TCR Repertoire Analysis During Therapeutic Interventions in Liver Diseases Using Next-Generation Sequencing.

Background and aim: The T cell receptor (TCR) can recognize a vast number of antigens and is closely associated with the pathogenesis of various diseases including autoimmune diseases and malignancies. However, the clinical significance of the TCR repertoire and its post-treatment changes remain unclear in liver diseases.

Methods: We performed next-generation sequencing (NGS)-based TCR analysis using DNA obtained from peripheral blood mononuclear cells (PBMCs) of healthy donors (HD, n = 5), primary biliary cholangitis (PBC, n = 5), autoimmune hepatitis (AIH, n = 5), and hepatocellular carcinoma (HCC, n = 5) and evaluated the changes after treatment.

Results: Baseline TCR repertoire analysis demonstrated that TCR clonotype usage is restricted and diversity is low in all three disease groups (PBC, AIH, and HCC), particularly in PBC and AIH compared to HD (p < 0.05). Following treatment, clonotype usage and diversity did not change significantly, except in AIH, where diversity decreased further (p < 0.05 for clone Shannon diversity and clone evenness). Disease-specific usage of TCR beta genes and specific changes after therapy were observed in all groups. Analysis of clonotypes shared with other individuals (public clonotypes) revealed that nine public clonotypes in PBC, eight in AIH, and eight in HCC disappeared after treatment. Motif analysis identified one characteristic motif (NQPQH) in PBC.

Conclusions: The diversity of the TCR repertoire, TCR beta chain usage, clonotypes, and motifs and their post-treatment changes are disease-specific in each liver disease, indicating that further TCR repertoire studies are needed to accelerate the understanding of liver disease pathogenesis from an immunological perspective.