From data to diagnosis: how machine learning is revolutionizing biomarker discovery in idiopathic inflammatory myopathies.

Idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of muscle disorders including adult and juvenile dermatomyositis, polymyositis, immune-mediated necrotising myopathy and sporadic inclusion body myositis, all of which present with variable symptoms and disease progression. The identification of effective biomarkers for IIMs has been challenging due to the heterogeneity between IIMs and within IIM subgroups, but recent advances in machine learning (ML) techniques have shown promises in identifying novel biomarkers. This paper reviews recent studies on potential biomarkers for IIM and evaluates their clinical utility. We also explore how data analytic tools and ML algorithms have been used to identify biomarkers, highlighting their potential to advance our understanding and diagnosis of IIM and improve patient outcomes. Overall, ML techniques have great potential to revolutionize biomarker discovery in IIMs and lead to more effective diagnosis and treatment.

In-depth proteomic analysis of juvenile dermatomyositis serum reveals protein expression associated with muscle-specific autoantibodies.

OBJECTIVES: The clinical symptoms and complications of JDM differ depending on the type of muscle-specific autoantibodies (MSAs) present. We aimed to identify protein expression profiles specific for MSAs that characterize various clinical features by comprehensively analyzing the proteins present in the serum of patients with JDM. METHODS: We analysed sera from patients with JDM that were positive for anti-melanoma differentiation-associated protein 5 (MDA5) antibodies (n = 5), anti-nuclear matrix protein 2 (NXP2) antibodies (n = 5) and anti-transcriptional intermediary factor 1 alpha or gamma subunit (TIF1-γ) antibodies (n = 5), and evaluated healthy controls (n = 5) via single-shot liquid chromatography-tandem mass spectrometry (MS) in data-independent acquisition mode, which is superior for comparative quantitative analysis. We identified different protein groups based on MSAs and performed pathway analysis to understand their characteristics. RESULTS: We detected 2413 proteins from serum MS analysis; 508 proteins were commonly altered in MSAs, including many myogenic enzymes and IFN-regulated proteins. Pathway analysis using the top 50 proteins that were upregulated in each MSA group revealed that the type I IFN and proteasome pathways were significantly upregulated in the anti-MDA5 antibody group alone. CONCLUSION: Although JDM serum contains many proteins commonly altered in MSAs, the pathways associated with clinical features of MSAs differ based on protein accumulation. In-depth serum protein profiles associated with MSAs may be useful for developing therapeutic target molecules and biomarkers.

[Dermatomyositis and juvenile dermatomyositis]. / Dermatomyositis und juvenile Dermatomyositis.

Dermatomyositis (DM) is an inflammatory multisystem disease of unknown etiology, which can already occur in children but first onset can also be in older adulthood. Myalgia and muscle weakness can occur later in the course of the disease or even be completely absent in some forms. Classical signs on the skin include heliotrope rash, facial erythema, Gottron's papules and nailfold capillary abnormalities. For the diagnosis, screening for the presence of myositis-specific autoantibodies has become increasingly more relevant. Muscle enzymes may be elevated but not in approximately one third of patients. In the absence of typical clinical or serologic findings, additional examination methods such as nailfold capillaroscopy, magnetic resonance imaging, electromyography, skin or muscle biopsies may help to establish the diagnosis. Depending on the clinical and serological subtype, additional screening for gastrointestinal or cardiopulmonary involvement should be considered. In adults, an age-appropriate tumor screening should also be performed. Apart from corticosteroids as induction therapy, biologics and small molecule inhibitors are gaining in importance in addition to conventional disease-modifying anti-rheumatic drugs and intravenous immunoglobulins. The prognosis for DM and juvenile DM (JDM) has improved. Most patients recover at least to some extent; however, a few patients die and a minority develop persisting muscle atrophy or severe calcinosis.

Thigh MRI in antisynthetase syndrome, and comparisons with dermatomyositis and immune-mediated necrotizing myopathy.

