The mucocutaneous and systemic phenotype of dermatomyositis patients with antibodies to MDA5 (CADM-140): a retrospective study

Autoantibodies against TIF-1-γ and CADM-140 in Spanish patients with clinically amyopathic dermatomyositis (CADM): clinical significance and diagnostic utility

BACKGROUND

Patients with clinically amyopathic dermatomyositis (CADM) appear to be at risk for developing cancer and interstitial lung diseases, but population data to confirm this hypothesis are limited. Moreover, CADM presents cutaneous and histological findings that may overlap with subacute cutaneous lupus erythematosus (SCLE).

OBJECTIVES

To determine the association between myositis-specific autoantibodies, myositis-associated autoantibodies and CADM in Spanish patients. In addition, to study the usefulness of these autoantibodies in the differential diagnosis between CADM and SCLE.

METHODS

Serum samples were tested for myositis-specific autoantibodies and myositis-associated autoantibodies through immunoprecipitation and other standardized methods.

RESULTS

Anti-CADM-p140 and anti-p155 antibodies were the only myositis-specific autoantibodies found and were associated with interstitial lung diseases and cancer respectively. No myositis-associated autoantibodies were found in CADM. Moreover, clinical subsets and proportions seemed to differ from Asian cohorts, where anti-CADM-p140 is considered a CADM hallmark antibody and a risk factor for the development of interstitial lung disease. Interestingly, anti-SSA was highly associated with SCLE, whereas no myositis-specific autoantibodies were found in this entity.

LIMITATIONS OF THE STUDY

Association between CADM and myositis-specific autoantibodies and differences between CADM and SCLE were tested on a relatively small cohort of patients.

CONCLUSION

There is an association between cancer-associated myositis and interstitial lung diseases and their hallmark autoantibodies in our cohort. In addition, the combined determination of myositis-specific autoantibodies and SSA autoantibodies may help to accurately discriminate SCLE from CADM.

Anti-MDA5 autoantibodies in juvenile dermatomyositis identify a distinct clinical phenotype: a prospective cohort study

INTRODUCTION

The aim of this study was to define the frequency and associated clinical phenotype of anti-MDA5 autoantibodies in a large UK based, predominantly Caucasian, cohort of patients with juvenile dermatomyositis (JDM).

METHODS

Serum samples and clinical data were obtained from 285 patients with JDM recruited to the UK Juvenile Dermatomyositis Cohort and Biomarker Study. The presence of anti-MDA5 antibodies was determined by immunoprecipitation and confirmed by ELISA using recombinant MDA5 protein. Results were compared with matched clinical data, muscle biopsies (scored by an experienced paediatric neuropathologist) and chest imaging (reviewed by an experienced paediatric radiologist).

RESULTS

Anti-MDA5 antibodies were identified in 7.4% of JDM patients and were associated with a distinct clinical phenotype including skin ulceration (P = 0.03) oral ulceration (P = 0.01), arthritis (P <0.01) and milder muscle disease both clinically (as determined by Childhood Myositis Assessment Score (P = 0.03)) and histologically (as determined by a lower JDM muscle biopsy score (P <0.01)) than patients who did not have anti-MDA5 antibodies. A greater proportion of children with anti-MDA5 autoantibodies achieved disease inactivity at two years post-diagnosis according to PRINTO criteria (P = 0.02). A total of 4 out of 21 children with anti-MDA5 had interstitial lung disease; none had rapidly progressive interstitial lung disease.

CONCLUSIONS

Anti-MDA5 antibodies can be identified in a small but significant proportion of patients with JDM and identify a distinctive clinical sub-group. Screening for anti-MDA5 autoantibodies at diagnosis would be useful to guide further investigation for lung disease, inform on prognosis and potentially confirm the diagnosis, as subtle biopsy changes could otherwise be missed.

Meta-analysis of the association of dermatomyositis and polymyositis with cancer

BACKGROUND

Although some features of dermatomyositis (DM) and polymyositis (PM) have been reported as possible prognostic indicators for cancer development, previous studies were small in size and were unable to establish a definitive relationship between neoplasms and DM and PM.

