Novel Serology Testing for Sporadic Inclusion Body Myositis

Disease-Specificity and Diagnostic Utility

Megan K. Herbert; Ger J.M. Pruijn


Curr Opin Rheumatol. 2015;27(6):596-600. 

In This Article


Over the years, substantial progress has been made in our understanding of the B-cell response in sIBM. The identification of serum auto-antibodies targeting cN-1A in sIBM substantiates the potential importance of an adaptive immune response in sIBM, which may also help to improve differential diagnosis of sIBM in clinical practice. However, there is currently no consistency in the methods used for the measurement of anti-cN-1A auto-antibodies. Therefore, consensus needs to be reached on the most appropriate method for detecting anti-cN-1A auto-antibodies, and this method will need to be fully standardized to provide consistency across studies. This is particularly important in view of the low anti-cN-1A reactivities observed with sera from other diseases in various assays in comparison with healthy control samples. Also, the question why these antibodies are found in only a subset of sIBM patients and whether they correlate with specific clinical features remains to be addressed. There is not yet clear evidence of clinical or pathophysiological differences between anti-cN-1A seropositive and seronegative sIBM patients. Therefore, further study is required to determine whether specific clinical phenotypes or particular muscle biopsy features can explain why some patients are seropositive and others seronegative. Also, more extensive epitope mapping studies will be required to ascertain whether additional epitopes exist for anti-cN-1A auto-antibodies, which might further improve the detection of anti-cN-1A auto-antibodies and which could improve distinction between sIBM and other forms of myositis.