CD4 and immunodeficiency disease: Around these age inflection points, the proportion of immune cells, including that of CD4+ T cells, CD8+ T cells, and γδ T cells, changed considerably and was generally considered to be related to the occurrence of cancers and some immunodeficiency diseases (Joosten and Ottenhoff 2008; Minami et al. 2006; Ribot et al. 2020; Strizova et al. 2020).