subset was more prevalent in the treatment group (36 vs 26%; P = 0.018), along with anti-topoisomerase I antibodies (34 vs 18%; P < 0.001) and tendon friction rubs (12 vs 6%; P = 0.038), whereas the lcSSc subset was more prevalent in the no-treatment group (57 vs 66%; P = 0.031) along with ACA (37 vs 46%; P = 0.031). CONCLUSION: There was no difference in the incidence rate of PAH and SRC between groups. However, treatment with ERAs and/or PDE5i appeared to delay the occurrence of SRC.

Serodiscordant patients with systemic sclerosis: when antibody does not correspond to skin involvement.

OBJECTIVES: Diffuse cutaneous systemic sclerosis (dcSSc) is associated with anti-topoisomerase (ATA) whereas limited cutaneous (lcSSc) and sine scleroderma (ssSSc) are mainly associated with anti-centromere antibody (ACA). Serodiscordant patients were defined as lcSSc subjects with ATA, dcSSc with ACA, and ssSSc with ATA. The aim of the present study was to compare the clinical manifestations and prognosis between serodiscordant patients and their counterparts (those with lcSSc with ACA, dcSSc with ATA and ssSSc with ACA, respectively). METHODS: From the Spanish Scleroderma Registry we selected those patients for whom skin involvement (dcSSc, lcSSc or ssSSc) was detailed at baseline and last visit and ACA and ATA had been determined. Demographic, clinical characteristics, and survival data were compared according to the antibody status. RESULTS: The whole cohort comprised 901 patients and six mutually exclusive groups were defined: lcSScACA in 511 (57%) patients, lcSScATA group in 87 (10%), dcSScATA group in 172 (19%), dcSScACA group in 21 (2%), ssSScACA group in 92 (10%), and ssSScATA group in 18 (2%) patients, respectively. Interstitial lung disease (ILD) and severe ILD were more frequent in patients with dcSScATA than in those with dcSScACA. Conversely, the prevalence of isolated pulmonary hypertension (without ILD) was higher in those with dcSScACA (15% vs. 2%; p=0.018). No differences were found regarding survival when comparing serodiscordant patients with the seroconcordants patients. CONCLUSIONS: In our cohort, the prevalence of serodiscordant SSc patients was low. They differed from their counterparts in some clinical manifestations. The management of patients with SSc should be guided by both serology and cutaneous subtype.

Clinical features of systemic sclerosis patients with anti-RNA polymerase III antibody in a single centre in Spain.

OBJECTIVES: To evaluate the clinical features and survival of patients with positive anti-RNA polymerase III (anti-RNAP III) in a Spanish single centre. METHODS: We analysed 221 patients with SSc according to LeRoy and Medsger criteria. Twenty-six patients with positivity for anti-RNAP III antibodies were compared with 195 negative patients. Epidemiological, clinical, immunological features and survival were analysed. RESULTS: In patients with anti-RNAP III positivity diffuse cutaneous SSc (dcSSc) subset was the most prevalent (20, 76.9% vs. 35, 17.9%, p < 0.001), with shorter diagnosis delay (4.11 ± 7.34 years vs. 6.77 ± 9.22 years, p = 0.005). Patients with anti-RNAP III antibodies had higher frequency of arterial hypertension (13, 50% vs. 55, 28.2%, p = 0.024), scleroderma renal crisis (SRC) (3, 11.5% vs. 3, 1.5%, p = 0.023), arthritis (9, 34.6% vs. 35, 17.9%, p = 0.046), tendon friction rubs (4, 15.4% vs. 1, 0.5%, p = 0.001) and contractures (5, 19.2% vs. 10, 5.1%, p = 0.02). There were no differences found in the presence of cancer or in global survival. In the multivariate survival analysis, severe interstitial lung disease (ILD) (HR: 8.61, 95%CI 3.40 - 21.81), pulmonary arterial hypertension (PAH) (HR: 4.05, 95%CI 1.42 - 11.61) and SRC (HR: 17.27, 95%CI 3.36 - 88.97) were the only factors associated with poor prognosis. CONCLUSIONS: In this cohort anti-RNAP III antibodies are related with dcSSc subset, shorter diagnostic delay and higher prevalence of musculoskeletal involvement, arterial hypertension and SRC. ILD, PAH and SRC were independent prognostic factors.

