CD4 and cancer: In cancer patients, it was found that the acidosis induced by elevated LAC can significantly inhibit NK cell activity and reduce the level of interferon-γby it, while correcting acidosis can promote the degeneration of tumor cells (Greppi et al., 2024); T cells have specific transport proteins to sense lactate, inhibit its mobility, and increase the conversion of CD4+ T cells to an IL-17+ fraction, while reducing the cytolytic activity of CD8+ T cells (Pucino et al., 2019).