IntroductionPruritus is a common excruciating symptom in systemic autoimmune diseases such as dermatomyositis (DM) but the pathogenesis is not fully understood. We intended to investigate the targeted expression analysis of candidate molecules involved in the development of pruritus in lesional vs. non-lesional skin samples of patients affected with active DM. We looked for correlations between the investigated pruriceptive signaling molecules, disease activity, and itching sensation of DM patients.MethodsInterleukins (IL-33 and IL-6), tumor necrosis factor α (TNF-α), peroxisome proliferator-activated receptor γ (PPAR-γ), and ion channels belonging to the transient receptor potential (TRP) family were analyzed. The expression of TNF-α, PPAR-γ, IL-33, IL-6, and TRP channels in lesional DM skin was evaluated by RT-qPCR and immunohistochemistry and was compared with non-lesional DM skin samples. Pruritus, disease activity, and damage of DM were evaluated by the 5-D itch scale and Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI), respectively. Statistical analysis was performed with IBM SPSS 28 software.ResultsA total of 17 active DM patients participated in the study. We could show that the itching score was positively correlated with the CDASI activity score (Kendall's tau-b = 0.571; p = 0.003). TNF-α gene expression was significantly higher in lesional DM skin than in non-lesional DM skin (p = 0.009) and differed in the subgroups of patients with different itch intensities (p = 0.038). The mRNA expression of lesional IL-6 correlated positively with 5-D itch and CDASI activity score (Kendall's tau-b = 0.585; p = 0.008 and 0.45; p = 0.013, respectively). TRPV4 expressions were positively correlated with CDASI damage score (Kendall's tau-b = 0.626; p < 0.001), but the mRNA expressions of the TRP family, PPAR-γ, IL-6, and IL-33 were not different in lesional and non-lesional samples. Immunohistochemistry analysis did not find significant alterations in the expressions of TNF-α, PPAR-γ, IL-6, and IL-33 in lesional and non-lesional regions.DiscussionOur results argue that cutaneous disease activity, TNF-α, and IL-6 might play a central role in DM-associated itch, while TRPV4 plays a central role in tissue regeneration.

Myalgia, myopathy and myositis are the most important types of muscle impairment in immune-mediated inflammatory arthropathies and connective tissue diseases. Multiple pathogenetic and histological changes occur in the striated muscles of these patients. Clinically, the most important muscle involvement is the one that causes complaints to the patients. In everyday practice, insidious symptoms present a serious problem for the clinician; in many cases, it is difficult to decide when and how to treat the muscle symptoms that are often present only subclinically. In this work, authors review the international literature on the types of muscle problems in autoimmune diseases. In scleroderma histopathological picture of muscle shows a very heterogeneous picture, necrosis and atrophy are common. In rheumatoid arthritis and systemic lupus erythematosus, myopathy is a much less defined concept, further studies are needed to describe it. According to our view, overlap myositis should be recognized as a separate entity, preferably with distinct histological and serological characteristics. More studies are needed to describe muscle impairment in autoimmune diseases which may help to explore this topic more in depth and be of clinical use.

