Deviations of the immune cell landscape between healthy pancreas and pancreatic adenocarcinoma

Background: Changes to the tumor-infiltrating cells (TILs) are highly associated with the prognosis and immunotherapy response in pancreatic adenocarcinoma (PDAC). The CIBERSORT method accurately estimate the immune cell profiling by deconvolution of gene expression microarray data. We used CIBERSORT to characterize the TILs proportion in 13 healthy human pancreas and 119 PDAC samples. Through the enumeration and activation status of 22 immune cell subtypes, Follicular helper T cells, resting NK cells, monocytes and resting mast cells were decreased in PDAC (p = 0.001; p = 0.019; p = 0.002; p = 0.001) and macrophages M0, M1, M2 and activated mast cells were increased compared to healthy controls (p = 0.022; p = 0.021; p = 0.045; p = 0.009). In all samples, the number of follicular helper