| dc.description.abstract | Introduction: Autoimmune Hepatitis (AIH) is an inflammatory liver disease, which without adequate diagnosis and treatment, can progress to cirrhosis. There are no distinguishing clinical features to discriminate this from other liver pathology; therefore, diagnosis is made by the presence of circulating autoantibodies, elevated serum globulin levels, and histologic examination. Initial treatment is with immunosuppression by glucocorticoid monotherapy or by combination of glucocorticoid with azathioprine.
Case: We present the case of a 65-year-old female with no PMH and non-specific abdominal complaints who was found to have unexplained liver cirrhosis. There was no evidence of past or present alcohol abuse. Transaminases were greater than 10x the upper limit of normal, while IgG was greater than 3x the upper limit of normal. Viral hepatitis panel and hemochromatosis mutation gene were negative. AIH was strongly suspected due to exclusion of other etiologies. Subsequently, ELISA for filamentous actin (FA) was tested and resulted positive; however, reflex to smooth muscle antibody (SMA) was negative. Autoantibodies including antinuclear, liver/kidney microsomal, soluble liver antigen, and antimicrosomal were negative. Without adequate evidence of autoantibodies, treatment was withheld until liver histopathology confirmed Type 1 AIH (AIH-1). Prior to discharge, the patient was started on oral prednisone with plans to taper immunosuppression based on therapeutic response (i.e. transaminase levels). Unfortunately, the patient was readmitted roughly 10 days later with severe complications of cirrhosis and ultimately passed away.
Discussion: The subset of SMA with specificity for FA, SMA-T, is the prototype autoantibody correlating with AIH-1. Testing for SMA-T is done by immunofluorescence staining, which can be difficult to visualize when titers are low. FA is detected by ELISA; however, this test has not been fully standardized leading to varying cutoff values depending on assay/laboratory, as well as inability to directly correlate with immunofluorescence titers. In addition, false positive results have been reported in which FA is instead linked to SMA-V, which is seen in a variety of viral illnesses, and not SMA-T. Several factors ultimately contributed to the outcome of this case including hesitation from the patient to pursue invasive measures resulting in a postponed biopsy, and thus diagnosis. However, FA levels were significantly elevated early in the course of illness, indicating the need for standardization of FA assays, as well as correlation between assay and immunofluorescence results. Development of reliable testing for FA has the potential to provide earlier diagnosis and treatment of AIH-1 in patients where SMA titers are negative. | en_US |