Changes in the pattern of death of 987 patients with systemic sclerosis from 1990 to 2009 from the nationwide Spanish Scleroderma Registry (RESCLE).

OBJECTIVES: To determine the changes in the pattern of death of patients with systemic sclerosis (SSc) throughout 20 years. METHODS: Data were collected from the Spanish Scleroderma Registry (RESCLE), retrospective multicentre database from 1990 to 2009. SSc-related and SSc-non related causes of death were assessed. RESULTS: 987 patients were recruited. Overall standardised mortality ratio (SMR) was 2.34 (2.24-2.44). SSc-related causes of death were responsible of 72% of all deaths of those patients diagnosed within 1990-99 vs. 48% within 2000-09 (p=0.006). Relative pulmonary death rate was stable over time (68.1% within 1990-99 vs. 63.9% within 2000-09, p=0.815). Relative renal death rate was decreasing over time (17% within 1990-99 vs. 5.5% within 2000-09, p=0.175). Heart distribution tripled its ratio (12.8% within 1990-99 vs. 30.6% within 2000-09, p=0.058). CONCLUSIONS: SSc-related causes of death were decreasing over time and, among them, pulmonary involvement was the leading cause of death in both decades. The ratio of renal causes decreased since 1990 at the time that the ratio of cardiac causes increased.

Influence of antibody profile in clinical features and prognosis in a cohort of Spanish patients with systemic sclerosis.

OBJECTIVES: To assess the clinical manifestations and prognosis of Spanish patients with systemic sclerosis (SSc) according to their immunological profile. METHODS: From the Spanish Scleroderma Study Group or RESCLE (Registro de ESCLErodermia as Spanish nomenclature) Registry we selected those patients in which anti-centromere (ACA), anti-topoisomerase I (ATA), and anti-RNA polymerase III (ARA) antibodies had been determined, and a single positivity for each SSc specific antibody was detected. Demographic, clinical, laboratory, and survival data were compared according to the serologic status of these antibodies. RESULTS: Overall, 209 SSc patients were included. In 128 (61%) patients ACA was the only positive antibody, 46 (22%) were only positive for ATA, and 35 (17%) for ARA. Of note, the three groups were mutually exclusive. In univariate analysis, patients with ACA presented more frequently limited cutaneous SSc (lcSSc) (p<0.001), whereas diffuse cutaneous SSc (dcSSc) was the most frequent subtype in patients with ATA (54%) and ARA (62%) (both p<0.001). Positive patients for ARA showed the highest prevalence of joint involvement (p<0.001) and those from ATA group had a higher prevalence of interstitial lung disease (ILD) (p<0.001). Scleroderma renal crisis was more frequent in the ARA group (p<0.001). In multivariate analysis, ACA were associated with female gender and were protective for dcSSc and ILD. ATA were found to be protective for lcSSc and they were independently associated with interstitial reticular pattern. ARA positivity was independently associated with dcSSc. We did not find differences in mortality between the three groups. CONCLUSIONS: In Spanish SSc patients, the presence of SSc specific antibodies conferred a distinctive clinical profile.

Clinical and epidemiological differences between men and women with systemic sclerosis: a study in a Spanish systemic sclerosis cohort and literature review.

