While it has been previously described that OX40 is expressed on activated human and rodent CD4 T cells after a malaria blood stage infection (Zander et al., 2015; Goncalves-Lopes et al., 2016) no data had been reported on the expression of OX40 on T cells after a sporozoite/liver stage Plasmodium infection/immunization. The gene discussed is CD4; the disease is malaria.