Standardization of Autoantibody Testing in Autoimmune Hepatitis
It is a comment on a recent review published on the Journal.
KeywordsAnti-smooth muscle antibodies Autoimmune hepatitis Anti-actin Autoantibodies
We read with great interest the review by Tozzoli et al.  on the standardization of autoantibody testing. Particularly, we appreciated the paragraph on the harmonization in the diagnosis of autoimmune hepatitis. We agree with Tozzoli et al. about the lack of a standardized immunochemical method able to detect the anti-actin antibody in a convincing manner, and the speculative explanation of these discrepancy could be reside on the immunogenic conformational epitope that when linearized for immunochemical test misses its immunogenic properties. On the other hand, it is right to underline how the immunomorphological technique remains the reference method for anti-actin reactivity. The detection of a peculiar pattern such as smooth muscle antibodies (SMA) with peritubular positivity (IgG class) on rodent kidney tissue (the so called SMA T pattern) has been demonstrated to be strongly associated with anti-actin reactivity and with an autoimmune hepatitis diagnosis .
Differently the SMA-T IgA pattern is associated to celiac disease with anti-actin positivity .
Unfortunately, only few and selected laboratories differentiate the SMA pattern in V (vessel), G (glomeruli), and T peritubular on the basis of its first description , and this could complicate the reaching for an autoimmune hepatitis diagnosis, since the SMA diction alone is too simplistic and inclusive of many cases of a specific and clinical irrilevant seropositivity.
Bologna, September 2018
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The authors declare that they have no conflict of interest.
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