Gábor Mócsai

Severe skin inflammation and filaggrin mutation similarly alter the skin barrier in patients with atopic dermatitis

Filaggrin (FLG) deficiency is a well‐known predisposing factor for the development of atopic dermatitis (AD). Decreased FLG expression can be the result of haploinsufficiency or severe inflammation, which can cause acquired FLG alterations. FLG mutations are related to several clinical and laboratory parameters of AD; however, some recent data seem to contradict these associations.

Regulatory T-cell subsets with acquired functional impairment: important indicators of disease severity in atopic dermatitis.

Our aim was to assess whether the presence of highly active effector T cells in atopic dermatitis (AD) is associated with changes in the number and/or function of regulatory T cells (Tregs). Flow cytometry was utilised to determine the percentage of CD4+ CD25bright CD127-/low FOXP3+ and skin-homing CLA+ CD4+ CD25bright FOXP3+ Tregs in healthy controls and AD patients. The correlation between disease severity and Treg percentages was estimated. Treg suppressor activity and cell proliferation were measured after T-cell stimulation. Significantly increased percentages of Tregs were found in AD patients compared to healthy individuals, and significant correlation between the frequency of Tregs and disease severity was also detected. The otherwise normal suppressor activity of Tregs decreased in the presence of Staphylococcus enterotoxin B (SEB). In conclusion, the continuous presence of SEB can trigger an acquired functional impairment of Tregs in AD patients and the correlation between the increased frequency of Tregs and disease severity supports their important role in AD pathogenesis.

Sebaceous Gland-Rich Skin Is Characterized by TSLP Expression and Distinct Immune Surveillance Which Is Disturbed in Rosacea

The microbial community exhibits remarkable diversity on topographically distinct skin regions, which may be accompanied by differences in skin immune characteristics. Our aim was to compare the immune milieu of healthy sebaceous gland-rich (SGR) and sebaceous gland-poor skin areas, and to analyze its changes in an inflammatory disease of SGR skin. For this purpose, immunohistochemical, immunocytochemical, and quantitative real-time PCR analyses of thymic stromal lymphopoietin (TSLP) and other cytokines, phenotypic immune cell markers and transcription factors were carried out in samples from sebaceous gland-poor, SGR skin and from papulopustular rosacea. TSLP mRNA and protein production was also studied in cultured keratinocytes. In SGR skin, higher TSLP expression, dendritic cell appearance without prominent activation, and T cell presence with IL-17/IL-10 cytokine milieu were detected compared with sebaceous gland-poor skin. Linoleic acid, a major sebum component, was found to induce TSLP expression dose-dependently in keratinocytes. In papulopustular rosacea, significantly decreased TSLP level and influx of inflammatory dendritic cells and T cells with IL-17/interferon-γ cytokine milieu were observed. According to our results, SGR skin is characterized by a distinct, noninflammatory immune surveillance, which may explain the preferred localization of inflammatory skin diseases, and can influence future barrier repair therapeutic concepts.

Immune-mediated skin inflammation is similar in severe atopic dermatitis patients with or without filaggrin mutation

Inflammatory cytokines can impair the skin barrier, but the question as to whether barrier alterations affect keratinocyte immune responses remains unanswered. The aim of this study was to investigate whether immune-mediated skin inflammation differs between severe atopic dermatitis patients with or without filaggrin mutation. The levels of filaggrin, inflammatory T helper 2 polarizing cytokines (thymic stromal lymphopoietin (TSLP) and interleukin 33 (IL-33)) and chemokine (C-C motif) ligand 27 (CCL27), histological severity markers, T and dendritic cell counts in biopsies from lesional skin of severe atopic dermatitis patients with and without filaggrin mutation and healthy skin were quantified by immunohistochemistry. The results were confirmed by quantitative PCR analyses. No significant differences were found between the 2 patient groups. Expression of atopic dermatitis-specific cytokines showed significant correlation with histological severity. These findings suggest that the immune-mediated skin inflammation (represented by keratinocyte-derived factors, T cell and dendritic cell counts) is similar in the 2 patient groups with severe atopic dermatitis, and that immune activation is connected to the severity of the disease rather than to the origin of barrier alterations.

The atopic skin-like microenvironment modulates the T-cell-polarising cytokine production of myeloid dendritic cells, as determined by laser scanning cytometry

Because it is not known exactly when or where myeloid dendritic cells (mDCs) acquire their atopic dermatitis (AD)‐specific T‐cell‐polarising ability in patients with this condition, we used laser scanning cytometry (LSC) to determine whether isolated peripheral blood mDCs from AD patients differed from cells from controls in their cytokine expression profiles de novo and after stimulation with Staphylococcus enterotoxin B (SEB) and thymic stromal lymphopoietin (TSLP), which represents an AD‐like microenvironment. Unstimulated mDCs from AD patients showed pluripotent T‐cell‐polarising capacity, and the surrounding skin microenvironment was essential for the distinctive, disease‐specific activity of mDCs (Th2‐Th22 bias). We also emphasise that LSC is an attractive technique to study the effect of new DC‐targeted therapeutic modalities in AD.

Investigation of Skin Barrier Functions and Allergic Sensitization in Patients with Hyper-IgE Syndrome

PurposeHyper-IgE syndrome (HIES) is a severe primary immunodeficiency, characterized by increased serum IgE levels as well as recurrent infections and atopic dermatitis (AD)-like skin lesions. AD is a chronic inflammatory skin disease with immunologic alterations (Th2-Th22 polarization) and characteristic skin barrier dysfunctions. Our aim was to investigate physicochemical skin barrier alterations and allergic sensitization in STAT3-HIES patients in order to explore whether skin barrier dysfunction can play a role in the eczematoid skin lesions in these patients.MethodsIn our experiments STAT3 and FLG mutation analyses were performed in STAT3-HIES (n = 7) and AD (n = 49) patients. Laboratory parameters (LDH and Eos counts), immunologic alterations (Th17 cell counts), allergic sensitization (total and specific IgE levels, skin prick tests, and medical history records), skin barrier changes [transepidermal water loss (TEWL), skin pH], serum and stratum corneum thymic stromal lymphopoietin (TSLP) levels were also examined.ResultsImpaired Th17 cell numbers, but normal physicochemical barrier functions, as well as serum and stratum corneum TSLP levels, were found in STAT3-HIES, while these parameters were significantly altered in AD patients. Allergic sensitization was detected in nearly all AD patients, while no signs of sensitization occurred in STAT3-HIES.ConclusionsOur study demonstrated that the skin barrier functions of STAT3-HIES patients are not damaged and they differ significantly from the altered skin barrier functions of AD patients. A well-functioning physicochemical skin barrier may be one of the explanations on the contradiction between the extremely high total IgE levels and the lack of allergic sensitization in these patients. Our study underlines the importance of skin barrier in the development of allergic sensitization.