Additionally, patients with early-to-middle-stage PD have been found to have higher blood levels of CD45RA+ effector memory CD8+ T cells (Capelle et al., 2023), which secrete elevated levels of TNF-α and IFN-γ cytokines, resulting in increased cytotoxicity (Hamann et al., 1997). The gene discussed is TNF; the disease is Parkinson disease.