Atopic dermatitis: disease characteristics and comorbidities in smoking and non-smoking patients from the TREATgermany registry.

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory skin disease with a multifactorial genesis including genetic predispositions and environmental risk and trigger factors. One of the latter possibly is smoking, indicated by an increased prevalence of AD in adults and children that are actively or passively exposed to cigarette smoke. OBJECTIVES: In this study, AD characteristics and its atopic comorbidities are compared in smoking and non-smoking AD patients. METHODS: TREATgermany is a non-interventional clinical registry which includes patients with moderate to severe AD in Germany. Baseline data of patients included in TREATgermany from inception in June 2016 to April 2020 in 39 sites across Germany was analysed comparing AD disease characteristics and comorbidities in smokers vs. non-smokers. RESULTS: Of 921 patients, 908 (male: 58.7%) with a mean age of 41.9 ± 14.4 reported their smoking status. The objective Scoring of Atopic Dermatitis (oSCORAD) did not differ between smokers (n = 352; 38.8%) and non-smokers, however, lesions' intensity of oozing/crusts and excoriations as well as patient global assessment scores (PGA) of AD severity were higher in smoking as opposed to non-smoking patients. Smokers reported a lower number of weeks with well-controlled AD and more severe pruritus than non-smokers. Total IgE levels were more elevated in smokers and they displayed a younger age at the initial diagnosis of bronchial asthma. After adjustment for potential confounders, the increased intensity of oozing/crusts, the reduced number of weeks with well-controlled AD and the greater pruritus remained different in smokers compared to non-smokers. In addition, smoking patients with adult-onset AD showed a 2.5 times higher chance of involvement of the feet. CONCLUSIONS: German registry data indicate that AD patients who smoke have a higher disease burden with a different distribution pattern of lesions in adult-onset AD.

Patients With Atopic Dermatitis Sensitized to Pet Dander Mount IgE and T-Cell Responses to Mammalian Cystatins, Including the Human Self-Protein.

BACKGROUND: Immediate and delayed-type hypersensitivity reactions to pet-borne allergens are common in atopic diseases. In atopic dermatitis (AD), controversy surrounds the contribution to the disease of cross-reactivity to self-proteins. Human cystatin A and the cat allergen Fel d 3 belong to the cystatins, an evolutionary conserved protein family. The objective of the present study was to assess crossreactivity between mammalian cystatins and to analyze T-cell responses to cystatin in AD patients sensitized to pet dander. METHODS: cDNA coding for dog cystatin was cloned from dog skin. Sera from 245 patients with IgE-mediated sensitization to cat and dog dander were tested for IgE binding to recombinantly expressed feline, canine, and human cystatin. Of these, 141 were also diagnosed with AD. RESULTS: Cystatin-specific IgE was detected in 36 patients (14.7%), of whom 19 were considerably affected by AD. Within the AD patients, 9 had measurable IgE against all 3 cystatins. Cystatin-sensitized AD patients did not differ from non-cystatin-sensitized patients in terms of disease severity, age, or total IgE levels. T-cell cytokine measurements showed elevated IL-4 levels after stimulation with feline and human cystatin. CONCLUSIONS: The humoral response suggests that in addition to Fel d 3, the homologous protein from dog might play a role in allergy. Furthermore, human cystatin appears to be capable of driving a type 2 immune response in sensitized AD patients and may therefore be considered a so-called autoallergen, as proposed for other evolutionary conserved proteins.

Topical therapy of atopic dermatitis with a focus on pimecrolimus.

Atopic dermatitis (AD) is a chronic and relapsing, inflammatory skin disease characterized by impaired skin barrier function and immune system dysregulation that results in dryness, skin microbiome dysbiosis and intense pruritus. It is highly heterogeneous, and its management is demanding. Patients with AD are at greater risk of comorbidities such as attention-deficit hyperactivity disorder as well as other atopic diseases. Early-onset AD cases typically improve or resolve in late childhood; however, it is proposed that the prevalence of persistent or adult-onset AD is higher than previously thought. Basic therapy consists of emollient application and trigger avoidance, and when insufficient, topical corticosteroids (TCS) are the first-line treatment. However, corticophobia/steroid aversion and TCS side-effects, particularly on sensitive skin areas, lead to low compliance and insufficient disease control. Several long- and short-term randomized controlled and daily practice studies have demonstrated that topical calcineurin inhibitors, such as pimecrolimus, have similar anti-inflammatory effects to low-to-medium strength TCS, reduce pruritus and improve the quality of life of patients. In addition, pimecrolimus does not cause skin atrophy, is steroid-sparing and has a good safety profile, with no evidence for an increased risk of malignancies or skin infections. In general, pimecrolimus cream is well-accepted and well-tolerated, encouraging patient adherence and leading to its use by many physicians as a preferred therapy for children and sensitive skin areas.