OBJECTIVES: To evaluate MRI changes to define muscle-lesion specific patterns in patients with antisynthetase syndrome (ASS), and compare them with those in other common idiopathic inflammatory myopathy subtypes. METHODS: Qualitative and semi-quantitative thigh MRI evaluations were conducted in patients with ASS, DM and immune-mediated necrotizing myopathy (IMNM). RESULTS: This study included 51 patients with ASS, 56 with DM and 61 with IMNM. Thigh MRI revealed muscle oedema (62.7%), myofascial oedema (90.2%), subcutaneous-tissue oedema (60.8%) and fatty infiltration of muscles (68.6%) in patients with ASS. Compared with IMNM, ASS and DM were associated with more frequent adductor-muscle relative sparing (40.6% vs 3.6%, P<0.001, and 25.6% vs 3.6%, P<0.001) and subcutaneous-tissue oedema (60.8% vs 23.0%, P<0.001, and 57.1% vs 23.0%, P<0.001). Although ASS and DM exhibited similar oedema patterns, there were certain subtle differences between them. The ASS group was less frequently symmetric (60.6% vs 88.4%, P=0.005, and 60.6% vs 80.0%, P=0.048), but more frequently showed myofascial oedema of the tensor fasciae latae (80.4% vs 48.2%, P<0.001, and 80.4% vs 31.1%, P<0.001) than either the DM or IMNM groups. The receiver operating characteristic curve analysis showed an optimal combination of thigh MRI findings had an area under the curve with 0.893 for diagnosing ASS. CONCLUSION: Thigh MRI in ASS exhibited frequent myofascial oedema. ASS oedema patterns resembled those of DM more than those of IMNM. Bilateral asymmetry, adductor-muscle relative sparing and remarkable myofascial oedema of tensor fasciae latae were the most characteristic ASS imaging findings.

Autoantibodies against four-and-a-half-LIM domain 1 (FHL1) in inflammatory myopathies: results from an Australian single-centre cohort.

OBJECTIVES: To determine the prevalence and associations of autoantibodies targeting a muscle-specific autoantigen, four-and-a-half-LIM-domain 1 (FHL1), in South Australian patients with histologically-confirmed idiopathic inflammatory myopathies (IIM) and in patients with SSc. MATERIAL AND METHODS: Sera from patients with IIM (n = 267) from the South Australian Myositis Database (SAMD), SSc (n = 174) from the Australian Scleroderma Cohort Study (ASCS) and healthy controls (HC, n = 100) were analysed for anti-FHL1 autoantibodies by Enzyme-Linked ImmunoSorbent Assay (ELISA). RESULTS: Autoantibodies to FHL1 were more frequent in patients with IIM (37/267, 13.8%) compared with SSc (12/174, 7%) (P < 0.02) and HC (2/100, 2%) (P < 0.001). The most common IIM subtypes among FHL1+ IIM patients were (32%) and IBM (2/37, 32%). No statistically significant differences in muscular or extra-muscular manifestations of IIM were found when comparing patients who were anti-FHL1+ with their anti-FHL1- counterparts. In 29/37 (78%) anti-FHL1+ patients, no myositis-specific autoantibodies (MSA) were present. In FHL1+ muscle biopsies, there was less frequent infiltration by CD45+ cells (P = 0.04). There was a trend for HLA alleles DRB1*07 and DRB1*15 to be more frequent in anti-FHL1+ compared with anti-FHL1- patients (9/25 vs 19/113, P = 0.09 and 8/25 vs 15/114, P = 0.09, respectively). CONCLUSIONS: We report a substantial prevalence (13.8%) of anti-FHL1 autoantibodies in a large cohort of patients with histologically confirmed IIM; 75% of these cases did not have a detectable myositis-specific autoantibody. Anti-FHL1 autoantibodies were also detected in a subgroup of patients with SSc (7%), indicating that anti-FHL1 autoantibodies may not be myositis-specific. The trend towards an HLA-DR association might indicate a specific immune response to the FHL1 protein.

