Epidermal Immunoreactivity Research Articles

T regulatory cells and related immunoregulatory factors in polymorphic light eruption following ultraviolet A1 challenge

Polymorphic light eruption (PLE) is considered to be an autoimmune-mediated skin condition in which the normal ultraviolet (UV)-induced local immunosuppression appears to be absent, leading to recognition of photoinduced autoantigens and subsequent inflammation. To investigate T regulatory cells (Tregs) and related immunoregulatory factors in PLE lesions and controls. Skin biopsies were performed in 13 patients with UVA1-challenged PLE, 12 female patients with chronic discoid lupus erythematosus (CDLE) and 11 healthy controls who had exposure to UVA1. Immunohistochemistry and four-colour immunofluorescence studies were performed. Patients with CDLE and UVA1-exposed controls showed significantly decreased epidermal immunoreactivity for CD1a compared with patients with PLE (P = 0·0001). Four-colour immunofluorescence revealed a median percentage of CD4+CD25+FOXP3+ Tregs of 7·6% (range 3·7-13·6%) in PLE, a median of 11·7% (range 9·5-13·9%) in CDLE and a median of 3·4% (range 0-6·8%) in controls. Compared with UVA1-exposed controls, PLE and CDLE lesions showed significantly decreased transforming growth factor (TGF)-β1 immunoreactivity in the epidermis (P = 0·0003). In PLE lesions, we observed significantly decreased interleukin (IL)-10 expression compared with CDLE (P = 0·022). In the dermis, receptor activator of nuclear factor-κB ligand (RANKL) expression was increased in UVA1-exposed controls compared with PLE and CDLE (P = 0·018). Similar to CDLE lesions, UVA1-challenged PLE lesions display an altered immunoregulatory network, as indicated by decreased epidermal or dermal expression of TGF-β1, IL-10 and RANKL, and a relatively low number of Tregs, particularly when compared with other inflammatory skin conditions reported in the literature.

Thyrotropin-Releasing Hormone Controls Mitochondrial Biology in Human Epidermis

Mitochondrial capacity and metabolic potential are under the control of hormones, such as thyroid hormones. The most proximal regulator of the hypothalamic-pituitary-thyroid (HPT) axis, TRH, is the key hypothalamic integrator of energy metabolism via its impact on thyroid hormone secretion. Here, we asked whether TRH directly modulates mitochondrial functions in normal, TRH-receptor-positive human epidermis. Organ-cultured human skin was treated with TRH (5-100 ng/ml) for 12-48 h. TRH significantly increased epidermal immunoreactivity for the mitochondria-selective subunit I of respiratory chain complex IV (MTCO1). This resulted from an increased MTCO1 transcription and protein synthesis and a stimulation of mitochondrial biogenesis as demonstrated by transmission electron microscopy and TRH-enhanced mitochondrial DNA synthesis. TRH also significantly stimulated the transcription of several other mitochondrial key genes (TFAM, HSP60, and BMAL1), including the master regulator of mitochondrial biogenesis (PGC-1α). TRH significantly enhanced mitochondrial complex I and IV enzyme activity and enhanced the oxygen consumption of human skin samples, which shows that the stimulated mitochondria are fully vital because the main source for cellular oxygen consumption is mitochondrial endoxidation. These findings identify TRH as a potent, novel neuroendocrine stimulator of mitochondrial activity and biogenesis in human epidermal keratinocytes in situ. Thus, human epidermis offers an excellent model for dissecting neuroendocrine controls of human mitochondrial biology under physiologically relevant conditions and for exploring corresponding clinical applications.