OBJECTIVES

To evaluate risk factors for developing malignancies in patients with DM and PM.

METHODS

Meta-analysis of the studies reported in the literature was performed to unveil risk factors for developing cancer among patients with DM and PM. The included studies were either cohort or retrospective case-control studies with information on cancer status. Risk for malignancy was determined as the odds ratio (OR) or weighted mean difference (WMD) with a 95% confidence interval (CI), determined by fixed and random effects models. Stata 10.0 software was used to identify possible publication bias.

RESULTS

Twenty studies with 380 patients and 1575 controls were included in the analysis. The factors that may increase the risk of cancer in patients with DM and PM were older age (WMD 11·41, 95% CI 9·84-12·98), male sex (OR 1·92, 95% CI 1·49-2·48), cutaneous necrosis (OR 5·52, 95% CI 3·49-8·74) and dysphagia (OR 2·41, 95% CI 1·50-3·86), whereas those that may provide protection against cancer included arthritis (OR 0·38, 95% CI 0·24-0·61) and interstitial lung disease (OR 0·32, 95% CI 0·20-0·51).

CONCLUSIONS

Our data suggest that age, sex, cutaneous necrosis, dysphagia, arthritis and lung complications may influence susceptibility to cancer in patients with DM and PM.

Anti-MDA5 antibodies in a large Mediterranean population of adults with dermatomyositis

A new myositis-specific autoantibody directed against melanoma differentiation-associated gene 5 (anti-MDA5) has been described in patients with dermatomyositis (DM). We report the clinical characteristics of patients with anti-MDA5 in a large Mediterranean cohort of DM patients from a single center, and analyze the feasibility of detecting this autoantibody in patient sera using new assays with commercially available recombinant MDA5. The study included 117 white adult patients with DM, 15 (13%) of them classified as clinically amyopathic dermatomyositis (CADM). Clinical manifestations were analyzed, with special focus on interstitial lung disease and its severity. Determination of anti-MDA5 antibodies was performed by a new ELISA and immunoblot technique. In sera, from 14 (12%) DM patients (8 CADM), MDA5 was recognized by ELISA, and confirmed by immunoblot. Eight of the 14 anti-MDA5-positive patients (57.14%) presented rapidly-progressive interstitial lung disease (RP-ILD) versus 3 of 103 anti-MDA5-negative patients (2.91%) (P < 0.05; OR: 44.4, 95% CI 9.3–212). The cumulative survival rate was significantly lower in anti-MDA5-positive patients than in the remainder of the series (P < 0.05). Patients with anti-MDA5-associated ILD presented significantly lower 70-month cumulative survival than antisynthetase-associated ILD patients. Among the cutaneous manifestations, only panniculitis was significantly associated with the presence of anti-MDA5 antibodies (P < 0.05; OR: 3.85, 95% CI 1.11–13.27). These findings support the reliability of using commercially available recombinant MDA5 for detecting anti-MDA5 antibodies and confirm the association of these antibodies with RP-ILD in a large series of Mediterranean patients with DM.

Paraneoplastic dermatomyositis: a study of 12 cases

INTRODUCTION AND OBJECTIVES

Adult dermatomyositis presents as a paraneoplastic syndrome in up to 25% of cases, but no clinical, histologic, or laboratory markers completely specific for paraneoplastic disease in dermatomyositis have been identified to date. Furthermore, studies on adult dermatomyositis do not usually report the frequency of cutaneous features of dermatomyositis in patients with associated cancer. Our aim was to review the characteristics of paraneoplastic dermatomyositis in patients seen at our hospital.

MATERIAL AND METHODS

We studied 12 cases of paraneoplastic dermatomyositis and recorded patient age and sex, associated cancer, time between onset of dermatomyositis and cancer, emergent cutaneous manifestations, muscle involvement, dysphagia, lung disease, and levels of creatine phosphokinase and circulating autoantibodies.