Association of various myositis-specific autoantibodies with dermatomyositis and polymyositis triggered by pregnancy.

Although pregnancy is an important risk factor for autoimmune rheumatic diseases, little is known regarding the association between pregnancy and dermatomyositis (DM) or polymyositis (PM). Herein, we present two patients with DM that developed during the perinatal period. The first patient was positive for anti-aminoacyl synthetase (ARS) antibody and developed DM in the 14th week of pregnancy. Despite treatment, her foetus died of intrauterine growth restriction in the 27th week. The second patient was positive for anti-melanoma differentiation-associated gene 5 (MDA-5) antibody and developed DM 1 week after miscarriage at 9 weeks of gestation. The patient developed severe interstitial pneumonia, and intensive therapy including tofacitinib and rituximab administration was required. Our cases and a literature review revealed that various myositis-specific autoantibodies, including anti-ARS, anti-Mi-2, anti-TIF-1γ, and anti-MDA-5, are associated with DM and PM triggered by pregnancy. We also found that delay in commencing treatment in case of active disease including myositis and interstitial pneumonia, and poor response to corticosteroids were related to poor foetal outcomes in DM and PM. Although rare in pregnant women, it is critical to consider the possibility of DM and PM in patients presenting with rash, fever, weakness, and cough, and testing for myositis-specific autoantibodies is recommended.

The associations between myositis autoantibodies and clinical presentations in dermatomyositis.

BACKGROUND: The myositis autoantibodies have been widely used clinically in recent years for the identification of an autoantibody-associated clinical phenotype in dermatomyositis (DM) patients. However, correlations between myositis autoantibodies and clinical presentations in different populations are lacking, especially in Taiwan. OBJECTIVES: To investigate the correlations among cutaneous manifestations, myositis autoantibodies, and systemic diseases, including interstitial lung disease (ILD) and internal malignancy. METHODS: A retrospective study of patients with histopathologically confirmed cutaneous manifestations of DM was conducted during 2005 to 2020 in Taiwan. A commercial line blot immunoassay technique was used to detect myositis autoantibodies. RESULTS: A total of 88 DM patients were enrolled, with a mean age of onset of 49.4 years old. The most common systemic features were myositis (56.8%, 50/88), internal malignancy (22.7%, 20/88), dysphagia (19.3%, 17/88), and ILD (17%, 15/88). Among the enrolled patients, 32 patients received serum myositis autoantibodies examination. The most common autoantibodies were ANA (50.7%, 37/73), followed by anti-TIF1-γ (34.4%, 11/32) and anti-MDA5 (31.3%, 10/32) antibodies. Patients with Gottron sign (OR 5.6), arthritis (OR 23.35), or the presence of anti-MDA5 antibody (OR 11.14) were more susceptible to progressing to ILD, whereas patients with pruritus (OR 1.04), dysphagia (OR 6.73), and the presence of ANA (OR 6.29) had significantly higher risks of developing internal malignancies. CONCLUSIONS: Physicians should pay special attention to certain clinical features, which can help with the early detection of systemic diseases. Cancer screening and myositis autoantibodies examination should be conducted in all DM patients if applicable.

[Clinical analysis of 5 cases of dermatomyositis complicated with macrophage activation syndrome].

