Participation of Increased Circulating MAIT Cells in Lung Cancer: a Pilot Study

Mucosal-associated invariant T (MAIT) cells are a subset of innate-like T cells that regulate the immune response via rapidly releasing inflammatory factors, including during progression of some tumors. However, the immunological role of MAIT cells is still unclear in lung cancer. We measured percentage, partial function, and clinical correlation of circulating MAIT cells from lung cancer patients through flow cytometry. Lung cancer patients displayed a high concentration of CD4⁺, CD8⁺, and activated CD38⁺CD8⁺MAIT cells, and a decrease of PD1⁺ double negative (DN) MAIT cells in peripheral blood. Meanwhile, increased levels of interferon-γ, interleukin (IL)-6, and 8 were examined in the serum of lung cancer patients. Importantly, we discovered a statistically positive association between accumulation of CD38⁺CD8⁺MAIT cells and reduced progression-free survival of lung cancer patients. While preliminary, the altering frequency of MAIT cells might be involved in dysfunctional immune response in lung cancer.