Abstract Background/Aims Anti-synthetase syndrome (ASS) represents a distinct entity within myositis spectrum disorders; however, correct classification of patients with anti-tRNA synthetase autoantibodies and skin manifestations akin to dermatomyositis (DM) remains uncertain. Our aim was to compare clinical characteristics, skin involvement, and malignancy, between patients with ASS and DM, classified by disease-specific autoantibodies. Methods Data from 05/2009-03/2016 from 9 countries from the prospective, myositis EuroMyositis registry were downloaded. Those with anti-tRNA synthetase autoantibodies (Jo-1/PL-7/PL-12/OJ/EJ/KS) were classified as ASS, and those with Mi-2/TIF1-γ/NXP2/SAE/MDA5 autoantibodies as DM. Clinical phenotypes including malignancies (except skin malignancies) were tabulated. Characteristics of patients with skin involvement (excluding mechanic’s hands and Raynaud’s phenomenon) were compared using Fisher’s exact test with Bonferroni corrected p-values. Results Of 3,067 patients, 2,028 had autoantibody profiling results (66.1%), of which 783 (38.6%) were positive for at least one of the autoantibodies being considered. Five patients with dual autoantibody specificities were excluded. Of the remaining 778, 320 (41.1%) were classified as DM, and 458 (58.9%) as ASS. Median age at diagnosis was 48.2 years (interquartile range [IQR] 37.5 to 57.8) in the DM cohort and 49 (IQR 38.3 to 62.2) in the ASS cohort. Skin involvement was present in 277 (86.6%) DM patients (DM skin) vs 204 (44.5%) ASS patients (ASS skin) (pcorr<0.01) (Table 1). Whilst relatively high proportions of so-called “DM-specific” rashes were seen in ASS skin, the frequency of heliotrope rash, Gottron’s papules, violaceous rash, periorbital rash, V-sign, shawl sign, and periungual erythema was significantly higher in DM skin (pcorr<0.01 for all). Conversely, mechanic’s hands, Raynaud’s, arthritis, and interstitial lung disease were more frequent in ASS skin (pcorr<0.01 for all). Malignancy was less frequent in ASS skin vs DM skin (pcorr<0.01) and occurred temporally closer to myositis diagnosis in DM skin (median 0.95 months [IQR -6.54. to 19.45]) vs ASS skin (median 12.17 months [IQR -15.85 to 79.31]). Conclusion Patients with ASS have frequent skin involvement but also a distinct clinical phenotype compared to DM. These findings may inform the development of future classification criteria for ASS. Disclosure R.M. Hum: None. J.B. Lilleker: None. J.A. Lamb: None. W.E. Ollier: None. G. Wang: None. L.R. Wedderburn: None. L.P. Diederichsen: None. J. Schmidt: None. P. Oakley: None. O. Benveniste: None. M.G. Danieli: None. K. Danko: None. N.T.P. Thuy: None. M.V.D. Mercado: None. H. Andersson: None. B.D. Paepe: None. J.L.D. Bleecker: None. B. Maurer: None. L.J. McCann: None. N. Pipitone: None. N. McHugh: None. P. New: None. J. Vencovsky: None. I.E. Lundberg: None. H. Chinoy: None.

Abstract Background Cardiac involvement in patients with idiopathic inflammatory myopathies (IIM) is associated with increased morbidity and mortality risk; however, little is known about the progression of cardiac dysfunction and long-term data are scarce. In the present work, we intended to prospectively study echocardiographic parameters in patients with IIM for 2 years. Methods Twenty-eight IIM patients (41.9±1.6 years) without cardiovascular symptoms were enrolled. Patients with monophasic/polyphasic disease patterns were studied separately and compared to age-matched healthy individuals. Conventional echocardiographic and tissue Doppler imaging (TDI) parameters of systolic [LV: ejection fraction (EF), mitral annulus systolic movement (MAPSE), lateral s′) and diastolic left (mitral inflow velocities, lateral anulus velocities: e′, a′, E/e′) and right ventricular function (fractional area change: FAC, tricuspid annulus plane systolic excursion: TAPSE) were measured at the time of the diagnosis and 2 years later. Results Subclinical LV systolic dysfunction is characterized by reduced lateral s′ (10.4 vs. 6.4 cm/s, p<0.05), EF (62.6±0.6%, vs. 51.7±0.7%) and MAPSE (18.5±0.6 vs. 14.5±0.6 mm) could be observed in IIM patients with polyphasic disease course 2 years after diagnosis compared to controls. Furthermore, diastolic LV function showed a marked deterioration to grade I diastolic dysfunction at 2 years in the polyphasic group (lateral e′: 12.9 ±0.6, vs. 7.4±0.3 cm/s; lateral a′: 10.7±0.3, vs. 17.3±0.8 cm/s; p<0.05) supported by larger left atrium (32.1±0.6 vs. 37.8±0.6 mm; p<0.05]. TDI measurements confirmed subclinical RV systolic dysfunction in polyphasic patients 2 years after diagnosis (FAC: 45.6±1.8%, vs. 32.7±1.4%; TAPSE: 22.7±0.5, vs. 18.1±0.3 mm; p<0.05). Similar, but not significant tendencies could be detected in patients with monophasic disease patterns. Polyphasic patients showed significantly (p<0.05) worse results compared to monophasic patients regarding EF (51.7±0.7% vs. 58.1±0.6%), lateral s′ (6.4±0.4 cm/sec vs. 8.6±0.4 cm/s,), left atrium (37.8±0.6 mm vs. 33.3±0.8 mm), FAC (32.7±1.4% vs. 41.0±1.6%) and TAPSE (18.1±0.3 mm vs. 21.3±0.7 mm). Conclusions Significant subclinical cardiac dysfunction could be detected in IIM patients with polyphasic disease course 2 years after diagnosis, which identifies them as a high-risk population. TDI is a useful method to detect echocardiographic abnormalities in IIM complementing conventional echocardiography and can recognize the high cardiac risk.

