During HIV infection, depletion of CD4 cells, decreased production of cytokines and IFNγ, and impaired cytotoxic T-lymphocyte activity result in reactivation of latent Toxoplasma infection (Basavaraju, 2016), and is associated with persistence of IgG antibodies against T gondii (Robert-Gangneux and Darde, 2012). Here, CD4 is linked to HIV infectious disease.