To investigate the clinical and immunological features of dermatomyositis (DM) complicated with macrophage activation syndrome (MAS). The demographic and clinical characteristics of five patients diagnosed with DM complicated with MAS hospitalized in the Department of Rheumatology and Immunology, Peking University People ' s Hospital from 2011 to 2021 were collected. The results of clinical manifestations, laboratory tests, immunological features, treatments and prognosis were analyzed and summarized. In this study, five female patients in Peking University People's Hospital with an average age of 63.8 (44.0-83.0) years and an average disease duration of 16.1 (1.5-48.0) months. All the patients had typical DM rash (such as heliotrope sign, V/shawl sign or Gottron's sign/papules). They all had muscle involvement (including myalgia or muscle weakness). Two patients had positive myositis-specific antibodies (MSAs), in which case 1 had anti-TIF1-γ antibody and case 5 had anti-NXP-2 antibody. Four patients had interstitial lung disease except case 3. All of the cases developed MAS in the active stage of DM. Common manifestations of MAS in these five patients included high-grade fever, cytopenia, decreased fibrinogen, elevated ferritin and increased soluble CD25. Case 1 presented with neutropenia (0.6×109 /L), thrombocytopenia (26.0×109 /L), hypofibrinogenemia (0.9 g/L), markedly elevated ferritin (26 331.0 µg/L), decreased NK cell activity. Case 2 had anaemia (hemoglobin 81.0 g/L), thrombocytopenia (55.0×109 /L), hypertriglyceridemia (4.7 mmol/L), hypofibrinogenemia (1.2 g/L), elevated ferritin (>100 000.0 µg/L), hemophagocytosis in bone marrow. Case 3 had anaemia (hemoglobin 88 g/L), decreased fibrinogen (1.9 g/L), increased ferritin (>27 759.0 µg/L), splenomegaly, hemophagocytosis in bone marrow. Case 4 suffered from neutropenia(0.3×109 /L), anaemia(hemoglobin 78 g/L), hypertriglyceridemia (4.2 mmol/L), hypofibrinogenemia (0.9 g/L), increased ferritin (>100 000.0 µg/L), and decreased NK cell activity. Case 5 presented anaemia (hemoglobin 60.0 g/L), thrombocytopenia (67.0×109 /L), hypertriglyceridemia (12.7 mmol/L), decreased fibrinogen (1.1 g/L), and elevated ferritin (>923.0 µg/L). All the patients were treated with methylprednisone pulse therapy (200-500 mg) combined with cyclosporine while case 5 received rituximab after methylprednisone pulses. In addition, case 3 also received the combination of mycophenolate mofetil. Case 1 was given etoposide while case 4 was treated with cyclophosphamide and repeated plasmapheresis at the same time. Moreover, intravenous immunoglobulin was added meantime apart from case 3. The condition of four patients improved significantly, nevertheless case 4 experienced recurred pulmonary symptoms and died of respiratory failure. As for complications about infection, case 2 had bacterial infection with high level procalcitonin (PCT) before MAS treatment and condition was improved after empiric antibacterial therapy. Case 3 had cytomegalovirus DNAemia before diagnosis of MAS and viral titer turned negative after ganciclovir therapy. After treatment of MAS, four patients developed cytomegalovirus DNAemia except case 3, in which case 5 was co-infected with bacteria. To sum, DM complicated with MAS is relatively rare, and its patients are of ten in life-threatening condition. Early detection, treatment and prevention of infection during treatment are critical to improve the prognosis.

Anti-MDA5 autoantibodies associated with juvenile dermatomyositis constitute a distinct phenotype in North America.

OBJECTIVE: Myositis-specific autoantibodies have defined distinct phenotypes of patients with juvenile myositis (JIIM). We assessed the frequency and clinical significance of anti-melanoma differentiation-associated gene 5 (MDA5) autoantibody-associated JIIM in a North American registry. METHODS: Retrospective examination of the characteristics of 35 JIIM patients with anti-MDA5 autoantibodies was performed, and differences from other myositis-specific autoantibody groups were evaluated. RESULTS: Anti-MDA5 autoantibodies were present in 35/453 (7.7%) of JIIM patients and associated with older age at diagnosis, and lower serum creatine kinase and aldolase levels. Patients with anti-MDA5 autoantibodies had more frequent weight loss, adenopathy, arthritis, interstitial lung disease (ILD), and less frequent falling compared with anti-transcriptional intermediary factor 1 (TIF1), anti-nuclear matrix protein 2 (NXP2) and myositis-specific autoantibody/myositis-associated autoantibody-negative patients. They had a different season of diagnosis and less frequent mechanic's hands and ILD compared with those with anti-synthetase autoantibodies. Anti-MDA5 patients received fewer medications compared with anti-TIF1, and corticosteroid treatment was shorter compared with anti-TIF1 and anti-nuclear matrix protein 2 autoantibody groups. The frequency of remission was higher in anti-MDA5 than anti-synthetase autoantibody-positive JIIM. In multivariable analyses, weight loss, arthritis and arthralgia were most strongly associated with anti-MDA5 autoantibody-positive JIIM. CONCLUSION: Anti-MDA5 JIIM is a distinct subset, with frequent arthritis, weight loss, adenopathy and less severe myositis, and is also associated with ILD. Anti-MDA5 is distinguished from anti-synthetase autoantibody-positive JIIM by less frequent ILD, lower creatine kinase levels and differing seasons of diagnosis. Anti-MDA5 has comparable outcomes, but with the ability to discontinue steroids more rapidly and less frequent flares compared with anti-TIF1 autoantibodies, and more frequent remission compared with anti-synthetase JIIM patients.

