After adjusting for gender, percentages of CD31+ Treg were associated with UPDRS-III scores, wherein Bonferroni adjustment for multiple comparisons demonstrated that the percentages of CD31+ Treg in PD patients with a UPDRS-III score ≥31 were significantly less than those from patients with scores of 1–20 (Fig. 2h). This evidence concerns the gene PECAM1 and Parkinson disease.