Increased MxA protein expression and dendritic cells in spongiotic dermatitis differentiates dermatomyositis from eczema in a single-center case-control study.

BACKGROUND: Dermatomyositis (DM) is conventionally characterized by interface dermatitis (ID) on skin histopathology. A subset of DM patients has skin biopsies showing spongiotic dermatitis (SD), a histopathology more commonly seen in eczema. In this study, we aimed to (a) identify the percentage of clinically diagnosed DM patients with SD skin biopsies, (b) identify cytokine and cell markers that can help determine if a SD skin biopsy is consistent with DM. METHODS: In this case-control study, biopsy specimens from ten DM patients with SD (DM-SD) were compared to specimens from ten healthy controls, ten patients with eczema, and 12 patients with DM with ID (DM-ID). Specimens were stained by immunohistochemistry for MxA, IFN-ß, CD11c, and BDCA2. One-way ANOVA with Bonferroni's multiple comparison test was used to compare protein expression between groups. RESULTS: Eleven of 164 (6.7%) patients with a clinical diagnosis of DM at our tertiary care center were identified as having SD. MxA, IFN-ß, CD11c, and BDCA2 protein expression was significantly higher in DM-SD compared to eczema and healthy controls. Expressions of MxA, IFN-ß, and BDCA2 were not significantly different between DM-SD and DM-ID. CONCLUSION: Increased MxA, IFN-ß, CD11c, and BDCA2 protein expression may aid in distinguishing between DM-SD and eczema and warrants further investigation.

Phenotypic characteristics and outcome of juvenile dermatomyositis in Arab children.

This study describes the disease characteristics and outcome of Arab children with juvenile dermatomyositis (JDM) and compares the findings with other ethnicities. We retrospectively reviewed the hospital registries of the participating hospitals for children with JDM seen between 1990 and 2016 in three Arab countries. All patients fulfilled Bohan and Peter criteria for JDM, diagnosed before 14 years of age and were of Arab ethnicity. Clinical and laboratory features as well as the long-term outcomes including accrual disease damage were collected at the last follow-up visit. A total of 92 JDM patients (58 girls) were included. Mean age at the onset was 6 ± 3 years, with a mean follow-up duration of 5 ± 4.4 years. Forty-three patients (46.7%) had polycyclic disease course, 34 (36.9%) had a monocyclic course, while 15 (16.3%) had a continuous progressive course. Forty-five patients (48.9%) had arthritis, 14 (15.2%) patients had an upper airway and dysphagia, and 10 patients (10.9%) had lung involvement. Eight patients (8.7%) were admitted to the intensive care unit (ICU), 4 of them required mechanical ventilation. Methotrexate had been the most frequently used immunosuppressive drug (86%) and rituximab was used in eight patients. Additionally, 31 patients received IVIG. Most of the patients achieved a complete clinical response, but 16 ended up with permanent skin changes and 12 had a residual muscle weakness. Twenty-seven patients developed calcinosis. There were two deaths due to infection during the follow-up period. We report the largest phenotypic data on Arab children with JDM. Our patients have similar characteristics to previously described cohorts. Majority of the patients remained with inactive disease.

Clinical and laboratory features of fatal rapidly progressive interstitial lung disease associated with juvenile dermatomyositis.

OBJECTIVE: Rapidly progressive interstitial lung disease (RP-ILD) is a rare but potentially fatal complication of JDM. The aim of this study was to establish markers for the prediction and early diagnosis of RP-ILD associated with JDM. METHODS: The clinical records of 54 patients with JDM were retrospectively reviewed: 10 had RP-ILD (7 died, 3 survived), 19 had chronic ILD and 24 were without ILD. Routine tests included a high-resolution CT (HRCT) scan of the chest and measurement of serum levels of creatine phosphokinase, ferritin and Krebs von den Lungen-6 (KL-6). Anti-melanoma differentiation-associated gene 5 (MDA5) antibodies and IL-18 levels were measured by ELISA. RESULTS: No differences were found in the ratio of juvenile clinically amyopathic DM between the three groups. Initial chest HRCT scan findings were variable and could not distinguish between RP-ILD and chronic ILD. Anti-MDA5 antibodies were positive in all 8 patients with RP-ILD and 10 of 14 with chronic ILD, but none of the patients without ILD. Serum levels of anti-MDA5 antibody, ferritin, KL-6 and IL-18 were significantly higher in the RP-ILD group than in the chronic ILD and non-ILD groups. Serum levels of IL-18 positively correlated with serum KL-6 (R = 0.66, P < 0.001). CONCLUSION: High serum levels of IL-18, KL-6, ferritin and anti-MDA5 antibodies (e.g. >200 units by ELISA) are associated with RP-ILD. These can be used as an indication for early intensive treatment. Both alveolar macrophages and autoimmunity to MDA5 are possibly involved in the development of RP-ILD associated with JDM.