RESULTS

The mean age of the patients was 61 years and the 2 most common malignancies were ovarian cancer and bladder cancer. The mean time between the diagnosis of cancer and dermatomyositis was 7 months and in most cases, the cancer was diagnosed first. Seven patients had amyopathic dermatomyositis. The most common cutaneous signs were a violaceous photodistributed rash sparing the interscapular area and a heliotrope rash, followed by Gottron papules and cuticle involvement. Superficial cutaneous necrosis was observed in 3 cases. Myositis-specific autoantibodies were not detected in any of the 6 patients who underwent this test.

CONCLUSIONS

Paraneoplastic dermatomyositis is often amyopathic. There are no specific cutaneous markers for malignancy in dermatomyositis. Myositis-specific antibodies are not associated with paraneoplastic dermatomyositis.

Most patients with cancer-associated dermatomyositis have antibodies to nuclear matrix protein NXP-2 or transcription intermediary factor 1γ

OBJECTIVE

Since dermatomyositis (DM) is associated with an increased risk of malignancy, accurate identification of patients likely to harbor cancers is important. Using immunoprecipitations from radiolabeled cell lysates, several groups recently showed that anti-transcription intermediary factor 1γ (anti-TIF-1γ) antibodies are associated with malignancy in DM. We undertook this study to develop sensitive, specific assays to detect antibodies against TIF-1γ and nuclear matrix protein NXP-2 and to evaluate their association with malignancy in DM.

METHODS

To detect anti-TIF-1γ antibodies, immunoprecipitations were performed using lysates made from HeLa cells overexpressing TIF-1γ, with detection by immunoblotting. Anti-NXP-2 antibodies were assayed by immunoprecipitation using (35) S-methionine-labeled NXP-2 generated by in vitro transcription/translation. We analyzed patient sera from DM cohorts seen at the Stanford University Dermatology Clinic (n = 111) and the Johns Hopkins Myositis Center (n = 102).

RESULTS

A total of 17% and 38% of patients had antibodies against NXP-2 and TIF-1γ, respectively. Reactivity against either NXP-2 or TIF-1γ identified 83% of patients with cancer-associated DM. In addition to older age and male sex, cancer was associated with antibodies to NXP-2 or TIF-1γ on multivariate analysis (odds ratio 3.78 [95% confidence interval 1.33-10.8]). Stratification by sex revealed that anti-NXP-2 was specifically associated with cancer in males (odds ratio 5.78 [95% confidence interval 1.35-24.7]).

CONCLUSION

These studies demonstrate that anti-NXP-2 and anti-TIF-1γ antibodies are frequent DM specificities (found in 55% of patients) and are present in most patients with cancer-associated DM.

[Recent findings in dermatomyositis-specific autoantibodies]

Recently, new autoantibodies specific for dermatomyositis have been identified, including anti-melanoma differentiation antigen 5 antibody, anti-transcriptional intermediary factor 1 antibody, and anti-nuclear matrix protein 1 antibody, in addition to those described previously such as anti-aminoacyl tRNA synthetase antibodies and anti-Mi-2 antibody. These disease-specific autoantibodies cover approximately 80% of the patients, and thus are useful for the diagnosis. Moreover, these antibodies are closely associated with specific disease phenotypes, and enable us to predict complications and prognosis and to evaluate disease activity.

Utility of anti-melanoma differentiation-associated gene 5 antibody measurement in identifying patients with dermatomyositis and a high risk for developing rapidly progressive interstitial lung disease: a review of the literature and a meta-analysis

OBJECTIVE

To assess the utility of anti-melanoma differentiation-associated gene 5 (anti-MDA5) antibody measurement for predicting a risk for developing rapidly progressive interstitial lung disease (RP-ILD) in patients with polymyositis/dermatomyositis (PM/DM).

METHODS

A single-center cohort of 64 consecutive Chinese patients with PM/DM was examined. Serum anti-MDA5 antibody was measured by enzyme-linked immunosorbent assay. For meta-analysis, we searched PubMed and the Institute for Scientific Information Web of Knowledge for original studies that measured anti-MDA5 antibodies in patients with PM/DM. We calculated pooled sensitivity, specificity, diagnostic odds ratio (DOR), and the summary receiver operating characteristic (sROC) curve.

