Concentration of filaggrin monomers, its metabolites and corneocyte surface texture in individuals with a history of atopic dermatitis and controls

Atopic dermatitis (AD) is characterized by skin barrier dysfunction. Notably, a high number of nano-scale protrusions on the surface of corneocytes, which can be expressed by the Dermal Texture Index (DTI), was recently associated with pediatric AD, loss-of-function mutations in filaggringene (FLG), and reduced levels of natural moisturizing factors (NMF). No study has so far examined the association between these parameters and monomeric filaggrinlevels in adults. To determine DTI, monomeric filaggrinand NMF in healthy controls and a group of patients with controlled dermatitis. A total of 67 adults (20 healthy controls and 47 dermatitis patients) were included. In the patient population, a personal history of AD was diagnosed by the U.K. Working Party's Diagnostic Criteria. All participants were tested for FLG mutations (R501X, 2282del4, R2447X). Transepidermal water loss, monomeric filaggrin, DTI and NMF were measured. In the patient population, 78.7% (37/47) had a history of AD and 59.5% (28/47) had FLG mutations. Patients had significantly higher levels of DTI and significantly lower levels of monomeric filaggrinand NMF compared to the 20 healthy controls. Among patients, reduced level of monomeric filaggrinand NMF correlated with the presence of FLG mutations and clinical phenotypes such as xerosis, palmar hyperlinearity and AD. Among healthy controls, DTI was significantly higher in the oldest age group compared to the two younger age groups. A significant difference in DTI, monomeric filaggrinand NMF levels was found when comparing dermatitis patients with healthy controls. These findings suggest that even mild dermatitis or non-visible inflammation has a significant and negative effect on the skin barrier as inflammation is known to reduce filaggrinlevels. DTI was significantly increased in aged individuals in the healthy control group, suggesting a gradual change in corneocytemorphology with age. This article is protected by copyright. All rights reserved