Brief report: ultraviolet radiation exposure is associated with clinical and autoantibody phenotypes in juvenile myositis.

OBJECTIVE: Genetic and environmental factors may contribute to the etiology of the juvenile idiopathic inflammatory myopathies (IIMs), which are systemic autoimmune diseases that are characterized by muscle and skin inflammation. We undertook this study to investigate the association between ultraviolet radiation (UVR) exposure and the clinical and autoantibody expression of juvenile IIM. METHODS: The relationship between UVR exposure in the month before symptom onset and the prevalence of juvenile dermatomyositis (DM), compared to juvenile polymyositis (PM), was assessed in 298 juvenile IIM patients. Among the patients with juvenile DM, the association between UVR exposure and presence of myositis autoantibodies was assessed. Regression models were stratified by sex and race. The association between the regional UV index in US geoclimatic zones and the clinical and autoantibody subgroups was examined by weighted least squares regression analysis. RESULTS: Among girls in this population, the odds of having juvenile DM, compared to juvenile PM, increased per unit increase in the patients' highest UV index in the month before symptom onset (odds ratio [OR] 1.18, 95% confidence interval 1.00-1.40). Moreover, both the mean and highest UV indices were associated with increasing odds of having anti-p155/140 autoantibodies, with the strongest odds in white males (ORs of 1.30 and 1.23, respectively). No association was observed between the UV index and presence of anti-MJ autoantibodies or lack of any myositis autoantibodies. Across all 9 US geoclimatic regions, the mean UV index was associated with increasing odds of having juvenile DM and anti-p155/140 autoantibodies, but decreasing odds of having anti-MJ autoantibodies. CONCLUSION: Short-term UVR exposure prior to illness onset may have a role in the clinical and serologic expression of juvenile myositis. Further research examining the mechanisms of action of UVR in the pathogenesis of juvenile IIM is suggested from these findings.

[Prevalence of cancer in the Afro-Caribbean population presenting dermatomyositis and anti-synthetase syndrome: a preliminary study conducted at Pointe-à-Pitre University Hospital, 2000-2012]. / Prévalence des cancers dans la population afro-caribéenne atteinte de dermatomyosite et de syndrome des anti-synthétases : étude préliminaire au CHU de Pointe-à-Pitre, 2000-2012.

BACKGROUND: An association with cancer is described in 17-32% of cases of dermatomyositis (DM) and in 5-16% of cases of anti-synthetase syndrome (ASS). The literature contains very few studies involving Afro-Caribbean patients with DM or ASS. The aim of our retrospective study was to determine the prevalence of cancer in a series of patients with DM or ASS at the University Hospital of Pointe-à-Pitre between 1st January 2000 and 31st December 2012. The secondary objective was to review the clinical and laboratory features as well as the course of DM/ASS in these patients. PATIENTS AND METHODS: The inclusion criteria were as follows: Afro-Caribbean origin; age >15 years; patient living in Guadeloupe; screening for malignancy. RESULTS: Twenty-two patients were included (15 DM, 7 ASS). Only one case of cancer was diagnosed in the entire study population at a mean follow-up of 6 ± 4 years (prevalence: 6.7%, CI95% [1.7-31.9]). Of the 15 patients presenting DM (sex ratio F/M: 4, mean age: 45 ± 14 years), 6 (40%) had associated connective tissue disease. CONCLUSION: Our study suggests a weak association between DM and cancer in Afro-Caribbean patients. These results may be explained by the features of the disease seen in these patients (female gender, young age at onset, associated connective tissue disease) and the low prevalence in the Caribbean region of cancers typically associated with DM.

