Immunoglobulin classes of smooth muscle antibody in the course of acute hepatitis B: prognostic significance.

A prospective longitudinal study was performed in 48 patients with acute hepatitis B (AHB) of whom 38 were previously healthy (PH) and 10 drug addicted (DA). Smooth muscle antibody was present in 23/38 PH and in 8/10 DA patients for a median of 4 weeks; other autoantibodies were not found. In the PH patients SMA was of IgM class in 23/23 and 8/23 of the IgG class as well. In the 8 DA patients 2 had IgM-SMA only, 3 (IgM+IgG)-SMA and 3IgG-SMA only. IgG-SMA presence could not be related to the duration or titer height of SMA nor to the type of fluorescence patterns. In SMA-negative patients IgM-anti-HBc was cleared within 6 weeks and in IgM-SMA positive patients within 32 weeks (medians 4 and 5 weeks) after maximal S-GPT. IgM-anti-HBc persisted for years in 3/3 IgG-SMA positive and in 2/11 IgG-IgM positive patients. In the remaining 9 IgG-IgM SMA positive patients it disappeared within 15 (median 9) weeks after maximal S-GPT. All 34 patients without SMA or with IgM-SMA only recovered completely. The 3 patients with IgG-SMA and 2 of the 11 patients with IgG+IgM SMA developed chronicity. Determination of SMA and of its immunoglobulin classes, at maximal SGPT may in acute hepatitis B be of help in predicting the outcome of disease.