CD4 and Parkinson disease: The effect of α-syn on the frequency of CD4+ T naive and memory cells was tested on PBMC obtained from a group of 8 HS (F/M = 4/4, age = 58.1 ± 14.5 years) and 6 PD patients (F/M = 2/4, age = 76.7 ± 7.0 years, UPDRS Part III = 20.5 ± 3.1, H&Y = 1.8 ± 0.8) all treated with l-DOPA without (n = 4) and with DA agents (n = 2, in both cases rasagiline, in one case also ropinirole), with LED = 551.7 ± 140.1 mg/day.