Unique characteristics of anti-MDA-5 associated dermatomyositis in Southern California with a large Hispanic population.

OBJECTIVES: There is little to no data about the presentation and clinical course of anti-melanoma differentiation-associated gene-5 antibody (anti-MDA-5) dermatomyositis in a primarily U.S. Hispanic population. We describe the clinical course of anti-MDA-5 dermatomyositis in our majority Hispanic population. METHODS: This is a multicenter, retrospective case series of anti-MDA-5 dermatomyositis. Patients diagnosed with anti-MDA-5 dermatomyositis from June 2015 to March 2023 at four medical centers in Los Angeles, California, were included. Demographics and clinical characteristics were obtained. Descriptive statistics, Pearson's chi-squared, Fisher's exact, Wilcoxon rank sum, and Kruskal-Wallis tests were performed as applicable. RESULTS: Thirty anti-MDA-5 dermatomyositis patients were included. Twenty-two (73 %) were Hispanic. Twenty-one patients (70 %) were female, with a median age of 40.5 years. Hispanic patients were diagnosed with anti-MDA-5 dermatomyositis at a younger age than non-Hispanic patients (p = 0.025). Inflammatory arthritis was prominent; more males were affected than females (p = 0.027). Thirteen patients (43 %) were amyopathic. Twenty-five patients (83.3 %) had evidence of interstitial lung disease (ILD), and a higher ferritin level was associated with ILD (p = 0.049). There were six deaths (20 %); five (17 %) were ascribed to rapidly progressive ILD. CONCLUSION: ILD was the most common presentation of anti-MDA-5 dermatomyositis in our cohort and was associated with higher ferritin levels. Hispanic patients had a younger age of diagnosis than non-Hispanic patients. Necrotic skin lesions and inflammatory arthritis were frequently seen. This is the first study looking at clinical phenotypes and outcomes of anti-MDA-5 dermatomyositis in a primarily Hispanic U.S. POPULATION: Future studies are needed to better understand the clinical manifestations (to promptly recognize and treat) of this population of anti-MDA-5 dermatomyositis.

Brief report: Association of HLA-DRB1*0101/*0405 with susceptibility to anti-melanoma differentiation-associated gene 5 antibody-positive dermatomyositis in the Japanese population.

OBJECTIVE: The complication of interstitial lung disease (ILD) in polymyositis/dermatomyositis (PM/DM) is associated with anti-aminoacyl-transfer RNA synthetase (anti-aaRS) antibody or anti-melanoma differentiation-associated gene 5 (anti-MDA-5) antibody positivity. Anti-MDA-5 antibody is associated with clinically amyopathic DM and fatal outcome due to rapidly progressive ILD in Asian populations. The association between genetic factors and anti-MDA-5 antibody-positive DM is unclear. This study was undertaken to investigate the HLA-DRB1 genotype in patients with anti-MDA-5 antibody-positive DM. METHODS: We examined genetic differences among 17 patients with anti-MDA-5 antibody-positive DM, 33 patients with anti-aaRS antibody-positive PM/DM, 33 patients with PM/DM without anti-aaRS antibody or ILD, and 265 healthy controls. RESULTS: The frequencies of HLA-DRB1*0101 and DRB1*0405 were 29% and 71%, respectively, in patients with anti-MDA-5 antibody-positive DM, which were higher than the frequencies in healthy controls (10% and 25%, respectively). Among the 17 patients with anti-MDA-5 antibody-positive DM, 16 (94%) harbored either the DRB1*0101 or DRB1*0405 allele. The combined frequency of the DRB1*0101 allele and the DRB1*0405 allele was significantly higher in patients with anti-MDA-5 antibody-positive DM than in patients with PM/DM without anti-aaRS antibody or ILD, with an odds ratio (OR) of 42.7 (95% confidence interval [95% CI] 4.9-370.2) (P = 1.1 × 10(-5)), or in patients with anti-aaRS antibody-positive PM/DM (OR 13.3 [95% CI 1.6-112.6], P = 4.5 × 10(-3)). CONCLUSION: Our findings indicate that HLA-DRB1*0101/*0405 is associated with susceptibility to anti-MDA-5 antibody-positive DM in the Japanese population.

