Background Allergic contact dermatitis (ACD) is the most common occupational disease. Although murine contact hypersensitivity provides a framework for understanding ACD, it carries important ...differences from its human counterpart. Unlike the contact hypersensitivity model, which is induced by potent sensitizers (ie, dinitrofluorobenzene), human ACD is induced by weak-to-moderate sensitizers (ie, nickel), which cannot induce reactions in mice. Distinct hapten-specific immune-polarizing responses to potent inducers were suggested in mice, with unclear relevance to human ACD. Objective We explored the possibility of distinct T-cell polarization responses in skin to common clinically relevant ACD allergens. Methods Gene-expression and cellular studies were performed on common allergens (ie, nickel, fragrance, and rubber) compared with petrolatum-occluded skin, using RT-PCR, gene arrays, and immunohistochemistry. Results Despite similar clinical reactions in all allergen groups, distinct immune polarizations characterized different allergens. Although the common ACD transcriptome consisted of 149 differentially expressed genes across all allergens versus petrolatum, a much larger gene set was uniquely altered by individual allergens. Nickel demonstrated the highest immune activation, with potent inductions of innate immunity, TH 1/TH 17 and a TH 22 component. Fragrance, and to a lesser extent rubber, demonstrated a strong TH 2 bias, some TH 22 polarization, and smaller TH 1/TH 17 contributions. Conclusions Our study offers new insights into the pathogenesis of ACD, expanding the understanding of T-cell activation and associated cytokines in allergen-reactive tissues. It is the first study that defines the common transcriptome of clinically relevant sensitizers in human skin and identifies unique pathways preferentially activated by different allergens, suggesting that ACD cannot be considered a single entity.
Background Atopic dermatitis (AD) is a common inflammatory skin disease with a TH 2 and “T22” immune polarity. Despite recent data showing a genetic predisposition to epidermal barrier defects in ...some patients, a fundamental debate still exists regarding the role of barrier abnormalities versus immune responses in initiating the disease. An extensive study of nonlesional AD (ANL) skin is necessary to explore whether there is an intrinsic predisposition to barrier abnormalities, background immune activation, or both in patients with AD. Objective We sought to characterize ANL skin by determining whether epidermal differentiation and immune abnormalities that characterize lesional AD (AL) skin are also reflected in ANL skin. Methods We performed genomic and histologic profiling of both ANL and AL skin lesions (n = 12 each) compared with normal human skin (n = 10). Results We found that ANL skin is clearly distinct from normal skin with respect to terminal differentiation and some immune abnormalities and that it has a cutaneous expansion of T cells. We also showed that ANL skin has a variable immune phenotype, which is largely determined by disease extent and severity. Whereas broad terminal differentiation abnormalities were largely similar between involved and uninvolved AD skin, perhaps accounting for the “background skin phenotype,” increased expression of immune-related genes was among the most obvious differences between AL and ANL skin, potentially reflecting the “clinical disease phenotype.” Conclusion Our study implies that systemic immune activation might play a role in alteration of the normal epidermal phenotype, as suggested by the high correlation in expression of immune genes in ANL skin with the disease severity index.
Atopic dermatitis (AD) is a common disease with an increasing prevalence. The primary pathogenesis of the disease is still elusive, resulting in the lack of specific treatments. AD is currently ...considered a biphasic disease, with TH2 predominating in acute disease and a switch to TH1 characterizing chronic disease. Elucidation of the molecular factors that participate in the onset of new lesions and maintenance of chronic disease is critical for the development of targeted therapeutics.
We sought to characterize the mechanisms underlying the onset and maintenance of AD.
We investigated intrapersonal sets of transcriptomes from nonlesional skin and acute and chronic lesions of 10 patients with AD through genomic, molecular, and cellular profiling.
Our study associated the onset of acute lesions with a striking increase in a subset of terminal differentiation proteins, specifically the cytokine-modulated S100A7, S100A8, and S100A9. Acute disease was also associated with significant increases in gene expression levels of major TH22 and TH2 cytokines and smaller increases in IL-17 levels. A lesser induction of TH1-associated genes was detected in acute disease, although some were significantly upregulated in chronic disease. Further significant intensification of major TH22 and TH2 cytokines was observed between acute and chronic lesions.
