Key result
Dysferlinopathy muscle biopsies had significantly fewer CD3+ T-lymphocytes than dermatomyositis (p=0.05) and inclusion body myositis (p<0.0001), demonstrating a pathology distinct from true inflammatory myopathies.
Why the study?
Muscle pathology in dysferlinopathy includes inflammatory infiltrates mimicking inflammatory myopathies, leading authors to hypothesize its histopathology is more similar to limb-girdle muscular dystrophies and distinct from true inflammatory myopathies.
Observational (n=152)
No
The unique profile of minimal inflammatory cell infiltrates, absent to focal MHC class I, and diffuse myofiber complement C5b-9 deposition is the pathologic signature of dysferlinopathy, distinguishing it from true inflammatory myopathies.
The descriptions of muscle pathology in dysferlinopathy patients have classically included an inflammatory infiltrate that can mimic inflammatory myopathies. Based on over 20 years of institutional experience in evaluating dystrophic and inflammatory myopathy muscle biopsies at the University of Iowa, we hypothesized the inflammatory histopathology of dysferlinopathy is more similar to limb-girdle pattern muscular dystrophies such as calpainopathy and Becker muscular dystrophy, and distinct from true inflammatory myopathies. Muscle biopsies from 32 dysferlinopathy, 30 calpainopathy, 30 Becker muscular dystrophy, and 30 inflammatory myopathies (15 each of dermatomyositis and inclusion body myositis) were analyzed through digital quantitation of CD3, CD4, CD8, CD20, and PU.1 immunostaining. The expression of MHC class I and deposition of complement C5b-9 was also evaluated. Dysferlinopathy, calpainopathy, and Becker muscular dystrophy muscle biopsies had similar numbers of inflammatory cell infiltrates and significantly fewer CD3+ T-lymphocytes than dermatomyositis (p = 0.05) and inclusion body myositis (p < 0.0001) biopsies. There was no statistically significant difference in the number of PU.1+ macrophages identified in any diagnostic group. MHC class I expression was significantly lower in the limb-girdle pattern muscular dystrophies compared to the inflammatory myopathies (p < 0.0001). In contrast, complement C5b-9 deposition was similar among dysferlinopathy, dermatomyositis, and inclusion body myositis biopsies but significantly greater than calpainopathy and Becker muscular dystrophy biopsies (p = 0.05). Compared to calpainopathy, Becker muscular dystrophy, and inflammatory myopathies, the unique profile of minimal inflammatory cell infiltrates, absent to focal MHC class I, and diffuse myofiber complement C5b-9 deposition is the pathologic signature of dysferlinopathy muscle biopsies.
No takes yet. Share an insight, caveat, or question.
Becker et al. (2022) conducted an observational in Dysferlinopathy, Calpainopathy, Becker muscular dystrophy, Inflammatory myopathies (n=152). Dysferlinopathy vs. Calpainopathy, Becker muscular dystrophy, and inflammatory myopathies was evaluated on Number of CD3+ T-lymphocytes and inflammatory cell infiltrates (p=<0.0001). Dysferlinopathy muscle biopsies had significantly fewer CD3+ T-lymphocytes than dermatomyositis (p=0.05) and inclusion body myositis (p<0.0001), demonstrating a pathology distinct from true inflammatory myopathies.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: