Dermatomyositis and Immune-Mediated Necrotizing Myopathies: A Window on Autoimmunity and Cancer

[Current update on dermatomyositis]

Dermatomyositis (DM) is a rare autoimmune disease with involvement of skin and muscle that is classified as an idiopathic inflammatory myopathy. In addition to cutaneous lesions as well as weakness and atrophy of muscles, the heart and lungs are the major affected organs. DM occurs in association with malignant tumors in 20% of affected adults. The pathogenesis of the disease is not completely understood. DM is a multifactorial disease influenced by genetic, environmental and immunological factors. The immune response is characterized by activation of innate and adaptive immune mechanisms and a strong activation of the type I interferon pathway. Myositis-specific antibodies are characteristic of DM and allow differential diagnosis. Therapies include corticosteroids, antimalarials, immunoglobulins, biologics such as rituximab or JAK inhibitors. Early diagnosis and treatment are essential for the prognosis.

Serum level of galectin-9 as a potential biomarker for high risk of malignancy in dermatomyositis

OBJECTIVES

Galectin-9, as immune checkpoint protein, plays a role in regulating autoimmunity and tumour immunity. Therefore, we explored the pathophysiological link between galectin-9 and malignancy in cancer-related DM (CRDM).

METHODS

Serum galectin-9 were quantified via enzyme-linked immunosorbent assay, and its association with serological indices was evaluated using Spearman analysis. Receiver operating characteristic (ROC) analysis was utilized to determine the cut-off value of galectin-9.

RESULTS

Serum levels of galectin-9 were significantly higher in DM patients [23.38 (13.85-32.57) ng/ml] than those in healthy controls (HCs) [6.81 (5.42-7.89) ng/ml, P < 0.0001], and were positively correlated with the cutaneous dermatomyositis disease area severity index activity (CDASI-A) scores (rs=0.3065, P = 0.0172). DM patients with new-onset and untreated cancer (new-CRDM) [31.58 (23.85-38.84) ng/ml] had higher levels of galectin-9 than those with stable and treated cancer (stable-CRDM) [17.49 (10.23-27.91) ng/ml, P = 0.0288], non-cancer-related DM (non-CRDM) [21.05 (11.97-28.02) ng/ml, P = 0.0258], and tumour patients without DM [7.46 (4.90-8.51) ng/ml, P < 0.0001]. Serum galectin-9 levels significantly decreased [27.79 (17.04-41.43) ng/ml vs 13.88 (5.15-20.37) ng/ml, P = 0.002] after anti-cancer treatment in CRDM patients. The combination of serum galectin-9 and anti-transcriptional intermediary factor 1-γ (anti-TIF1-γ) antibody (AUC = 0.889, 95% CI 0.803-0.977) showed the highest predictive value for the presence of cancer in DM.

CONCLUSION

Increased galectin-9 levels were related to tumor progression in CRDM, and galectin-9 was downregulated upon cancer treatment. Monitoring serum galectin-9 levels and anti-TIF1-γ antibodies might be an attractive strategy to achieve tumour diagnosis and predict CRDM outcome.

A case report of dermatomyositis mimicking myasthenia gravis

RATIONALE

Patients who have myasthenia gravis or dermatomyositis show clinical signs of muscular weakening. Ocular muscle involvement is uncommon, and symmetrical proximal limb weakness is the typical presentation of dermatomyositis. However, the earliest and most noticeable sign in those with myasthenia gravis is extraocular muscular paralysis. Dermatomyositis is frequently complicated by malignancy, and the common malignancies associated with dermatomyositis vary by region and ethnicity, while thymoma is relatively rare. About 10% to 15% of people with myasthenia gravis have thymoma, which is involved in the etiology of the disease.

PATIENT CONCERNS

A 68-year-old female presented with ocular muscle weakness for 10 days that manifested as bilateral blepharoptosis with the phenomenon of "light in the morning and heavy in the evening." Imaging examination showed anterior mediastinal thymic tumor with metastasis.

DIAGNOSES

After a thorough physical examination, we discovered bilateral upper limbs with grade IV muscle strength and the typical rash of dermatomyositis. In combination with elevated serum kinase levels and electromyography suggesting myogenic damage, the patient was finally diagnosed as dermatomyositis with multiple metastases of thymoma.

INTERVENTIONS

The patient received oral hydroxychloroquine sulfate, topical corticosteroids, and tacrolimus ointment, but these did not work very well. Subsequently, the patient underwent surgery combined with radiotherapy for the thymoma.

OUTCOMES

Muscle weakness in the patient improved after effective treatment of tumor, and the rash mostly disappeared.

CONCLUSION

Ocular muscle weakness and thymoma are more common in myasthenia gravis, but we cannot ignore the possibility of dermatomyositis. To further establish the diagnosis, a thorough physical examination and laboratory findings are required. Further tumor screening should be performed for patients with dermatomyositis. Early detection and management of possible tumors are essential to the treatment of dermatomyositis linked to malignancies.

Dermatomyositis with Eosinophils

Dermatomyositis is an idiopathic inflammatory myopathy that often presents with symmetric proximal skeletal muscle weakness and characteristic skin findings. Typical skin biopsy findings include vacuolar changes of the basal layer, increased dermal mucin, and a predominantly lymphocytic infiltrate. We report a case of dermatomyositis presenting as intensely pruritic papules and plaques, with initial histopathology being atypical of dermatomyositis due to the presence of eosinophils. The initial biopsy demonstrated a superficial dermatitis with eosinophils, initially thought to represent a drug eruption. A second biopsy of the same cutaneous manifestation was performed at a later time given high clinical suspicion for dermatomyositis and demonstrated a more classic vacuolar interface dermatitis with increased mucin and an absence of eosinophils. Notably, increased pruritus was specifically associated with the lesion that demonstrated tissue eosinophilia. The case illustrates the importance of considering tissue eosinophilia in the histologic presentation of dermatomyositis.

Skin of color in dermatopathology: does color matter?

Skin of color (SoC) remains an understudied and under taught area of dermatology despite its rising importance. Race and ethnicity play a particularly important role in dermatology as skin pigmentation can affect the manifestation and presentation of many common dermatoses. With this review, we seek to review pertinent differences in SoC histology, as well as highlight the histopathology of conditions more common in SoC and address inherent bias that may affect accurate dermatopathology sign out.

Paraneoplastic pemphigus misdiagnosed as juvenile dermatomyositis: A case report

Paraneoplastic pemphigus (PNP) is a rare autoimmune skin disease closely related to tumors, characterized by a maculopapular rash with mucosal pain, bronchiole occlusion, and respiratory failure may occur over time, even resulting in death. We report a rare case of a child with autoimmune PNP misdiagnosed as juvenile dermatomyositis (JDM), and summarize the key points of differentiation of clinical manifestations and auxiliary examinations of PNP and JDM. When the diagnosis is not clear because the patient has features not typical of JDM, then skin biopsy and other diagnostic studies should be considered prior to any immunosuppressive therapy, as this could potentially obscure and delay the diagnosis of malignancy.

