Dysfunctional skin barrier plays a key role in the pathophysiology of atopic dermatitis (AD), a common inflammatory skin disease. Altered composition of ceramides is regarded as a major cause of skin barrier dysfunction, however it is not clear whether these changes are intrinsic or initiated by inflammation and aberrant immune response in AD. This study investigated the levels of free sphingoid bases (SBs) sphingosine and sphinganine and their ceramides and glucosylceramide in the stratum corneum (SC) and related them to skin barrier function, disease severity and local cytokine milieu. Ceramides were measured in healthy skin, and lesional and non-lesional skin of AD patients by a novel method based on deacylation of ceramides which were subsequently determined as corresponding sphingoid bases by using liquid chromatography–tandem mass spectrometry (LC–MS/MS). The cytokine levels were determined by multiplex immunoassay. Atopic skin showed increased levels of most investigated markers, predominantly in lesional skin. The largest difference in respect to healthy skin was found for glucosylceramide with respective median values of 0.23 (IQR 0.18–0.61), 0.56 (IQR 0.32–0.76) and 19.32 (IQR 7.86–27.62) pmol/g protein for healthy, non-lesional and lesional skin. The levels of investigated ceramide markers were correlated with disease severity (scoring atopic dermatitis, SCORAD) and skin barrier function (trans-epidermal water loss, TEWL) and furthermore with cytokines involved in innate, Th-1, and Th-2 immune response. Interestingly, the strongest association with SCORAD was found for sphinganine/sphingosine ratio (r = −0.69, p < 0.001; non-lesional skin), emphasizing the importance of SBs in AD. The highest correlation with TEWL was found for glucosylceramide (r² = 0.60, p < 0.001), which was investigated for the first time in AD. Findings that the changes in SBs and ceramide levels were predominant in lesional skin and their association with disease severity and cytokine levels suggest an immune-system driven effect. a novel analysis method demonstrates a robust and simple approach that might facilitate wider use of lipid biomarkers in the clinics e.g., to monitor (immune) therapy or dissect disease endotypes.

E-selectin, ICAM-1 (intercellular adhesion molecule-1), and VCAM-1 (vascular cell adhesion molecule-1) play a role in atopic dermatitis (AD). This study aimed to evaluate their expression in skin biopsy specimens of patients diagnosed with AD using an optimized computer program. A descriptive analysis and comparison of digitally measured surface area and cell number were performed. The number of E-selectin-positive cells did not vary between the groups. In patients with AD, decreases of 1.2-fold for ICAM-1- and 1.3-fold for VCAM-1- positive cells were observed. The E-selectin-positive epidermal surface area increased (p < 0.001), while ICAM1 and VCAM1 decreased 2.5-fold and 2-fold, respectively, compared to controls. In the AD-affected skin, the E-selectin-positive endothelial area was 3.5-fold larger (p < 0.001), and the ICAM1-positive area was almost 4-fold larger (p < 0.001). E-selectin and ICAM-1 were expressed in the control dermis moderately and weakly, respectively. A strong E-selectin signal was detected in the AD-affected skin macrophages and a strong ICAM-1 signal in the dermal vessel endothelium. In the endothelial cells of AD-affected skin, no VCAM-1 signal could be found. E-selectin, ICAM-1, and VCAM-1 expression show significant disease-specific changes between AD-affected and control skin. The combination of digital analysis and a pathologist’s evaluation may present a valuable follow-up of AD activity parameters.