Abstract: Objective Comparing a series of clinical features and pathological manifestations of patients with primary biliary cirrhosis (PBC) with negative and positive anti-mitochondrial antibodies (AMA), in order to provide a theoretical basis for the diagnosis and treatment of AMA-negative PBC patients.Methods From January 2017 to December 2020, patients with abnormal liver function for half a year or more, accompanied by elevated γ-glutamyl transpeptidase (GGT) and alkaline phosphatase (ALP) were selected, and the final subjects were obtained according to the inclusion and exclusion criteria. Liver puncture pathological examination was performed on all selected subjects, and they were divided into AMA negative and positive groups. Routine blood, serum biochemical, thyroid function and pathological tests were performed on the two groups. After collecting the clinical data, SPSS25.0 was used for data analysis. The counting data were expressed as (mean±standard deviation), and t test was used for comparison between the two groups. The measurement data was expressed by rate or percentage (%), and chi-square test was used for the comparison of rates between two groups.Results The results showed that the majority of PBC patients with AMA negative (19 cases) and positive (49 cases) were female, and the patients were mainly 50-55 years old. There was no difference in age and sex between the two groups (P<0.05). Laboratory test results showed that there was statistically significant difference between AMA negative (183.27±1.67) and AMA positive (265.67±1.37) in PLT levels of blood routine (P<0.05), and no difference in other indicators. In addition, liver function test results showed that the GGT value of patients in the AMA negative group (444.5±2.72) was higher than that in the AMA positive group (276.33±3.86). For biochemical factors, the results showed that the levels of triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) in AMA negative group were lower than those in AMA positive group [TG: (1.74±0.58) vs (1.97±0.94), P=0.023; LDL-C: (3.57±0.42) vs (4.87±0.7), P=0.016], while the expression of immunoglobulin IgE was opposite. The IgE expression in the AMA negative group was lower that in the AMA positive group [(70.15±0.91) vs (33.67±0.65), P=0.011]. Thyroid function analysis showed that the T4 expression level of AMA negative group was lower than that of AMA positive group [(110.72±10.34) nmol/L vs (122.56±10.88) nmol/L, P<0.05]. Positive results of autoimmunity antibody showed that anti-liver and kidney microsomal antibody 1 (LKM1) was not expressed in PBC, while antinuclear antibody (ANA) and RO52 in AMA negative group were higher than those in AMA positive group (86.36% vs 9.26%, 81.82% vs 14.81%, both P<0.05). Immunohistochemical results of cytokeratin 7 (CK7) and CK19 showed that there was no statistical difference in positive rate between the two groups.Conclusion The clinical features and pathological manifestations of AMA-negative and positive PBC patients are very similar, and equal attention should be paid to AMA-negative patients to improve the diagnosis rate of PBC and the treatment effect.

Key words: AMA, AMA-M2, Negative, Primary biliary cirrhosis, Clinical features