Dermatomyositis Presenting with Generalized Subcutaneous Edema

Generalized subcutaneous edema is rare in dermatomyositis. We herein report an 82-year-old woman with dermatomyositis who presented with generalized subcutaneous edema. Three weeks before admission, she first noticed facial edema, and the symptoms exacerbated, with limb edema occurring. On admission, muscle weakness in the limbs and skin rash were noted. Her muscle enzyme levels were elevated, and serum anti-transcriptional intermediary factor 1-γ antibody was detected. She was diagnosed with dermatomyositis and treated with corticosteroids and tacrolimus, which improved her muscle weakness, muscle enzymes, and edema. Thus, generalized subcutaneous edema can occur during dermatomyositis, with facial edema as the initial symptom.

Trichoscopic, oral, and periungual fold findings as activity and damage markers in dermatomyositis patients and their correlation with myositis antibodies

There is little clarity about the clinical manifestations of dermatomyositis (DM) in the periungual folds, scalp, and oral cavity and their association with disease activity and damage. The objective of this study was to compare the prevalence of trichoscopic, oral, and periungual changes between DM and healthy patients and assess their possible association with disease activity and damage. We conducted an observational, transversal, and analytical study between 2020 and 2021. Forty DM patients were matched by sex and age with 40 healthy individuals. On the same day, all patients had a clinical evaluation of the hands, periungual folds, scalp, and oral cavity. Photographs of these areas and peripheral venous blood tests, including myositis-associated (MAAs) and myositis-specific antibodies (MSAs), were taken. Two dermatologists blinded to their diagnosis, damage, and activity levels registered the lesions. The disease activity and damage were evaluated using the Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI). The presence of mechanic's hands, Gottron's sign, and Gottron's papules in hands; capillary dilation, capillary tortuosity, cuticular hemorrhage, avascular areas, and cuticular hyperkeratosis in periungual folds; thick tortuous capillaries in scalp; gingival telangiectasias in the oral cavity; and positive MSAs associated with severe cutaneous involvement in DM patients (Anti-TIF1g, Anti-MDA5, Anti-SAE1/2) were associated with a higher CDASI activity score. The presence of MSAs associated with intense muscle involvement in DM patients (Anti-Mi2a, Anti-Mi2b, Anti-NPX2, and Anti-SAE1/2) was related to a lower CDASI activity score. Gottron's sign and Gottron's papules in hands; capillary dilation, capillary tortuosity, cuticular hemorrhage, avascular areas, and cuticular hyperkeratosis in periungual folds; basal erythema in scalp; and gingival telangiectasias in the oral cavity were associated with a higher CDASI damage score. There are trichoscopic, oral and periungual fold findings and some myositis-specific antibodies that correlate with disease activity and damage in DM patients.

Rapidly progressive interstitial lung disease combined with pneumocystis jiroveci pneumonia in a patient with single anti-TIF-1γ antibody positive dermatomyositis in the context of an underlying tumor

BACKGROUND

Interstitial lung disease (ILD) is a frequently observed comorbidity in autoimmune diseases such as dermatomyositis/polymyositis (DM/PM), and it is significantly associated with specific autoantibody types. One unique antibody type is the anti-transcription intermediate factor-1γ antibody (anti-TIF-1γ Ab), which has a positive rate of only 7%. It is often found in combination with malignancy and rarely with ILD, particularly rapidly progressive ILD (RPILD). In some cases, the presence of ILD in individuals with DM may indicate a paraneoplastic syndrome. Pneumocystis jiroveci pneumonia (PJP) typically occurs due to intensive immunosuppressive therapy, human immunodeficiency virus (HIV) infection, or malignancy, and rarely as an isolated condition.

CASE PRESENTATION

A 52-year-old man with a history of rapid weight loss but non-HIV infected and not immunosuppressed who presented with fever, cough, dyspnea, weakness of the extremities, characteristic rash and mechanic's hand. Pathogenic tests suggested PJP, laboratory tests suggested a single anti-TIF-1γ Ab positive DM, imaging suggested ILD, and pathology revealed no malignancy. RPILD and acute respiratory distress syndrome (ARDS) developed after anti-infection and steroid hormone therapy. After mechanical support therapy such as Extracorporeal Membrane Oxygenation (ECMO), the patient developed late-onset cytomegalovirus pneumonia (CMVP), complicated bacterial infection, and ultimately death. Additionally, we discuss the potential causes of rapid weight loss, the mechanisms by which anti-TIF-1γ Ab may lead to ILD, and the possible connection between anti-TIF-1γ Ab positivity, rapid weight loss, immune abnormalities, and opportunistic infections.

CONCLUSIONS

This case emphasizes the importance of early recognition of malignant tumors and pulmonary lesions, assessment of the body's immune status, prompt initiation of immunosuppressive treatment, and prevention of opportunistic infections in individuals with single anti-TIF-1γ Ab positive DM presenting with rapid weight loss.

Genetic Influences in Cancer-Associated Myositis

Idiopathic inflammatory myopathies (IIMs) comprise a heterogeneous group of rare immune-mediated disorders that primarily affect muscles but also lead to dysfunction in other organs. Five different clinical subphenotypes of IIM have been distinguished: dermatomyositis, polymyositis, inclusion body myositis, antisynthetase syndrome, and immune-mediated necrotizing myopathy. Excess mortality and morbidity associated with IIM are largely attributed to comorbidities, particularly cancer. The risk of malignancy is not equally distributed among IIM groups and is particularly high among patients with dermatomyositis. The cancer risk peaks around 3 years on either side of the IIM diagnosis and remains elevated even 10 years after the onset of the disease. Lung, colorectal, and ovarian neoplasms typically arise before the onset of IIM, whereas melanoma, cervical, oropharyngeal, and nonmelanoma skin cancers usually develop after IIM diagnosis. Given the close temporal proximity between IIM diagnosis and the emergence of malignancy, it has been proposed that IIM could be a consequence rather than a cause of cancer, a process known as a paramalignant phenomenon. Thus, a separate group of IIMs related to paramalignant phenomenon has been distinguished, known as cancer-associated myositis (CAM). Although the relationship between IIM and cancer is widely recognized, the pathophysiology of CAM remains elusive. Given that genetic factors play a role in the development of IIM, dissection of the molecular mechanisms shared between IIM and cancer presents an opportunity to examine the role of autoimmunity in cancer development and progression. In this review, the evidence supporting the contribution of genetics to CAM will be discussed.

Five genes as diagnostic biomarkers of dermatomyositis and their correlation with immune cell infiltration

Background

Dermatomyositis (DM) is a rare autoimmune disease characterized by severe muscle dysfunction, and the immune response of the muscles plays an important role in the development of DM. Currently, the diagnosis of DM relies on symptoms, physical examination, and biopsy techniques. Therefore, we used machine learning algorithm to screen key genes, and constructed and verified a diagnostic model composed of 5 key genes. In terms of immunity, The relationship between 5 genes and immune cell infiltration in muscle samples was analyzed. These diagnostic and immune-cell-related genes may contribute to the diagnosis and treatment of DM.