Overlap myositis is a distinct subgroup of idiopathic inflammatory myositis (IIM) with various clinical phenotypes. The aim of this study was to determine the clinical, serological, and genetic features of systemic sclerosis (SSc)-IIM overlap patients. It was a retrospective study using clinical database of 39 patients, fulfilling both the criteria of SSc and IIM. 56.4% of the patients had limited cutaneous, 43.6% had diffuse cutaneous SSc, whereas 7.7% of the patients had dermatomyositis and 92.3% polymyositis. The two diseases occurred simultaneously in 58.97%, while 10.26% in myositis and 30.77% in scleroderma were initially diagnosed. The frequencies of organ involvement were interstitial lung disease 71.8%, dysphagia 66.7%, cardiac involvement 41%, pulmonary arterial hypertension (PAH) 30.8%, and renal involvement 12.8%, respectively. The presence of human leukocyte antigen (HLA) − DRB1∗03 and DQA1∗051∗01 alleles were significantly higher in the overlap patients than in healthy controls (82.35% vs. 27.54%; p < 0.0001 and 88.24% vs. 30.16; p < 0.0001). Certain clinical parameters, such as fever at diagnosis (41.67% vs. 7.41%, p = 0.0046), cardiac involvement (83.33% vs. 22.22%, p = 0.0008), subcutaneous calcinosis (41.66 vs. 11.11, p = 0.01146), and claw hand deformity (25% vs. 11.11%, p = 0.00016) were significantly associated with the presence of PAH. Upon comparison, the overlap patients and anti-Jo-1 positive antisynthetase patients showed similarities in terms of genetic results and major clinical features; however, SSc-IIM overlap patients could be distinguished with higher erythrocyte sedimentation rate (ESR) level, more frequent presence of Raynaud's phenomenon (p < 0.0001; OR: 20.00), dysphagia (p < 0.0001; OR: 15.63), and infrequent livedo reticularis (p < 0.01; OR: 0.11). SSc-IIM overlap myositis is a unique group within IIM-s possessing characteristic clinical features.

Oncorheumatology is the meeting point of tumour formation and rheumatic diseases. Multiple interactions exist between these two medical specialties. One major field is the topic of malignancies associated with rheumatic diseases, while the other topic covers the development of musculoskeletal disease in cancer patients. In the first group, secondary malignancies associated with rheumatic diseases, role of tumour-associated antigens in rheumatology, the possible carcinogenicity of conventional and targeted antirheumatic drugs and physical therapy of rheumatic patients with recent or current cancer will be discussed. The second large topic includes paraneoplastic syndromes, autoimmune-rheumatic side effects of oncotherapies (chemotherapy and immunotherapy), effects of hormone-deprivation therapies on bone and primary and secondary malignancies of the musculoskeletal system. Orv Hetil. 2020; 161(28): 1151-1165.

