IL10 and neoplasm: CD14+ cells from both tumours and blood released significantly more IL-10 (Fig. 3b) than those from healthy donors and HLA-DR− cells from colorectal patients are the main source of IL10 secretion (Fig. 3b).To determine whether the suppressive activity of the M-MDSCs in both tumours and blood might be IL-10 dependent, IL-10 receptor blocking antibody was added to T cell proliferation assays.