RESULTS

In Chinese patients, anti-MDA5 antibodies were detected in 26 patients with classic DM or clinically amyopathic DM (CADM). Compared with anti-MDA5-negative patients, anti-MDA5-positive patients showed a higher prevalence of RP-ILD (P = 0.001). In a total of 233 patients with anti-MDA5 antibody, derived from 16 studies, a higher frequency of CADM was found in Japanese than in non-Japanese patients (74.7% versus 39.2%; P = 1.2 × 10(-7) ). Meta-analysis revealed that the pooled sensitivity and specificity of anti-MDA5 antibody for RP-ILD was 77% (95% confidence interval [95% CI] 64-87%) and 86% (95% CI 79-90%), respectively. The pooled DOR was 20.41 (95% CI 9.02-46.20) with a favorable area under the sROC curve of 0.89 (95% CI 0.63-0.98).

CONCLUSION

Detection of anti-MDA5 antibody is a valuable tool for identifying DM patients with a high risk for developing RP-ILD, but the distribution of classic DM and CADM in patients with this antibody varies among ethnic groups.

Anti-melanoma differentiation-associated protein 5-associated dermatomyositis: expanding the clinical spectrum

OBJECTIVE

Autoantibodies against melanoma differentiation-associated protein 5 (MDA-5) have been described in several Asian dermatomyositis (DM) cohorts, often associated with amyopathic DM and rapidly progressive interstitial lung disease (ILD). A recent study of a DM cohort seen at a US dermatology clinic reports that MDA-5 autoantibodies are associated with a unique cutaneous phenotype. Given the widening spectrum of clinical findings, we evaluated the clinical features of anti-MDA-5-positive patients seen at a US myositis referral center.

METHODS

One hundred sixty DM patients were screened for MDA-5 autoantibodies by immunoprecipitation and antibody titers were analyzed in longitudinal serum samples. Anti-MDA-5-positive patients were evaluated for the presence of additional myositis autoantibodies. Patient clinical characteristics were compared by retrospective chart review.

RESULTS

MDA-5 was targeted in 11 (6.9%) of 160 patients with DM. Of these, 9 presented with a symmetric polyarthropathy, 6 demonstrated overt clinical myopathy, and 8 had ILD. Eight anti-MDA-5-positive patients exhibited the clinical attributes of the antisynthetase syndrome in the absence of Jo-1 or other antisynthetase autoantibodies. MDA-5 autoantibody titers did not correlate with clinical course.

CONCLUSION

MDA-5 autoantibodies are found in DM patients presenting with a symmetric polyarthritis, clinically similar to rheumatoid arthritis. These patients often have features of the antisynthetase syndrome, but in the absence of antisynthetase autoantibodies. Most anti-MDA-5-positive patients had overt clinical myopathy and ILD. The latter, while occasionally severe, typically resolved with immunosuppressive therapy. In this cohort, the MDA-5 phenotype is frequently a clinical mimic of the antisynthetase syndrome and is not associated with rapidly progressive ILD.

Cutaneous dermatomyositis: an updated review of treatment options and internal associations

Dermatomyositis is a specific type of inflammatory myopathy with characteristic cutaneous findings. Patients may have skin disease without clinically apparent muscle disease, but this disorder is best thought of as a systemic process. Therefore, all patients with dermatomyositis skin lesions need appropriate evaluation for muscle disease, esophageal dysfunction, cardiopulmonary disease, and potential internal malignancy. There are many therapies that have been used for patients with dermatomyositis, but most are based upon case series or expert opinion rather than meta-analyses or randomized, placebo-controlled trials. Even those therapies that have been subjected to randomized, blinded, placebo-controlled trials include a mixture of patients with idiopathic inflammatory myopathy and do not utilize a validated assessment tool for measuring cutaneous disease responses. In this review, we discuss the therapies available as well as the internal associations with dermatomyositis.

Adult and juvenile dermatomyositis: are the distinct clinical features explained by our current understanding of serological subgroups and pathogenic mechanisms?