Our data identified increased S100A7, S100A8, and S100A9 gene expression with AD initiation and concomitant activation of TH2 and TH22 cytokines. Our findings support a model of progressive activation of TH2 and TH22 immune axes from the acute to chronic phases, expanding the prevailing view of pathogenesis with important therapeutic implications.
Current atopic dermatitis (AD) models link epidermal abnormalities in lesional skin to cytokine activation. However, there is evolving evidence of systemic immune activation and detectable ...abnormalities in nonlesional skin. Because some of the best single correlations with severity (Scoring of AD, or SCORAD) are detected not only in lesional but also nonlesional skin and blood, more complex biomarker models of AD are needed. We thus performed extensive biomarker measures in these compartments using univariate and multivariate approaches to correlate disease biomarkers with SCORAD and with a combined hyperplasia score thickness and keratin 16 (K16) mRNA at baseline and after cyclosporine A treatment in 25 moderate to severe AD patients. Increases in serum cytokines and chemokines (IL-13, IL-22, CCL17) were found in AD versus healthy individuals and were reduced with treatment. SCORAD correlated with immune (IL-13, IL-22) and epidermal (thickness, K16) measures in lesional and, even more strongly, in nonlesional AD. Serum cytokines also had higher correlations with nonlesional markers at baseline and with treatment. Multivariate U statistics improved baseline and treatment-response SCORAD correlations. Nonlesional models showed the strongest correlations, with further improvement upon integration of serum markers. Even better correlations were obtained between biomarkers and the hyperplasia score. Larger cohorts are needed to confirm these preliminary data.
Alopecia areata (AA) is a common T cell–mediated disorder with limited therapeutics. A molecular profile of cytokine pathways in AA tissues is lacking. Although studies have focused on TH1/IFN-γ ...responses, several observations support a shared genetic background between AA and atopy.
We sought to define the AA scalp transcriptome and associated biomarkers with comparisons with atopic dermatitis (AD) and psoriasis.
We performed microarray and RT-PCR profiling of 27 lesional and 17 nonlesional scalp samples from patients with AA for comparison with normal scalp samples (n = 6). AA gene expression was also compared with samples from patients with lesional or nonlesional AD and those with psoriasis. A fold change of greater than 1.5 and a false discovery rate of less than 0.05 were used for differentially expressed genes (DEGs).
We established the AA transcriptomes (lesional vs nonlesional: 734 DEGs 297 upregulated and 437 downregulated; lesional vs normal: 4230 DEGs 1980 upregulated and 2250 downregulated), including many upregulated immune and downregulated hair keratin genes. Equally impressive as upregulation in TH1/interferon markers (IFNG and CXCL10/CXCL9) were those noted in TH2 (IL13, CCL18, CCL26, thymic stromal lymphopoietin, and periostin), TH9/IL-9, IL-23 (p40 and p19), and IL-16 mediators (all P < .05). There were no increases in TH17/TH22 markers. Hair keratin (KRT) expressions (ie, KRT86 and KRT85) were significantly suppressed in lesional skin. Greater scalp involvement (>25%) was associated with greater immune and keratin dysregulation and larger abnormalities in nonlesional scalp samples (ie, CXCL10 and KRT85).
Our data associate the AA signature with TH2, TH1, IL-23, and IL-9/TH9 cytokine activation, suggesting consideration of anti-TH2, anti-TH1, and anti–IL-23 targeting strategies. Similar to psoriasis and AD, clinical trials with selective antagonists are required to dissect key pathogenic pathways.
Identifying differences and similarities between cutaneous lymphocyte antigen (CLA)+ polarized T-cell subsets in children versus adults with atopic dermatitis (AD) is critical for directing new ...treatments toward children.
We sought to compare activation markers and frequencies of skin-homing (CLA+) versus systemic (CLA−) “polar” CD4 and CD8 T-cell subsets in patients with early pediatric AD, adults with AD, and control subjects.
