[Clinicopathological analysis of anti-mitochondrial antibody negative primary biliary cholangitis-autoimmune hepatitis overlap syndrome]

Autoimmune hepatitis and primary biliary cholangitis overlap syndrome after COVID-19

COVID-19 is commonly associated with high serum levels of pro-inflammatory cytokines, and the post-infection status can disturb self-tolerance and trigger autoimmune responses. We are reporting a 45-year-old male who was admitted with fatigue, jaundice, elevated liver enzymes (with cholestatic pattern), and acute kidney injury two weeks after recovering from a mild SARS-CoV-2 infection. Serologies for viral hepatitis and anti-mitochondrial antibody were negative, while anti-nuclear and anti-smooth muscle antibodies were positive. There were no signs of chronic liver disease, and a magnetic resonance cholangiography showed no dilatation of biliary ducts. Histologic evaluation of the liver evidenced numerous foci of lobular necrosis without ductopenia or portal biliary reaction. Considering the autoantibody profile and histologic changes, the medical team started oral prednisone, but there was a suboptimal biochemical response in the outpatient follow-up. Two months later, a second liver biopsy was performed and revealed non-suppurative destructive chronic cholangitis, extensive areas of confluent necrosis with hepatocytes regenerating into pseudorosettes, and numerous plasma cells. According to the Paris Criteria, the patient was then diagnosed with an autoimmune hepatitis-primary biliary cholangitis overlap syndrome (AIH-PBC-OS). After adding azathioprine and ursodeoxycholic acid to the treatment, there was a satisfactory response. This is the second worldwide report of an AIH-PBC-OS triggered by COVID-19, but the first case with a negative anti-mitochondrial antibody. In this setting, histologic evaluation of the liver by an experienced pathologist is a hallmark of achieving the diagnosis and correctly treat the patient.

Poor performance of anti-mitochondrial antibodies for the diagnosis of primary biliary cholangitis in female Colombian patients: A single-center study

BACKGROUND

Primary biliary cholangitis (PBC) is a serious disease that causes significant morbidity. PBC is confirmed with liver biopsy but autoantibodies are frequently used as proxies for diagnosis. The performance of autoantibodies for the diagnosis of PBC seems to vary widely across populations.

AIM

To assess the diagnostic performance of several autoantibodies for the diagnosis of PBC in Latin American individuals.

METHODS

We studied 85 female adult Colombians, 43 cases with biopsy-confirmed PBC and 42 controls in whom a liver biopsy ruled out PBC. Plasma anti-mitochondrial antibodies (AMAs), anti-smooth muscle antibodies (ASMAs) and anti-nuclear antibodies (ANAs), as well as total immunoglobulin (Ig) M and IgG were determined using immunofluorescence or enzyme-linked immunosorbent assay in all study participants within 1 year of the biopsy. For all variables, values analyzed were those closest to the date of the biopsy. Patients with viral or alcoholic hepatitis were excluded.

RESULTS

Mean age at diagnosis was 58.7 years for cases and 56.9 years for controls, and the body mass index was lower among cases. Most cases received ursodeoxycholic acid, while most controls received vitamin E. Sjögren syndrome and Hashimoto’s thyroiditis were the most frequent autoimmune comorbidities of PBC. The prevalence of AMA positivity among PBC cases was unexpectedly low. The sensitivity and specificity values were respectively 44.2% and 76.2% for AMA, 74.4% and 38.1% for ANA, 14.0% and 73.8% for ASMA, 26.7% and 80.0% for IgG, and 57.1% and 85.7% for IgM. The combination of positive AMA plus positive IgM had 91% positive predictive value for PBC. Among AMA-negative cases, the most prevalent antibodies were ANA (87.5%). In all, 62% of AMA-positive and 84.6% of IgM-positive individuals had fibrosis in their biopsy.

CONCLUSION

AMA positivity was very low among female Latin American patients with PBC. The performance of all antibodies was quite limited. These results highlight the urgent need for better PBC biomarkers.