During infection, the proportion of CD4+ naive T cells decreases, while the proportions of CD4+ effector memory T cells and CD45RA+ effector memory T cells increase.[252, 253] These CD4+ effector memory T cells can differentiate into a subset (CD57+CD27‐CD28‐CD244+CD4+ T cells), characterized by high cytotoxicity and TCR oligoclonality. This evidence concerns the gene CD4 and infection.