The key role of MIF in the pathogenesis of AD was verified by the stronger communication between ligand MIF from keratinocytes and receptors Cd74 and Cd44 on APCs from the results of scRNA-seq, the higher immunofluorescence signals of MIF in HDM-WT skin, and the increased MIF secretion from keratinocytes after Der f1 stimulation. This evidence concerns the gene CD44 and Alzheimer disease.