Flow cytometry was used to measure CD69/inducible costimulator/HLA-DR frequency in memory cell subsets, as well as IFN-γ, IL-13, IL-9, IL-17, and IL-22 cytokines, defining TH1/cytotoxic T (TC) 1, TH2/TC2, TH9/TC9, TH17/TC17, and TH22/TC22 populations in CD4 and CD8 cells, respectively. We compared peripheral blood from 19 children less than 5 years old and 42 adults with well-characterized moderate-to-severe AD, as well as age-matched control subjects (17 children and 25 adults).
Selective inducible costimulator activation (P < .001) was seen in children. CLA+ TH2 T cells were markedly expanded in both children and adults with AD compared with those in control subjects, but decreases in CLA+ TH1 T-cell numbers were greater in children with AD (17% vs 7.4%, P = .007). Unlike in adults, no imbalances were detected in CLA− T cells from pediatric patients with AD nor were there altered frequencies of TH22 T cells within the CLA+ or CLA− compartments. Adults with AD had increased frequencies of IL-22–producing CD4 and CD8 T cells within the skin-homing population, compared with controls (9.5% vs 4.5% and 8.6% vs 2.4%, respectively; P < .001), as well as increased HLA-DR activation (P < .01).
These data suggest that TH2 activation within skin-homing T cells might drive AD in children and that reduced counterregulation by TH1 T cells might contribute to excess TH2 activation. TH22 “spreading” of AD is not seen in young children and might be influenced by immune development, disease chronicity, or recurrent skin infections.
Background Psoriasis and atopic dermatitis (AD) are common, complex inflammatory skin diseases. Both diseases display immune infiltrates in lesions and epidermal growth/differentiation alterations ...associated with a defective skin barrier. An incomplete understanding of differences between these diseases makes it difficult to compare human disease pathology to animal disease models. Objective To characterize differences between these diseases in expression of genes related to epidermal growth/differentiation and inflammatory circuits. Methods We performed genomic profiling of mRNA in chronic psoriasis (n = 15) and AD (n = 18) skin lesions compared with normal human skin (n = 15). Results As expected, clear disease classifications could be constructed on the basis of expected immune polarity (TH 1, TH 2, TH 17) differences. However, even more striking differences were identified in epidermal differentiation programs that could be used for precise disease classifications. Although both psoriasis and AD skin lesions displayed regenerative epidermal hyperplasia, which is a general alteration in epidermal growth, keratinocyte terminal differentiation was differentially polarized. In AD, we found selective defects in expression of multiple genes encoding the cornified envelope, with the largest alteration in loricrin (expressed at 2% of the level of normal skin). At the ultrastructural level, the cornified envelope in AD was broadly defective with highly decreased compaction of corneocytes and reduced intercellular lipids. Hence, the entire keratinocyte terminal differentiation program (cytoplasmic compaction, cornification, and lipid release) is defective in AD, potentially underlying the immune differences. Conclusion Our study shows that although alterations in barrier responses exist in both diseases, epidermal differentiation is differentially polarized, with major implications for primary disease pathogenesis.
