Objectives: To describe a novel subtype of autoimmune myopathy, immune-mediated megaconial myopathy (IMMM), myopathologically characterized by giant mitochondria (megaconia).
Methods: In this case series, we reviewed the Mayo Clinic Muscle Pathology database, between 2018 and 2023, to identify patients with megaconial pathology, subacute progressive weakness, and hyperCKemia, clinically resembling myositis. We recruited 1 patient from another institute, who had similar clinicopathologic features.
Results: Five patients were identified. Age at onset of weakness ranged from 19 to 45.5 years. All patients had proximal weakness, elevated creatine kinase levels (1,214 to 5,920 U/L), negative myositis antibodies, necrotizing myopathology, and nonnecrotic myofibers harboring giant mitochondria. Immunohistochemical studies conducted in 4 patients showed sarcolemmal MHC-1 and C5b9 immunoreactivities. Megaconial pathology was considered pathognomonic of congenital muscular dystrophy due to biallelic pathogenic variants in . Sequencing of in 4/5 patients was unrevealing. Immunomodulatory therapy improved weakness and hyperCKemia in 4 treated patients. Of interest, all patients had coexisting pancreatic diseases (3 cystic fibrosis-related exocrine pancreatic insufficiency, 1 pancreatic cancer, and 1 pancreatitis).
Discussion: In addition to incurable -congenital muscular dystrophy, giant mitochondria can also occur in this new subtype of treatable autoimmune myopathy, IMMM. The association between IMMM and pancreatic disorders remains to be elucidated.
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http://dx.doi.org/10.1212/WNL.0000000000210001 | DOI Listing |
Inflammation
December 2024
Department of Rheumatology and Immunology, the Second Hospital of Lanzhou University, Lanzhou, 730030, Gansu, China.
Our previous study has shown that neutrophil extracellular traps (NETs) were associated with idiopathic inflammatory myopathy-related interstitial lung disease (IIM-ILD). Colchicine plays an anti-inflammatory role mainly by inhibiting the activity and chemotaxis of neutrophils. This study aims to verify therapeutic effects and mechanism of colchicine in IIM-ILD.
View Article and Find Full Text PDFDiagnostics (Basel)
November 2024
Department of Internal Medicine-Rheumatology, Faculty of Medicine, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania.
Interstitial lung disease (ILD) is one of the common and potentially lethal manifestations of systemic autoimmune rheumatic diseases (SARDs). ILD's prevalence, clinical patterns, imaging, and natural history are variable. Each of the representative diseases-systemic sclerosis (SSc), idiopathic inflammatory myopathies (IIMs), rheumatoid arthritis (RA), Sjӧgren's syndrome (SjS), mixed connective tissue disease (MCTD), systemic lupus erythematosus (SLE)-have distinct clinical, paraclinical and evolutionary features.
View Article and Find Full Text PDFImmunol Lett
December 2024
Laboratory of Clinical Pathology, Azienda Sanitaria Universitaria Integrata, Udine, Italy.
Objective: Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of systemic autoimmune disorders affecting skeletal muscles but also other organs. There are different forms of IIM, each with peculiar clinical manifestations and prognosis. Accordingly, several autoantibodies have been described in IIM, with different prevalence in the different forms of the disease.
View Article and Find Full Text PDFArthritis Rheumatol
December 2024
Institute for Clinical and Translational Research, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.
Objective: Idiopathic inflammatory myopathies (myositis, IIMs) are rare, systemic autoimmune disorders that lead to muscle inflammation, weakness, and extra-muscular manifestations, with a strong genetic component influencing disease development and progression. Previous genome-wide association studies identified loci associated with IIMs. In this study, we imputed data from two prior genome-wide myositis studies and analyzed the largest myositis dataset to date to identify novel risk loci and susceptibility genes associated with IIMs and its clinical subtypes.
View Article and Find Full Text PDFBMJ Case Rep
December 2024
Rheumatology, Western Health, Melbourne, Victoria, Australia.
Regional ischaemic immune myopathy (RIIM) is a subtype of dermatomyopathy which has distinct histopathology features of regional muscle fibre necrosis and regeneration. This case report aims to provide an in-depth exploration of RIIM, emphasising its clinical features and the crucial role of muscle biopsy as a diagnostic investigation, as well as the potential role of immunomodulatory therapies.
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