Profiling of the pattern of the human TRB/IGH-CDR3 repertoire in primary biliary cholangitis patients.

Introduction: Primary biliary cholangitis (PBC) is characterized by lymphocyte cell-induced immune destruction of cholangiole. However, the immunological characteristics of peripheral blood cells in PBC patients remain unknown. This study was designed to reveal the differences in the immunological characteristics between PBC patients and healthy adults.

Methods: We performed high-throughput sequencing to determine the TRB-CDR3 and IGH-CDR3 repertoires of T and B cells in 19 healthy controls and 29 PBC patients. Different immunological characteristics, such as distinctive complementarity determining region 3 (TRB-CDR3) lengths, usage bias of V and J segments, and random nucleotide addition were identified in PBC and healthy control (HC) groups.

Results: The diversity of TRB-CDR3 was significantly lower in the PBC group compared with the HC group. CDR3 and the N addition length distribution were significantly changed compared with the HC group. It appeared that the PBC group had more short N additions and the HC group had more long N additions in the TRB-CDR3 repertoire. The results also revealed a set of PBC-associated clonotypes compared with the HC group.

Conclusion: This study suggested that PBC is a complex autoimmune disease process with evidence of different TRB-CDR3 rearrangements compared with healthy adults that share IGH-CDR3 peptides with some autoimmune diseases. This new insight may contribute to a better understanding of the immune functions of PBC patients and benefit efficient applications of PBC diagnosis and treatments.