Novel serology testing for sporadic inclusion body myositis: disease-specificity and diagnostic utility.
OBJECTIVE
The purpose of this article is to discuss recent advances in serological testing for sporadic inclusion body myositis (sIBM) and to provide a review of their diagnostic utility and disease-specificity of auto-antibodies in sIBM.


RESULTS
The identification, prevalence and diagnostic utility of a new auto-antibody targeting cytosolic 5'-nucleotidase 1A (cN-1A) in the serum of sIBM patients have recently been published. These studies have shown that anti-cN-1A auto-antibodies have diagnostic utility for differentiating sIBM from other forms of myositis and from other neuromuscular diseases. Anti-cN-1A-positive patient sera are directed to multiple epitopes of cN-1A and contain, in addition to IgG, IgA and IgM, anti-cN-1A auto-antibodies. Recent studies have also shown a relatively high prevalence of these auto-antibodies in sera form Sjögren's syndrome and systemic lupus erythematosus patients.


CONCLUSIONS
The recent discovery of auto-antibodies to cN-1A provides a serological tool to aid the differentiation between inflammatory myopathies and supports the idea that apart from degeneration, an adaptive immune response may also play a role in sIBM pathophysiology. Future research will need to focus on standardization of methods to detect these auto-antibodies in order to further explore their specificity and diagnostic utility for sIBM.
Department of Biomolecular Chemistry, Radboud Institute for Molecular Life Sciences and Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands.
Megan K
MK
Herbert
Ger J M
GJ
Pruijn
D015720:5'-Nucleotidase / Q000096:biosynthesis* / Q000097:blood; D001323:Autoantibodies / Q000097:blood*; D006801:Humans; D018979:Myositis, Inclusion Body / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D012680:Sensitivity and Specificity; D012698:Serologic Tests
D001323:Autoantibodies; D015720:5'-Nucleotidase