Body Composition in Cholangiocarcinoma Affects Immune Cell Populations in the Tumor and Normal Liver Parenchyma

Background: Due to malnutrition and tumor cachexia, body composition (BC) is frequently altered and known to adversely affect short- and long-term results in patients with cholangiocarcinoma (CCA). Here, we explored immune cell populations in the tumor and liver of CCA patients with respect to BC.

Methods: A cohort of 96 patients who underwent surgery for CCA was investigated by multiplexed immunofluorescence (MIF) techniques with computer-based analysis on whole-tissue slide scans to quantify and characterize immune cells in normal liver and tumor regions. BC was characterized by obesity, sarcopenia, myosteatosis, visceral obesity and sarcopenic obesity. Associations between BC and immune cell populations were determined by univariate and multivariable binary logistic regressions.

Results: BC was frequently altered in intrahepatic CCA (iCCA, n = 48), with 47.9% of the patients showing obesity, 70.8% sarcopenia, 18.8% sarcopenic obesity, 58.3% myosteatosis and 54.2% visceral obesity as well as in perihilar CCA (pCCA, n = 48) with 45.8% of the patients showing obesity, 54.0 sarcopenia, 14.6% sarcopenic obesity, 47.9% myosteatosis and 56.3% visceral obesity. From an immune cell perspective, independent associations within the tumor compartment were observed for iCCA (myosteatosis: TIM-3+CD8+cells; obesity: PD-1+TIM-3+CD4+cells) and for pCCA (myosteatosis: PD-L2+CD68-cells and CD4+cells). Further, independent associations were observed within the normal liver parenchyma for iCCA (visceral obesity: PD-1+PD-L1+PD-L2+CD68+cells) and for pCCA (sarcopenia: CD68+cells and TIM-3+CD8+cells; visceral obesity: ICOS+-TIGIT+CD8+cells and sarcopenic obesity: PD-1+PD-L1+PD-L2+CD8+cells).

Conclusion: This is the first systematic analysis of the association of BC and immune cells in cholangiocarcinoma showing a strong association between BC and distinct immune cell populations within the tumor itself as well as within the normal parenchyma.