CLDN1 and Alzheimer disease: Furthermore, we analyzed cell–cluster-specific expression of the tight junction genes CLDN1, PARD3, and TIAM1 (Mertens et al., 2005) in KCs from AD patients treated with recombinant Der p 2 (AD_rec) and Der p 2 peptides (AD_pep) and compared it with KCs from healthy individuals that were treated with the same allergens and allergen peptides (H_rec and H_pep) (Supplementary Figure S2B).