Dermatomiositis asociada al autoanticuerpo anti-MDA5 / Dermatomyositis associated with anti-MDA5 autoantibody

La dematomiositis es una miopatía inflamatoria idiopática con espectro clínico variable. En los últimos años se ha identificado un número de autoanticuerpos específicos de miositis útiles para el diagnóstico, la clasificación y el pronóstico de las diversas formas de la enfermedad, entre los que se encuentra el anti-MDA5. Este anticuerpo se asocia al desarrollo de úlceras cutáneas, enfermedad intersticial pulmonar rápidamente progresiva, mortalidad temprana y mal pronóstico por lo que la detección del mismo, en un contexto clínico adecuado, plantea la necesidad de un tratamiento inmunosupresor agresivo. Describimos un caso de dermatomiositis hipomiopática, (es decir, con afección muscular leve) que presentaba compromiso cutáneo específico, enfermedad pulmonar intersticial y anticuerpo anti-MDA5 que respondió favorablemente al tratamiento combinado con ciclofosfamida, gamaglobulina y corticoides.

Dematomyositis is an idiopathic inflammatory myopathy with a variable clinical spectrum. In recent years, a number of myositis-specific antibodies have been identified including anti-MDA5, which is us eful for diagnosis, prognosis and classification of the diverse clinical forms of the disease. This antibody is associated with cutaneous ulcers, rapidly progressive interstitial lung disease, early mortality and poor prognosis, so the detection of this antibody in a suitable clinical context, raises the need for an aggressive immunosuppressive treatment. We describe a case of dermatomyositis classified as hypomyopathic (i.e. involving mild muscle weakness), presenting specific skin lesions, interstitial lung disease, and presence of anti-MDA5 antibody that had a favorable response to combined treatment with cyclophosphamide, gamma globulin and corticosteroids.

Prevalence and reactivity of anti-melanoma differentiation-associated gene 5 (anti-MDA-5) autoantibody in Brazilian patients with dermatomyositis

Abstract: Background: There have been no studies to date on the frequency and reactivity of aanti-melanoma differentiation-associated gene 5 (anti-MDA-5) in samples from the Brazilian population with dermatomyositis. Objectives: To analyze this autoantibody in the Brazilian population. Methods: This was a single-center cross-sectional study in which 131 consecutive adult patients (109 dermatomyositis and 22 clinically amyopathic dermatomyositis) with active disease were evaluated from 2000 to 2016. Analysis of the anti-MDA-5 autoantibody was performed by ELISA. Results: The presence of this autoantibody was observed in 14.7% and 22.7% of patients with dermatomyositis and clinically amyopathic dermatomyositis, respectively. In the case of dermatomyositis, the autoantibody was associated less frequently with Raynaud's phenomenon and periungual hyperemia (P<0.05). In clinically amyopathic dermatomyositis, the presence of this autoantibody was not associated statistically with any demographic, clinical, laboratory, or imaging characteristics. Study limitations: The cross-sectional study design did not allow establishing a temporal correlation between anti-MDA-5 autoantibody and various study variables. In addition, pulmonary function tests were not performed in the patients. Conclusions: The frequency of anti-MDA-5 autoantibody was comparable to that of other populations with dermatomyositis, but with a different reactivity than described in the literature. In addition, there was a phenotypic variability between our patients with clinically amyopathic dermatomyositis and those described in the literature. Further studies are needed to confirm the current study's findings and elucidate this autoantibody's reactivity in Brazilians with idiopathic inflammatory myopathies.