Predictive factors for sustained remission with stratification by myositis-specific autoantibodies in adult polymyositis/dermatomyositis.

OBJECTIVE: The aim of this study was to clarify predictive factors for sustained remission in adult patients with PM/DM, particularly focusing on stratification by myositis-specific autoantibodies (MSAs). METHODS: A total of 162 adult patients with PM/DM who were followed up for >1 year after diagnosis were retrospectively enrolled. MSAs were evaluated comprehensively in 102 patients whose sera were available. Sustained remission was defined as no evidence of disease activity (active skin rash, active myositis or active interstitial lung disease) for longer than a 6-month continuous period while undergoing myositis therapy or no medication. Clinical data were reviewed in patients' medical charts. RESULTS: The sustained remission rate for all patients was 58% during the median follow-up period at 4 years. With regard to MSAs, the achievement rate of sustained remission among MSA-negative patients was significantly higher than that for patients with anti-aminoacyl-tRNA synthetase (P = 0.004), anti-melanoma differentiation-associated gene 5 (P = 0.037) or anti-transcriptional intermediary factor 1-γ (P = 0.013) antibodies. MSA-negative status (odds ratio 5.84, P = 0.009) and absence of severe muscle weakness requiring assistance at diagnosis (odds ratio 43.6, P < 0.001) were independent factors associated with sustained remission in multivariate analysis. Cumulative remission rates were significantly higher (P < 0.001) in patients with both the MSA-negative status and absence of severe muscle weakness at diagnosis than the others. CONCLUSION: MSA-negative status and the absence of severe muscle weakness requiring assistance at diagnosis are independent predictive factors for sustained remission in adult PM/DM patients.

Double anti-PL-7 and anti-MDA-5 positive Amyopathic Dermatomyositis with rapidly progressive interstitial lung disease in a Hispanic patient.

BACKGROUND: Each myositis-specific autoantibody (MSA) tends to have a distinct clinical presentation. Coexistence of MSAs do not commonly occur. If they do, it is unknown if there is an overlap of clinical features or prognostic implications. There are a few reported cases of overlap between these antibodies, mostly reported in patients with Japanese descent. Our aim for this case report is to turn more attention and interest for future MSA profile studies in the Hispanic population, which may hopefully spur better therapies if we realize the prognostic implications of certain myositis subsets including double-positive autoantibody syndromes. CASE PRESENTATION: A 27-year-old Hispanic female was admitted to the medical intensive care unit due to acute hypoxemic respiratory failure secondary to acute respiratory distress syndrome (ARDS). She had failed conventional mechanical ventilation and was cannulated for venovenous extracorporeal membrane oxygenation (VV-ECMO) to manage her respiratory failure. She had erythematous scaly plaques on bilateral 3rd metacarpophalangeal joints on examination. Her autoimmune workup revealed positivity for both anti-PL-7(threonyl) and anti-melanoma differentiation-associated gene 5 (MDA5) autoantibodies. After extensive evaluation, it was concluded that she had rapidly progressive interstitial lung disease (RPILD) due to amyopathic dermatomyositis. Despite maximal medical management, she was ultimately transitioned to comfort care measures and expired. CONCLUSION: We would like to highlight the rarity of double antibody positive amyopathic dermatomyositis. This unique clinical presentation has only been reported in persons of Japanese descent. Our case is likely to be the first reported to occur in a person of Hispanic descent in the United States. The rarity of our case could stimulate further study of overlapping MSA to understand its varied presentations and prognoses including possible tendency toward a rapidly progressive ILD phenotype. Earlier detection of these clinical syndromes can lead to better outcomes for patients with RPILD. This case report could also herald an increased recognition and understanding of MSA profile in the Hispanic population in the USA.