Human thioredoxin, a damage-associated molecular pattern and Malassezia-crossreactive autoallergen, modulates immune responses via the C-type lectin receptors Dectin-1 and Dectin-2.

Human thioredoxin (hTrx), which can be secreted from cells upon stress, functions in allergic skin inflammation as a T cell antigen due to homology and cross-reactivity with the fungal allergen Mala s13 of the skin-colonizing yeast Malassezia sympodialis. Recent studies have shown that cell wall polysaccharides of Malassezia are detected by the immune system via the C-type lectin receptors Dectin-1 and Dectin-2, which are expressed on myeloid cells. Therefore, this study aimed to investigate a putative interaction between Dectin-1, Dectin-2 and the allergens Mala s13 and hTrx. Stimulation of human monocyte-derived dendritic cells or macrophages with Mala s13 or hTrx resulted in remarkable secretion of IL-1ß and IL-23. Blocking experiments suggest that hTrx induces IL-23 by Dectin-1 binding and IL-1ß by binding to either Dectin-1 or Dectin-2. Regarding Mala s13, Dectin-1 appears to be involved in IL-1ß signaling. Interference of Syk kinase function was performed to investigate downstream signaling, which led to diminished hTrx responses. In our experiments, we observed rapid internalization of Mala s13 and hTrx upon cell contact and we were able to confirm direct interaction with Dectin-1 as well as Dectin-2 applying a fusion protein screening platform. We hypothesize that this cytokine response may result in a Th2/Th17-polarizing milieu, which may play a key role during the allergic sensitization in the skin, where allergen presentation to T cells is accompanied by microbial colonization and skin inflammation.

ETFAD/EADV Eczema task force 2015 position paper on diagnosis and treatment of atopic dermatitis in adult and paediatric patients.

Atopic dermatitis (AD) is a clinically defined, highly pruritic, chronic inflammatory skin disease of children and adults. The diagnosis is made using evaluated clinical criteria. Disease activity is best measured with a composite score assessing both objective signs and subjective symptoms, such as SCORAD. The management of AD must consider the clinical and pathogenic variabilities of the disease and also target flare prevention. Basic therapy includes hydrating topical treatment, as well as avoidance of specific and unspecific provocation factors. Anti-inflammatory treatment of visible skin lesions is based on topical glucocorticosteroids and the topical calcineurin inhibitors tacrolimus and pimecrolimus. Topical calcineurin inhibitors are preferred in sensitive locations. Tacrolimus and mid-potent steroids are proven for proactive therapy, which is long-term intermittent anti-inflammatory therapy of the frequently relapsing skin areas. Systemic anti-inflammatory or immunosuppressive treatment is indicated for severe refractory cases. Biologicals targeting key mechanisms of the atopic immune response are promising emerging treatment options. Microbial colonization and superinfection may induce disease exacerbation and can justify additional antimicrobial treatment. Systemic antihistamines (H1R-blockers) may diminish pruritus, but do not have sufficient effect on lesions. Adjuvant therapy includes UV irradiation, preferably UVA1 or narrow-band UVB 311 nm. Dietary recommendations should be patient specific and elimination diets should only be advised in case of proven food allergy. Allergen-specific immunotherapy to aeroallergens may be useful in selected cases. Psychosomatic counselling is recommended to address stress-induced exacerbations. 'Eczema school' educational programmes have been proven to be helpful for children and adults.

Digital ultraviolet therapy: a novel therapeutic approach for the targeted treatment of psoriasis vulgaris.

