CCL17 and Alzheimer disease: Pretreatment with iMSC secretome before AD induction reduced mRNA expression levels of TNF‐α, IFN‐γ, IL‐4, IL‐13, IL‐17, IL‐22, IL‐31, CCL17, CCL22, and TSLP, while increasing filaggrin mRNA levels (p  < 0.0001), compared to MSC secretome treatment or untreated controls (Figure 3C).