Methods

GSE5370 and GSE128470 datasets were utilised from the Gene Expression Omnibus database as DM test sets. And we also used R software to merge two datasets and to analyze the results of differentially expressed genes (DEGs) and functional correlation analysis. Then, we could detect diagnostic genes adopting least absolute shrinkage and selection operator (LASSO) logistic regression and support vector machine recursive feature elimination (SVM-RFE) analyses. The validity of putative biomarkers was assessed using the GSE1551 dataset, and we confirmed the area under the receiver operating characteristic curve (AUC) values. Finally, CIBERSORT was used to evaluate immune cell infiltration in DM muscles and the correlations between disease-related biomarkers and immune cells.

Results

In this study, a total of 414 DEGs were screened. ISG15, TNFRSF1A, GUSBP11, SERPINB1 and PTMA were identified as potential DM diagnostic biomarkers(AUC > 0.85),and the expressions of 5 genes in DM group were higher than that in healthy group (p < 0.05). Immune cell infiltration analyses indicated that identified DM diagnostic biomarkers may be associated with M1 macrophages, activated NK cells, Tfh cells, resting NK cells and Treg cells.

Conclusion

The study identified that ISG15, TNFRSF1A, GUSBP11, SERPINB1 and PTMA as potential diagnostic biomarkers of DM and these genes were closely correlated with immune cell infiltration.This will contribute to future studies in diagnosis and treatment of DM.

Cancer associated autoantibodies in idiopathic inflammatory myopathies: A retrospective cohort from a single center in China

OBJECTIVES

Idiopathic inflammatory myopathies (IIMs) are systemic, heterogeneous diseases, which mainly affect skeletal muscle. Myositis with cancer is often referred to as cancer-associated myositis (CAM), which is associated with poor prognosis. This study aimed to determine the cancer associated myositis-specific autoantibodies (MSAs) and to elucidate their associations with clinical features in Chinese patients with IIMs.

METHODS

This retrospective study enrolled 312 patients with IIMs who were treated at Tianjin Medical University General Hospital, China, from January 2015 to December 2020. Clinical data were collected. Serum MSAs, including anti-Mi-2, anti-TIF1-γ, anti-NXP2, anti-SAE, anti-MDA5, anti-SRP, anti-Jo-1, anti-PL-7, anti-PL-12, anti-OJ, anti-EJ and anti-HMGCR antibodies were detected. Cancer-associated MSAs, their phenotypic and survival features were estimated through SPSS 20.0.

RESULTS

The results revealed that anti-TIF1-γ antibody and anti-SAE antibody were cancer-associated autoantibodies with odds ratios (95% CI) of 8.70 (3.35-22.64) and 22.31 (4.32-115.05), respectively. Skin lesions, proximal weakness, dysphagia and dysarthria were observed more frequently in patients carrying anti-TIF1-γ antibody. By contrast, patients with anti-TIF1-γ antibody had a lower frequencies of fever, arthritis/arthralgia and interstitial lung disease (ILD). Anti-TIF1-γ antibody positive CAM comprised about half of CAM entities and had the characteristic of close temporal association with cancer detection/recurrence. Female-dominant, common reproductive system tumors were other clinical features of this subset. Besides, patients with anti-TIF1-γ antibody positive had significantly lower survival rates than the anti-TIF1-γ antibody negative group.

CONCLUSIONS

Anti-TIF1-γ antibody and anti-SAE antibody were cancer-associated autoantibodies. Anti-TIF1-γ antibody positive CAM was a subset that comprised about half of CAM entities and had the characteristic of poor prognosis.

Necrotizing autoimmune myositis following coronavirus disease 2019 infection: a case report

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 may be associated with late-onset necrotizing myositis, mimicking autoimmune inflammatory myositis; however, the exact underlying pathogenesis of severe acute respiratory syndrome coronavirus 2-induced myositis is still unclear.

CASE PRESENTATION

Herein, we report a rare case of necrotizing autoimmune myositis in a 67-year-old middle eastern male following coronavirus disease 2019 infection, who presented with muscle weakness. The patient had positive anti-NXP2. The diagnosis of necrotizing autoimmune myositis was made according to muscle weakness, increased liver enzymes, electromyography and nerve conduction velocity results, and muscle biopsy. The patient underwent a full malignancy evaluation, which was unremarkable, and was discharged in relatively well condition with a daily dose of 1 mg/kg prednisolone and azathioprine 150 mg (2 mg/kg).

CONCLUSION

Our report highlights the already known possible protracted sequence of coronavirus disease 2019 infection and the potential for delayed-onset necrotizing myositis.

Therapeutic potential of mesenchymal stem cells for refractory inflammatory and immune skin diseases

Inflammatory and immunological skin diseases such as psoriasis, systemic sclerosis, dermatomyositis and atopic dermatitis, whose abnormal skin manifestations not only affected life quality but also caused social discrimination, have been wildly concerned. Complex variables such as hereditary predisposition, racial differences, age and gender can influence the prevalence and therapeutic options. The population of patients with unsatisfactory curative effects under current therapies is growing, it's advisable to seek novel and advanced therapies that are less likely to cause systemic damage. Mesenchymal stem cells (MSCs) have been proven with therapeutic benefits in tissue regeneration, self-renewal and differentiation abilities when treating refractory skin disorders in preclinical and clinical studies. Here we highlighted the immune modulation and inflammation suppression of MSCs in skin diseases, summarized current studies, research progress and related clinical trials, hoping to strengthen the confidence of promising MSCs therapy in future clinical application.

Histopathological risk factors for malignancy in dermatomyositis

AIMS

To identify possible histopathological risk factors for malignancy in skin biopsies of dermatomyositis patients.

METHODS AND RESULTS

We analysed clinical metadata and studied 30 skin biopsies of 11 patients with and 12 patients without associated malignancy that were treated in one secondary and one tertiary German medical center between 2009 and 2022 and fulfilling the EULAR/ACR classification criteria for dermatomyositis. Specimens were categorized by malignancy status and evaluated based on H&E, PAS, Alcian Blue and anti-CD123 immunohistochemistry stains. After correcting for multiple testing, biopsies of patients with cancer exhibited more severe basement membrane thickening (p<0.05) and pigment incontinence (p<0.05) compared to patients without tumour burden. Patients with numerous subepidermal melanophages had a more than 5-times increased odds ratio to suffer from an internal malignancy (OR 5.3, 95%CI 1.3-54.2, p<0.05). Furthermore, specimens of the malignancy group presented a distinct superficial distribution pattern of CD123+ plasmacytoid dendritic cells (PDCs, p<0.01). Extravascular eosinophils were absent in all cases.

CONCLUSIONS

Severity of basement membrane thickening, extent of pigment incontinence and superficial distribution pattern of CD123+ PDCs could serve as useful histopathological indicators of risk for malignancy in dermatomyositis.

