Anti‐NT5C1A autoantibodies for the diagnosis and study of the pathogenesis of sporadic inclusion body myositis

Abstract

Sporadic inclusion body myositis (sIBM) is a chronic and progressive inflammatory myopathy that is commonest in the population aged >50 years. Asymmetric muscle weakness and wasting of the quadriceps, and finger and wrist flexor muscles are characteristic of sIBM. Histological findings for sIBM are characterized by a combination of inflammatory and myodegenerative pathologies. The pathogenesis of sIBM is not yet fully understood, and serum markers have not been identified for diagnosis of the disease or assessment of therapeutic efficacy. Recently, autoantibodies against cytosolic 5 0 -nucleotidase 1A have been identified in plasma and serum samples from patients with sIBM. Various methods with clinical utility have been established to detect anti-cN1A autoantibodies for the diagnosis of sIBM. Importantly, the autoantibodies might have direct roles in the development of the disease by causing dysfunction in proteasomal and lysosomal degradation. Future studies should be carried out to elucidate the molecular mechanisms by which the sarcoplasmic autoantigen is recognized and involved in the degeneration of myofibers. Additional research is essential to provide a better understanding of the relationship between the inflammatory and degenerative processes of sIBM. EpidemiologyGenerally, sIBM is the commonest acquired myopathy in older individuals, and males are more commonly affected than females (3:1). Its prevalence varies among countries and ethnic groups. The