TIGIT and HIV infectious disease: HIV infection was also associated with a lower percentage of PD-1+ TIGIT- CD160- (“PD-1 only”) cells and a higher percentage of three populations: PD-1- TIGIT+ CD160- (“TIGIT+ only”), PD1-, TIGIT+ CD160+ (“TIGIT and CD160 double positive”) and PD-1+ TIGIT+ CD160+ (“triple positive”) cells (Figure 3A).