Interstitial lung disease in clinically amyopathic dermatomyositis (CADM) patients: a retrospective study of 41 Chinese Han patients.

To study the clinical features and associated risk factors of interstitial lung disease (ILD) in clinically amyopathic dermatomyositis (CADM) in Chinese patients. Forty-one Chinese Han patients with a diagnosis of CADM in West China Hospital from August 2008 to 2011 were retrospectively analyzed. The prevalence of ILD in CADM patients is 60.98 %, in which 26.83 % for acute/subacute interstitial pneumonia (A/SIP) and 34.15 % for chronic interstitial pneumonia (CIP). Mortality of A/SIP is 63.64 %, with a 6-month survival rate of 54.50 %. Levels of erythrocyte sedimentation rate, serum ferritin, alanine aminotransferase, aspartate aminotransferase, creatine kinase, lactate dehydrogenase, hydroxybutyric dehydrogenase, and immunoglobulin A (IgA) are higher in CADM-ILD patients than CADM patients without ILD. Levels of serum ALB and lymphocyte count in peripheral blood are significant lower in A/SIP than in CIP group. Sign of ground glass opacities in high-resolution computed tomography (HRCT) images is more common in A/SIP group, and diffusion function is worse in these patients compared with CIP group. The prevalence of ILD in Chinese CADM patients is strikingly high, and A/SIP is a major cause of death in CADM patients. Laboratory findings combined with HRCT examination and pulmonary function tests can provide valuable predictive information of ILD or A/SIP in CADM patients.

Incidence and prevalence of polymyositis and dermatomyositis in a health management organization in Buenos Aires.

BACKGROUND: Polymyositis (PM) and dermatomyositis (DM) are infrequent diseases. Data on incidence and prevalence are scarce and conflicting. There are no such data in Latin America and in Argentina in particular. OBJECTIVES: We undertook to examine the incidence and prevalence of PM/DM in the prepaid health maintenance organization (HMO) of our hospital, in the city of Buenos Aires. METHODS: Members of the HMO between January 1999 and June 2009 were identified from medical records of patients followed up by us at the HMO. Incident cases and prevalence were calculated at the end of the period. RESULTS: During the study period, 146,747 persons contributed a total of 937,902.6 person-years (mean age was 46.6 [SD, 18.4] years, and 59% were female). Ten incident cases were detected, 7 women and 3 men with a global incidence rate (IR) of 1.07 per 100,000 person-years (95% confidence interval [CI], 0.5-1.84). Three subjects had DM with an IR of 0.32 per 100,000 person-years (95% CI, 0.1-0.99), and 7 had PM with an IR of 0.75 per 100,000 person-years (95% CI, 0.35-0.16). On June 1, 2009, 17 prevalent cases were detected, with a mean age of 48.9 (SD, 17.7) years; 76% were female, representing a prevalence of 17.4 per 100,000 persons (95% CI, 10.1-27.8). Among the 17 patients with idiopathic inflammatory myopathy, 10 patients had DM, with a prevalence of 10.22 per 100,000 persons (95% CI, 4.9-18.8), and 7 had PM (prevalence, 7.2 per 100,000 persons [95% CI, 2.9-14.7]). CONCLUSIONS: It is difficult to compare studies from different populations and using different ascertainment techniques. These first data from Latin America are in general agreement with many studies.

Comparison of clinical features and drug therapies among European and Latin American patients with juvenile dermatomyositis.

