[Clinical value of anti-liver/kidney microsomal-1 antibody in patients with liver disease]

Objective: To investigate the clinical and laboratory features of patients with liver disease and positive anti-liver/kidney microsomal-1 (anti-LKM-1) antibody, and to provide a reference for clinical diagnosis and differential diagnosis. Methods: The clinical data of patients with positive anti-LKM-1 antibody who were treated in our hospital from 2006 to 2016 were collected, and clinical and laboratory features were analyzed and compared. An analysis was also performed for special cases. Results: The measurement of related autoantibodies was performed for about 100 thousand case-times, and 15 patients were found to have positive anti-LKM-1 antibody. Among the 15 patients, 7 were diagnosed with type 2 autoimmune hepatitis (AIH) with an age of 11.0 ± 9.0 years and were all adolescents with acute onset; 8 were diagnosed with hepatitis C with an age of 51.5 ± 9.0 years, among whom 7 were middle-aged patients and 1 was a child aged 12 years, and all of them had an insidious onset. Compared with the patients with hepatitis C, the AIH patients had significantly higher levels of alanine aminotransferase (1 003.9 ± 904.3 U/L vs 57.0 ± 84.1 U/L, P < 0.05), aspartate aminotransferase (410.7 ± 660.3 U/L vs 34.9 ± 42.9 U/L, P < 0.05), and total bilirubin (98.0 ± 191.0 μmol/L vs 15.4 ± 6.0 μmol/L, P < 0.05). There was a reduction in immunoglobulin G after the treatment with immunosuppressant, compared with the baseline. Of all 8 patients with hepatitis C, 6 received antiviral therapy with interferon and ribavirin, and 5 out of them achieved complete response, among whom 4 had a reduction in the level of anti-LKM-1 antibody after treatment; however, a 12-year-old child developed liver failure after interferon treatment and died eventually. Conclusion: Positive anti-LKM-1 antibody is commonly seen in patients with type 2 AIH or hepatitis C, but there are differences between these two groups of patients in terms of age, disease onset, liver function, and the level of anti-LKM-1 antibody. The hepatitis C patients with a confirmed diagnosis and exclusion of autoimmune hepatitis can achieve good response to interferon under close monitoring, even if anti-LKM-1 antibody is positive. As for adolescent patients with hepatitis C and positive anti-LKM-1 antibody, the possibility of AIH should be excluded.