Skewed immunological balance between Th17 (CD4⁺IL17A⁺) and Treg (CD4⁺CD25⁺FOXP3⁺) cells in human oral squamous cell carcinoma

Several studies have documented modulation of Th17 and T regulatory (Treg) cells in various human malignancies which may vary with the type and extent of the disease. However, such data in patients with oral cancer is scarce and hence the current study was designed to elaborate the immunological balance between these two T cell subsets in oral cancer.

We analyzed various T cell subsets in the peripheral blood of 45 oral squamous cell carcinoma (OSCC) patients and 40 healthy volunteers. We found that, compared with the healthy controls, patients had a significantly (p < 0.0001) higher proportion of both Th17 (CD4⁺IL17A⁺) and Treg (CD4⁺CD25⁺FOXP3⁺) cells, which further showed a reciprocal balance in relation to clinico-pathological parameters in patients. We also detected a circulating CD8⁺ subset of these cells in both patients and healthy controls, although the difference between the two groups was statistically insignificant. Higher frequencies of Th17 cells were found in patients with early stages and without lymph node involvement, while an increased prevalence of Tregs was associated with higher clinical stages and lymph node involvement. Moreover, Th17 cells were quantitatively and positively correlated to CD4⁺T and CD8⁺T cells and inversely correlated with Tregs. Contrarily, Tregs showed a negative association with CD4⁺T and CD8⁺T cells.

Our results suggest an increase in Th17/Tregs ratio in early stages and a decrease in this ratio in higher stages of oral cancer. Such counter regulation of Th17 and Tregs may be a significant prognostic factor in oral cancer patients.