OBJECTIVES: To compare the demographic features, presenting manifestations, diagnostic investigations, disease course, and drug therapies of children with juvenile dermatomyositis (JDM) followed in Europe and Latin America. METHODS: Patients were inception cohorts seen between 1980 and 2004 in 27 paediatric rheumatology centres. The following information was collected through the review of patient charts: sex; age at disease onset; date of disease onset and diagnosis; onset type; presenting clinical features; diagnostic investigations; course type; and medications received during disease course. RESULTS: Four hundred and ninety patients (65.5% females, mean onset age 7.0 years, mean disease duration 7.7 years) were included. Disease presentation was acute or insidious in 57.1% and 42.9% of the patients, respectively. The course type was monophasic in 41.3% of patients and chronic polycyclic or continuous in 58.6% of patients. The more common presenting manifestations were muscle weakness (84.9%), Gottron's papules (72.9%), heliotrope rash (62%), and malar rash (56.7%). Overall, the demographic and clinical features of the 2 continental cohorts were comparable. European patients received more frequently high-dose intravenous methylprednisolone, cyclosporine, cyclophosphamide, and azathioprine, while methotrexate and antimalarials medications were used more commonly by Latin American physicians. CONCLUSIONS: The demographic and clinical characteristics of JDM are similar in European and Latin American patients. We found, however, several differences in the use of medications between European and Latin American paediatric rheumatologists.

The relevance of anti-Jo-1 autoantibodies in patients with definite dermatomyositis.

BACKGROUND: To assess the prevalence and clinical relevance of anti-Jo-1 autoantibodies in a representative sample of patients with definite dermatomyositis (DM). METHODS: This retrospective cohort study took place from 2005 to 2020 and assessed 118 adult patients from a tertiary center who were diagnosed with definite DM. A commercial kit was used to detect anti-Jo-1 autoantibodies. RESULTS: The presence of anti-Jo-1 autoantibodies was observed in 10 out of 118 (8.5%) patients with definite DM. The following variables were comparable between individuals with and without anti-Jo-1 autoantibodies: age at diagnosis, sex, ethnicity, disease duration, follow-up period, recurrence rate, complete clinical response, death rate, and cancer incidence. There was no difference in clinical features between groups, except for an increased prevalence of "mechanic's hands," joint involvement, and lung disease, as well as a reduced occurrence of skin findings in patients positive for anti-Jo-1 autoantibodies. No anti-Jo-1-positive patients went into remission; they required greater use of glucocorticoids and immunosuppressive drugs. CONCLUSIONS: Anti-Jo-1 positivity was found in 8.5% of patients with definite DM. This autoantibody was associated with an antisynthetase syndrome phenotype and might predict clinical outcomes in patients with definite DM.

Malignancies associated with dermatomyositis and polymyositis in Taiwan: a nationwide population-based study.

BACKGROUND: Previous studies showed that idiopathic inflammatory myopathies (IIM) carried an increased risk of cancers. However, no large-scale study of IIM has been conducted in the Chinese population. OBJECTIVES: We sought to delineate the association of IIM and various cancer types from a nationwide database in Taiwan. METHODS: We analysed the published national data from records of National Health Insurance claims. Cases of dermatomyositis (DM) and polymyositis (PM) from 2000 to 2005 and cancers registered in the catastrophic illness profile from 1997 to 2006 were collected. A nationally representative cohort of 1,000,000 enrollees was included for comparison. RESULTS: In total, 136 patients (12.8%) among 1059 cases of DM and 46 persons (7.0%) among 661 cases of PM carried internal malignancies. Patients with DM tended to have cancers of nasopharynx, lung and breast. On the other hand, patients with PM tended to have breast, uterine cervix and lung cancers. Compared with the general population, DM gave a 10-fold increased risk for cancers, in which a 66-fold increased risk for nasopharyngeal carcinoma and a 31-fold increased risk for lung cancer were the two most significant. For patients with PM, a 6-fold increased risk for cancer was observed. Juvenile DM had a 16-fold increased risk for haematopoietic or lymphoid malignancy. Two thirds of comorbid malignancies were detected shortly after the diagnoses of IIM, within a mean of 1-2 years. Overall, younger patients with IIM carried the highest risk for malignancies, especially those in their twenties and thirties. CONCLUSIONS: This is the first large-scale study to report the associated malignancies and the cancer risk of IIM in Taiwan.

