TNF and Parkinson disease: Although we have no information on the extent of sleep disruption in subjects participating in this study, we noted a decrease in serum TNF with disease, we similarly noted stable TNF levels across the day in PD and HC subjects and found similar levels of IL-6 and TNF in our ~ 50-year old subjects (~ 3–6 pg/ml and ~ 2–3 pg/ml, respectively).