To analyze the characteristics of clinical and laboratory indexes in patients with liver disease with positive anti-liver cytosol antibody type 1 (anti-LC1), in order to provide references for clinical and differential diagnosis.

The clinical data of 23 832 inpatients and outpatients with positive anti-LC1 autoantibodies detected in routine autoantibody test from January 2010 to January 2020 were retrospectively analyzed, and their clinical and laboratory indexes were compared. Western blotting was used to detect anti-LC1, anti-soluble liver antigen antibody (anti-SLA), anti-glycoprotein 210 antibodies and anti-nucleosome 100 antibodies. Indirect immunofluorescence assay was used to detect anti-nuclear antibody (ANA), anti-mitochondrial antibody, anti-Smooth muscle antibody (ASMA), anti-liver and kidney microsomal antibody (anti-LKM) and other autoantibodies. Normally distributed measurement data between the two groups were compared by independent-sample t-test, and the multiple groups comparison were compared by one-way analysis of variance. Non-normally distributed measurement data were compared by non-parametric rank sum test.

38 anti-LC1 positive patients were detected in 23832 autoantibody tests. The age of initial diagnosis ranged from 11.0 to 84.0 (50.6 ± 16.0) years. There were 8 males (21.1%) and 30 females (78.9%). A total of 31 cases (81.6%) were positive for anti-LC1 and ANA, and the dominant karyotype was speckled pattern, accounting for 54.8%. Five cases (13.2%) were positive for ASMA, and no simultaneous positive with anti-LKM or anti-SLA. Among the 38 anti-LC1 positive patients, 9 were diagnosed with autoimmune hepatitis (AIH), 6 with possible AIH, 6 with primary biliary cholangitis (PBC), 8 with hepatitis B, 2 with hepatitis C, 1 with alcoholic liver disease, 2 with non-alcoholic fatty liver disease, 1 with drug-induced liver injury, 1 with hepatolenticular degeneration, and 2 with tumor. Confirmed and probable AIH cases accounted for 39.5% (15/38) of anti-LC1 positive cases. Among anti-LC1 positive patients, 47.4% (18/38) had entered the stage of liver cirrhosis. AIH group globulin level was higher than HBV group (P = 0.006) and other disease groups (P = 0.001). AIH group IgG level was higher than PBC group (P = 0.027), HBV group (P = 0.009) and other disease groups (P = 0.004). the of the PBC group IgM level was higher than AIH group (P = 0.003), HBV group (P = 0.003) and other disease groups (P = 0.006).

Anti-LC1 is not only detected in AIH, but also observed in patients with primary biliary cholangitis, hepatitis B and C, alcoholic and non-alcoholic liver disease, drug-induced liver injury, hereditary metabolic liver disease and tumor. In addition, it is mainly female gender dominance and nearly half of ANA-positive young, middle-aged and elderly patients develop liver cirrhosis. For the diagnosis of type 2 autoimmune hepatitis, whether anti-LC1 is a specific antibody needs further research, but if AIH is highly suspected, this antibody can be used as a substitute.

Liver disease; Autoimmune hepatitis; Antibodies to liver cytosol type 1