Stereological estimates revealed a statistically significant ~ 3.58-fold increase of CD4+ T cells/mm3 in the putamen (Control: 1043 ± 90.48, MSA: 3743 ± 249.9, p = 0.0079) and a ~ 2.47-fold increase in the substantia nigra of MSA cases when compared to control cases (Control: 1469 ± 209.4, MSA: 2625 ± 500.5, p = 0.0079) (Fig. 2b). This evidence concerns the gene CD4 and multiple system atrophy.