Adult and juvenile dermatomyositis share the hallmark features of pathognomic skin rash and muscle inflammation, but are heterogeneous disorders with a range of additional disease features and complications. The frequency of important clinical features such as calcinosis, interstitial lung disease and malignancy varies markedly between adult and juvenile disease. These differences may reflect different disease triggers between children and adults, but whilst various viral and other environmental triggers have been implicated, results are so far conflicting. Myositis-specific autoantibodies can be detected in both adults and children with idiopathic inflammatory myopathies. They are associated with specific disease phenotypes and complications, and divide patients into clinically homogenous subgroups. Interestingly, whilst the same autoantibodies are found in both adults and children, the disease features remain different within autoantibody subgroups, particularly with regard to life-threatening disease associations, such as malignancy and rapidly progressive interstitial lung disease. Our understanding of the mechanisms that underlie these differences is limited by a lack of studies directly comparing adults and children. Dermatomyositis is an autoimmune disease, which is believed to develop as a result of an environmental trigger in a genetically predisposed individual. Age-specific host immune responses and muscle physiology may be additional complicating factors that have significant impact on disease presentation. Further study into this area may produce new insights into disease pathogenesis.

Classification, diagnosis, and management of idiopathic inflammatory myopathies

The detection and characterization of a large array of autoantibodies, including at least 8 different antisynthetase, anti-SRP, -200/100 (HMGCR), -Mi-2, -CADM-140 (MDA5), -SAE, -p155, -MJ (NXP-2), and -PMS1, frequently associated with distinct and well-defined clinicopathological features, allowed for significant improvement in the definition and diagnosis of idiopathic inflammatory myopathies (IIM). Classification remains difficult, with lingering divergence between the different specialties involved in IIM care, but several categories clearly stand out, including dermatomyositis (DM), overlap myositis (OM), polymyositis, necrotizing myositis, and sporadic inclusion body myositis (s-IBM). Biopsy and histological analysis remain crucial, particularly in the absence of autoantibodies, to accurately specify the diagnosis and rule out mimics such as muscular dystrophies and metabolic myopathies. Numerous infectious agents (in particular human immunodeficiency virus and human T cell lymphotrophic virus-1) and drugs (statins, tumor necrosis factor inhibitors, and proton pump inhibitors) can cause mimic IIM that must also be excluded. Pharmacological treatment, in addition to glucocorticoids and immunoglobulins, now includes mycophenolate mofetil and rituximab, which proved helpful in resistant cases, particularly rituximab in DM and OM. Exercise, initially seen as potentially deleterious, recently was shown to be efficacious and safe. IIM can thus be reasonably well controlled in most cases, although aggressive disease remains refractory to treatment, including some cases of necrotizing myopathy. Sporadic IBM still seems resistant to all medications tested to date.

The prognostic value of HRCT in myositis-associated interstitial lung disease

BACKGROUND

Polymyositis and dermatomyositis-associated interstitial lung disease (PM/DM-ILD) can have variable courses. We evaluated the prognostic value of high-resolution computed tomography (HRCT) in PM/DM-ILD.

METHODS

The cases of 51 patients newly diagnosed with PM/DM-ILD were retrospectively reviewed. HRCT images at diagnosis were categorized into four radiological patterns based on the major findings and distributions of these abnormalities, and the disease extent on HRCT was scored. The impact of HRCT findings and other clinical parameters on day 90 and overall mortality were analyzed.

RESULTS

Of the 51 patients (11 with polymyositis and 40 with dermatomyositis), the lower consolidation/ground-glass attenuation (GGA) pattern was observed in 21 patients (41%), lower reticulation was observed in 23 patients (45%), random GGA was observed in four patients (8%), and other patterns were observed in three patients (6%). Twenty-one patients (42%) were positive for anti-CADM-140. The lower consolidation/GGA pattern, clinically amyopathic dermatomyositis, fever (≥38.0 °C), ferritin levels >500 ng/mL, and the presence of anti-CADM-140 were significantly associated with 90-day mortality in univariate analysis. Multivariate analysis revealed that the lower consolidation/GGA pattern (odds ratio, 23.1; P = 0.02) and the presence of anti-CADM-140 (odds ratio, 14.1; P = 0.03) were independent predictors of 90-day mortality. This HRCT pattern was also associated with a higher 90-day morality rate among anti-CADM-140-positive patients. The lower consolidation/GGA pattern was also associated with overall mortality in univariate analysis, whereas only the presence of anti-CADM-140 was an independent determinant of overall mortality in multivariate analysis.

