TIGIT and HIV-1 infection: Since TIGIT is predominantly expressed on NKG2A−NKG2C+NK cells, it is understandable that NKG2A−NKG2C+NK cells in frequency are positively correlated with the levels of HIV-1 viral load in acute HIV-1 infection (Table 1), although they did not expand during acute HIV-1 infection but did so in chronic HIV-1 infection.