Antinuclear autoantibodies ANAs

The most common adverse reaction to etanercept is mild to moderate erythema, pain, or pruritus at the injection site (37%). Headaches and abdominal pain can also occur. New positive autoantibodies, such as antinuclear antibodies (ANA), anti-dsDNA antibodies, and anticardiolipin antibodies, can develop in patients treated with etanercept. Although there is so far no association between this and the development of autoimmune diseases or malignancies, long-term studies have yet to be done. Rare cases of pancytopenia may be associated with this drug. Although clinical trials showed no increased risk of infection with etanercept treatment, postmarketing reports of serious infections, sepsis, and associated fatalities exist. 

AIH is associated with the presence of liver- and nonliver-related autoantibodies m plasma. These are helpful in diagnosis, but are not likely to be the cause of liver injury. The most important antibodies for diagnosis include antinuclear antibody (ANA), antismooth muscle antibody (ASMA), and antiliver-kidney microsomal antigen type 1 (LKMi). A variety of other autoantibodies are found frequently in AIH, some of which are found in other disorders. A summary of the most common autoantibodies, their associations, and their molecular targets (when known) is given... 

Evidently, ANA (first described by G.J. Friou et al. in 1957) belong to the natural autoantibodies which are continuously stimulated by a still unknown mechanism (possibly a persisting agent) in certain diseases. However, this antibody phenomenon is inconsistent and neither organ- nor disease-specific. ANA can be visualized by immunofluorescence in cryostat tissue sections of the rat liver and rat kidney as a homogeneous (s. fig. 5.10), speckled (s. fig. 5.11), circular or nuclear fluorescence pattern. This allows conclusions to be drawn as to the specificity of antinuclear antibodies and in some cases as to the nature of the underlying disease as well. 

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