Autoimmune cholangitis: not just AMA-negative primary biliary cirrhosis

Clinical pathology and HLA-DRB1 allele associations of primary biliary cirrhosis and autoimmune cholangitis in Han Chinese

AIM: To analyze the clinical and pathological characte-ristics of both primary biliary cirrhosis (PBC) and auto- immune cholangitis (AIC), and to explore their associ-ations with HLA-DRB1 alleles in Han Chinese.

METHODS: Of 94 patients diagnosed with PBC, 12 cases of AIC and 9 cases of overlap syndrome of PBC and au-toimmune hepatitis (AIH) were identified. The clinical manifestations and pathological changes exhibited in the liver biopsies from AIC, pure PBC and overlap syndrome were comparatively analyzed. The frequencies of HLA-DRB1 alleles were determined in AIC and PBC patients and healthy controls by polymerase chain reaction with sequence specific primers.

RESULTS: The age, sex, clinical manifestations, bio-chemical markers and histological findings were not significantly different between the AIC and pure PBC patients. However, the score for AIH and the positive rate of serum antinuclear antibody and/or smooth muscle antibody were higher in patients (8.8±0.9 vs 4.6±0.8, t = 17.45, P <0.01; 84.6% vs 22.2%, χ² = 17.003 9, P <0.01). The serum levels of alanine aminotransferase (ALT), aspartate transaminase (AST) and immunoglobulin G in AIC patients were markedly lower than those in the overlap syndrome patients (t = 3.44, P <0.01; t = 2.83, P <0.01; t = 2.18, P <0.05). Higher allele frequency of HLA-DRB1*08 was found in pure PBC patients, versus controls (9.7% vs 3.3%, RR = 4.42, P <0.05), and the allele frequency of HLA-DRB1*08 tended to increase in pure PBC patients.

CONCLUSION: Except the pretreatment score for AIH and the types of immunoserological marker, there were no differences between AIC and pure PBC. AIC may only be a variant pattern of PBC, rather than a separate disease.