Analysis of myositis autoantibodies in Chinese patients with cancer-associated myositis.

BACKGROUND: Cancer-associated myositis (CAM) has poor prognosis and causes higher mortality. In general, myositis-specific autoantibodies (MSAs) and myositis-associated autoantibodies (MAAs) have been shown to be useful biomarkers for its diagnosis. METHODS: In the present study, focus was given in assessing the presence, prevalence, and diagnostic values of myositis autoantibodies in Chinese patients diagnosed with CAM. The sera collected from 49 CAM patients, 108 dermatomyositis/polymyositis (DM/PM) patients without cancer, 105 disease controls, and 60 healthy controls were detected for the presence of 16 autoantigens (Jo-1, OJ, EJ, PL-7, PL-12, MDA5, TIF1γ, Mi-2α, Mi-2ß, SAE1, NXP2, SRP, Ku, PM-Scl75, PM-Scl100, and Ro-52) using a commercial Euroline assay. RESULTS: The frequency of anti-TIF1γ was significantly higher in CAM patients than in DM/PM patients without cancer (46.9% vs 14.8%, P < .001). Importantly, the sensitivity and specificity for this MSA were 46.9% and 85.2%, respectively. These helped to differentiate CAM patients from DM/PM patients without cancer. However, there was no difference in other MSAs and MAAs between CAM and DM/PM patients without cancer. CONCLUSION: The present study indicates that anti-TIF1γ levels can serve as important biomarkers for CAM diagnosis and help in distinguishing between CAM and DM/PM patients without cancer.

Clinical practice guidance for juvenile dermatomyositis (JDM) 2018-Update.

Juvenile dermatomyositis is the most common type of juvenile idiopathic inflammatory myopathy mainly affecting the skin and proximal muscles. We have published the Japanese version of 'Clinical practice guidance for juvenile dermatomyositis (JDM) 2018 'consisting of a review of articles in the field and evidence-informed consensus-based experts' opinion on the treatment strategy in collaboration with The Pediatric Rheumatology Association of Japan and The Japan College of Rheumatology under the financial support by 'Research on rare and intractable diseases, Health and Labor Sciences Research Grants'. This article is a digest version of the Japanese guidance.

Dermatomyositis Clinical and Pathological Phenotypes Associated with Myositis-Specific Autoantibodies.

PURPOSE OF REVIEW: Dermatomyositis is an idiopathic inflammatory myopathy with a variety of systemic and cutaneous manifestations. The myositis-specific autoantibodies (MSAs) are associated with phenotypic features and provide a tool for sub-classification of dermatomyositis patients. This review focuses on recent work characterizing the clinical features that accompany the MSAs in dermatomyositis. RECENT FINDINGS: There is increasing recognition of the distinct clinical and pathological phenotypes associated with each MSA. Most of these features display considerable overlap between MSA groups. Despite this, there are notable differences between the typical combinations of cutaneous and systemic manifestations, response to therapy, prognosis, and disease sequelae that define each dermatomyositis MSA group. The MSAs may ultimately improve diagnosis and sub-classification of dermatomyositis patients. However, more work is needed to understand the pathologic basis for much of the heterogeneity found within these subgroups.

A New Immunodot Assay for Multiplex Detection of Autoantibodies in a Cohort of Italian Patients With Idiopathic Inflammatory Myopathies.

