Fig. 4

High ILT4 expression in combination with decreased CD8⁺ T cell or increased Treg infiltration are stronger indicators for poor patient outcomes. a & b Compared with the high counterpart, low CD8⁺T cell proportion in TILs predicted poorer OS (a) (p = 0.017; HR = 1.71, 95%CI:1.11–2.66) and advanced TNM stages (b) (p = 0.013) in LUAD patients. The cutoff value for high and low CD8⁺T cell frequency were defined as ≥ median and < median respectively. c & d Compared with the low counterpart, high Treg proportion in TILs predicted poorer OS (c) (p = 0.029; HR = 1.62, 95%CI:1.05–2.52), advanced lymph node involvement and TNM stages (d) (both p < 0.001) in LUAD patients. The cutoff value for high and low Treg frequency were defined as ≥ median and < median respectively. e & f High ILT4 level combined with low CD8⁺T cell/high Treg frequency were stronger predictors for poor patient OS. Compared with the corresponding counterpart controls, ILT4-high+CD8-low (e) (p < 0.001; HR = 3.34, 95%CI: 1.84–6.05) and ILT4-high+Treg-high (f) (p < 0.001; HR = 3.25, 95%CI:1.77–5.96) patients showed statistically shortened OS. It is noteworthy the combined groups had higher HR values compared with any of the single marker groups (HR = 2.22 for ILT4 alone, HR = 1.71 for CD8⁺T cell alone and HR = 1.62 for Treg alone). The cutoff value for ILT4/CD8⁺T cell/Treg high and low were defined as in Fig. 1c, Fig. 4a and c. g & h Compared with the corresponding counterpart controls, ILT4-high+CD8-low (g) (p = 0.011 for LN involvement and p = 0.004 for TNM stages) and ILT4-high+Treg-high (h) (p < 0.001 for both LN involvement and TNM stages) patients showed more advanced lymph node involvement and TNM stages