RIG-I expression in perifascicular myofibers is a reliable biomarker of dermatomyositis
Por:
Suarez-Calvet, X, Gallardo, E, Pinal-Fernandez, I, De Luna, N, Lleixa, C, Diaz-Manera, J, Rojas-Garcia, R, Castellvi, I, Martinez, MA, Grau, JM, Selva-O'Callaghan, A, Illa, I
Publicada:
24 jul 2017
Resumen:
Background: Dermatomyositis (DM) is inflammatory myopathy or myositis characterized by muscle weakness and skin manifestations. In the differential diagnosis of DM the evaluation of the muscle biopsy is of importance among other parameters. Perifascicular atrophy in the muscle biopsy is considered a hallmark of DM. However, perifascicular atrophy is not observed in all patients with DM and, conversely, perifascicular atrophy can be observed in other myositis such as antisynthetase syndrome (ASS), complicating DM diagnosis. Retinoic acid inducible-gene I (RIG-I), a receptor of innate immunity that promotes type I interferon, was observed in perifascicular areas in DM. We compared the value of RIG-I expression with perifascicular atrophy as a biomarker of DM.
Methods: We studied by immunohistochemical analysis the expression of RIG-I and the presence of perifascicular atrophy in 115 coded muscle biopsies: 44 patients with DM, 18 with myositis with overlap, 8 with ASS, 27 with non-DM inflammatory myopathy (16 with polymyositis, 6 with inclusion body myositis, 5 with immune-mediated necrotizing myopathy), 8 with muscular dystrophy (4 with dysferlinopathy, 4 with fascioscapulohumeral muscle dystrophy) and 10 healthy controls.
Results: We found RIG-I-positive fibers in 50% of DM samples vs 11% in non-DM samples (p < 0.001). Interestingly, RIG-I staining identified 32% of DM patients without perifascicular atrophy (p = 0.007). RIG-I sensitivity was higher than perifascicular atrophy (p < 0.001). No differences in specificity between perifascicular atrophy and RIG-I staining were found (92% vs 88%). RIG-I staining was more reproducible than perifascicular atrophy (K coefficient 0.52 vs 0.37).
Conclusions: The perifascicular pattern of RIG-I expression supports the diagnosis of DM. Of importance for clinical and therapeutic studies, the inclusion of RIG-I in the routine pathological staining of samples in inflammatory myopathy will allow us to gather more homogeneous subgroups of patients in terms of immunopathogenesis.
Filiaciones:
Suarez-Calvet, X:
Univ Autonoma Barcelona, Neuromuscular Dis Unit, Neurol Dept, Hosp Santa Creu & St Pau, St Antoni Maria Claret 167, Barcelona 08025, Spain
Univ Autonoma Barcelona, Inst Recerca St Pau, St Antoni Maria Claret 167, Barcelona 08025, Spain
Ctr Biomed Network Res Rare Dis CIBERER, Madrid, Spain
Gallardo, E:
Univ Autonoma Barcelona, Neuromuscular Dis Unit, Neurol Dept, Hosp Santa Creu & St Pau, St Antoni Maria Claret 167, Barcelona 08025, Spain
Univ Autonoma Barcelona, Inst Recerca St Pau, St Antoni Maria Claret 167, Barcelona 08025, Spain
Ctr Biomed Network Res Rare Dis CIBERER, Madrid, Spain
Pinal-Fernandez, I:
Univ Autonoma Barcelona, Hosp Vall dHebron, Dept Internal Med, Autoimmune Syst Dis Unit, Barcelona, Spain
De Luna, N:
Univ Autonoma Barcelona, Neuromuscular Dis Unit, Neurol Dept, Hosp Santa Creu & St Pau, St Antoni Maria Claret 167, Barcelona 08025, Spain
Univ Autonoma Barcelona, Inst Recerca St Pau, St Antoni Maria Claret 167, Barcelona 08025, Spain
Ctr Biomed Network Res Rare Dis CIBERER, Madrid, Spain
Lleixa, C:
Univ Autonoma Barcelona, Neuromuscular Dis Unit, Neurol Dept, Hosp Santa Creu & St Pau, St Antoni Maria Claret 167, Barcelona 08025, Spain
Univ Autonoma Barcelona, Inst Recerca St Pau, St Antoni Maria Claret 167, Barcelona 08025, Spain
Ctr Biomed Network Res Rare Dis CIBERER, Madrid, Spain
Diaz-Manera, J:
Univ Autonoma Barcelona, Neuromuscular Dis Unit, Neurol Dept, Hosp Santa Creu & St Pau, St Antoni Maria Claret 167, Barcelona 08025, Spain
Univ Autonoma Barcelona, Inst Recerca St Pau, St Antoni Maria Claret 167, Barcelona 08025, Spain
Ctr Biomed Network Res Rare Dis CIBERER, Madrid, Spain
Rojas-Garcia, R:
Univ Autonoma Barcelona, Neuromuscular Dis Unit, Neurol Dept, Hosp Santa Creu & St Pau, St Antoni Maria Claret 167, Barcelona 08025, Spain
Univ Autonoma Barcelona, Inst Recerca St Pau, St Antoni Maria Claret 167, Barcelona 08025, Spain
Ctr Biomed Network Res Rare Dis CIBERER, Madrid, Spain
Castellvi, I:
Hosp Santa Creu & Sant Pau, Rheumatol Unit, Barcelona, Spain
Martinez, MA:
Univ Autonoma Barcelona, Hosp Santa Creu & St Pau, Immunol Dept, Barcelona, Spain
Grau, JM:
Ctr Biomed Network Res Rare Dis CIBERER, Madrid, Spain
Hosp Clin Barcelona, Internal Med Serv, Muscle Res Unit, Barcelona, Spain
Selva-O'Callaghan, A:
Univ Autonoma Barcelona, Hosp Vall dHebron, Dept Internal Med, Autoimmune Syst Dis Unit, Barcelona, Spain
Illa, I:
Univ Autonoma Barcelona, Neuromuscular Dis Unit, Neurol Dept, Hosp Santa Creu & St Pau, St Antoni Maria Claret 167, Barcelona 08025, Spain
Univ Autonoma Barcelona, Inst Recerca St Pau, St Antoni Maria Claret 167, Barcelona 08025, Spain
Ctr Biomed Network Res Rare Dis CIBERER, Madrid, Spain
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