CD38 and Huntington disease: To further investigate the role of MD in regulating T-cell activation and function, we examined biomarkers of T-cell hyperactivation (HLA-DR+CD38+) and activation/exhaustion (PD-1+) in memory subsets along with monitoring MD in APs (8 mild and 9 severe APs during 11–15 days p.s.o.)as compared to HD controls (Figure 4A).