CONCLUSION

HRCT patterns at diagnosis can help predict the prognosis of patients with PM/DM-ILD as well as the presence of anti-CADM-140.

Myositis autoantibodies

PURPOSE OF REVIEW

To review recent advances in our understanding of autoantibodies associated with dermatomyositis and the autoimmune necrotizing myopathies.

RECENT FINDINGS

Autoantibodies preferentially associated with dermatomyositis include those recognizing Mi-2, MDA5, TIF1γ, and NXP-2. Each of these is associated with a distinct clinical phenotype. Autoantibodies found in patients with autoimmune necrotizing myopathies recognize signal recognition particle and 3-hydroxy-3-methylglutaryl-coenzime A reductase (HMG-CoA) reductase. The latter are found in patients with statin-associated autoimmune muscle disease.

SUMMARY

As these are helpful both diagnostically and prognostically, a rheumatologist should be familiar with autoantibodies found in patients with dermatomyositis and the autoimmune necrotizing myopathies.

Skin disease in dermatomyositis

PURPOSE OF REVIEW

This review will provide the clinician with an update on the pathogenesis, clinical manifestations, and therapy for skin disease in dermatomyositis. Recent insights into the role for interferon in skin disease as well as the development and validation of quantitative tools to measure skin disease activity allow the possibility that, for the first time, dermatomyositis skin disease can serve as a valid outcome for clinical trials of targeted therapies. Also, the increasing appreciation of the heterogeneity of skin disease in dermatomyositis has already provided evidence that clinical subtypes of disease can provide important prognostic and diagnostic information to the clinician.

RECENT FINDINGS

It is becoming apparent that the skin inflammation alone has implications for systemic and malignancy risk in dermatomyositis patients, and that there may be several pathogenic similarities between muscle and skin inflammation in dermatomyositis. Recent data on therapy for calcinosis cutis highlights that more prospective studies are needed to evaluate how best to manage all manifestations of skin inflammation in dermatomyositis.

SUMMARY

A more careful description and classification of skin disease in dermatomyositis may allow the clinician to predict more accurately which patients will be at higher risk for cancer, lung disease, or muscle inflammation. In addition, given the similarities in perturbed gene expression between skin and muscle tissue, it is likely that analysis of a more readily evaluable target organ such as skin might shed light on mechanisms of disease propagation throughout the body.

Comparison of children with onset of juvenile dermatomyositis symptoms before or after their fifth birthday in a UK and Ireland juvenile dermatomyositis cohort study

Objective

To compare 2 groups of children with juvenile dermatomyositis (DM), those with onset of symptoms before their fifth birthday versus those whose disease begins either on or after their fifth birthday, and to assess whether age at onset is associated with differences in disease presentation, treatments received, or outcomes 2 years after diagnosis.

Methods

Data were analyzed on children recruited to a UK juvenile DM cohort study with a diagnosis of probable or definite juvenile DM and less than 12 months between diagnosis and recruitment.

Results

Fifty-five (35%) of 157 children had onset of symptoms before their fifth birthday. At diagnosis, cutaneous ulceration was found in 32.7% of the younger group versus 11.8% of the older group (P = 0.003). Facial or body swelling was reported more often in the younger group, whereas headaches, alopecia, and Raynaud's phenomenon were all more frequently reported in the older group. At followup 2 years later, there were no important differences in outcomes between the groups. More than 90% of patients in both groups received both methotrexate and steroids. Twenty-three percent of both groups remained on steroids 2 years after diagnosis.

Conclusion

Our study showed that children with juvenile DM with disease onset at age <5 years are more likely to present with ulcerative skin disease and edema. There were no clinically significant differences in outcomes between the 2 groups.

