CTL- vs Treg lymphocyte-attracting chemokines, CCL4 and CCL20, are strong reciprocal predictive markers for survival of patients with oesophageal squamous cell carcinoma

Background: Tumoural infiltration of T lymphocytes is determined by local patterns of specific chemokine expression. In this report, we examined the roles of CCL4 and CCL20 in the accumulation of CD8 + cytotoxic T lymphocytes (CTLs) and regulatory T (T reg ) lymphocytes in oesophageal squamous cell carcinoma (ESCC), and determined the correlations between chemokine expressions and ESCC patients’ survival. Methods: Reverse transcriptase–PCR and immunohistochemistry (IHC) staining were performed to examine the expressions of interested genes. Flow cytometry was adopted to check the expressions of CCL4- and CCL6-specific receptors, CCR5 and CCR6, on CTLs and T reg cells. In addition, transwell assay was carried on. Results: The CCL4 expression was significantly correlated with the expression of CTL markers ( CD8 and Granzyme B ), whereas CCL20 was positively correlated with T reg markers ( FoxP3 and IL-10 ). Consistently, CCR5 was found to be mainly expressed on CD8 + T lymphocytes, while CCR6 showed prevalence on T reg lymphocytes and the frequencies of CCR5 + CD8 + CTLs and CCR6 + T reg cells were higher in TIL compared with PBMC. Respectively, CCL4 and CCL20 recruited CD8 + and regulatory T cells in vitro . Importantly, high levels of CCL4 in the lesions of ESCC patients predicted prolonged survival. Furthermore, CCL4 high /CCL20 low group demonstrated better overall survival, whereas CCL4 low /CCL20 low and CCL4 low /CCL20 high groups showed the worst overall survival. Conclusions: Our data showed that CCL4 and CCL20 recruit functionally different T lymphocyte subsets into oesophageal carcinoma, indicating CCL4 and CCL20 are potential predictors of ESCC patients’ survival.