Introduction
Tertiary lymphoid structure (TLS) is a pathological structure existing in chronic inflammation or autoimmune diseases by promoting the immunotherapy response. However TLS neogenesis has not been evaluated in primary biliary cholangitis (PBC).
Aims & Methods
To determine the characteristics of liver TLSs neogenesis in patients with PBC and investigate the effect of inhibition of TLSs in a murine model of PBC. We performed a retrospective study of patients with PBC who underwent liver biopsy from April 2015 to November 2022. The cohort was divided into two groups based on TLS neogenesis (TLS- vs TLS+). A comparison of the severity of cholangitis between two groups was performed. Bulk RNA sequencing was performed between the groups of TLS- and TLS+ in liver biopsy. Sphingosine-1-phosphate receptor agonist FTY720 was administrated to suppress TLSs formation in dnTGFβRII mice, in which liver TLSs were developed.
Results
In total, 70 patients were included in the study cohort, of which 50 patients with TLSs formation and 20 patients without TLSs formation. The group of TLS+ showed a higher level of serum liver function compared with TLS- (Table1). The level of IgM and the proportion of liver cirrhosis were higher in the group of TLS+. Transcriptomic analysis in liver biopsy indicated a group of 1,548 significantly upregulated genes and 1,365 downregulated genes comparing the group of TLS+ with TLS-. The KEGG pathway identified liver with TLS expression signatures associated with phospholipase D signaling pathway and B cell receptor signaling pathway. GO assessment of DEGs confirmed the activation of immune system process and leukocyte migration. FTY720 significantly attenuated serum liver function and reduced the levels of inflammation cytokines in dnTGFβRII mice. Notably, TLSs were significantly smaller in FTY720-treated mice, with the levels of TLS-related chemokine and lymphotoxin decreasing significantly. Flow cytometry indicated the percentage of CD19+ B cells and CD4+ T cells out of the liver CD45+population was reduced significantly in FTY720-treated liver.
Table1: Clinical and demographic characteristics in patients of tertiary lymphoid structures at the time of biopsy
| TLS+ (n=50)
| TLS-(n=20)
| P Value
|
Female, n (%)
| 44 (88.0)
| 19 (95.0)
| 0.445
|
Age at liver biopsy
| 54.5 (48.0-62.5)
| 50.0 (46.0-55.0)
| 0.528
|
ALT (U/L)
| 46.5 (31.0-79.5)
| 26.0 (12.0-39.0)
| 0.018*
|
AST (U/L)
| 50.5 (30.0-90.3)
| 27.0 (22.0-40.0)
| 0.005*
|
ALP (U/L)
| 196.0 (114.3-305.5)
| 107.0 (72.0-154.0)
| 0.008*
|
GGT (U/L)
| 150.0 (62.5-299.0)
| 153.0 (61.0-306.0)
| 0.826
|
IgG (g/L)
| 1765.0 (1507.5-2037.5)
| 1770.0 (1290.0-1890.0)
| 0.207
|
IgM (g/L)
| 342.0 (187.8-507.3)
| 206.0 (138.0-338.0)
| 0.013*
|
Liver cirrhosis, n (%)
| 14 (28.0)
| 0
| 0.007*
|
Note: Data are presented as a percentage or as the median (25th-75th percentile). Comparisons between the groups were performed by chi-squared tests or nonparametric tests. *
P < 0.05.
Abbreviations: ALT, alanine aminotransferase; AST, aspartate aminotransferase; ALP, alkaline phosphatase; GGT, gamma glutamyl transpeptidase;IgG, immunoglobulin G; IgM, immunoglobulin M.
Conclusion
Our results suggest the potential role of TLSs in building the severity of cholangitis and this understanding may guide therapeutic interventions of PBC.
References
[1]Sato Y, Silina K, van den Broek M, Hirahara K, Yanagita M. The roles of tertiary lymphoid structures in chronic diseases. Nat Rev Nephrol. 2023 : 1-13.
[2]Zhang QY, Ye XP, Zhou Z, et al. Lymphocyte infiltration and thyrocyte destruction are driven by stromal and immune cell components in Hashimoto's thyroiditis. Nat Commun. 2022. 13(1): 775.
[3]Al-Diwani A, Theorell J, Damato V, et al. Cervical lymph nodes and ovarian teratomas as germinal centres in NMDA receptor-antibody encephalitis. Brain. 2022. 145(8): 2742-2754.
Disclosure
Nothing to disclosure
