Comparison of pathological features of patients with antibody-negative and positive primary biliary cholangitis.

Objective: To examine the differences and similarities among primary biliary cholangitis (PBC) with positive and negative expression of autoantibodies (anti-mitochondrial antibodies AMA and AMA-M2, antinuclear antibodies anti-gp210, and anti-sp100).

Methods: Clinical and pathological data of 85 PBC in patients who underwent liver puncture biopsy were retrospectively collected from January 2016 to September 2018 at the Second Hospital of Nanjing. The differences in clinical and pathological indexes of PBC between autoantibody negative and positive groups were analyzed by SPSS 25.0, and the patients' previous autoantibody indexes were collected for follow-up.

Results: The average age of 85 PBC patients was (52.2 ± 9.2) years old, including 15 males (17.6%) and 70 females (82.4%), with a male-to-female ratio of 1:4.7. Fifty-nine autoantibody-positive cases and 26 autoantibody-negative cases were 50 (84.7%) AMA positive, 51 (86.4%) AMA-M2 positive, 21 (35.6%) anti-gp210 positive, and 15 (25.4%) anti-sp100 positive. The distribution of CK7-positive hepatocytes and the degree of bile duct injury in the portal area of PBC patients in the antibody-negative group were lower than those in the antibody-positive group (P < 0.05). There was no significant difference in the distribution of interface inflammation, plasma cell grade, ductular reaction, and fibrosis between the two groups. When the autoimmune antibodies were reexamined at 2 months-7 years (median time 1 year), AMA, AMA-M2, anti-gp210, and anti-sp100 were still negative in 16 antibody-negative patients.

Conclusions: The pathological symptoms and diagnostic patterns of autoantibody-negative and positive PBC were generally comparable. In this study, the pathological manifestations of antibody-negative PBC were similar to those of antibody-positive PBC, but the lymphocyte aggregation in antibody-negative PBC was more severe than that in antibody-positive PBC, while the degree of bile duct injury and CK7-positive hepatocytes were milder than that in antibody-positive PBC, suggesting that the overall pathological changes of antibody-negative PBC were slightly milder than those of antibody-positive PBC.