Atopic dermatitis and skin disease

Background: Loss-of-function (LOF) mutations in the filaggrin gene (FLG) are a well-replicated risk factor for atopic dermatitis (AD) and are known to cause an epidermal barrier defect. The nature of this barrier defect is not fully understood. Patients with AD with FLG LOF mutations are known to have more persistent disease,more severe disease, and greater risk of food allergies and eczema herpeticum. Abnormalities in corneocyte morphology have been observed in patients with AD, including prominent villus-like projections (VP); however, these ultrastructural features have not been systematically studied in patients with AD in relation to FLG genotype and acute and convalescent status. Objective: We sought to quantitatively explore the relationship between FLG genotype, filaggrin breakdown products (natural surface pattern has also been shown in patients with ichthyosismethods. M. A. McAleer has received research support from the National Children’s vulgaris and in squamous cells from patients with psoriasis.7 In most of these studies, VPs were observed qualitatively, and only in one study were the VPs determined semiquantitatively,5 suggesting a correlation between VP numbers and skin barrier function, as assessed based on transepidermal water loss (TEWL). The nature and cause of VPs on the stratum corneum (SC) surface is not well understood. Several mechanistic suggestions have been proposed for the occurrence of VPs, including disturbed organization of the cytoskeleton on desmosome disruption, immature and fragile cornified envelopes (CEs), and attachment sites of desmosomes.1,2,6,8 Rankl et al4 showed that staining for corneodesmosin protein mostly matched the beadlike topographic features, although not all of thes