TNF and Parkinson disease: We employed backward-elimination multiple logistic regression analyses to identify optimal biomarker panels for bilateral comparisons between: [1] asymptomatic LRRK2 mutation carriers and Ctrl, and [2] PD patients and Ctrl, for which t-, o- and pS129-α-syn, TNF-α, and IL-16 were entered as predictors and the Ctrl group was used as the reference group in each comparison.