Characteristics of Hispanic Patients With Dermatomyositis.

This cohort study compares the clinical features and outcomes of dermatomyositis between Hispanic and non-Hispanic patients.

Association of Short-Term Ultraviolet Radiation Exposure and Disease Severity in Juvenile Dermatomyositis: Results From the Childhood Arthritis and Rheumatology Research Alliance Legacy Registry.

OBJECTIVE: Ultraviolet (UV) radiation is considered to be an important environmental factor in the clinical course of children with juvenile dermatomyositis (DM). We aimed to evaluate the association between UV radiation and severe disease outcomes in juvenile DM. METHODS: This is a cross-sectional study of patients with juvenile DM enrolled in the US multicenter Childhood Arthritis and Rheumatology Research Alliance (CARRA) Legacy Registry from 2010 to 2015. The mean UV index (UVI) in the calendar month prior to symptom onset in each subject's zip code was calculated from daily satellite solar noon measurements. Multivariable logistic regression was used to model the relationship between the mean UVI and calcinosis as well as other outcomes of severe disease. Covariates included sex, race, age, time to diagnosis, disease duration, and latitude. RESULTS: In a multivariable model, there was no association between the mean UVI and calcinosis. African American race was associated with a 3-fold greater odds of calcinosis. However, there was a significant statistical interaction between race and mean UVI. Accounting for this interaction, the odds of calcinosis markedly decreased in African American subjects and steadily increased in non-African American subjects over a range of increasing the mean UVI. Higher mean UVI was associated with decreased odds of using biologics or nonmethotrexate disease-modifying antirheumatic drugs and skin ulceration. CONCLUSION: We described a novel association between UV radiation, calcinosis, and race in a large cohort of patients with juvenile DM. This study furthers our knowledge of the role of UV radiation in the clinical course of juvenile DM and highlights the complex interplay between genes and environment in the clinical phenotypes and development of calcinosis in children with juvenile DM.

Diffuse pruritic erythema as a clinical manifestation in anti-SAE antibody-associated dermatomyositis: a case report and literature review.

Anti-small ubiquitin-like modifier-1 activating enzyme (anti-SAE) antibodies have been recently discovered especially for myosin and identified as dermatomyositis (DM) marker. The frequency of anti-SAE antibodies in DM patients is extremely low. Diffuse pruritic erythema may be one kind of clinical manifestations of DM with anti-SAE antibodies. In this report, a 48-year-old female patient with amyopathic dermatomyositis (ADM) carrying anti-SAE antibodies presented diffuse pruritic erythema for 5 months. Diffuse pruritic erythema improved after treatment with prednisolone, cyclosporine, and thalidomide. The clinical characteristics of 75 previously reported cases with anti-SAE antibody-positive DM were reviewed, and the manifestations of the Asian and Western cohorts were compared. It was revealed that the Asian patients were more susceptible to diffuse erythema (17/34 vs. 3/41, P = 0.000), dysphagia (16/34 vs. 10/41, P = 0.040), and interstitial lung disease (ILD) (21/34 vs. 5/41, P = 0.000) compared with the Western patients. The frequency of malignancy in the Asian cohort was significantly higher than that in the Western cohort (10/34 vs. 4/41, P = 0.030).

Muscular and extramuscular features of myositis patients with anti-U1-RNP autoantibodies.