OBJECTIVES: The low overall prevalence of systemic sclerosis (SSc) and the low proportion of male patients have resulted in a scarcity of studies assessing sex differences in Ssc patients, and contradictory results have often been show among those studies that have been performed. METHODS: A prospective study was conducted with the Spanish RESCLE register to analyse the influence of gender on survival of SSc patients. RESULTS: In total, 1506 SSc patients (1341 women, 165 men) were recruited from 21 centres. Older age at onset (OR 1.02), shorter time from onset to diagnosis (OR 0.96), smoking (OR 2.57), interstitial lung disease (ILD) (OR 1.58), less predisposition to sicca syndrome and to antinuclear antibody positivity (OR 0.29 and 0.43, respectively), and higher compliance with the ACR 1980 criteria (OR 1.79) were independently associated with the male sex. During follow-up, 30.4% of men versus 14.6% of women died (p<0.001). Survival at 10 years from the onset of symptoms was 75.3% for men and 92.9% for women (p<0.001), and the difference remained after selecting only SSc-related deaths (85.6% vs. 96.1%, p<0.001). The mortality predictive factors were diffuse SSc (OR 2.26), ILD (OR 1.82), digital ulcers (OR 1.38), tendon friction rubs (OR 1.74), male sex (OR 1.53), increased age at onset (OR 1.13) and isolated PH (considering only deaths from diagnosis), both in the overall (OR 3.63) and female cohorts (OR 3.97). The same risk factors were observed in the male cohort, except for isolated PH and ILD. CONCLUSIONS: The present study confirms the existence of epidemiological, clinical, laboratory and prognostic gender differences in systemic sclerosis patients.

Cardiac involvement in systemic sclerosis: differences between clinical subsets and influence on survival.

Cardiac involvement (CI) is a known complication of SSc associated with increased mortality. Our objective was to describe a cohort of patients with SSc and CI and to assess the differences between cutaneous subsets regarding their presentation and survival. Three hundred and ninety-three Spanish patients from a single center, diagnosed with SSc, were retrospectively studied for evidence of CI using noninvasive and invasive tests from 1976 to 2011. Clinical, epidemiological, immunological and therapeutic features of patients with CI were compared to those without it and within the different cutaneous subsets of SSc. CI was present in 173 (44 %) patients. Mitral regurgitation (67 %), conduction alterations (45 %) and left ventricle diastolic dysfunction (40 %) were the most common findings. Pericardial involvement and heart failure were more frequent in diffuse SSc (dcSSc) than in limited or sine scleroderma SSc. CI accounted for 20 % of deaths, and it was an independent mortality risk factor (HR 2.1, P = 0.02), but once CI was established, classical dcSSc mortality risk factors determined mortality. Patients with dcSSc developed CI faster than limited (HR 1.9, P = 0.003) or sine SSc patients (HR 2.5, P = 0.002), specially during the first year after SSc onset. We found statistically significant differences between the 3 SSc subsets in the presentation of pericardial involvement and heart failure. CI increased the mortality and appeared at a higher rate, especially during the first year after SSc onset. Screening for heart involvement should be performed at diagnosis and during follow-up.

Pleural irregularity, a new ultrasound sign for the study of interstitial lung disease in systemic sclerosis and antisynthetase syndrome.

OBJECTIVES: To evaluate a new ultrasound sign, pleural irregularity (PI), for the study of interstitial lung disease (ILD) in patients with systemic sclerosis (SSc) and antisynthetase syndrome (ASS). METHODS: The study included patients from our SSc and ASS cohorts with varying degrees of ILD, enrolled from 2011 to 2014. Chest high-resolution computed tomography (HRCT), pulmonary function tests (FVC and DLCO) and chest sonography were performed in each patient. Ultrasound PI and B-lines were quantified using a 72-sonographic point score and HRCT lung abnormalities were quantified using Warrick and Wells scores and categorised through Goh's algorithm. PI was correlated with HRCT and pulmonary function test parameters and its diagnostic performance to detect and classify the extent of ILD was evaluated and compared with B-lines. RESULTS: Thirty-seven patients were studied, 21 with ASS and 16 with SSc (8 without ILD). PI correlated with the Warrick score both in SSc (r=0.6, p=0.01) and ASS patients (r=0.6, p=0.005), showing a higher performance to detect ILD than using B-lines (p=0.01). In SSc patients PI also correlated with Wells score (r=0.7, p<0.001) and with DLCO (r=-0.5, p=0.05), showing a high diagnostic value for detecting ILD (AUC=0.85, 95% CI 0.64-1) and classifying it into limited or extensive (AUC=0.81, 95% CI 0.57-1). A modification of the Goh algorithm including PI was developed as a screening tool to avoid the use of HRCT in SSc patients without ultrasound evidence of extensive ILD. CONCLUSIONS: PI is useful for evaluation of ILD in SSc and ASS patients, and can be incorporated into a diagnostic algorithm in SSc patients to reducing the need for exposure to ionising radiation.

