Interestingly, an involvement of PD-1 in the control of malaria blood-stage infection has already been reported: in P. falciparum infections, higher expression of PD-1 was associated with T cell dysfunction, and therapeutic blockade of PD-1 ligand in a murine model of infection rapidly cleared blood-stage malaria in a B- and T-cell dependent manner12. Here, PDCD1 is linked to infection.