As expected, following the addition of AD-associated cytokines (Th2 cytokines IL4 and IL13) to the 3D skin culture, we found increased transcript levels of the inflammatory markers CA2, NELL2 and CCL26 accompanied by a decrease in the epidermal differentiation markers FLG and LOR and increased expression of the proliferation marker PCNA (Figure 5B–G). Here, PCNA is linked to Alzheimer disease.