CD4 and Alzheimer disease: In contrast, Verhagen et al. [37] reported that CD4+ CD25+ Foxp3+ Treg cells were absent from AD lesions and APT-positive sites, but observed considerable infiltration of IL-10-secreting CD4+ Treg type-1 cells (Tr1 cells), which can suppress allergen-specific activation of both INF-γ-secreting Th1 cells and IL-4-secreting Th2 cells.