Clinical case and features of progression of dermatomyositis with anti-Mi2 antibodies

Aim. To present a clinical case and describe the features of dermatomyositis (DM) with myositis-specific anti-Mi2 antibodies (MSAs).

Material and methods. Clinical manifestations, abnormalities of laboratory and immunologic tests, strategy and efficacy of pharmacotherapy in a patient with DM are described.

Results. A clinical case of DM is presented in a patient born in 1992. The disease manifested through lesions in the skin (periorbital edema with heliotropic rash, Gottron papules, diffuse alopecia, cheilitis, digital ulcers), mucous membranes (enanthem), muscles (myalgia), joints (polyarthritis), peripheral nervous system (polyneuropathy), and constitutional symptoms (weight loss, general weakness, subfebrile temperature). Laboratory examination showed increased erythrocyte sedimentation rate of 40 mm/h and lactate dehydrogenase level of 672 U/L, antinuclear factor was measured at 1:320, and anti-Mi2 antibodies were detected by MSAs panel. Combination immunosuppressive therapy with methylprednisolone at an initial dose of 1 mg/kg/day and subcutaneous methotrexate at a dose of 15 mg/week was initiated, followed by correction depending on the clinical and laboratory dynamics. This case demonstrates benign course of anti-Mi2 antibody-positive DM. Classic skin symptoms (periorbital edema with heliotrope rash, Gottron papules) and muscle damage completely regressed after 21 months of combination pharmacotherapy with methylprednisolone and methotrexate. Stable immunological seroconversion of MSAs and drug-free clinical remission were achieved. Low risk of malignant neoplasms with this DM serotype is emphasized. Atypical symptoms of polyneuropathy and myalgia are considered.

Conclusion. The presented clinical case demonstrates the characteristic features of the DM subtype with anti-Mi2 antibodies: a combination of classic skin symptoms with muscle damage, benign course during two-year combination pharmacotherapy with a glucocorticoid and a cytostatic, persistent immunological seroconversion of MSAs, drug-free clinical remission. Presumably, determination of DM serotype can be useful in clinical practice for predicting the course of the disease, response to pharmacotherapy, and the risk of developing neoplasia.

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