To uncover deregulated T cell signaling in Parkinson’s disease (PD), we analyzed peripheral CD4+ T cells from five PD patients in an age range between 53–86 and at different stages of disease i.e., stage 4, 4, 2.5, 1, and 1 according to the Hoehn & Yahr scale. The gene discussed is CD4; the disease is Parkinson disease.