• Decreased levels of Tregs observed in PD patients compared to controls• No significant difference in Th1, Th2, and Th17 levels between patients and control, however serum levels of IL-17A were decreased in PD patients• Serum levels of pro-inflammatory cytokines TNF-α, IL-1β, IL-6, and GM-CSF not significantly different between groups. Here, TNF is linked to Parkinson disease.