Pro-inflammatory cytokines BLC, Eotaxin, GM-CSF, I-309, IL-2, IL-6, IL-7, IL-12p40, IL-15, MIP-1d, PDGFB, RANTES, TNF RI, and anti-inflammatory cytokines IL-5, IL-10, IL-12p70, MCSF and TNF RII each had significantly greater variance in levels across the PD Braak 5-6 group compared with controls. The gene discussed is IL15; the disease is Parkinson disease.