Pathogenic autoantibody internalization in myositis.

Objectives: Myositis is a heterogeneous family of autoimmune muscle diseases. As myositis autoantibodies recognize intracellular proteins, their role in disease pathogenesis has been unclear. This study aimed to determine whether myositis autoantibodies reach their autoantigen targets within muscle cells and disrupt the normal function of these proteins. Methods: Confocal immunofluorescence microscopy was used to localize antibodies and other proteins of interest in myositis muscle biopsies. Bulk RNA sequencing was used to study the transcriptomic profiles of 668 samples from patients with myositis, disease controls, and healthy controls. Antibodies from myositis patients were introduced into cultured myoblasts by electroporation and the transcriptomic profiles of the treated myoblasts were studied by bulk RNA sequencing. Results: In patients with myositis autoantibodies, antibodies accumulated inside myofibers in the same subcellular compartment as the autoantigen. Each autoantibody was associated with effects consistent with dysfunction of its autoantigen, such as the derepression of genes normally repressed by Mi2/NuRD in patients with anti-Mi2 autoantibodies, the accumulation of RNAs degraded by the nuclear RNA exosome complex in patients with anti-PM/Scl autoantibodies targeting this complex, and the accumulation of lipids within myofibers of anti-HMGCR-positive patients. Internalization of patient immunoglobulin into cultured myoblasts recapitulated the transcriptomic phenotypes observed in human disease, including the derepression of Mi2/NuRD-regulated genes in anti-Mi2-positive dermatomyositis and the increased expression of genes normally degraded by the nuclear RNA exosome complex in anti-PM/Scl-positive myositis. Conclusions: In myositis, autoantibodies are internalized into muscle fibers, disrupt the biological function of their autoantigen, and mediate the pathophysiology of the disease.

Diffusing Capacity of the Lungs for Carbon Monoxide and Echocardiographic Parameters in Identifying Mild Pulmonary Hypertension in the EUSTAR Cohort of Patients With Systemic Sclerosis.

BACKGROUND: The 2022 European Society of Cardiology/European Respiratory Society guidelines define pulmonary hypertension (PH) as a resting mean pulmonary artery pressure (mPAP) > 20 mm Hg at right heart catheterization (RHC). Previously, patients with an mPAP between 21 and 24 mm Hg were classified in a "gray zone" of unclear clinical significance. RESEARCH QUESTION: What is the diagnostic performance of the main parameters used for PH screening in detecting patients with systemic sclerosis (SSc) with an mPAP of 21 to 24 mm Hg at RHC? STUDY DESIGN AND METHODS: Patients with SSc from the European Scleroderma Trials and Research (EUSTAR) database with available tricuspid annular plane systolic excursion (TAPSE), systolic PAP (sPAP), and mPAP data were included. Patients with mPAP 21 to 24 mm Hg and patients with mPAP ≤ 20 mm Hg were considered for the analysis. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated. RESULTS: TAPSE/sPAP was lower in the group of patients with SSc with mPAP 21 to 24 mm Hg than in the non-PH group (0.58 [0.46-0.72] vs 0.69 [0.57-0.81] mm/mm Hg, respectively; P < .01). No difference was found in other parameters between the two groups. Diffusing capacity of the lungs for carbon monoxide < 80% of the predicted value had the highest sensitivity (88.9%) and NPV (80%), but the lowest specificity (18.2%) and PPV (30.8%) in detecting patients with SSc with mPAP 21 to 24 mm Hg. TAPSE/sPAP < 0.55 mm/mm Hg had the highest specificity (78.9%), PPV (50%), and accuracy (68.1%); its NPV was 75.4%, and its sensitivity was 45.1%. INTERPRETATION: In this study, diffusing capacity of the lungs for carbon monoxide < 80% of the predicted value was the parameter with the highest sensitivity and NPV in detecting patients with SSc with mPAP 21 to 24 mm Hg. TAPSE/sPAP < 0.55 mm/mm Hg had the highest specificity, PPV, and accuracy and, therefore, can be a useful additional parameter to decrease the number of unnecessary RHCs.

