Support of precision medicine through risk-stratification in autoimmune liver diseases - histology, scoring systems, and non-invasive markers.

Autoimmune liver diseases (AILDs) are complex conditions, which arise from the interaction between a genetic susceptibility and unknown environmental triggers. They represent a relevant cause of liver failure and liver transplantation worldwide. As a testimony of our progress in understanding the biology of AILDs and the disease progression is the overall median survival which has increased over the last decade. However, there are still major challenges such as the lack of therapies and surveillance strategies in primary sclerosing cholangitis (PSC), the management and treatment of non-responders to first-line therapies in primary biliary cholangitis (PBC) and the need for tailoring immunosuppressive drugs in autoimmune hepatitis (AIH). The different disease course and treatment response in patients with AILDs might be related to a heterogeneous genetic background between individuals which translates in a heterogeneous clinical phenotype. Thus, it becomes essential to personalise management and treatment based on specific risk profiles, e.g. low-risk and high-risk, based on genetic and molecular signatures. It is now possible, thanks to the development of large-scale AILDs patient cohorts, that such diseases can be analysed using various high-throughput methods like gene expression profiling, next generation sequencing and other omics technologies to identify unique fingerprints based on which a personalised or tailor-made management and therapy can be developed. The final aim being to facilitate treatment decision-making that balances patient-specific risks and preferences. This is critical especially now with the current and forthcoming availability of more efficacious medications. To reach this point we need specific interventions such as creating bigger biobanks, sequencing more genomes and linking biological information to health-related data. We have already identified subsets of patients with different risk profiles among patients with PBC, PSC and AIH by using clinical tools such as liver histology, laboratory investigation and non-invasive methods. In this manuscript, we review the clinical features and investigations that already enable us to individualize the care of PBC patients and that might support the development of precision medicine (PM) in AILDs.