Behavior and significance of autoantibodies in type 1 autoimmune hepatitis

Background/Aim: Smooth muscle antibodies and antinuclear antibodies characterize type 1 autoimmune hepatitis. Our aim was to correlate the appearance and disappearance of these autoantibodies with clinical and histological events. Methods: One hundred and seven patients were evaluated successively over 128±9 months. Autoantibodies were determined by indirect immunofluorescence during routine follow-up and at key clinical events. Results: Eighty-one patients (76%) lost one or both of the autoantibodies, and disappearance was associated with improved laboratory and histological features. Autoantibody status, however, was not highly predictive of laboratory (69%) or histological activity (72%). Patients who relapsed were seronegative at the time of drug withdrawal as commonly as patients who sustained remission (29% versus 25%). Only 27 patients (25%) lost their autoantibodies long term. Patients who eventually entered a sustained remission lost their autoantibodies more commonly than those who required retreatment (76% versus 43%, p=0.03). Disappearance of the autoantibodies, however, preceded sustained remission in only 38%. Serum titers at presentation did not distinguish patients with more severe disease or different treatment outcomes. Conclusions: Smooth muscle antibodies and antinuclear antibodies commonly disappear and reappear. Their loss is associated with improved laboratory tests and biopsy findings, but disappearance does not predict treatment outcome. Autoantibody titer at presentation and autoantibody behavior during therapy are not accurate indices of disease severity or prognosis.