Autoantibodies: Pathogenic or epiphenomenon

Idiopathic inflammatory myopathies (IIM) are heterogeneous autoimmune diseases. There are distinct subgroups, including antisynthetase syndrome, dermatomyositis, polymyositis, immune-mediated necrotizing myopathy, and sporadic inclusion body myositis. In patients with IIM, autoantibodies are present in up to 80% of the patients. These autoantibodies are often characterized as myositis-specific autoantibodies (MSA) or myositis-associated autoantibodies (MAA). The recognition of the importance of autoantibodies, especially MSA, is increasing in recent years. In this chapter, we provide an overview of the MSAs, including some new autoantibodies of interest as they target mainly muscle-specific autoantigen, in clinical classification, the measurement of the disease activity, and a possible role in the pathogenesis in the patients with IIM.

Thigh Muscle MRI Edema Features of Dermatomyositis Patients With Ovarian Cancer: A Report of Three Cases

Dermatomyositis (DM) is a rare inflammatory disease with systemic manifestations, including internal malignancy. Ovarian cancer is one of the most commonly found tumor types in DM patients. To date, no study has analyzed the MRI signals of dermatomyositis patients with cancer. Thus, in this report, we describe three cases in which we found ovarian cancer after the diagnosis of DM and observed a symmetrical honeycomb pattern edema signal distributed to the peripheral area of vastus laterals while adductors and posterior thigh compartments were relatively spared. Our report has important implications for clinicians to identify patients with dermatomyositis at potential ovarian cancer risk.

Pathophysiological Mechanisms and Treatment of Dermatomyositis and Immune Mediated Necrotizing Myopathies: A Focused Review

Idiopathic inflammatory myopathies (IIM), collectively known as myositis, are a composite group of rare autoimmune diseases affecting mostly skeletal muscle, although other organs or tissues may also be involved. The main clinical feature of myositis is subacute, progressive, symmetrical muscle weakness in the proximal arms and legs, whereas subtypes of myositis may also present with extramuscular features, such as skin involvement, arthritis or interstitial lung disease (ILD). Established subgroups of IIM include dermatomyositis (DM), immune-mediated necrotizing myopathy (IMNM), anti-synthetase syndrome (ASyS), overlap myositis (OM) and inclusion body myositis (IBM). Although these subgroups have overlapping clinical features, the widespread variation in the clinical manifestations of IIM suggests different pathophysiological mechanisms. Various components of the immune system are known to be important immunopathogenic pathways in IIM, although the exact pathophysiological mechanisms causing the muscle damage remain unknown. Current treatment, which consists of glucocorticoids and other immunosuppressive or immunomodulating agents, often fails to achieve a sustained beneficial response and is associated with various adverse effects. New therapeutic targets have been identified that may improve outcomes in patients with IIM. A better understanding of the overlapping and diverging pathophysiological mechanisms of the major subgroups of myositis is needed to optimize treatment. The aim of this review is to report on recent advancements regarding DM and IMNM.

Myositis-specific Antibodies: Overview and Clinical Utilization

Purpose of review-To review autoantibodies associated with different subtypes of idiopathic inflammatory myopathy (IIM) and their clinical applications. IIM are a heterogenous group of autoimmune disorders characterized by muscle weakness, cutaneous features, and internal organ involvement. The diagnosis and classification, which is often challenging, is made using a combination of clinical features, muscle enzyme levels, imaging, and biopsy. The landmark discoveries of novel autoantibodies specific to IIM subtypes have been one of the greatest advancements in the field of myositis. The specificity of these autoantibodies has simplified the diagnostic algorithm of IIM with their heterogenous presentation and outdated the earlier diagnostic criteria. Myositis-specific antibodies (MSAs) have improved diagnostics, clinical phenotyping, and prognostic stratification of the subtypes of IIMs. Furthermore, the levels of certain MSAs correlate with disease activity and muscle enzyme levels such that titers may be able to be used to predict disease course and treatment response.

Machine Learning Algorithms Identify Clinical Subtypes and Cancer in Anti-TIF1γ+ Myositis: A Longitudinal Study of 87 Patients

Background

Anti-TIF1γ antibodies are a class of myositis-specific antibodies (MSAs) and are closely associated with adult cancer-associated myositis (CAM). The heterogeneity in anti-TIF1γ+ myositis is poorly explored, and whether anti-TIF1γ+ patients will develop cancer or not is unknown at their first diagnosis. Here, we aimed to explore the subtypes of anti-TIF1γ+ myositis and construct machine learning classifiers to predict cancer in anti-TIF1γ+ patients based on clinical features.

Methods

A cohort of 87 anti-TIF1γ+ patients were enrolled and followed up in Xiangya Hospital from June 2017 to June 2021. Sankey diagrams indicating temporal relationships between anti-TIF1γ+ myositis and cancer were plotted. Elastic net and random forest were used to select and rank the most important variables. Multidimensional scaling (MDS) plot and hierarchical cluster analysis were performed to identify subtypes of anti-TIF1γ+ myositis. The clinical characteristics were compared among subtypes of anti-TIF1γ+ patients. Machine learning classifiers were constructed to predict cancer in anti-TIF1γ+ myositis, the accuracy of which was evaluated by receiver operating characteristic (ROC) curves.

Results

Forty-seven (54.0%) anti-TIF1γ+ patients had cancer, 78.7% of which were diagnosed within 0.5 years of the myositis diagnosis. Fourteen variables contributing most to distinguishing cancer and non-cancer were selected and used for the calculation of the similarities (proximities) of samples and the construction of machine learning classifiers. The top 10 were disease duration, percentage of lymphocytes (L%), percentage of neutrophils (N%), neutrophil-to-lymphocyte ratio (NLR), sex, C-reactive protein (CRP), shawl sign, arthritis/arthralgia, V-neck sign, and anti-PM-Scl75 antibodies. Anti-TIF1γ+ myositis patients can be clearly separated into three clinical subtypes, which correspond to patients with low, intermediate, and high cancer risk, respectively. Machine learning classifiers [random forest, support vector machines (SVM), extreme gradient boosting (XGBoost), elastic net, and decision tree] had good predictions for cancer in anti-TIF1γ+ myositis patients. In particular, the prediction accuracy of random forest was &gt;90%, and decision tree highlighted disease duration, NLR, and CRP as critical clinical parameters for recognizing cancer patients.

Conclusion

Anti-TIF1γ+ myositis can be separated into three distinct subtypes with low, intermediate, and high risk of cancer. Machine learning classifiers constructed with clinical characteristics have favorable performance in predicting cancer in anti-TIF1γ+ myositis, which can help physicians in choosing appropriate cancer screening programs.