Heme released from red blood cells targets a number of cell components including the cytoskeleton. The purpose of the present study was to determine the impact of free heme (20–300 µM) on human skeletal muscle fibres made available during orthopedic surgery. Isometric force production and oxidative protein modifications were monitored in permeabilized skeletal muscle fibre segments. A single heme exposure (20 µM) to muscle fibres decreased Ca2+-activated maximal (active) force (Fo) by about 50% and evoked an approximately 3-fold increase in Ca2+-independent (passive) force (Fpassive). Oxidation of sulfhydryl (SH) groups was detected in structural proteins (e.g., nebulin, α-actinin, meromyosin 2) and in contractile proteins (e.g., myosin heavy chain and myosin-binding protein C) as well as in titin in the presence of 300 µM heme. This SH oxidation was not reversed by dithiothreitol (50 mM). Sulfenic acid (SOH) formation was also detected in the structural proteins (nebulin, α-actinin, meromyosin). Heme effects on SH oxidation and SOH formation were prevented by hemopexin (Hpx) and α1-microglobulin (A1M). These data suggest that free heme has a significant impact on human skeletal muscle fibres, whereby oxidative alterations in structural and contractile proteins limit contractile function. This may explain and or contribute to the weakness and increase of skeletal muscle stiffness in chronic heart failure, rhabdomyolysis, and other hemolytic diseases. Therefore, therapeutic use of Hpx and A1M supplementation might be effective in preventing heme-induced skeletal muscle alterations.

Objectives: To describe the prevalence and clinical associations of autoantibodies to a novel autoantigen, eukaryotic initiation factor 3 (eIF3), detected in idiopathic inflammatory myositis. Methods: Sera or plasma from 678 PM patients were analysed for autoantigen specificity by radio-labelled protein immunoprecipitation (IPP). Samples immunoprecipitating the same novel autoantigens were further analysed by indirect immunofluorescence and IPP using pre-depleted cell extracts. The autoantigen was identified through a combination of IPP and MALDI-TOF mass spectrometry, and confirmed using commercial antibodies and IPP-western blots. Additional samples from patients with DM (668), DM-overlap (80), PM-overlap (191), systemic sclerosis (150), systemic lupus erythematosus (200), Sjogren's syndrome (40), rheumatoid arthritis (50) and healthy controls (150) were serotyped by IPP as disease or healthy controls. Results: IPP revealed a novel pattern in three PM patients (0.44%) that was not found in disease-specific or healthy control sera. Indirect immunofluorescence demonstrated a fine cytoplasmic speckled pattern for all positive patients. Mass spectrometry analysis of the protein complex identified the target autoantigen as eIF3, a cytoplasmic complex with a role in the initiation of translation. Findings were confirmed by IPP-Western blotting. The three anti-eIF3-positive patients had no history of malignancy or interstitial lung disease, and had a favourable response to treatment. Conclusion: We report a novel autoantibody in 0.44% of PM patients directed against a cytoplasmic complex of proteins identified as eIF3. Although our findings need further confirmation, anti-eIF3 appears to correlate with a good prognosis and a favourable response to treatment.