OBJECTIVE: To define the clinical phenotype of patients with myositis with anti-U1-ribonucleoprotein (RNP) autoantibodies. METHODS: In this longitudinal cohort study, the prevalence and severity of clinical features at disease onset and during follow-up in patients with anti-U1-RNP-positive myositis were compared to those with dermatomyositis (DM), immune-mediated necrotizing myopathy (IMNM), and the antisynthetase syndrome (AS). RESULTS: Twenty anti-U1-RNP-positive patients, 178 patients with DM, 135 patients with IMNM, and 132 patients with AS were included. Anti-U1-RNP-positive patients were younger (∼37 years) and more likely to be black (60%) than patients with AS, DM, or IMNM. Muscle weakness was a presenting feature in 15% of anti-U1-RNP-positive patients; 80% eventually developed weakness. Four of 7 anti-U1-RNP-positive patients had necrotizing muscle biopsies. Arthritis occurred in 60% of anti-U1-RNP-positive patients; this was increased compared to DM (18%) or IMNM (6%) (all p < 0.01). DM-specific skin features developed in 60% of anti-U1-RNP-positive patients. Interstitial lung disease (ILD) occurred in 45% of anti-U1-RNP-positive patients; fewer patients with DM (13%) and IMNM (6%) and more patients with AS (80%) developed ILD (all p < 0.01). Glomerulonephritis and pericarditis occurred in 25% and 40% of anti-U1-RNP-positive patients, respectively, but rarely in the other groups; these features occurred only in those with coexisting anti-Ro52 autoantibodies. No anti-U1-RNP patient had cancer-associated myositis or died during the study period. CONCLUSIONS: Patients with anti-U1-RNP myositis typically present with proximal weakness and necrotizing muscle biopsies. Arthritis, dermatitis, and ILD are the most common extramuscular clinical features. Pericarditis and glomerulonephritis are uniquely found in patients with anti-U1-RNP-positive myositis.

Analysis of anti-melanoma differentiation-associated gene 5 antibody in Hong Kong Chinese patients with idiopathic inflammatory myopathies: diagnostic utility and clinical correlations.

AIM: To compare the prevalence of the anti-melanoma differentiation-associated gene 5 antibody (anti-MDA5 Ab) in Hong Kong Chinese patients with dermatomyositis (DM) and polymyositis (PM); in addition, to examine the association of anti-MDA5 Ab and the clinical characteristics of these patients. METHODS: Twenty consecutive existing patients with DM being followed up at the Rheumatology Clinic of Kwong Wah Hospital, Hong Kong were recruited. Twenty patients with PM were recruited from the same clinic as the controls. A commercial line blot immunoassay was used to detect the anti-MDA5 Ab in all the participants. The frequencies of anti-MDA-5 Ab in the two groups were compared. The clinical characteristics of the patients with and without the antibody were analyzed. RESULTS: Anti-MDA5 Ab was found in 30% of patients with DM but not in patients with PM. All patients with the antibody exhibited the clinically amyopathic DM (CADM) phenotype. These patients were predominantly male, younger and with shorter disease duration. Anti-MDA5 Ab was significantly associated with rapidly progressive interstitial lung disease (RP-ILD) and digital ulcers. No statistically significant association was found between other disease or treatment variables and the antibody. CONCLUSION: Anti-MDA5 Ab is found exclusively in DM patients of the CADM subtype and is associated with RP-ILD and digital ulcers, suggesting that examination of this antibody is clinically useful in Hong Kong Chinese patients with idiopathic inflammatory myopathies. However, further studies are required to assess its prognostic significance, and to explore the difference of its presentations in various populations.

Clinical characteristics of Japanese patients with anti-PL-7 (anti-threonyl-tRNA synthetase) autoantibodies.

OBJECTIVE: The clinical and laboratory features of seven Japanese patients with anti-aminoacyl-tRNA synthetase (ARS) autoantibodies against PL-7 (anti-threonyl-tRNA synthetase) were analyzed and compared with previously published findings. METHODS: Serum samples from 1,135 Japanese patients with various autoimmune diseases were screened for anti-PL-7 antibodies using RNA and protein immunoprecipitation assays. The patients whose sera contained anti-PL-7 antibodies were assessed regarding clinical symptoms and clinical course. RESULTS: Sera from seven patients were found to have anti-PL-7 antibodies. These autoantibodies were associated with polymyositis/dermatomyositis (PM/DM) and/or interstitial lung disease (ILD). The clinical diagnoses of these seven patients were PM - systemic sclerosis (SSc) overlap (5 patients), DM (1 patient) and idiopathic pulmonary fibrosis (IPF) (1 patient). All patients had ILD with a chronic course and six also had arthritis (85%) and five sclerodactyly (71%). CONCLUSIONS: These results indicate that anti-PL-7 autoantibodies are closely associated with PM-SSc overlap as well as ILD, arthritis and sclerodactyly in our series of Japanese patients.

