Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8957383 | Neuromuscular Disorders | 2018 | 19 Pages |
Abstract
Sporadic inclusion body myositis (IBM) is the most common acquired myopathy affecting patients over age 50. The discovery of an autoantibody directed against a 43-44â¯kD protein (anti-cytosolic-5â²-nucleotidase 1A or anti-cN1A) has provided support for the hypothesis of an immune-mediated pathogenesis. Previous studies have reported variable test sensitivity and specificity, and inconsistent results on the predictive value. In our cohort of 40 patients with clinico-pathologically or clinically defined IBM, we found the sensitivity of the anti-cN1A antibody test to be 50%. Comparing characteristics for test positive and test negative groups, we found that patients in our cohort testing positive for the anti-cN1A antibody were significantly more likely to be older than age 60 years at symptom onset. We found no positive association between anti-cN1A reactivity and other clinical, laboratory, and muscle histopathologic findings. Based on all clinical studies published to date including the present, the anti-cN1A antibody test shows high diagnostic specificity, moderate sensitivity, and a low predictive value in regards to age of onset, disease severity and other associated clinicopathological findings.
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Authors
Kevin J. Felice, Charles H. Whitaker, Qian Wu, Daniel T. Larose, Shen Guo, Allan L. Metzger, Randall W. Barton,