BACKGROUND: 8-Methoxypsoralen-UVA (PUVA) and narrowband ultraviolet B (NB-UVB) are well-established treatments for chronic plaque-type psoriasis vulgaris. However, long-term risks of PUVA therapy include premature skin ageing and squamous cell carcinoma. OBJECTIVES: To develop a device for targeted UV therapy of psoriatic plaques with protection of the healthy adjacent skin to reduce the risk for premature skin ageing and squamous cell carcinoma. METHODS: In total 28 patients with exacerbated psoriasis vulgaris were treated with the digital phototherapy device skintrek(®) [cream PUVA (n = 8), bath PUVA (n = 11) and UVB (n = 9)] or with conventional bath PUVA (n = 9) or NB-UVB (n = 4). RESULTS: The local Psoriasis Area and Severity Index (PASI) score was significantly reduced from a mean of 6·25 at baseline to 2·75 at the end of therapy in the skintrek cream PUVA group, from 6·4 to 3·0 in the skintrek bath PUVA group and from 5·5 to 2·0 in the skintrek UVB group. Treatment with skintrek cream PUVA reduced the mean local PASI by 54%, while skintrek bath PUVA did so by 51% and skintrek UVB by 63%. Targeted skintrek PUVA and skintrek UVB of inflamed psoriatic skin avoided skin pigmentation and were not inferior to conventional bath PUVA and NB-UVB therapy regimens. CONCLUSIONS: Targeted UV therapy of psoriatic plaques with the digital phototherapy device skintrek is as effective as conventional cream and bath PUVA, as well as NB-UVB, while simultaneously sparing the healthy adjacent skin. It therefore potentially reduces the carcinogenic risk, reduces premature skin ageing and avoids tanning of healthy surrounding skin.

Interleukin (IL)-31 activates signal transducer and activator of transcription (STAT)-1, STAT-5 and extracellular signal-regulated kinase 1/2 and down-regulates IL-12p40 production in activated human macrophages.

BACKGROUND: Interleukin-31 is a cytokine expressed by activated T cells. A major function of IL-31 in atopic dermatitis (AD) is the induction of pruritus in the skin. We recently showed that IL-31 induces pro-inflammatory cytokines following staphylococcal exotoxins' stimulation in human macrophages. However, signalling pathways of IL-31 in activated human macrophages still remain unclear. The aim of the study was to investigate the signalling pathways of IL-31 receptor as well as functional effects of IL-31 in activated macrophages. METHODS: Human macrophages were prestimulated with staphylococcal exotoxins (SEB, α-toxin) to up-regulate the IL-31 receptor with and without IL-31. Phospho-signal transducer and activator of transcription (pSTAT) 1/3/5, phospho-extracellular signal-regulated kinase (ERK 1/2), ß-actin as well as p21/WAF/Cip1 levels were determined by means of Western blot analysis. Interleukin-12p40, IL-12p70 and IL-23 secretions were assessed by using an enzyme-linked immunosorbent assay. RESULTS: Interleukin-31 strongly activated STAT-1 and 5 but not STAT-3 in human macrophages after up-regulation of IL-31 receptor with staphylococcal exotoxins. p21/WAF/Cip1 expression was induced by IL-31 in activated human macrophages. Furthermore, IL-31 down-regulated. IL-12p40 secretion via ERK 1/2 phosphorylation in human macrophages following up-regulation of IL-31 receptor with staphylococcal exotoxins. CONCLUSIONS: The T helper (Th) 2 cytokine IL-31 induces pro-inflammatory effects in activated human macrophages via STAT-1 and 5 phosphorylation. Interleukin-31-induced ERK 1/2 activation contributes to the underlying mechanism of Th1 cytokine IL-12 suppression in macrophages. This mechanism may be relevant in Th2 inflammatory responses and may help to develop therapeutic strategies in IL-31-associated diseases such as AD.

Interleukin-33 modulates the expression of human ß-defensin 2 in human primary keratinocytes and may influence the susceptibility to bacterial superinfection in acute atopic dermatitis.

BACKGROUND: Interleukin (IL)-33 is a member of the IL-1 family and has been implicated in Th2-driven allergic diseases such as atopic dermatitis (AD) and asthma. The principal Th2 cytokine IL-4, found highly expressed in acute allergic eczema, is known to downregulate human ß-defensin 2 (hBD2) expression in human keratinocytes and this is associated with superinfection in patients with AD. OBJECTIVES: To investigate the effect of IL-33 on the expression of hBD2 in human keratinocytes. METHODS: hBD2 production by stimulated keratinocytes was measured by enzyme-linked immunosorbent assay. RESULTS: Our results showed that serum is a very potent inducer of hBD2 and 2·5% human serum was much more potent in inducing hBD2 than 20 ng mL(-1) of tumour necrosis factor-α. Interestingly, serum from patients with AD showed an impaired ability to induce hBD2 in normal keratinocytes. IL-33 significantly downregulated serum-induced hBD2. The downregulatory capacity of IL-33 was found to be 1·5- to 2-fold weaker compared with IL-4. CONCLUSIONS: Our data suggest that IL-33 can significantly contribute to the decreased expression of hBD2 in acute eczematous reaction clinically characterized by spongiosis and oozing - thus indicative for contact of the epidermis with serum components.

