IFN-ß-induced reactive oxygen species and mitochondrial damage contribute to muscle impairment and inflammation maintenance in dermatomyositis.

Dermatomyositis (DM) is an autoimmune disease associated with enhanced type I interferon (IFN) signalling in skeletal muscle, but the mechanisms underlying muscle dysfunction and inflammation perpetuation remain unknown. Transcriptomic analysis of early untreated DM muscles revealed that the main cluster of down-regulated genes was mitochondria-related. Histochemical, electron microscopy, and in situ oxygraphy analysis showed mitochondrial abnormalities, including increased reactive oxygen species (ROS) production and decreased respiration, which was correlated with low exercise capacities and a type I IFN signature. Moreover, IFN-ß induced ROS production in human myotubes was found to contribute to mitochondrial malfunctions. Importantly, the ROS scavenger N-acetyl cysteine (NAC) prevented mitochondrial dysfunctions, type I IFN-stimulated transcript levels, inflammatory cell infiltrate, and muscle weakness in an experimental autoimmune myositis mouse model. Thus, these data highlight a central role of mitochondria and ROS in DM. Mitochondrial dysfunctions, mediated by IFN-ß induced-ROS, contribute to poor exercise capacity. In addition, mitochondrial dysfunctions increase ROS production that drive type I IFN-inducible gene expression and muscle inflammation, and may thus self-sustain the disease. Given that current DM treatments only induce partial recovery and expose to serious adverse events (including muscular toxicity), protecting mitochondria from dysfunctions may open new therapeutic avenues for DM.

Cutaneous improvement in refractory adult and juvenile dermatomyositis after treatment with rituximab.

OBJECTIVE: The aim was to assess the efficacy of rituximab for the cutaneous manifestations of adult DM and JDM. METHODS: Patients with refractory adult DM (n = 72) and JDM (n = 48) were treated with rituximab in a randomized placebo-phase-controlled trial [either rituximab early drug (week 0/1) or rituximab late arms (week 8/9), such that all subjects received study drug]. Stable concomitant therapy was allowed. Cutaneous disease activity was assessed using the Myositis Disease Activity Assessment Tool, which grades cutaneous disease activity on a visual analog scale. A myositis damage assessment tool, termed the Myositis Damage Index, was used to assess cutaneous damage. Improvement post-rituximab was evaluated in individual rashes as well as in cutaneous disease activity and damage scores. The χ2 test, Student's paired t-test and Wilcoxon test were used for analysis. RESULTS: There were significant improvements in cutaneous disease activity from baseline to the end of the trial after rituximab administration in both adult DM and JDM subsets. The cutaneous visual analog scale activity improved in adult DM (3.22-1.72, P = 0.0002) and JDM (3.26-1.56, P <0.0001), with erythroderma, erythematous rashes without secondary changes of ulceration or necrosis, heliotrope, Gottron sign and papules improving most significantly. Adult DM subjects receiving rituximab earlier in the trial demonstrated a trend for faster cutaneous response (20% relative improvement from baseline) compared with those receiving B cell depletion later (P = 0.052). CONCLUSION: Refractory skin rashes in adult DM and JDM showed improvement after the addition of rituximab to the standard therapy in a clinical trial.

Efficacy and safety of creatine supplementation in juvenile dermatomyositis: A randomized, double-blind, placebo-controlled crossover trial.

INTRODUCTION: It has been suggested that creatine supplementation is safe and effective for treating idiopathic inflammatory myopathies, but no pediatric study has been conducted to date. The objective of this study was to examine the efficacy and safety of creatine supplementation in juvenile dermatomyositis (JDM) patients. METHODS: In this study, JDM patients received placebo or creatine supplementation (0.1 g/kg/day) in a randomized, crossover, double-blind design. Subjects were assessed at baseline and after 12 weeks. The primary outcome was muscle function. Secondary outcomes included body composition, aerobic conditioning, health-related quality of life, and muscle phosphocreatine (PCr) content. Safety was assessed by laboratory parameters and kidney function measurements. RESULTS: Creatine supplementation did not affect muscle function, intramuscular PCr content, or any other secondary outcome. Kidney function was not affected, and no side effects were reported. CONCLUSIONS: Twelve weeks of creatine supplementation in JDM patients were well-tolerated and free of adverse effects, but treatment did not affect muscle function, intramuscular PCr, or any other parameter.

Skin Signs of Rheumatoid Arthritis and its Therapy-Induced Cutaneous Side Effects.

Rheumatoid arthritis (RA) is a systemic inflammatory disorder that primarily affects the joints, but may exhibit extra-articular, including cutaneous, manifestations such as rheumatoid nodules, rheumatoid vasculitis, granulomatous skin disorders, and neutrophilic dermatoses. A large burden of cutaneous disease may be an indication of RA disease activity and the need for more aggressive treatment. Many of the therapeutic agents used to treat RA can also result in cutaneous adverse effects, which pose their own diagnostic and therapeutic challenges. Anti-TNFα agents, in particular, have a wide variety of adverse effects including psoraisiform eruptions, granulomatous conditions, and cutaneous connective tissue disorders. Herein we provide an update on the clinical presentations and management of RA-associated cutaneous findings as well as drug-induced cutaneous effects, with particular attention to the adverse effects of biologic disease-modifying agents.

[Dermatomyositis in a family of Working Kelpies].