Distinct profiles of myositis-specific autoantibodies in Chinese and Japanese patients with polymyositis/dermatomyositis.

The study aims to comprehensively assess the profiles of myositis-specific autoantibodies (MSAs) in Chinese patients with polymyositis (PM)/dermatomyositis (DM) and compare them with a Japanese cohort. One hundred forty-five Chinese patients (68 classic DM, 25 clinically amyopathic DM [CADM], and 52 PM) and 165 Japanese patients (56 classic DM, 52 CADM, and 57 PM) were recruited. MSAs were measured with immunoprecipitation, enzyme-linked immunosorbent assay, or immunoprecipitation-immunoblotting. MSA frequencies were compared. The overall frequency of anti-melanoma differentiation-associated gene 5 (MDA5) antibodies was significantly higher in the Chinese patients than in the Japanese cohort (36.6 % [53/145] versus 15.8 % [26/165], respectively, P < 0.001), whereas the frequencies of anti-signal recognition particle (SRP) antibodies (1.4 % [2/145] versus 7.9 % [13/165], respectively, P = 0.008) and anti-aminoacyl-transfer RNA synthetase (anti-ARS) antibodies (27.6 % [40/145] versus 40 % [66/165], respectively, P = 0.02,) were significantly lower. The significantly lower frequency of anti-ARS antibodies and significantly higher frequency of anti-MDA5 antibodies in the Chinese patients were observed in the classic DM subset (14.7 % [10/68] versus 46.4 % [26/56], respectively, P < 0.001, and 45.6 % [31/68] versus 5.4 % [3/56], respectively, P < 0.001) and CADM subset (8.0 % [2/25] versus 28.8 % [15/52], respectively, P = 0.04, and 88.0 % [22/25] versus 44.2 % [23/52], respectively, P = 0.0002), but not in the PM subset. The first detailed profile of MSAs in Chinese patients with PM/DM was established. The differences in MSA frequencies in the Chinese cohort and Japanese cohort suggest underlying genetic and/or environmental differences between these two populations. Key Messages • A significantly higher frequency of anti-melanoma differentiation-associated gene 5 (MDA5) antibodies was observed in Chinese patients with polymyositis/dermatomyositis (PM/DM) than in Japanese patients. • Our findings suggest that distinct genetic and/or local environmental factors affect Chinese and Japanese patients with PM/DM, who have been considered a "homogeneous" population in previous studies.

Cutaneous ulceration in dermatomyositis: association with anti-melanoma differentiation-associated gene 5 antibodies and interstitial lung disease.

OBJECTIVE: To identify clinical and serologic correlates of cutaneous ulcers in dermatomyositis (DM). METHODS: We retrospectively examined a cohort of 152 DM patients. We compared the features of patients with ulcers to those without ulcers using chi-square or Fisher's exact tests and used univariate and multivariate logistic regression models to assess the association between ulcers and clinical features such as malignancy, interstitial lung disease (ILD), and amyopathic disease. RESULTS: Forty-three patients (28%) had cutaneous ulcers. Nearly half the patients had ulcers present in more than 1 location: 24 (56%) had ulcers over the extensor surfaces of joints, 18 (42%) at the digital pulp or periungual areas, and 25 (58%) had ulcers located elsewhere. In univariate analysis ulcers were associated with Asian race, but not with other clinical and demographic features, including malignancy or ILD. In multivariate analysis ulcers were significantly associated with anti-melanoma differentiation gene 5 (anti-MDA5) antibodies (odds ratio 10.14, 95% confidence interval 1.95-52.78; P = 0.0059) and this was greatest for ulcers located at the digital pulp. In patients with cutaneous ulcers, ILD risk was specifically increased only in patients with anti-MDA5-positive antibodies. CONCLUSION: We confirmed the strong association between anti-MDA5 antibodies and cutaneous ulcers, with the novel finding that the association of cutaneous ulcers with ILD depends upon the presence of anti-MDA5 antibodies. DM patients who display this cutaneous phenotype should undergo appropriate evaluation for ILD.