Clinical presentation and evaluation of dermatomyositis

Dermatomyositis (DM) is a chronic inflammatory disorder of the skin and muscles. Evidence supports that DM is an immune-mediated disease and 50–70% of patients have circulating myositis-specific auto-antibodies. Gene expression microarrays have demonstrated upregulation of interferon signaling in the muscle, blood, and skin of DM patients. Patients with classic DM typically present with symmetric, proximal muscle weakness, and skin lesions that demonstrate interface dermatitis on histopathology. Evaluation for muscle inflammation can include muscle enzymes, electromyogram, magnetic resonance imaging, and/or muscle biopsy. Classic skin manifestations of DM include the heliotrope rash, Gottron's papules, Gottron's sign, the V-sign, and shawl sign. Additional cutaneous lesions frequently observed in DM patients include periungual telangiectasias, cuticular overgrowth, “mechanic's hands”, palmar papules overlying joint creases, poikiloderma, and calcinosis. Clinically amyopathic DM is a term used to describe patients who have classic cutaneous manifestations for more than 6 months, but no muscle weakness or elevation in muscle enzymes. Interstitial lung disease can affect 35–40% of patients with inflammatory myopathies and is often associated with the presence of an antisynthetase antibody. Other clinical manifestations that can occur in patients with DM include dysphagia, dysphonia, myalgias, Raynaud phenomenon, fevers, weight loss, fatigue, and a nonerosive inflammatory polyarthritis. Patients with DM have a three to eight times increased risk for developing an associated malignancy compared with the general population, and therefore all patients with DM should be evaluated at the time of diagnosis for the presence of an associated malignancy. This review summarizes the immunopathogenesis, clinical manifestations, and evaluation of patients with DM.

Identification of novel autoantigens by a triangulation approach

High titer autoantibodies, which are often associated with specific clinical phenotypes, are useful diagnostically and prognostically in systemic autoimmune diseases. In several autoimmune rheumatic diseases (e.g. myositis and Sjogren's syndrome), 20-40% of patients are autoantibody negative as assessed by conventional assays. The recent discovery of new specificities (e.g., anti-MDA5) in a subset of these autoantibody-negative subjects demonstrates that additional specificities await identification. In this manuscript, we describe a rapid multidimensional method to identify new autoantigens. A central foundation of this rapid approach is the use of an antigen source in which a pathogenic pathway active in the disease is recapitulated. Additionally, the method involves a modified serological proteome analysis strategy which allows confirmation that the correct gel plug has been removed prior to sending for sequencing. Lastly, the approach uses multiple sources of information to enable rapid triangulation and identification of protein candidates. Possible permutations and underlying principles of this triangulation strategy are elaborated to demonstrate the broad utility of this approach for antigen discovery.

A novel dermato-pulmonary syndrome associated with MDA-5 antibodies: report of 2 cases and review of the literature

Melanoma differentiation-associated protein 5 (MDA-5) is a novel autoantibody frequently characterized by interstitial lung disease and a distinct cutaneous phenotype with palmar papules, ulceration, and rash. Virtually all patients have underlying dermatomyositis, but many lack the characteristic clinical myopathy associated with it. In the setting of amyopathic disease, the absence of clinically available biomarkers or clear pathologic diagnosis can complicate effective prognostic and therapeutic intervention. Until recently the presence of MDA-5 antibody associated dermato-pulmonary syndrome was described only in Asian populations. We present 2 cases of MDA-5-associated dermato-pulmonary syndrome and provide a comprehensive review of available literature.

Anti-CADM-140/MDA5 autoantibody titer correlates with disease activity and predicts disease outcome in patients with dermatomyositis and rapidly progressive interstitial lung disease

OBJECTIVES

We examined the relationship between disease activity and anti-CADM-140/MDA5 titer measured by enzyme-linked immunosorbent assay (ELISA).

METHODS

Sera from 63 patients with dermatomyositis (DM) [46 classic DM, 17 clinically amyopathic DM (CADM)] were screened for autoantibody using immunoprecipitation assay. Anti-CADM-140/MDA5-positive sera were examined for their titer by anti-CADM-140/MDA5 ELISA. Potential associations between anti-CADM-140/MDA5 titer and clinical course or outcome were analyzed.