Etanercept plus narrowband ultraviolet B phototherapy of psoriasis is more effective than etanercept monotherapy at 6 weeks

A substantial portion of patients with psoriasis does not achieve a satisfactory response under antitumour necrosis factor (TNF)-α biological therapies. We aimed to evaluate whether etanercept plus narrowband ultraviolet B (NB-UVB) phototherapy is superior to etanercept monotherapy in the management of psoriasis. In this prospective study, patients with psoriasis were treated with etanercept 25 mg twice weekly. Two marker lesions were selected for determination of the modified Psoriasis Area and Severity Index (M-PASI). NB-UVB was administered thrice weekly whereby one marker lesion was covered as nonirradiated control. Skin biopsies for histology and immunohistochemistry were performed in both marker lesions after a 6-week treatment course. After 6 weeks of therapy, the relative M-PASI reduction (mean ± SD) in etanercept-treated sites (53·7 ± 36·9%) was significantly lower than the reduction in etanercept plus NB-UVB-treated lesions (64 ± 27·8%; P = 0·011). At the end of treatment, histology scores of etanercept-treated psoriatic plaques were significantly higher than scores of etanercept plus NB-UVB-treated sites (4·6 ± 2·7 vs. 3·7 ± 2·4; P =0·045). Epidermal immunoreactivity for CD1a, CD4 and CD8 was significantly lower in etanercept plus NB-UVB-treated lesions when compared with etanercept monotherapy. Etanercept combined with NB-UVB is more effective than etanercept monotherapy at 6 weeks as demonstrated at a clinical, histological and immunohistological level. However, as there is an increased risk for malignancy by treatment with TNF-α blockers alone or in combination with phototherapy, we recommend to restrict this highly effective combination to short periods of time, for instance to obtain a quicker response, and to avoid long-term treatment.

Effect of chronic mild stress on serotonergic markers in the skin and brain of the NC/Nga atopic-like mouse strain

Atopic eczema is often worsened by stress. While acute stress is associated with increased turnover of serotonin (5-hydroxytryptamine; 5-HT), chronic stress causes a decrease. In chronic stress, there is a decrease of the 5-HT1A receptor (R)- and an increase in the 5-HT2AR-responsiveness to 5-HT. In the present study, the impact of chronic mild stress on the expression of 5-HT1A and 5-HT2A receptors and serotonin transporter protein (SERT) was investigated in eczematous skin and brain of atopic-like NC/Nga mice. Twenty-four NC/Nga mice were subjected to chronic mild stress for 12weeks, and eczema was induced by applying a mite antigen (Dermatophagoides pteronyssinus) on the ears for the last 4weeks. The mice were divided into three groups, eight per group, stressed eczematous (SE), non-stressed eczematous (NSE) and stressed control (SC). The biopsies were analysed by immunohistochemistry, using a streptavidin-biotin technique. There was an increased number of 5-HT containing dermal mast cell-like mononuclear cells in the skin of mice with eczema (SE and NSE, respectively) compared with the SC, and a tendency to more 5-HT-positive cells in the SE compared with the NSE group. Increased 5-HT1AR immunoreactivity (IR) in the skin and hippocampus of the eczematous groups compared to the control group was seen, but no difference between the SE and NSE groups. The epidermal immunoreactivity for 5-HT2AR was highest in the SE and NSE compared to the SC group, and was also higher in the SE compared to NSE. 5-HT2AR expression was also seen on nerve bundles, the number and intensity of such bundles being decreased in the SE compared to the NSE group. In the CA1 area of the hippocampus, there was an increase in the quantity of cells immunoreactive for 5-HT2AR in the SE versus the NSE group and also in the SE versus the SC group. SERT-IR was found also on nerve bundles with a decreased number in the SE compared to the NSE and SC group. There is a modulation of the expression of serotonergic markers in the eczematous skin and brain of the atopic-like mouse during chronic mild stress.