Antinuclear Antibody (ANA) and Anti-Mi-2-Alpha Positive Dermatomyositis Hinting a Cancer Diagnosis

Dermatomyositis (DM) is a relatively uncommon inflammatory myopathy that has been linked to cancer. We report the case of an 81-year-old woman with cecum adenocarcinoma presenting with antinuclear antibody (ANA) and anti-Mi-2-alpha antibody-positive DM. The patient complained of anorexia, symmetric proximal muscle weakness and skin rash and presented with elevated muscle enzymes. A skin and muscle biopsy supported the diagnosis of DM as did the limbs magnetic resonance imaging (MRI) and electromyography. A diagnosis of localized adenocarcinoma of the cecum was made through colonoscopy and the patient was successfully surgically managed, with decreasing muscle enzymes at discharge and gradual recovery of muscle strength. The presence of both ANA and anti-Mi-2 autoantibodies has classically been described as comprising a better prognosis with a lower risk of underlying malignancy.

This case highlights the importance of pursuing a cancer diagnosis in elderly patients presenting with DM even in presence of less predisposing immunological profiles.

A Commercial Anti-TIF1γ ELISA Is Superior to Line and Dot Blot and Should Be Considered as Part of Routine Myositis-Specific Antibody Testing

Objectives

Anti-TIF1γ is an important autoantibody in the diagnosis of cancer-associated dermatomyositis and the most common autoantibody in juvenile onset dermatomyositis. Its reliable detection is important to instigate further investigations into underlying malignancy in adults. We previously showed that commercial assays using line and dot blots do not reliably detect anti-TIF1γ. We aimed to test a new commercial ELISA and compare with previously obtained protein immunoprecipitation.

Methods

Radio-labelled immunoprecipitation had previously been used to determine the autoantibody status of patients with immune-mediated inflammatory myopathies and several healthy controls. ELISA was undertaken on healthy control and anti-TIF1γ sera and compared to previous immunoprecipitation data.

Results

A total of 110 serum samples were analysed: 42 myositis patients with anti- TIF1γ and 68 autoantibody negative healthy control sera. Anti-TIF1γ was detected by ELISA in 41 out of 42 of the anti-TIF1γ-positive samples by immunoprecipitation, and in none of the healthy controls, giving a sensitivity of 97.6% and specificity of 100%. The false negative rate was 2%.

Conclusion

ELISA is an affordable and time-efficient method which is accurate in detecting anti-TIF1γ.

COVID-19 Disease and Dermatomyositis: A Mini-Review

The pandemic of coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 has caused a large number of deaths, and there is still no effective treatment. COVID-19 can induce a systemic inflammatory response, and its clinical manifestations are diverse. Recently, it has been reported that COVID-19 patients may develop myositis and interstitial pulmonary disease similar to dermatomyositis (DM). This condition is similar to the rapidly progressive interstitial lung disease associated with MDA5+ DM that has a poor prognosis and high mortality, and this poses a challenge for an early identification. Suppression of the immune system can protect COVID-19 patients by preventing the production of inflammatory cytokines. This article attempts to explore the possibility of a relationship between COVID-19 and DM in terms of the potential pathogenesis and clinical features and to analyze the therapeutic effect of the immunosuppressive drugs that are commonly used for the treatment of both DM and COVID-19.

En garde! The duel functions of MORC3

Effector-triggered immunity involves "guarded" host processes that, when perturbed by pathogen factors, prompt a secondary response. A recent study published in Nature by Gaidt et al. demonstrates that MORC3 serves as both the guard and the guarded antiviral host factor-creating a "heads, I win; tails, you lose!" scenario.

Update on Malignancy in Myositis—Well-Established Association with Unmet Needs

Idiopathic inflammatory myopathies are a group of rare connective tissue diseases with a well-documented association with malignancy. The mechanisms underlying the increased risk of neoplasms in the course of myositis are not fully understood. The Pubmed database has been thoroughly screened for articles concerning cancer-associated myositis (CAM). The article summarizes the current state of knowledge on the epidemiology and pathogenesis of CAM. Furthermore, it analyses potential risk and protective factors for developing CAM, with particular emphasis on the association with distinct serological profiles. The review summarizes recommendations proposed so far for the management of CAM and presents a novel scheme for cancer screening proposed by the authors. Moreover, promising areas requiring further research were indicated.

Autoantibodies in Common Connective Tissue Diseases: A Primer for Laboratory Professionals

Background

Autoimmune connective tissue disorders are a significant health concern throughout the world with an estimated prevalence of 3% to 5%. They are associated with a variety of autoantibodies that play roles in their diagnosis, risk stratification, prognostication, and/or management. While some autoantibodies have been well-characterized for use in clinical laboratories, many more are in the research stage. Rapid transition from research to clinical practice, lack of clinical guidelines, and harmonization across a rapidly growing number of commercially available tests create numerous challenges to clinicians and laboratories.

Content

This article briefly discusses common connective tissue disorders and their association with well-known autoantibodies, describes current methods used in clinical laboratories, and outlines their advantages and limitations in the context of these diseases.

Summary

Understanding the role of specific autoantibodies and various methodologies for autoantibody testing are important for laboratory professionals who may be introducing/repatriating new tests, updating existing tests, or advising clinicians/patients about testing options/results. Collaboration between laboratory professional staff and clinicians, around the advantages and limitations of each methodology, is also important in their appropriate clinical utilization.

A rare case of NXP-2 positive dermatomyositis

Dermatomyositis is an idiopathic inflammatory myopathy with variable cutaneous manifestations. Several autoantibodies each with distinct clinical phenotypes are associated with the disease. Here we present the case of a 36-year-old Laotian woman with hypothyroidism who presented with severe proximal and distal muscle weakness, dysphagia, diffuse rash, and anasarca that was diagnosed with NXP-2 (nuclear matrix protein 2) antibody positive dermatomyositis. The patient's hospitalization was complicated by disease resistant to conventional therapy.

Polymyositis and dermatomyositis: ocular manifestations and potential sight-threatening complications

Dermatomyositis (DM) and polymyositis (PM) are idiopathic inflammatory myopathies characterized by progressive, symmetric, mainly proximal muscle weakness. DM is also characterized by cutaneous involvement. However, other clinical features, systemic involvement, histopathological findings, response to treatment, and prognosis, differ significantly. Although uncommon, ocular manifestations in DM and PM may potentially affect any structure within the eye. Notwithstanding being generally mild, ocular involvement in DM and PM may result in significant morbidity. Left untreated, significant retinal inflammation associated with hemorrhage and detachment may occur, leading to significant vision loss. This review aims to present an up-to-date overview for rheumatologists about the ocular involvement and potential complications of DM and PM and when to refer to the ophthalmologist to avoid sight-threatening complications.

Anti-TIF1 gamma-positive IPAF patient developed stage IVB lung squamous carcinoma in 1 year: a case report

Background

Patients with connective tissue disease, such as dermatomyositis (DM), and positive anti-TIF1γ self-antibodies are commonly diagnosed with malignant tumors as a comorbidity. The relationship between anti-TIF1γ self-antibodies and existing malignant tumors has been confirmed by several reports. However, interstitial pneumonia with autoimmune features (IPAF) cases with a positive anti-TIF1γ self-antibody developing to solid malignant tumors are rarely reported now.

