We have examined mitochondrial dysregulation in CD4 T cells during HCV or HIV infections and discovered that oxidative stress, caused by excess ROS production, induces mitochondrial injury and accelerates telomere erosion - a dual effect that can promote the T cell aging process and, eventually, cell death (Schank et al., 2020; Schank et al., 2021; Schank et al., 2021; Wang et al., 2021; Zhao et al., 2021). The gene discussed is CD4; the disease is HIV infectious disease.