A significant difference between CD68 immunoreactivity in PD cases with a DD of 10 years or less (n = 9, mean 7.3 ± 2.4 years) compared to those with a DD greater than 10 years (n = 8, mean 17 ± 5.0 years) was detected when using Student's t-test, with CD68 immunoreactivity significantly higher in cases with a shorter DD (p < 0.05). The gene discussed is CD68; the disease is Parkinson disease.