Absztrakt: Az onkoreumatológia a daganatképződés és a reumatológiai kórképek kapcsolatát jelenti. Számos összefüggés van a két orvosi szakterület között. Ezek egy része a reumatológiai kórképben szenvedő betegben jelentkező daganatokat, a másik fele pedig a daganatos betegen fellépő mozgásszervi jelenségeket foglalja magában. Az előbbi csoport keretében a reumatológiai betegségekben jelentkező szekunder tumorokat, a tumorasszociált antigének reumatológiai szerepét, a mozgásszervi betegségek kezelésére használt hagyományos és célzott terápiák esetleges onkogenitását és a korábban vagy jelenleg daganatos, mozgásszervi betegek fizioterápiáját tárgyaljuk. A másik nagy csoport magában foglalja a paraneoplasiás szindrómákat, az onkológiai kezelések (kemoterápia és immunterápia) lehetséges autoimmun-reumatológiai mellékhatásait, a hormondeprivatiós kezelés csonthatásait és a mozgásszervrendszer primer és szekunder daganatait. Orv Hetil. 2020; 161(28): 1151–1165.

Oncorheumatology: relationship between malignancies and musculoskeletal diseases: Oncorheumatology is the meeting point of tumor formation and rheumatic musculoskeletal diseases (RMD). Multiple interactions exist between these two medical specialties. One major field is the topic of malignancies associated with rheumatic diseases, while the other topic covers the development of musculoskeletal disease in cancer patients. Within the first group, secondary malignancies may be associated with rheumatic diseases. Mostly sustained inflammation is responsible for transition into cancer. Tumor-associated antigens (TAA) with adhesive properties are present on tumor cells. These molecules may also be expressed by inflammatory leukocytes and soluble TAA levels may be elevated in RMDs. There has been continuous debate with respect to the possible carcinogenicity of conventional and targeted antirheumatic drugs. Very recent data from registries suggest that neither biologics, nor JAK inhibitors increase cancer risk in arthritis patients. The issue of physiotherapy in rheumatic patients with recent or current cancer has also been controversial. Some modalities, primarily exercise, may be safely applied to patients with RMD and cancer. The second large topic includes paraneoplastic syndromes. Musculoskeletal paraneoplasias are triggered by tumor-derived mediators. These syndromes are sometimes slightly different from the classical RMDs. Various chemotherapies may also be associated with autoimmune side effects. Recently, these immune-related complications have also been observed in cancer patients treated with immune-checkpoint inhibitors. Sex hormone-deprivation therapies, such as aromatase inhibitors and anti-androgens are widely used for the treatment of breast and prostate cancer, respectively. These compounds may induce bone loss and lead to osteoporosis. Finally, primary and secondary malignancies of the musculoskeletal system may also interest rheumatologists. In this review, the clinical, practical aspects of these eight pillars of oncorheumatology will be discussed.

Background: The prevalence of osteoporosis and risk of fractures is elevated in rheumatoid arthritis, but we have little information about the bone mineral density and fracture risk in patients with inflammatory myopathies. We intended to ascertain and compare fracture risk, bone mineral density (BMD) and the prevalence of vertebral fractures in patients with inflammatory myositis and rheumatoid arthritis (RA) and to assess the effect of prevalent fractures on the quality of life and functional capacity. Methods: Fifty-two patients with myositis and 43 patients with rheumatoid arthritis were included in the study. Fracture Risk was determined using FRAX® Calculation Tool developed by the University of Sheffield. Dual energy X-ray absorptiometry and bidirectional thoracolumbar radiographs were performed to assess BMD and vertebral fractures. Quality of life was measured with Short Form-36 (SF-36) and physical function assessment was performed using Health Assessment Questionnaire (HAQ). Results: We found a significantly elevated fracture risk in RA compared to myositis patients if the risk assessment was performed without the application of the BMD results. If BMD results and glucocorticoid dose adjustment were taken into account, the differences in fracture risk were no longer significant. The prevalence of osteoporosis was found to be significantly higher in the myositis group (7% vs. 13.5%, p: 0,045), but the fracture prevalence was similar in the two groups (75% vs. 68%). The fractures rates were associated with age in both groups, but not with cumulative dose of steroid and BMD results correlated with fracture prevalence only in the RA patients. The number of prevalent fractures was significantly correlated to poorer physical function in both groups, and poorer health status in the myositis group, but not in the RA group. Conclusions: Our findings suggest that inflammatory myopathies carry significantly elevated risk for osteoporosis and fractures. This higher risk is comparable to one detected with RA in studies and strongly affects the physical function and quality of life of patients. Therefore further efforts are required to make the fracture risk assessment reliable and to facilitate the use early preventive treatments.