Onychomycosis is estimated at a prevalence of 10% worldwide with the infecting organism most commonly Trichophyton rubrum (T. rubrum). Traditional culture identification of causative organisms has ...inherent risks of overestimating dermatophytes, like T. rubrum, by inhibiting the growth of possible nondermatophyte mould (NDM) environmental contaminants which could be causative agents. Recently, molecular methods have revealed that a proportion of onychomycosis cases in North America may be caused by mixed infections of T. rubrum as an agent co-infecting with one or more NDM. Determining the global burden of mixed infections is a necessary step to evaluating the best therapies for this difficult-to-treat disease. To determine the prevalence of mixed infections in a global population, nail samples from onychomycosis patients in Brazil, Canada, and Israel (n = 216) were analyzed by molecular methods for the presence of dermatophytes and five NDMs. If an NDM was detected, repeat sampling was performed to confirm the NDM. T. rubrum was detected in 98% (211/216) of infections with 39% mixed (84/216). The infection type was more likely to be mixed in samples from Brazil, but more likely to be a dermatophyte in samples from Canada and Israel (Χ2 = 16.92, df = 2, P<0.001). The most common cause of onychomycosis was T. rubrum. In all countries (Brazil, Canada and Israel combined) the prevalence of dermatophyte (Χ2 = 211.15, df = 3, P<0.001) and mixed (dermatophyte and NDM; Χ2 = 166.38, df = 3, P<0.001) infection increased with patient age. Our data suggest that mixed infection onychomycosis is more prevalent than previously reported with the aging population being at increased risk for mixed infections.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
To the Editor: Recent studies have demonstrated that the number of group 3 innate lymphoid cells (ILC3s) is increased in peripheral blood, lesional skin, and nonlesional skin of patients with ...psoriasis.1,E1,E2 However, definitive evidence is as yet entirely missing that these innate immunocytes, which produce IL-22 and IL-17, but not TNF-α or IFN-γ, and lack cytotoxic effectors,E2 are functionally involved in the induction of psoriatic lesions in human skin. ...the present study aimed to determine whether human ILC3s (ie, CD3− RORγt+ NKp44+ cells)E1 suffice to induce psoriatic lesions in healthy human skin in vivo. Flow cytometric analysis documented the absence of γδ T cells and natural killer (NK) cells in the ILC3 preparation, while 5% γδ T cells and NK cells were present in the TH17/Tc17 cell cultures (Fig E2, D).6 The purified ILC3s were associated with the expected intracellular cytokine expression pattern5,7,E9: 78% of ILC3s showed IL-22 expression, and 10% ± 3% of these cells were double-positive for both IL-17 and IL-22 (Fig E3, B). Animal handling was in accordance with the national guidelines and approved by the Technion Animal Care and Use Committee.Culture of cells with IL2 and AhR agonist To obtain an enriched RORγt + cell culture, PBMCs from 8 normal volunteers were incubated with a high dose of IL-2 (100 U/mL) and AhR agonistE12,E13 200 nM (6-formylindolo carbazole, Enzo) for 14 days.E7Magnetic isolation of TH17-cell and ILC subsets from IL2+AhR-activated PBMC cultures Separation was performed using anti-CD3 antibodies conjugated to ferromagnetic microbeads (Miltenyi Biotec, Bergisch Gladbach, Germany) and directed through a cell separation column containing a magnetic field (Miltenyi Biotec).
Background Petrolatum is a common moisturizer often used in the prevention of skin infections after ambulatory surgeries and as a maintenance therapy of atopic dermatitis (AD). However, the molecular ...responses induced by petrolatum in the skin have never been assessed. Objective We sought to define the cutaneous molecular and structural effects induced by petrolatum. Methods Thirty-six healthy subjects and 13 patients with moderate AD (mean SCORAD score, 39) were studied by using RT-PCR, gene arrays, immunohistochemistry, and immunofluorescence performed on control skin, petrolatum-occluded skin, and skin occluded with a Finn chamber only. Results Significant upregulations of antimicrobial peptides (S100A8/fold change FCH, 13.04; S100A9/FCH, 11.28; CCL20/FCH, 8.36; PI3 elafin/FCH, 15.40; lipocalin 2/FCH, 6.94, human β-defensin 2 DEFB4A/FCH, 4.96; P < .001 for all) and innate immune genes ( IL6 , IL8 , and IL1B ; P < .01) were observed in petrolatum-occluded skin compared with expression in both control and occluded-only skin. Application of petrolatum also induced expression of key barrier differentiation markers (filaggrin and loricrin), increased stratum corneum thickness, and significantly reduced T-cell infiltrates in the setting of “normal-appearing” or nonlesional AD skin, which is known to harbor barrier and immune defects. Conclusions Petrolatum robustly modulates antimicrobials and epidermal differentiation barrier measures. These data shed light on the beneficial molecular responses of petrolatum in barrier-defective states, such as AD and postoperative wound care.
PDF
