CD8A and Parkinson disease: Flow analysis revealed a trend toward reduced total CD8+ T cells in subjects with GG genotype (p=0.0514; Figure 8E), while evaluation of CD8 subsets showed a significant SNIP effect in CD8 central memory cells, decreased CD8 naïve cells in PD AA participants relative to health control AA participants, and increased CD8 effector T cells in PD AA relative to healthy control AA participants (Figure 8F–I).