AIM:To evaluate detailed anterior segment parameters of patients with idiopathic inflammatory myopathies（IIM）,including polymyositis（PM）,and dermatomyositis（DM）,and to clarify the associations between these data and clinical variables of IIM.METHODS:Totally 57 PM,41 DM patients and 62 controls were enrolled in this cross-sectional,observational,case-control study.All study participants underwent Pentacam evaluation.Laboratory investigations consisted of different antibody assays,while extramuscular clinical assessments included Raynaud’s phenomenon,dysphagia,interstitial lung disease,arthritis/arthralgia,and weight loss.Objective signs and subjective symptoms of dry eye disease（DED） were also evaluated.RESULTS:All pachymetric parameters [center,apex,thinnest and maximal keratometry(K max )] and corneal volume（CV） of both sides of PM patients proved to be significantly lower.Some pachymetric data were also noticed as significantly decreased compared to those of controls.Several significant differences were traced between anterior segment values and extramuscular manifestations of myositis,largely in case of arthritis/arthralgia and weight loss,whereas associations between anterior segment parameters and antibodies were weak.Objective clinical tests of DED were also significantly decreased in IIM patients.CONCLUSION:The results suggest that all IIM patients have thinner corneas compared with those of controls,and decreased corneal parameters are significantly associated with the occurrence of some extramuscular manifestations.In addition,IIM patients tend to develop objective signs of DED.

To the Editor: Dermatomyositis (DM) is a rare inflammatory disease of muscle and skin. DM severity is thought to be driven, in part, by type I interferon signaling.1 Because interferon is primarily induced by toll-like receptors (TLRs) 7/9, we hypothesized that antagonizing TLR7/9 could improve DM disease activity.2,3

Background Pruritus is a common symptom in systemic autoimmune diseases like dermatomyositis (DM). Recent researches have indicated that interleukin-31 (IL-31), IL-33, IL-6, or inflammatory cytokines, such as tumor necrosis factor (TNFα), peroxisome proliferator-activated receptor γ (PPARγ) and ion channels belonging to the transient receptor potential (TRP) family are involved in pruriception. Objectives We examined targeted gene expression analysis of lesional versus non-lesional skin samples of patients affected with active DM. We looked for correlations between the examined pruriceptive signaling molecules, disease activity and itching sensation of DM patients. Methods Gene expression of TNFα, PPARγ, IL-33, IL-6 and TRPV channels in lesional DM skin was evaluated by RT-qPCR and was compared with non-lesional DM skin samples. Pruritus and disease activity of DM was evaluated by the 5-d itch scale and Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI), respectively. Statistical analysis was performed with IBM SPSS 20.0 software. Results Skin samples of 17 active DM patients were analyzed. We could show, that itching index in DM was positively correlated with CDASI score with a correlation coefficient of 0.82 (p<0.001). TNFα gene expression was significantly higher (34.87%) in lesional DM skin than non-lesional DM skin (p=0.03). The normalized TNFα mRNA expression was positively correlated with itch scale (R= 0.605, p=0.022) and its level was significantly higher in skin samples of patients with severe itch (itching score: 15-20) versus mild itch (itching score: 5-10) (2.02±0.38 vs. 1.12±0.20; p<0.01). The level of PPARγ was decreased in lesional DM skin, but this was statistically not significant. The mRNA expression of normalized PPARγ was negatively correlated with itch scale (R= -0.618, p=0.019), and its level was significantly lower in skin samples of patients with severe itch versus mild itch (0.28±0.36 vs. 1.53±0.98; p=0.038). Lesional IL-6 mRNA levels were associated with CDASI activity score (R=0.619, p=0.018). The mRNA levels of TRPV1-4 channels were not associated with 5-D itch score, but normalized TRPV1 and TRPV4 mRNA expressions were positively correlated with CDASI damage score (R=0.699, p=0.008; R=0.789, p=0.001). Interestingly, itching sensation of DM patients was not correlated with IL-33 mRNA levels measured in skin samples. Conclusion Our results argue for that higher cutaneous disease activity generate pruritus. TNFα and PPARγ might play a determining, but opposite role in DM-associated itch. Furthermore IL-6, TRPV1 and TRPV4 channels might participate in pathomechanism of cutaneous manifestation of the disease. Disclosure of Interests:

