Circulating Th and Treg absolute counts or frequency, DR expression, and transcription factors mRNA levels in CD4+ T cells did not correlate with age in HS or with age, UPDRS part III score, and H&Y stage in PD-dn and PD-dt patients, or with disease duration and LED in PD-dt patients (data not shown). This evidence concerns the gene CD4 and Parkinson disease.