Immune-mediated bile duct injury: The case of primary biliary cirrhosis

Clinical and pathological features of primary biliary cirrhosis in anti-mitochondria antibody/anti-mitochondrial antibody M2 subtype negative patients

AIM: To improve the level of awareness and diagnosis of primary biliary cirrhosis (PBC) by exploring the clinical and pathological features of PBC in patients who are negative for anti-mitochondria antibody (AMA)/anti-mitochondrial antibody M2 subtype (AMA-M2).

METHODS: A retrospective study was carried out in 101 patients with PBC. Clinical manifestations, biochemical, immunological and histopathological data were analyzed. The clinical and pathological features were compared between 50 AMA/AMA-M2 negative patients and 51 AMA/AMA-M2 positive patients.

RESULTS: The ratio of male to female in the 101 patients with PBC was 1.1:9, and the mean age at diagnosis was 48.52 ± 8.99 years. Common manifestations were fatigue (30.7%), jaundice (29.7%), pruritus (19.8%), dry mouth (12.9%), dry eye (7.9%), hepatalgia (7.9%), lipomyoma (6.9%), anorexia (5.9%), and abdominal distension (1.98%). There were no significant differences in manifestation between the AMA/AMA-M2 negative group and AMA/AMA-M2 positive group. There were also no significant differences in routine blood indices [white blood cells (WBC), hemoglobin (Hb), red blood cells (RBC), and platelet (PLT)], biochemical indices [aspartate aminotransferase (AST), alanine aminotransferase (ALT), AST/ALT, alkaline phosphatase (ALP), gamma glutamine transpeptidase (GGT), total bilirubin (TBIL), total protein (TP), albumin (ALB), triglycerides (TG), and total cholesterol (TC)], coagulation function [prothrombin time activity (PTA), international normalized ratio (INR)], C3, C4, and histopathology between the two groups. γ-globulin, IgG and IgM in the AMA/AMA-M2 positive group were significantly higher than those in the AMA/AMA-M2 negative group (F = 0.019, Z = 0.028, 0.012, P < 0.05).

CONCLUSION: AMA/AMA-M2 negative PBC has no specific clinical manifestations. There may be difference in immune state between the AMA/AMA-M2 positive group and AMA/AMA-M2 negative group. Liver histology is still a gold standard for diagnosis of AMA/AMA-M2 negative PBC.

Autoimmune hepatitis type 2 associated with an unexpected and transient presence of primary biliary cirrhosis-specific antimitochondrial antibodies: a case study and review of the literature

Background

Unlike other autoimmune liver diseases, primary biliary cirrhosis (PBC) has never been reported in early childhood, while type 2 autoimmune hepatitis (AIH) is eminently a paediatric disease.

Case presentation

We describe a case of type 2 AIH with serological positivity for PBC-specific anti-mitochondrial antibodies (AMA) in a 3-year old girl. We found this observation intriguing as AMA and indeed an overlap with PBC are virtually absent in Type 2 AIH, a pediatric form of AIH which is distinct precisely because it is characterized by pathognomonic anti-liver kidney microsomal type 1 (LKM-1) showing a remarkable antigen-specificity directed against cytochrome P4502D6. We also review the literature in relation to AMA positivity in paediatric age and adolescence. In our case, the presence of AIH-2-specific anti-LKM-1 and PBC-specific AMA was confirmed by indirect immunofluorescence (IIF), and immunoblotting and ELISA based on recombinant mitochondrial antigens. The clinical, laboratory and histological features of the child are given in detail. Interestingly the mother was AMA positive without other features of PBC. The child was successfully treated with immunosuppression and five years after the original diagnosis is on a low dose of prednisolone and azathioprine, with no signs of relapse. Anti-LKM-1 antibodies are still present in low titres. AMA were detectable for the first 4 years after the diagnosis and disappeared later.

Conclusion

This is the first case report in the literature of AIH type 2 with an unexpected PBC-specific AMA positivity in a young child. Response to immunosuppressive treatment was satisfactory and similar to that described in AIH. A review of published reports on AMA positivity in paediatric age shows that the antibody may arise in the context of immunodeficiency and is variably associated with liver damage.