Case presentation

Herein, we presented an IPAF patient with anti-TIF1γ self-antibodies. No evidence of malignant tumors was found at the initial visit. However, the patient had developed stage IVB lung squamous cell carcinoma at the 1-year follow-up review.

Conclusions

Altogether, this report described a rare case of IPAF patient with anti-TIF1γ self-antibodies developed to advanced lung squamous cell carcinoma in 1 year. The present case highlights more frequent imaging examinations to identify the occurrence of malignant tumors as early as possible in IPAF patients with positive anti-TIF1γ self-antibodies.

Autoimmunity as an Etiological Factor of Cancer: The Transformative Potential of Chronic Type 2 Inflammation

Recent epidemiological studies have found an alarming trend of increased cancer incidence in adults younger than 50 years of age and projected a substantial rise in cancer incidence over the next 10 years in this age group. This trend was exemplified in the incidence of non-cardia gastric cancer and its disproportionate impact on non-Hispanic white females under the age of 50. The trend is concurrent with the increasing incidence of autoimmune diseases in industrialized countries, suggesting a causal link between the two. While autoimmunity has been suspected to be a risk factor for some cancers, the exact mechanisms underlying the connection between autoimmunity and cancer remain unclear and are often controversial. The link has been attributed to several mediators such as immune suppression, infection, diet, environment, or, perhaps most plausibly, chronic inflammation because of its well-recognized role in tumorigenesis. In that regard, autoimmune conditions are common causes of chronic inflammation and may trigger repetitive cycles of antigen-specific cell damage, tissue regeneration, and wound healing. Illustrating the connection between autoimmune diseases and cancer are patients who have an increased risk of cancer development associated with genetically predisposed insufficiency of cytotoxic T lymphocyte-associated protein 4 (CTLA4), a prototypical immune checkpoint against autoimmunity and one of the main targets of cancer immune therapy. The tumorigenic process triggered by CTLA4 insufficiency has been shown in a mouse model to be dependent on the type 2 cytokines interleukin-4 (IL4) and interleukin-13 (IL13). In this type 2 inflammatory milieu, crosstalk with type 2 immune cells may initiate epigenetic reprogramming of epithelial cells, leading to a metaplastic differentiation and eventually malignant transformation even in the absence of classical oncogenic mutations. Those findings complement a large body of evidence for type 1, type 3, or other inflammatory mediators in inflammatory tumorigenesis. This review addresses the potential of autoimmunity as a causal factor for tumorigenesis, the underlying inflammatory mechanisms that may vary depending on host-environment variations, and implications to cancer prevention and immunotherapy.

Inflammatory myopathies associated with myelodysplastic syndromes: A French multicenter case control study and literature review

OBJECTIVE

Patients with inflammatory myopathies (IM) are known to have an increased risk of developing malignancies. Autoimmune and inflammatory diseases occur in up to 25% of patients with myelodysplastic syndrome (MDS). This study aimed to describe the rare association between IM and MDS.

METHODS

We report here the main characteristics, treatment, and outcome of 21 patients (11 national cases and 10 additional cases from a literature review) with IM associated to MDS.

RESULTS

Median age of patients at IM diagnosis was 66 years (range 26 - 78). Diagnosis of the two conditions were concomitant in most patients (n=14/21) whereas MDS diagnosis preceded IM diagnosis in 5 patients. Different types of IM were observed but dermatomyositis was the most frequent (59%). Compared to IM without MDS (IM/MDS^-), patients with MDS (IM/MDS⁺) were older (median 66 vs 55, p=0.3), more frequently male (sex ratio M/F 1.125 vs 0.41, p=0.14) and positive for anti-TIF1γ (24% vs 4%, p=0.0039). Antisynthetase syndrome was never observed among IM/MDS⁺ patients (0% vs 28%, p=0.01). MDS WHO type was not univocal, but the prognostic score was of low risk in almost all cases. IM was usually steroid sensitive (82% of patients) but often steroid dependent (56% of patients). Overall survival of IM patients with MDS was worse compared to patients with IM without MDS (p=0.0002).

CONCLUSION

IM associated with MDS are mainly represented by dermatomyositis and/or anti-TIF1γ autoantibodies. Antisynthetase syndrome has not been described in association with MDS. Despite low-risk MDS, overall survival of IM patients with MDS is worse than IM patients without MDS.

TRIM33 gene somatic mutations identified by next generation sequencing in neoplasms of patients with anti-TIF1γ positive cancer-associated dermatomyositis

OBJECTIVE

To deep sequence the TRIM33 gene in tumours from patients with cancer-associated anti-TIF1γ autoantibody-positive dermatomyositis (DM) since TRIM33 somatic mutations in tumours may trigger this auto-immune disease.

METHODS

Next generation sequencing of tumour DNA samples from patients with cancer-associated anti-TIF1γ autoantibody-positive DM. Fourteen tumours from 13 anti-TIF1γ autoantibody-positive DM individuals were sequenced along with 2 control tumours from non-DM individuals.

RESULTS

Fourteen probable somatic variants from 4 tumours were identified in the TRIM33 gene.

CONCLUSION

These results are in accordance with the previous report of Pinal-Fernandez et al. and support the hypothesis of a role of TRIM33 gene mutations in the pathophysiology of anti-TIF1γ autoantibody-positive DM.

Anti-transcription intermediary factor 1 gamma (TIF1γ) antibody-positive dermatomyositis associated with ascending colon cancer: a case report and review of the literature

Background

Anti-transcriptional intermediary factor 1 gamma (TIF1γ) antibody is a marker for predicting cancer association in patients with dermatomyositis (DM). The overall survival rate in DM patients with cancer was reported to be considerably worse than that in DM patients without cancer. However, the treatment for cancer-associated DM remains controversial, because the treatment priority between surgical resection for the tumor and internal treatments, including glucocorticoids, immunosuppressive agents, and intravenous immune globulin, has not been established.

Case presentation

We report the case of a 57-year-old Japanese man diagnosed with anti-TIF1γ antibody-positive DM associated with ascending colon cancer. His clinical symptoms included facial and brachial edema, muscle weakness, dysphagia, myalgia, and rash. Physical examination revealed periorbital edema and Gottron's papules over his knuckles with brachial edema, and tenderness and weakness of the proximal limb muscles. The findings of hyperintense muscles in T2-weighted sequences of brachial contrast-enhanced magnetic resonance imaging and the infiltration of lymphocytic cells and CD4-positive lymphocytes from muscle biopsy were compatible with the diagnostic criteria for dermatomyositis. Anti-TIF1γ antibody was positive by immunoprecipitation assay. He first started internal treatment including intravenous immunoglobulin, steroid pulse, prednisolone, and azathioprine, followed by surgical resection for the tumor because of the elevation of creatine kinase and progression of dysphagia. However, clinical symptoms did not improve, and the patient died 6 months later.

