Diagnostic and prognostic value of double-negative T cells in colorectal cancer

To evaluate the T-lymphocyte subset distribution and the diagnostic and prognosis value of double-negative T (DNT) cells in colorectal cancer (CRC).

This retrospective study compared the T-lymphocyte subsets and DNT of 114 patients with CRC with those of 107 healthy controls (HC). The diagnostic potential of DNT and T-lymphocyte subsets was assessed using the receiver operating characteristic (ROC) curve, and prognostic values were evaluated using the Kaplan-Meier curve and the Cox regression model.

The percentages of CD8⁺ T cells and DNT cells, and value of carcinoembryonic antigen (CEA), were remarkably higher in patients with CRC than in those with HC, but the ratio of CD4⁺/CD8⁺ was decreased. Using ROC curve analysis, DNT cell percentage, CEA, and CD4⁺/CD8⁺ ratio all had good diagnostic efficacy, with areas under the curve (AUCs) of 0.865, 0.786 and 0.624, respectively. The combination of DNT cell percentage and CEA had an AUC of 0.905, which was significantly higher than that of any single biomarker (p < 0.05). In univariate analysis, the Tumor Node Metastasis (TNM) clinical stage, CD4⁺/CD8⁺ ratio, and DNT cell percentage were significantly associated with overall survival (OS) (p < 0.05). In multivariate analysis, TNM clinical staging (HR = 2.37, 95 % CI: 1.15-4.90), a decreased CD4⁺/CD8⁺ ratio (HR = 0.33, 95 % CI: 0.15-0.74), and an increased DNT cell percentage (HR = 2.29, 95 % CI: 1.11-4.73) were independent prognostic factors for CRC.

The percentage of DNT cells may be useful as an evaluation index for CRC diagnosis and prognosis, which was even better when combined with serum CEA.