Autoimmune hepatitis

Circulating autoantibodies have come to play a significant role in the diagnosis of AIH. They occur in the majority of patients, although their role in the pathogenesis is still unclear. There is also no clear correlation between the disease activity or prognosis and the antibody titer. 

The following autoantibodies are associated with AIH: antibodies against cell nuclei (ANA), native DNA, smooth muscles (ASMA, most important target antigen: F-actin), SLA/LP, liver-kidney microsomes (LKM-1, target antigen: cytochrome P450 2D6) and liver cytosolic antigen type 1 (LC-1, target antigen: formiminotransferase cyclodeaminase). Of all of these antibodies, autoantibodies against SLA/LP, which can today be detected by various EUROIMMUN enzyme immunoassays, have the highest specificity for AIH. Anti-SLA/LP antibodies occur in AIH either alone or together with other autoantibodies. Their prevalence is only between 10 % and 30 %, but the predictive value is almost 100 %. Furthermore, high concentrations of ASMA indicate AIH. A large part of the antibodies is directed against conformational epitopes of F-actin, which are best preserved in frozen tissue sections or tissue cells. In contrast to other ASMA, antibodies against F-actin are a very specific marker for type I AIH. The VSM47 (vascular smooth muscle) cell line allows fibrillar fluorescence patterns to be easily and reliably distinguished from non-fibrillar patterns, facilitating the diagnosis of type 1 AIH by indirect immunofluorescence. In addition, the determination on triple sections of rat tissue (liver, kidney, stomach; LKS) can be used for diagnosis. The multiparametric line blots – EUROLINE Autoimmune Liver Diseases profiles – enable efficient confirmation of all relevant autoantibodies.