CD4 and Alzheimer disease: Wild type AD mice (Treg/CD4+: 169 ± 36/6165 ± 540) showed significantly less Treg cells in spleen compared with either sham mice (Treg/CD4+: 532 ± 115/8519 ± 1456) and IL-37b Tg (Treg/CD4+: 426 ± 35/7224 ± 659) AD mice (Figure 3K and Supplementary Figure 5, all P < 0.05).