Expression of ILT3 predicts poor prognosis and is inversely associated with infiltration of CD45RO+ T cells in patients with colorectal cancer

Immunoglobulin like transcript 3 (ILT3) was previously identified as an inhibitory receptor to induce T cell anergy in tranplantation, autoimmunity and allergy. Here we aimed to investigate the expression of ILT3 in colorectal cancer, analyze the association between ILT3 expression and clinicopathological variables and prognosis, and evaluate the correlation between the expression of ILT3 and CD45RO+ T cells density. Expression of ILT3 was identified on the cell membrane and/or in the cytoplasm. High expression ILT3 was identified in 55 of 85 (64.7%) tumor specimens, which was significantly higher than that in the adjacent normal tissues(5/30) (P < 0.001). High ILT3 expression was significantly associated with positive lymph node metastasis (N1-2; P = 0.03), advanced disease (stage III-IV; P = 0.03), and reduced OS in patients. The ILT3 expression level was an independent prognostic factor (P = 0.004) and inversely correlated with the number of CD45RO+ T cells (P = 0.019). In the present study, high ILT3 expression was observed in colorectal cancer and inversely associated with CD45RO+ T cells density and prognosis, suggesting that ILT3 played an important role in tumor progression by possible influence on CD45RO+ T cells in the tumor microenvironment.