Time‐dependent modulation of serotonin and its receptors 1A and 2A expression in allergic contact dermatitis

Serotonin implication in allergic contact dermatitis was earlier suggested. To study the expression of serotonin (5-HT) and its receptors 1A and 2A during the kinetics of allergic contact dermatitis (ACD). Biopsies from 10 female nickel-allergic patients were obtained at 0, 6, 24, 48 and 72 h after nickel application using a patch testing procedure and then analysed by immunohistochemistry. Higher 5-HT epidermal immunoreactivity was seen at 0 and 6 h compared with 24, 48 and 72 h. The number of 5-HT labelled platelets was higher at 48 and 72 h compared with 0, 6 and 24 h. There was a decrease in the number of 5-HT1AR positive cells at 24, 48 and 72 h compared with 0 h. Furthermore, epidermal 5-HT1AR immunoreactivity was stronger at 48 and 72 h compared with 0 h. Total (dermis plus epidermis) number of 5-HT2AR positive cells was gradually increased in a time-dependent manner at 6, 24, 48 and 72 h compared with 0 h. Our results suggest the implication of 5-HT, 5-HT1AR and 5-HT2AR in the development of human ACD and the possibility to target those receptors at an early stage of this inflammatory condition.

Acanthosis nigricans, Papillomatosis mucosae und „tripe palms” bei einem Patienten mit metastasiertem Magenkarzinom

A 48-year-old obese man presented with thickening, coarseness and hyperpigmentation of the skin, especially of the intertriginous areas, papillomatous to verrucous lesions of the lips and buccal oral mucosa, and hyperkeratosis of the palms ("tripe palms") and soles. He was obese, reported sleep apnea and had a history of hyperuricemia, mixed hyperlipidemia and previous myocardial infarction. He was on a maintenance dose of a proton pump inhibitor for chronic gastro-esophageal reflux. Immunohistochemical studies of the skin lesion revealed increased epidermal immunoreactivity for the melanocortin-1-receptor. Increased levels of tumor markers CA 19-9 (141100 U/ml), CA 72-4 (755 U/ml) and CEA (189 ng/ml) were found in the serum. Gastroscopic findings were suspicious of adenocarcinoma of the stomach: it was classified histologically as a signet-ring cell, non-mucinous adenocarcinoma. At the time of diagnosis the tumor had already metastasized to perigastric and peripancreatic lymph nodes with peritoneal carcinosis. Since a curative resection was impossible a gastrojejunostomy was carried out. After this the patient received several courses of chemotherapy according to different schemes. Serum tumor marker levels and cutaneous signs regressed several times. Marked acanthosis nigricans -- especially when associated with further cutaneous markers of malignancy, e.g. mucocutaneous papillomatosis or so-called tripe palms -- calls for thorough search for malignant tumor, also if metabolic or endocrinological abnormalities co-exist. A pathogenetic role of a-melanocyte-stimulating hormone in the development of the skin changes is suggested.

Preferential Binding of Staphylococcus aureus to Skin Sites of Th2-Mediated Inflammation in a Murine Model

Staphylococcus aureus is found on over 90% of atopic dermatitis skin lesions and is thought to contribute to skin inflammation via the production of potent exotoxins. In contrast, less than 5% of normal subjects harbor S. aureus. This suggests that an atopic immune response itself may play a role in preferential binding of S. aureus to the skin. To examine this issue more directly, we analyzed the S. aureus binding characteristics of skin in mice undergoing different T helper type 1 cell versus T helper type 2 cell inflammatory responses using a novel in vitro bacterial binding assay. BALB/C female mice were first sensitized to ovalbumin with alum or ovalbumin with complete Freund's adjuvant to induce T helper type 2 or T helper type 1 responses, respectively. Mice were then challenged intradermally with either saline (control) or ovalbumin. Forty-eight hours later, skin specimens were obtained from the challenge sites, and the number of S. aureus binding to each skin section was quantitated. Bacterial binding was found to be significantly greater at skin sites of BALB/C mice that had been ovalbumin/alum sensitized compared with ovalbumin/complete Freund's adjuvant sensitized (p < or = 0.01). When compared to the ovalbumin sensitized/challenged skin of wild type BALB/C mice or interferon-gamma gene knockout mice, interleukin-4, but not interferon-gamma, gene knockout mice had significantly less S. aureus binding at their ovalbumin sensitized/challenged skin sites. Mutant S. aureus strains that lacked either fibronectin- or fibrinogen-binding protein expression showed significantly reduced S. aureus binding compared with the parent wild type strain (p < 0.005). Moreover, preincubation of the wild type bacteria with fibronectin or fibrinogen, but not collagen, resulted in significantly less skin binding of S. aureus (p < 0.01). Incubation of skin with interleukin-4, and less so with interferon-gamma, led to more binding of wild type S. aureus but not of an S. aureus mutant deficient in fibronectin binding protein expression. After interleukin-4 incubation, but not interferon-gamma, epidermal immunoreactivity for fibronectin was observed in murine skin explants. These results show that a T helper type 2 inflammatory environment can promote skin binding by S. aureus and that this binding is mediated by fibronectin and fibrinogen.

