Autoantigen characterization in liver/kidney microsome positive hepatitis

Liver/kidney microsome autoantibodies are detectable in different forms of chronic hepatitis, namely autoimmune, viral, and drug-induced hepatitis and in hepatitis associated with Type 1 autoimmune polyglandular syndrome. Based on the aetiology of chronic hepatitis, liver/kidney microsome autoantibodies are directed against different enzymes with very little overlap. Thus, the simple Indirect Immunofluorescence test, which is universally used as a screening test to detect autoantibodies, does not allow subtyping of liver/kidney microsome autoantibodies. This brief review stresses the need to use methods such as Western-Blotting and enzyme-linked immunosorbent assay together with Indirect Immunofluorescence to characterize the liver/kidney microsome autoantibodies. Identification of the liver/kidney microsome target antigens, when possible, makes differential diagnosis easier and, at times, may help the clinician to choose the best approach to treatment.