The role of TAPSE/sPAP ratio in predicting pulmonary hypertension and mortality in the systemic sclerosis EUSTAR cohort.

OBJECTIVES: The study aim was to evaluate the predictive role of the echocardiography-derived tricuspid annular plane systolic excursion/systolic pulmonary artery pressure (TAPSE/sPAP) ratio for pulmonary hypertension (PH) diagnosis and mortality in the European Scleroderma Trials and Research (EUSTAR) cohort. METHODS: Eligible patients were systemic sclerosis (SSc) patients registered in the EUSTAR database with at least one visit recording TAPSE and sPAP data. Individual centres were required to provide TAPSE and sPAP data at 12 ± 3 months before right heart catheterization (RHC). Logistic regression analysis was applied to analyse the predictive ability of TAPSE/sPAP ratio for PH diagnosis. Cox regression analysis was performed to evaluate TAPSE/sPAP ratio as a predictive factor for all-cause mortality. RESULTS: 2555 SSc patients met the inclusion criteria for this study with 355 SSc patients having available RHC data at baseline. PH was confirmed by RHC in 195 SSc patients (54.9%). TAPSE/sPAP ratio < 0.55 mm/mmHg [OR 0.251 (95% CI 0.084-0.753), p < 0.05] and FVC/DLCO [OR 2.568 (95% CI 1.227-5.375), p < 0.05] were significantly associated with PH diagnosis. In logistic regression analysis with echocardiographic parameters at 12 ± 3 months before RHC, TAPSE/sPAP ratio < 0.55 mm/mmHg [OR 0.265 (95% CI 0.102-0.685), p < 0.01] and FVC/DLCO [OR 2.529 (95% CI 1.358-4.711), p < 0.01] were associated with PH diagnosis. In multivariate Cox regression analysis, TAPSE/sPAP ratio ≤ 0.32 mm/mmHg [HR 0.310 (0.164-0.585), p < 0.001] was the most significant predictive factor for death. CONCLUSIONS: TAPSE/sPAP ratio < 0.55 mm/mmHg is a predictive risk factor for PH. TAPSE/sPAP ratio ≤ 0.32 mm/mmHg is a predictive risk marker for all-cause mortality.

Anti-U11/U12 Antibodies as a Rare but Important Biomarker in Patients with Systemic Sclerosis: A Narrative Review.

Anti-nuclear (ANA) are present in approximately 90% of systemic sclerosis (SSc) patients and are key biomarkers in supporting the diagnosis and determining the prognosis of this disease. In addition to the classification criteria autoantibodies for SSc [i.e., anti-centromere, anti-topoisomerase I (Scl-70), anti-RNA polymerase III], other autoantibodies have been associated with important SSc phenotypes. Among them, anti-U11/U12 ribonucleoprotein (RNP) antibodies, also known as anti-RNPC-3, were first reported in a patient with SSc, but very little is known about their association and clinical utility. The U11/U12 RNP macromolecular complex consists of several proteins involved in alternative mRNA splicing. More recent studies demonstrated associations of anti-anti-U11/U12 antibodies with SSc and severe pulmonary fibrosis as well as with moderate to severe gastrointestinal dysmotility. Lastly, anti-U11/U12 autoantibodies have been strongly associated with malignancy in SSc patients. Here, we aimed to summarize the knowledge of anti-U11/U12/RNPC-3 antibodies in SSc, including their seroclinical associations in a narrative literature review.