Patients with primary biliary cholangitis (PBC) and those with autoimmune hepatitis (AIH) exhibit unique immunologic profiles that share both similarities and differences, according to findings from a study conducted in China and published in the Journal of Leukocyte Biology.
PBC and AIH are both recognized as autoimmune disorders, with the former targeting hepatocytes and the latter targeting the small interlobular bile ducts. In the study, Despite both diseases having autoimmune characteristics, however, the variations in their immunologic features have been essentially unexplored and remain to be elucidated.
Patients with PBC and AIH both experience autoimmunity-generated hepatic damage. In both disorders, female patients predominate, with 80% to 90% of those with PBC and 90% of individuals with AIH being females.
Regarding serology, patients with PBC exhibit the presence of antimitochondrial autoantibodies and increased total immunoglobulin M (IgM), alkaline phosphatase (ALP), and gamma-glutamyl transpeptidase (GGT) serum concentrations. In fact, among individuals with PBC, IgM, ALP, and GGT levels can reveal the severity of a person’s disease.
Read more about PBC signs and symptoms
In comparison, AIH is differentiated by the presence of autoantibodies; elevated serum levels of IgG, aspartate aminotransferase (AST), and alanine aminotransferase (ALT); and specific hepatic histologic patterns. In patients with AIH, biochemical remission is associated with normalized ALT, AST, and immunoglobulin G (IgG) serum concentrations.
The researchers sought to clarify the unique immunologic profiles of PBC and AIH, as well as to identify major differences between those with the 2 autoimmune disorders. A comprehensive analysis of various T-cell subsets and their receptor expression was evaluated in a group of 45 individuals—27 of whom had PBC and 18 of whom had AIH.
First-line therapy for patients with PBC is ursodeoxycholic acid, whereas the primary treatment approach for individuals with AIH involves the use of long-term immunosuppression. A considerable number of patients, however, are unresponsive to these standard therapies and thus have a poor prognosis. In fact, even among responders, progression of disease is reported in spite of treatment that appears to be effective.
In the current study, peripheral blood samples, which were treated with heparin, were obtained from patients with PBC, those with AIH, and healthy controls at the Third Affiliated Hospital of Sun Yat-Sen University in Guangdong, China.
Results of the study revealed that patients with both disorders demonstrated T-cell exhaustion and senescence, as well as a surge in inflammatory cytokines. Among participants with both conditions, significantly increased CD38+HLA–DR+CD8+ T-cell populations were seen.
The immune scenarios reported among those with both PBC and AIH were associated strongly with the severity of disease. Via the use of logistic regression analysis, frequencies of γδ T, TIGIT+Vδ2 T,and Tfh1 cells were shown to be distinct markers that were capable of distinguishing PBC from AIH.
“In conclusion, our analyses reveal that PBC and AIH share similarities and differences . . . [in their] immune profiles,” the authors wrote. “The [immunologic] fingerprint may provide indications for individualized risk assessment and therapy in patients, especially the hard-to-treat cohort.”
