MYD88 and Parkinson disease: To detect the expression of high‐mobility group box protein 1 (HMGB1) and toll‐like receptor 4 (TLR4) and their downstream signaling factors—myeloid differentiation factor 88 (MyD88), nuclear factor kappa B (NF‐κB), and tumor necrosis factor alpha (TNF‐α)—in the sera of patients with Parkinson's disease (PD) in order to evaluate the relationship of the HMGB1–TLR4 axis with PD development and progression.