Conclusions

We faced difficulties in determining the treatment priority between surgical resection and internal treatment for our case; therefore, this case would be educational for readers. We searched PubMed to identify English-language case reports of anti-TIF1γ antibody-positive dermatomyositis with malignancy and found 21 reported cases. We herein review and summarize previously reported cases of anti-TIF1γ antibody-positive DM with malignancy. Cancer screening is essential in patients with anti-TIF1γ antibody-positive dermatomyositis because it is associated with a high prevalence of malignancies. Our review revealed that initial surgical treatment should be recommended for better prognosis if the general condition allows.

Risk factors for cancer-associated myositis: A large-scale multicenter cohort study

AIM

The aim of this study was to identify the risk factors and prognosis of patients with cancer-associated myositis (CAM).

METHOD

Four hundred and eighty-seven patients with dermatomyositis (DM), clinical amyopathic dermatomyositis (CADM) and polymyositis (PM) from 3 clinical centers were enrolled retrospectively in this study. Clinical and laboratory data of CAM and non-CAM patients were compared. Logistic regression analysis was used to identify risk factors of CAM.

RESULTS

Out of the 487 patients with DM/CADM/PM, 7.0% (34/487) of patients were classified as CAM. Older age (53.91 ± 13.32 vs. 48.76 ± 14.34 years), heliotrope rash (61.8% vs. 41.9%), shawl sign (41.2% vs. 22.1%), V sign (58.8% vs. 38.6%) were observed significantly more commonly in patients with CAM than those without CAM (all P < .05). Fever (17.7% vs. 37.8%), arthralgia/arthritis (23.5% vs. 45.7%), interstitial lung disease (ILD, 38.2% vs 68.9%) were significantly less common in the CAM group than the non-CAM group. Age at onset (odds ratio [OR] 1.036, 95% CI 1.001-1.072, P = .042), shawl sign (OR 2.748, 95% CI 1.107-6.822, P = .029), anti-transition initiation factor (TIF)-1γ antibody (OR 4.012, 95% CI 1.268-12.687, P = .018) were identified as the initial risk factors for the onset of CAM, and ILD was identified as a protective factor for CAM (OR 0.292, 95% CI 0.115-0.739, P = .009). All-cause mortality was significantly higher in CAM patients compared with non-CAM patients (P = .001).

CONCLUSION

The mortality of patients with CAM was higher than DM/CADM/PM patients without cancer. Malignancy should be screened in DM/CADM/PM patients especially with risk factors, including older age, shawl sign, anti-TIF-1γ antibody, and lack of ILD.

Overall and site-specific cancer before and after diagnosis of idiopathic inflammatory myopathies: A nationwide study 2002-2016

OBJECTIVE

To examine the association between idiopathic inflammatory myopathy (IIM) and cancer before and after IIM diagnosis.

METHODS

We used prospectively collected nationwide register data to design a case-control study to investigate the occurrence of cancer before IIM, and a cohort study to investigate the occurrence of cancer after IIM. Patients diagnosed with IIM between 2002 and 2016 in Sweden, were compared to the general population. The association between cancer and IIM was estimated before and after IIM diagnosis via logistic regression and Cox regression models, respectively.

RESULTS

We included 1419 patients with IIM and 7045 individuals from the general population. The overall odds of cancer before IIM diagnosis were increased in IIM compared to the general population, adjusted odds ratio (AOR) 1.5, 95% confidence interval (CI) 1.3-1.8. This association was also noted after IIM diagnosis, adjusted hazard ratio (AHR) 1.7 (95% CI 1.4-2.0), or one additional cancer in every 125 IIM patients per year. Colorectal (AOR 2.1), lung (AOR 5.4) and ovarian (AOR 7.0) cancers were associated with IIM before diagnosis. Oropharyngeal (AHR 9.1) and cervical (AHR 3.8) cancers, malignant melanoma (AHR 3.2) and non-melanoma skin cancer (AHR 3.1) were associated with IIM after diagnosis. Adenocarcinomas were associated with dermatomyositis before diagnosis and squamous cell cancers after IIM diagnosis. Lymphatic hematopoietic cancers were associated with IIM both before and after diagnosis.

CONCLUSIONS

The cancer types that occur before IIM diagnosis differ from the ones that occur after diagnosis. This may have an impact on screening decisions for IIM.

A novel autoantibody targeting calreticulin is associated with cancer in patients with idiopathic inflammatory myopathies

Objectives

To investigate the prevalence and clinical significance of anti‐calreticulin autoantibodies (anti‐CRT Ab) in a large cohort of idiopathic inflammatory myopathy (IIM) patients.

Methods

Sera from 469 patients with IIM, 196 patients with other connective tissue diseases, 28 patients with solid tumors and 81 healthy controls were screened for anti‐CRT Ab by enzyme‐linked immunosorbent assay using human recombinant CRT protein. Sera from 35 IIM patients were tested using an immunoprecipitation assay to confirm the presence of anti‐CRT Ab. Subsequently, IIM–cancer patients were identified and divided into new‐onset, remission and recurrent groups based on their cancer status. The relationships between anti‐CRT Ab levels and IIM disease activity were also investigated.

Results

Serum anti‐CRT Ab was detected positive in 81 of the 469 (17.3%) IIM patients. Immunoprecipitated bands were observed at a molecular weight of 60 kDa corresponding to the CRT protein. The IIM patients with anti‐CRT Ab more frequently had cancers compared to the patients without anti‐CRT Ab. Moreover, the prevalence of anti‐CRT Ab differed according to the cancer status. The IIM patients with recurrent cancers had a much higher prevalence of anti‐CRT Ab than those with cancers in remission. Also, serum anti‐CRT Ab levels positively correlated with disease activity at baseline and at follow‐up visits.

Conclusion

We report the existence of serum anti‐CRT Ab in IIM patients and demonstrate the possible association of anti‐CRT Ab with malignancy in IIM patients. Serum anti‐CRT Ab could serve as a novel candidate marker of cancer in IIM patients.

Clinical features of anti-transcription intermediary factor 1γ (TIF1γ)-positive dermatomyositis with internal malignancy and investigation of the involvement of TIF1γ expression in tumors in the pathogenesis of cancer-associated dermatomyositis