Macrophages from patients with atopic dermatitis show a reduced CXCL10 expression in response to staphylococcal α-toxin.

BACKGROUND: Patients with atopic dermatitis (AD) are frequently colonized with Staphylococcus aureus (S. aureus), one-third of them producing α-toxin, which is correlated with the severity of eczema in AD. Staphylococcus aureus colonizes in patients with psoriasis as well. Distinct expression of chemokine (C-C motif) ligand (CCL) and chemokine (C-X-C motif) ligand (CXCL) chemokines has been documented in both diseases. In this study, we investigated the effects of sublytic α-toxin concentrations on human macrophages that accumulate in the skin of patients with AD and psoriasis. METHODS: IFN-γ-induced protein of 10-kDa (IP-10)/CXCL10 and macrophage-derived chemokine (MDC)/CCL22 production were evaluated at the mRNA or at the protein level using qRT-PCR or ELISA, respectively. Cell surface markers' expression and chemotaxis were determined by flow cytometry and Boyden chamber technique, respectively. RESULTS: Sublytic concentrations of α-toxin strongly induced CXCL10 in macrophages at both the mRNA and the protein levels and significantly up-regulated MHC class II expression. Supernatants of α-toxin-stimulated macrophages induced the migration of human CD4+ lymphocytes via the CXCL10 receptor (CXCR3). Macrophages from patients with AD produced lower levels of CXCL10 compared to cells from patients with psoriasis as well as healthy controls in response to α-toxin. α-Toxin did not lead to a large variation in CCL22 production in macrophages from all three groups. CONCLUSIONS: Staphylococcal α-toxin contributes to Th1 polarization by induction of CXCL10 in macrophages. Macrophages from patients with AD and psoriasis responded to α-toxin in the induction of Th1-related chemokine CXCL10 diversely, which could favour the recruitment of distinct leucocyte subsets into the skin.

Functional effects of interleukin 31 in human primary keratinocytes.

BACKGROUND: Interleukin (IL)-31 is a T-cell cytokine acting through a heterodimeric receptor composed of IL-31RA and OSMR which is expressed on epithelial cells including keratinocytes. A major function of IL-31 in atopic dermatitis (AD) is the induction of pruritus in the skin. Inflammatory effects of IL-31 in human primary keratinocytes (HPKs) still remain unclear. We investigated expression, regulation of the IL-31 receptor as well as functions of IL-31 in HPKs. METHODS: Human primary keratinocytes were stimulated with TLR-2 ligands (Pam3Cys, lipoteichoic acid and peptidoglycan), or Th1 and Th2 associated cytokines (IFN-γ and IL-4), respectively. IL-31R expression and regulation as well as functional effects of IL-31 stimulation were then investigated at both the mRNA and protein level and compared with HPKs from patients with AD. The STAT signalling pathway and TLR-2 expression were investigated using Western blot and Immunohistochemical stainings, respectively. RESULTS: Pam3Cys or IFN-γ significantly up-regulated IL-31RA and OSMR expression. IL-31 activated STAT-3 phosphorylation in HPKs which was augmented after preactivation with Pam3Cys or IFN-γ. IL-31 enhanced the secretion of CCL2 after up-regulation of the receptor with Pam3Cys or IFN-γ. However, this was not observed in keratinocytes from AD patients where an impaired TLR-2 expression was found. CONCLUSIONS: Together, our findings show a functional role of IL-31 in HPKs and provide a new link between TLR-2 ligands and IL-31 which might be dysregulated in AD. Altered function of IL-31 may have implications for cutaneous inflammation in eczema where skin colonization with Staphylococcus aureus and dysregulation of TLR-2 have been described.

The role of T-cell reactivity towards the autoantigen α-NAC in atopic dermatitis.

