Examining the spatial distribution of tumor-infiltrating immune cells in patients with stage I-IIIA LUAD.

Abstract

This study aimed to examine the spatial distribution of immune cells by application of Gcross function in 170 patients with stage I-IIIA lung adenocarcinoma (LUAD) and explore its prognostic value. A total of 170 stage I-IIIA LUAD patients who underwent radical surgery were enrolled. Paraffinized tumor sections were collected for two panels of multicolor immunofluorescence staining as follows: Panel 1 (CD4, CD8, FOXP3, CD69, CD39, CD73, and DAPI) and Panel 2 (CD68, CD163, CD20, CD11c, PDL1, IDO, and DAPI). The immune cells were categorized as CD8+, CD4+ T-helper cell (CD4Th), Regulatory T cell (Treg), Macrophage type 1 (M1), Macrophage type 2 (M2), Dendritic cell (DC) and B cell. The immune cell numbers were enumerated, and the immune cell proximity score was calculated employing the Gcross function. The correlation between immune cell variables and Disease-Free Survival (DFS) was explored through univariate Cox regression analyses. Factors with P<0.05 were subjected to multivariate analyses. According to univariate Cox regression analyses, total PDL1+ and PDL1+ DC counts were negative factors (P=0.003, 0.031). CD4Th and IDO-DC counts were positive factors (P=0.022, 0.024). The proximity score (M1 to M2) was a positive factor for DFS (P=0.032), and the proximity score (PDL1+DC to M1) was a negative factor (P=0.009) according to univariate Cox analyses. In multivariate analyses, stage (IIIA vs. I+II) [HR: 1.77(1.18, 2.64), P=0.006] and proximity score (PDL1+DC to M1) [HR: 1.60(1.07, 2.37), P=0.021] were independent negative factors and CD4Th counts [HR: 0.60(0.40, 0.90), P=0.013] was an independent positive factor. Our study indicated that a higher level of tumor-infiltrating CD4Th cells predicted longer DFS, and a closer proximity of PDL1+ DCs to M1 cells was associated with dismal DFS in stage I-IIIA LUAD patients.