Eight members of a family of Working Kelpies were presented with signs compatible with dermatomyositis. Alopecia, crusts, ulcerations of the skin, depigmentation of nasal planum and lips, onychodystrophy and atrophy of the masticatory muscles were present with varying degree. Histopathology of the skin, but not from muscles was performed in three dogs and confirmed the clinical diagnosis. Different immunomodulating drugs (steroids, cyclosporine, mycophenolate mofetil, pentoxifylline, doxycyline/niacinamid, omega-3 fatty acids and vitamin E) were used with variable success. Dermatomyositis is an immune-mediated disease and a genetic predisposition is known in humans and certain canine breeds, mainly Shetland Sheepdogs and Collies, but also for the Beauceron. The responsible genes have not been identified so far. It is assumed that the Working Kelpie derives from the Collie which could explain a hereditary predisposition in the Kelpie.

[A woman with skin abnormalities and muscle weakness]. / Een vrouw met huidafwijkingen en spierzwakte.

A 54-year-old woman presented to the emergency department with progressive proximal muscle weakness and a symmetric skin rash. Physical examination demonstrated a heliotrope rash, Gottron lesions, mechanic's hands and symmetrical erythema of the face, neck and upper legs. The diagnosis 'dermatomyositis' was established. Subsequently, the patient was successfully treated with prednisolone 1 mg/kg.

A comparative study of clinical characteristics, work-up, treatment, and association to malignancy in dermatomyositis between two tertiary skin centers in the USA and Singapore.

BACKGROUND: To date, no study has compared the clinical characteristics, malignancy associations, and treatment of dermatomyositis in predominantly Caucasian vs. Asian populations. MATERIALS AND METHODS: This prospective study was conducted to compare clinical characteristics of dermatomyositis, its relationship to malignancy, and treatment between two tertiary medical centers in the USA and Singapore. A total of 19 newly-diagnosed patients in the USA and 15 patients in Singapore were enrolled. Dermatomyositis or amyopathic dermatomyositis were diagnosed based on clinical assessment, skin and muscle biopsies, and muscle testing. RESULTS: Ninety-five percent of patients in the USA group were of Caucasian descent, while 93% of patients in the Singapore group were of Chinese descent. Both groups were predominantly female. Pruritus was the most common initial symptom reported in both groups, while periungual erythema and Gottron's papules were the most common skin presentations. Heliotrope eruption was more common in the Singapore group, occurring in 80% of patients vs. 32% of patients in the USA group (P = 0.007). Three patients in the Singapore group developed a malignancy, with two of these patients having nasopharyngeal carcinoma. None of the USA patients developed malignancies in a follow- up period of 2-5 years. Immunosuppressive steroid sparing therapy with hydroxychloroquine was more frequently used in Singapore, while topical tacrolimus was more frequently used in the USA. CONCLUSION: The clinical presentations of dermatomyositis vary among different ethnic populations. Chinese patients with dermatomyositis have a significant risk for nasopharyngeal carcinoma.

Chronic graft-versus-host-disease-like dermopathy in a child with CD4+ cell microchimerism.

We report the case of an 11-year-old boy suffering from a severe progressive chronic skin disease with clinical features of progressive systemic scleroderma, systemic lupus erythematosus and dermatomyositis. Skin biopsies revealed fibrosis and lichenoid changes and muscle biopsy a myositis. Immunohistology of the skin showed a lichen-ruber-like pattern. Despite repeated extensive investigations, no autoantibodies were detectable. Some of these findings looked like those described in juvenile dermatomyositis. Finally, it could be demonstrated that the boy showed microchimerism with approximately 1% maternal CD4+ lymphocytes in his peripheral blood leukocytes. Furthermore maternal cells could be demonstrated in inflamed muscle tissue. So a graft-versus-host-disease-like pathomechanism appears to be likely. Several systemic therapies have been used with limited success to improve the condition including corticosteroids, azathioprine, cyclosporine A and mycophenolate mofetil. A distinct improvement of erythemas and sclerosis could be achieved by means of low-dose UVA1 phototherapy which was applied with escalating single doses of 3-12 J/cm2 for 35 consecutive days.

Low-dose methotrexate as an adjunctive therapy with surgery for ectropion complicating dermatomyositis.

We describe the clinical and histopathologic features of a 44-year-old woman who developed bilateral lower eyelid ectropion and upper lid entropion presumably secondary to dermatomyositis. A variety of inflammatory, infiltrative and/or scarring dermatoses have been associated with ectropion. Chronic inflammation, poikilodermatous change and mucinous infiltration of the eyelids due to dermatomyositis are the postulated mechanisms leading to ectropion in our patient. This case is unique in that neither dermatomyositis nor papular mucinosis has previously been reported as a cause of ectropion. Also interesting was the adjunctive effect of methotrexate therapy.

Dermatomyositis occurring during psoralen A (PUVA) therapy.

Dermatomyositis (DM) developed in a 35-year-old woman after 2 months of psoralen ultraviolet-A (PUVA) therapy for presumed psoriasis. Her disease was characterized by symmetrical proximal muscle weakness and cutaneous lesions compatible with DM. In addition, laboratory abnormalities included a positive antinuclear antibody, and elevated levels of creatine kinase and aldolase. This is the first report of DM developing during PUVA therapy.

Ipecac-induced myopathy simulating dermatomyositis.

We studied a young woman with an eating disorder. To induce vomiting, she took syrup of ipecac daily for 2 years, and then developed insidious, progressive muscle weakness. Skin findings were similar to those of dermatomyositis. Muscle biopsy, however, was similar to experimental emetine myopathy and lacked inflammatory features. Upon cessation of ipecac abuse, strength returned. We believe that this patient had ipecac-induced muscle weakness.