RESULTS

Sera from 14 patients with DM (2 classic DM, 12 CADM) had anti-CADM-140/MDA5. Of ten patients with DM and rapidly progressive interstitial lung disease (RP-ILD), the mean titer of anti-CADM-140/MDA5 before treatment was significantly lower in patients who responded to therapy and survived (responder group, n = 4) than in those who did not respond and died (nonresponder group, n = 6) (110.3 vs. 356.9, P = 0.019). In the responder group, the mean titer of anti-CADM-140/MDA5 significantly decreased down to below the cutoff level after treatment (n = 3, 113.4 vs. 1.6, P = 0.033), whereas that of the nonresponder group did not decrease sufficiently and sustained high level (n = 4, 372.5 vs. 198.4, P = 0.31).

CONCLUSIONS

These results emphasize the clinical importance of anti-CADM-140/MDA5 antibody levels to predict outcomes of RP-ILD as well as to monitor disease activity in patients with DM and RP-ILD.

Role of environmental factors in autoantibody production - importance of a detailed analysis in a small cohort

In the previous issue of Arthritis Research & Therapy, Muro and colleagues reported a detailed epidemiologic analysis in central Japan on one of the new myositis-specific autoantibodies to MDA-5 (melanoma differentiation-associated gene 5), which is associated with clinically amyopathic dermatomyositis accompanying interstitial lung disease. The increasing prevalence of anti-MDA-5, higher prevalence in small rural towns, and geographical clustering in two areas along the Kiso River suggest a role of environmental factors associated with rural communities or the river/water system or both. A detailed analysis of a small cohort may offer clues, which is ignored in multi-center studies, to the pathogenesis of systemic rheumatic diseases and autoantibody production.

[What's new in clinical dermatology?]

This year more than 3000 medical articles referenced in PubMed concerned dermatology. Our critical analysis covers different fields of dermatology: including epidemiology, clinical, diagnostic and prognostic factors. AIDS is 30 years old and the national HIV/AIDS plan for 2010-2014 recommends generalized screening facilitated by the introduction of rapid tests for diagnostic orientation. In infectious diseases, novelties concern polyomavirus, HTLV-1, leprosy, staphylococcus infections, resistance to antibiotics and scabies. Diseases of the scalp consecutive to practices of black women hairstyles were the subject of important articles. There were two important developments in acne: first, a simplified and more operational classification, secondly a suicidal risk associated with severe forms. Lymphocyte Th-17 immunity is involved in clinical phenomena either by excess (genetic or drug) or default (genetic causes). Allergology: in several studies, false negative patch tests have been published. The natural history of nevi is specified by three important articles. Serological tests to practice in cases of dermatomyositis and bullous pemphigoid are specified.

Amyopathic dermatomyositis developing rapidly progressive interstitial lung disease with elevation of anti-CADM-140/MDA5 autoantibodies

Anti-clinically amyopathic dermatomyositis (CADM)-140/MDA5 autoantibodies are specifically detected in patients with dermatomyositis and are known to have a strong association with rapidly progressive interstitial lung disease (RP-ILD). Here we report an amyopathic dermatomyositis (ADM) patient who developed RP-ILD characterized by elevated anti-CADM-140/MDA5 titer. Respiratory symptoms gradually improved, and anti-CADM-140/MDA5 titer decreased in parallel to below the cutoff level. It may be useful to quantify CADM-140-specific autoantibodies for monitoring disease activity in patients with ADM and RP-ILD.

The lung as a possible target for the immune reaction in myositis

Interstitial lung disease is a common manifestation of autoimmune myositis that confers significant morbidity and mortality. The vulnerability of the lung may offer insight into the etiology of this autoimmune disease. The frequency and patterns of lung injury vary based on the autoantibody. Antibodies against the aminoacyl-tRNA synthetases and melanoma differentiation-induced gene-5 are frequently associated with interstitial lung disease. Although the mechanisms underlying these associations have not been fully elucidated, emerging data highlight the importance of autoantigen expression and conformation in the target tissue (lung and muscle, in this case), as well as identifying relevant amplifying pathways (such as regeneration).