Upregulation of TNF-α and IL-3 expression in lesional and uninvolved skin in different types of urticaria

Although mast cells are known to secrete a broad spectrum of proinflammatory and immunomodulatory cytokines, the role of these molecules in mast cell-dependent cutaneous inflammation is not clear. We decided to study biopsy specimens from lesional and nonlesional skin of patients with acute, chronic recurrent, delayed pressure, and cold urticaria; from fleeting wheals of prick test reactions to allergens; and from normal skin of nonallergic subjects. Cryostat sections were stained by immunohistochemistry with antibodies against IL-3, IL-8, TNF-alpha, and mast cell-specific tryptase. In serial sections with tryptase and each cytokine, reactivity of mast cells was studied as well. Compared with normal skin and prick test reactions, immunoreactivity for TNF-alpha and IL-3 was significantly increased on endothelial and perivascular cells of the upper dermis in all urticaria lesions. In nonlesional skin comparable upregulation was noted on endothelial cells and for TNF-alpha on perivascular cells of patients with delayed pressure urticaria. In addition, TNF-alpha was expressed throughout the epidermis in lesional and nonlesional skin of patients with all types of urticaria, but not in normal control subjects. Sequential biopsy specimens from patients with cold urticaria showed upregulation of TNF-alpha and IL-3 on endothelial cells 30 minutes after elicitation of lesions with an ice cube. In contrast to these findings, epidermal immunoreactivity, as well as endothelial and perivascular cell expression of IL-8, were only slightly altered in urticaria compared with normal skin. In sequentially stained sections, few tryptase-positive mast cells reacted to TNF-alpha, few reacted to IL-3 in pressure urticaria only, and practically none stained for IL-8. These findings suggest that the cytokines studied here are involved in the pathology of urticaria, possibly by inducing subthreshold inflammation in endothelial cells of uninvolved skin.

Localization of Neutrophil-Activating Peptide-1/Interleukin-8-Immunoreactivity in Normal and Psoriatic Skin

Various cytokines have in the past been detected in human skin. Among these, the neutrophil-activating peptide NAP-1/IL-8 is a potent 8-kD proinflammatory peptide that has been purified from psoriatic scales. Its chemotactic activity on human neutrophils, as well as its presence in psoriatic scales, may relate to a role in this disease. In the present study, the tissue distribution of the peptide was examined immunohistochemically using two monoclonal antibodies (52E8, 46E5) recently produced and characterized in our laboratory. Immunoreactivity was detected in both normal and psoriatic skin, resulting in uniform suprabasal keratinocyte staining in normal skin with 52E8 and of all keratinocytes with 46E5. Immunoreactivity in psoriasis correlated to the inflammatory tissue reaction, varying from uniform absence in highly active psoriasis to focally weak staining in plaque type psoriasis. Cells of the acrosyringium and hair follicles were always positive and were unaffected by the inflammatory activity. Epidermal immunoreactivity detected in this study may be associated with closely related peptides of the IL8 family or with truncated or extended forms of NAP-1/IL-8.