As seen in Fig. 1c and d, the median IFN-gamma levels on two time point were higher in PD patents than in HD patients, and the percent decrease in IFN-gamma level from baseline QFT-IT to sequential 4 month QFT-IT was significantly higher in PD patients than in HD patients (median value of percent decrease, 75.5 VS. This evidence concerns the gene IFNG and Huntington disease.