Three hub genes—AMD1, SPTLC2, and IGSF3—exhibited significant Th2 cell associations (AMD1: r = 0.575; SPTLC2: r = 0.563; IGSF3: r = 0.432; all p < 0.001), suggesting Th2 polarization as a potential immunoregulatory axis in AD pathogenesis (Figure 8C–E). Here, SPTLC2 is linked to Alzheimer disease.