There were 33 key genes involved in the AD severity-associated pathways, of which 18 genes showed high diagnostic performance in discriminating lesional AD vs. non-lesional AD as well as non-lesional AD vs. health skin, as shown Figure 5B. More specifically, the glucocorticoid receptor and IL-33 signaling-related gene SELE showed high diagnostic efficacy in the GSE121212 (AUC = 0.947) and GSE107361 (AUC = 0.727) datasets between lesional AD vs. non-lesional AD. Here, IL33 is linked to Alzheimer disease.