MicroRNA (miRNA) research has intensively developed over the past decade. Characterization of dysregulated miRNA expression profiles could give a better understanding of the development of pathological conditions and clinical disorders, such as autoimmune diseases with polygenic etiology, including idiopathic inflammatory myopathies (IIMs). IIMs are a group of rare autoimmune disorders characterized by skeletal weakness and inflammation. Polymyositis (PM) is one of the conditions of autoimmune myopathies with proximal skeletal muscle weakness. A novel group of miRNAs, known as myomiRs are described as striated muscle-specific or muscle-enriched miRNAs. They are involved in myoblast proliferation/differentiation as well as muscle regeneration. To determine the role of myomiRs in the development and progression of PM, we performed an initial skeletal muscle miRNA profiling using microarray technique at diagnosis. The aim of the study was to examine myomiRs expression profile in patients with PM in order to remark the association between the dysregulated myomiRs' expression and the development of the disease. As a results of microarray investigation, most of the myomiRs showed altered expression patterns in the muscle samples of PM patients compared to controls. These results suggest that myomiRs, especially miR-1, miR-133a, miR-208b, miR-486, and miR-499 function in a network, and are associated with the development of PM.

Background: Dermatomyositis (DM) is an inflammatory disease of skin and muscle. Increased interferon (IFN) signaling is a prominent feature of DM, but the mechanisms leading to IFN production in DM are not understood. As toll-like receptor (TLR) 7/8/9 activation can lead to type I IFN production, TLR7/8/9 antagonism may provide therapeutic benefit in DM. Methods: A double-blind, randomized, placebo-controlled, 24-week trial of IMO-8400 [a novel oligonucleotide TLR7/8/9 antagonist (Idera Pharmaceuticals, Inc.)] was conducted with 30 participants meeting definite or probable criteria of Bohan and Peter for DM. Participants were randomized to treatment with IMO-8400 0.6 mg/kg, IMO-8400 1.8 mg/kg, or placebo. The primary endpoint was the change in the Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI) activity score. Exploratory analysis included type I IFN signaling and the 5-D Itch Scale. Blood and skin samples were obtained at baseline and end of treatment to measure changes in type I IFN signaling. Results: CDASI activity scores decreased in all arms by the end of the trial, per repeated measures mixed model analysis: −9.3 in 0.6 mg/kg, −8.8 in 1.8 mg/kg, and −7.3 in placebo. We observed no change in skin and blood type I IFN signature scores or CDASI activity scores across treatment arms. We found an association between CDASI and skin IFN signature scores (β=12.9, P=0.0002), an association between 5-D Itch Scale and skin IFN signature scores (Rho =0.65, P<0.0001), a lack of association between 5-D Itch Scale and blood IFN signature scores (Rho =0.22, P=0.24), and a positive trend that did not reach significance between CDASI and 5-D Itch Scale scores. Five patients experienced treatment-emergent adverse effects prompting discontinuation: 3 in low-dose (abdominal discomfort/flu, anxiety, urticaria), 1 in high-dose (thrombocytopenia), and 1 in placebo (muscle weakness). Conclusions: IMO-8400 did not significantly reduce DM disease activity or type I IFN expression. Our study demonstrates that cutaneous DM disease activity may be better studied through skin biopsies, rather than peripheral blood draws, and that type I IFN signaling could be a potential target in improving pruritus in DM patients.

