Determination of cN1A Autoantibodies by Cell-Based Immunofluorescence Cytochemistry.

Sporadic inclusion body myositis (sIBM) is a chronic and progressive inflammatory myopathy that is the commonest among population over 50s. Recently, autoantibodies against cytosolic 5'-nucleotidase 1A (cN1A) have been identified in plasma and serum samples from patients with sIBM. So far, various methods have been established to detect the anti-cN1A autoantibodies, which showed a clinical utility of detection of the autoantibodies in the diagnosis of sIBM. Here we describe a novel cell-based assay for detection of the autoantibodies, which seems equivalent in sensitivity and better in specificity for the diagnosis of sIBM, compared with the previous methods.