BACKGROUND: Autoantibody detection has been assessed as tool for the diagnosis and the definition of idiopathic inflammatory myopathies (IIM). The aim of the study was to characterize the autoantibody profiling of a cohort of Italian patients with IIM. METHODS: Sera of 53 adult patients with definite IIM, according to Bohan-Peter criteria, were tested for anti-nuclear autoantibodies (ANA), using indirect immunofluorescence (IIF) method, and for myositis-specific autoantibodies (MSAs) and myositis-associated autoantibodies (MAAs), using two new commercial immunodot assays. RESULTS: MSAs and/or MAAs were detected in 29 of 53 (54.7%) patients with IIM. Twenty-three patients (43.4%) were positive for at least one MSAs: 13 (24.5%) had anti-histidyl-tRNA synthetase autoantibodies (Jo1), 4 (7.5%) had other anti-aminoacyl-tRNA synthetases autoantibodies (anti-ARS), 1 (1.8%) had anti-transcription intermediary factor 1 gamma autoantibodies (anti-TIF1γ), 2 (3.7%) had anti-nuclear helicase protein Mi-2 autoantibodies (anti-Mi-2), 4 (7.5%) had anti-small ubiquitin like modifier activating enzyme heterodimer autoantibodies (anti-SAE). Moreover, 17 patients (32%) were positive for at least one MAAs. Coexisting MSAs and MAAs were observed in 9 of 53 (16.9%) patients, anti-Jo1/SS-A autoantibodies in most cases. Overall sensitivity of immunodot assays was 54.7%, the specificity was almost absolute. At cut-off value of 1:160, the sensitivity of ANA-IIF was 52.8%, increasing to 66% if cytoplasmatic fluorescence reaction was reported. Notably, two (5.7%) ANA-IIF negative patients had MSAs, detected only by immunodot assays. CONCLUSION: It was possible to identify MSAs otherwise undetectable because of the use of new assays. Immunodot can reveal MSAs even when IIF results are inconclusive or, in some cases, ANA negative.

[New insights of myositis-specific and -associated autoantibodies in juvenile and adult type myositis]. / Újabb adatok a myositisspecifikus és -asszociált antitestekrol juvenilis és felnottkori myositisekben.

Myositis, which means inflammation of the muscles, is a general term used for inflammatory myopathies. Myositis is a rare idiopathic autoimmune disease. It is believed that environmental factors such as virus, bacteria, parasites, direct injuries, drugs side effect can trigger the immune system of genetically susceptible individuals to act against muscle tissues. There are several types of myositis with the same systemic symptoms such as muscle weakness, fatigue, muscle pain and inflammation. These include dermatomyositis, juvenile dermatomyositis, inclusion-body myositis, polymyositis, orbital myositis and myositis ossificans. Juvenile and adult dermatomyositis are chronic, immune-mediated inflammatory myopathies characterized by progressive proximal muscle weakness and typical skin symptoms. The aim of the authors was to compare the symptoms, laboratory and serological findings and disease course in children and adult patients with idiopathic inflammatory myopathy. Early diagnosis and aggressive immunosuppressive treatment improve the mortality of these patients. Myositis-specific autoantibodies have predictive and prognostic values regarding the associated overlap disease, response to treatment and disease course. The authors intend to lighten the clinical and pathogenetic significance of the new target autoantigens. Orv. Hetil., 2016, 157(29), 1179-1184.

An overview of polymyositis and dermatomyositis.

Polymyositis and dermatomyositis are inflammatory myopathies that differ in their clinical features, histopathology, response to treatment, and prognosis. Although their clinical pictures differ, they both present with symmetrical, proximal muscle weakness. Treatment relies mainly upon empirical use of corticosteroids and immunosuppressive agents. A deeper understanding of the molecular pathways that drive pathogenesis, careful phenotyping, and accurate disease classification will aid clinical research and development of more efficacious treatments. In this review we address the current knowledge of the epidemiology, clinical characteristics, diagnostic evaluation, classification, pathogenesis, treatment, and prognosis of polymyositis and dermatomyositis.