OBJECTIVES:Idiopathic inflammatory myopathies (IIM) are a spectrum of rare autoimmune diseases characterised clinically by muscle weakness and heterogeneous systemic organ involvement. The strongest genetic risk is within the major histocompatibility complex (MHC). Since autoantibody presence defines specific clinical subgroups of IIM, we aimed to correlate serotype and genotype, to identify novel risk variants in the MHC region that co-occur with IIM autoantibodies. METHODS:We collected available autoantibody data in our cohort of 2582 Caucasian patients with IIM. High resolution human leucocyte antigen (HLA) alleles and corresponding amino acid sequences were imputed using SNP2HLA from existing genotyping data and tested for association with 12 autoantibody subgroups. RESULTS:We report associations with eight autoantibodies reaching our study-wide significance level of p<2.9×10-5. Associations with the 8.1 ancestral haplotype were found with anti-Jo-1 (HLA-B*08:01, p=2.28×10-53 and HLA-DRB1*03:01, p=3.25×10-9), anti-PM/Scl (HLA-DQB1*02:01, p=1.47×10-26) and anti-cN1A autoantibodies (HLA-DRB1*03:01, p=1.40×10-11). Associations independent of this haplotype were found with anti-Mi-2 (HLA-DRB1*07:01, p=4.92×10-13) and anti-HMGCR autoantibodies (HLA-DRB1*11, p=5.09×10-6). Amino acid positions may be more strongly associated than classical HLA associations; for example with anti-Jo-1 autoantibodies and position 74 of HLA-DRB1 (p=3.47×10-64) and position 9 of HLA-B (p=7.03×10-11). We report novel genetic associations with HLA-DQB1 anti-TIF1 autoantibodies and identify haplotypes that may differ between adult-onset and juvenile-onset patients with these autoantibodies. CONCLUSIONS:These findings provide new insights regarding the functional consequences of genetic polymorphisms within the MHC. As autoantibodies in IIM correlate with specific clinical features of disease, understanding genetic risk underlying development of autoantibody profiles has implications for future research.

OBJECTIVE:Immune-mediated inflammatory diseases (IMIDs) are heterogeneous and complex conditions with overlapping clinical symptoms and elevated familial aggregation, which suggests the existence of a shared genetic component. In order to identify this genetic background in a systematic fashion, we performed the first cross-disease genome-wide meta-analysis in systemic seropositive rheumatic diseases, namely, systemic sclerosis, systemic lupus erythematosus, rheumatoid arthritis and idiopathic inflammatory myopathies. METHODS:We meta-analysed ~6.5 million single nucleotide polymorphisms in 11 678 cases and 19 704 non-affected controls of European descent populations. The functional roles of the associated variants were interrogated using publicly available databases. RESULTS:Our analysis revealed five shared genome-wide significant independent loci that had not been previously associated with these diseases: NAB1, KPNA4-ARL14, DGQK, LIMK1 and PRR12. All of these loci are related with immune processes such as interferon and epidermal growth factor signalling, response to methotrexate, cytoskeleton dynamics and coagulation cascade. Remarkably, several of the associated loci are known key players in autoimmunity, which supports the validity of our results. All the associated variants showed significant functional enrichment in DNase hypersensitivity sites, chromatin states and histone marks in relevant immune cells, including shared expression quantitative trait loci. Additionally, our results were significantly enriched in drugs that are being tested for the treatment of the diseases under study. CONCLUSIONS:We have identified shared new risk loci with functional value across diseases and pinpoint new potential candidate loci that could be further investigated. Our results highlight the potential of drug repositioning among related systemic seropositive rheumatic IMIDs.