Anti-transcription intermediary factor 1γ (anti-TIF1γ) antibody (Ab) is significantly associated with internal malignancies in adult patients with dermatomyositis (DM). Although pathogenesis of cancer-associated DM is unknown, TIF1γ overexpression in tumors has been considered to be critical for the development of DM. The objective of this study was to investigate clinical characteristics of patients with anti-TIF1γ Ab-positive DM and elucidate risk factors that are potentially associated with internal malignancy. In addition, we compared the expression of TIF1γ in tumor tissues of patients with anti-TIF1γ Ab-positive DM, anti-TIF1γ Ab-negative DM and without DM in order to investigate the pathogenesis of cancer-associated DM. We analyzed 77 Japanese patients with DM, and found 19 patients to be positive for anti-TIF1γ Ab. Patients with anti-TIF1γ Ab-positive DM were older and presented heliotrope rash and flagellate erythema more frequently than patients without anti-TIF1γ Ab (P < 0.05). Interstitial lung disease (ILD) and rapidly progressive ILD, as well as palmar violaceous erythema, were less frequent in patients with anti-TIF1γ Ab than in patients without. Furthermore, internal malignancy and dysphagia were significantly more frequent in the anti-TIF1γ Ab-positive group (P < 0.01). Male sex and dysphagia were significantly associated with internal malignancy in patients with anti-TIF1γ Ab-positive DM (P < 0.01 and <0.05, respectively). Using immunohistochemistry, we examined the TIF1γ expression in tumors of 11 patients with cancer-associated DM (anti-TIF1γ Ab-positive, nine; anti-TIF1γ Ab-negative, two) and 25 patients without DM. TIF1γ was highly expressed in all tumors, and there was no significant difference in TIF1γ expression between patients with and without DM. Furthermore, TIF1γ expressions in tumors were similar irrespective of the presence of anti-TIF1γ Ab. These results suggest that anti-TIF1γ antibody may not be simply induced by overexpression of TIF1γ in tumors in patients with DM, but that other mechanisms may exist.

Anti-TIF1-γ autoantibodies: warning lights of a tumour autoantigen

Anti-transcription intermediary factor 1 (TIF1)-γ autoantibodies are robustly linked with cancer-associated DM in adults. This review aims to give an overview of the physiological context of TIF1-γ and to determine whether there is a pathophysiological link between anti-TIF1-γ autoantibodies and the occurrence of cancer. Detection of anti-TIF1-γ autoantibodies has a high sensitivity and specificity for cancer-associated DM in adults and is therefore useful for both diagnosis and cancer risk stratification. The function of the autoantigen, TIF1-γ, may provide insight into the mechanism behind this association. TIF1-γ is a ubiquitously present protein involved in various biological pathways, including TGF-β signalling. In cancer, it can act either as a tumour suppressor or promoter, depending on the cellular context and cancer stage. Evolving data provide pathophysiological insights, linking anti-TIF1-γ autoantibodies to both the anti-tumour response and to muscle and skin damage. TIF1-γ expression is increased in muscle and skin tissue of patients with DM. Mutations or loss-of-heterozygosity in TIF1-γ alleles in malignant tissue may result in the expression of tumour-specific neo-antigens stimulating autoantibody production. The newly formed autoantibodies are hypothesized to cross-react with antigens in muscle and skin, driving the development of DM. Based on the current evidence, anti-TIF1-γ autoantibodies should be considered warning lights of a potential tumour autoantigen and should alert the physician to the possibility of an underlying cancer.

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‐2β, 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.

Anti-TIF1gamma Antibody-Positive Dermatomyositis Associated with Myelodysplastic Syndrome: Response to Treatment

Dermatomyositis (DM) classically presents as a dyad of typical cutaneous findings and varying degrees of proximal muscle weakness. Interestingly, the development of DM may signal underlying malignancy, and numerous myositis-specific autoantibodies have been associated with this paraneoplastic phenomenon. Positivity for anti-TIF1gamma antibody, in particular, raises suspicion for cancer-associated DM. Here, we present an unusual case of anti-TIF1gamma antibody-positive DM that ultimately lead to the diagnosis of myelodysplastic syndrome (MDS). Importantly, topical treatment and chemotherapy targeting MDS resulted in a swift and remarkable amelioration of cutaneous disease.

Malignancy and myositis, from molecular mimicry to tumor infiltrating lymphocytes

Cancer-associated dermatomyositis provides a unique opportunity to explore the relationship between autoimmunity and cancer. In this review, we describe the related epidemiological issues, considering the various currently accepted myositis phenotypes, their link with cancer, and the possible mechanisms leading to this relationship. We discuss current evidence regarding the role of molecular mimicry, somatic DNA tumor mutations, and the PD-1/PD-L1 pathway in the association between cancer and myositis. We also review tumor-infiltrating lymphocytes as a relevant factor to be evaluated in cancer-associated myositis, their interaction with tumor neoantigens, and the tumor mutational burden, all of which have implications for the treatment of these patients with immunotherapy. Finally, we discuss clinical scenarios related to the relationship between cancer and myositis, delineating a comprehensive theory linking autoimmunity and cancer.

Autoantibodies in myositis

The discovery of novel autoantigen systems related to idiopathic inflammatory myopathies (collectively referred to as myositis) in adults and children has had major implications for the diagnosis and management of this group of diseases across a wide range of medical specialties. Traditionally, autoantibodies found in patients with myositis are described as being myositis-specific autoantibodies (MSAs) or myositis-associated autoantibodies (MAAs), depending on their prevalence in other, related conditions. However, certain MSAs are more closely associated with extramuscular manifestations, such as skin and lung disease, than with myositis itself. It is very rare for more than one MSA to coexist in the same individual, underpinning the potential to use MSAs to precisely define genetic and disease endotypes. Each MSA is associated with a distinctive pattern of disease or phenotype, which has implications for diagnosis and a more personalized approach to therapy. Knowledge of the function and localization of the autoantigenic targets for MSAs has provided key insights into the potential immunopathogenic mechanisms of myositis. In particular, evidence suggests that the alteration of expression of a myositis-related autoantigen by certain environmental influences or oncogenesis could be a pivotal event linking autoantibody generation to the development of disease.

Clinical characteristics of cancer-associated myositis complicated by interstitial lung disease: a large-scale multicentre cohort study

Objective

To clarify the incidence, risk factors, and impact of malignancy in patients with PM/DM-associated interstitial lung disease (ILD).

Methods

This study used data from 497 patients with PM/DM-associated ILD enrolled in a multicentre, retrospective and prospective cohort of incident cases. Cancer-associated myositis (CAM) was defined as malignancy diagnosed within 3 years before or after PM/DM diagnosis. Demographic and clinical information was recorded at the time of diagnosis, and data about the occurrence of mortality and malignancy was collected.

Results

CAM was identified in 32 patients with PM/DM-associated ILD (6.4%). Patients with CAM were older (64 vs 55 years, P &lt; 0.001), presented with arthritis less frequently (24% vs 49%, P = 0.01), and showed a lower level of serum Krebs von den Lungen-6 (687 vs 820 IU/l, P = 0.03) than those without CAM. The distribution of myositis-specific autoantibodies, including anti-melanoma differentiation–associated gene 5, anti-aminoacyl tRNA synthetase, and anti-transcriptional intermediary factor 1-γ antibodies, did not differ between the groups. Survival analysis demonstrated that CAM patients had a poorer survival than non-CAM patients (P = 0.006), primarily due to excess deaths by concomitant malignancy, while mortality due to ILD-related respiratory failure was similar between the groups (P = 0.51).

Conclusion

Concomitant malignancy can occur in patients with PM/DM-associated ILD, and has significant impact on mortality. Older age, lack of arthritis, and a lower level of serum Krebs von den Lungen-6 at diagnosis are predictors of concomitant malignancy.