Elevated soluble programmed death-ligand 1 levels indicate immunosuppression and poor prognosis in hepatocellular carcinoma patients undergoing transcatheter arterial chemoembolization

Aims: The present study aimed to determine the prognostic significance of soluble Programmed Death-ligand 1 (sPD-L1) in hepatocellular carcinoma (HCC) patients undergoing transcatheter arterial chemoembolization (TACE).

Methods: We treated 114 HCC patients with TACE from 2012 to 2013 and determined their sPD-L1 levels by enzyme-linked immunosorbent assay. We evaluated prognosis according to mRESIST criteria and analyzed prognostic values by Cox regression and Kaplan-Meier analysis. We further evaluated correlations between sPD-L1 level and inflammatory status, as well as immunosuppressive environment.

Results: sPD-L1 levels were significantly increased in patients who developed HCC progression (P = 0.002) and death (P < 0.001). Patients with higher pre-treatment sPD-L1 levels had a significantly shorter time to progression (10.50 vs. 18.25 months, P = 0.001) and decreased overall survival (16.50 vs. 28.50 months, P = 0.003). Importantly, sPD-L1 levels positively correlated with SII (r = 0.284, P = 0.002), sIL-2R (r = 0.239, P = 0.010), IL-10 (r = 0.283, P = 0.002), HBV-DNA loads (r = 0.229, P = 0.014), and CRP (r = 0.237, P = 0.011). Moreover, high sPD-L1 levels had increased numbers of Treg cells (FOXP3+; P = 0.026), Macrophage cells (CD68+; P = 0.014), and M2-Macrophage cells (CD163+; P = 0.026) CONCLUSIONS: sPD-L1 level is a prognostic indicator of poor outcomes after TACE. High sPD-L1 might reflect increased immune activation in an immunosuppressive environment that hindered anti-tumor response activity.