BACKGROUND: A subgroup of patients with atopic dermatitis (AD) produces IgE autoantibodies to human proteins which may be present in inflamed skin and perpetuate cutaneous inflammation. OBJECTIVES: In order to investigate mechanisms of 'autoallergy' for AD we studied T-cell responses to the autoallergen Hom s 2, the human transcriptional coactivator α-nascent polypeptide-associated complex (α-NAC). METHODS: Specific proliferation of blood lymphocytes from 30 patients and 12 healthy control individuals was investigated by flow cytometry. The proliferation of skin- and blood-derived T cells was assessed in limiting-dilution assays. T-cell clones (TCC) were generated from peripheral blood and from biopsies of lesional skin of patients with AD and the phenotype and cytokine patterns were determined. RESULTS: α-NAC-specific T-cell responses were detected in patients and control individuals. α-NAC induced a significantly higher proliferation of CCR4+ (compared with CCR4-) and CLA+ (compared with CLA-) T cells from the circulation. Limiting-dilution assays revealed a high proliferation of blood and skin-infiltrating lymphocytes in the presence of α-NAC compared with control cultures. α-NAC-specific TCC generated from lesional skin of AD predominantly produced interferon-γ and some TCC also produced interleukin-17. The cytokine pattern of α-NAC TCC may contribute to keratinocyte apoptosis and eczema formation in AD. CONCLUSIONS: α-NAC-specific TCC can be generated from blood and lesional skin of patients with AD. These TCC produce not only Th2 but also Th1 cytokines which may explain the Th1 phenotype of inflammation in AD.

[Successful symptomatic treatment of epidermodysplasia verruciformis with imiquimod 5% cream]. / Erfolgreiche symptomatische Therapie einer Epidermodysplasia verruciformis mit Imiquimod 5% Creme.

A 19-year-old patient presented with epidermodysplasia verruciformis (EV). In this genodermatosis, pathogenetic factors such as infection by human papilloma viruses as well as sun exposure are considered responsible for the malignant transformation of EV lesions to skin cancer within decades. So far, several therapeutic strategies have been unsatisfactory. In our case HPV 5b was detected and the associated skin lesions were successfully treated with imiquimod 5% cream.

Interleukin (IL)-31 induces pro-inflammatory cytokines in human monocytes and macrophages following stimulation with staphylococcal exotoxins.

BACKGROUND: IL-31 is a cytokine expressed by T cells following activation with cytokines or staphylococcal exotoxins. A major function of IL-31 in atopic dermatitis (AD) is the induction of pruritus in the skin via the IL-31 receptor on sensory nerve cells. However, the regulation of the IL-31 receptor and pro-inflammatory functions of IL-31 in human monocytes and monocyte-derived cells are yet to be studied in detail. OBJECTIVE: To investigate the regulation and function of IL-31 receptors in resting and activated human monocytes, macrophages and dendritic cells. METHODS: Human monocytes, macrophages and dendritic cells were stimulated with staphylococcal exotoxins (SEB, alpha-toxin) or cytokines (IFN-gamma, IL-13). IL-31RA expression and regulation were then investigated at both the mRNA and the protein level. Subsequently, functional effects of IL-31 stimulation on cytokine secretion were measured at the protein level. RESULTS: Staphylococcal exotoxins significantly up-regulated IL-31RA expression on monocytes and macrophages but not on dendritic cells at both the mRNA and the protein level. IL-31 enhanced the secretion of IL-1beta, IL-6 and IL-18 and up-regulated CD86 expression. In patients with AD, functional IL-31RA was also detected following stimulation of PBMC with IFN-gamma. However, this was not observed in healthy individuals. CONCLUSION: IL-31 induces pro-inflammatory effects in activated human monocytes and macrophages. This may have implications for cutaneous inflammation in eczema where an over-expression of IL-31 has been described previously. Moreover, our findings provide a new link between staphylococcal colonization and the worsening of inflammation via IL-31. Further therapeutic considerations may include IL-31 as a target in AD.

Impaired TLR-2 expression and TLR-2-mediated cytokine secretion in macrophages from patients with atopic dermatitis.

BACKGROUND: In many patients with atopic dermatitis (AD), the disease is complicated by their enhanced susceptibility to bacterial skin infections, especially with Staphylococcus aureus. The pattern recognition receptor toll-like receptor (TLR)-2 recognizes components of S. aureus, for example, lipoteichoic acid (LTA) and peptidoglycan (PGN) and, therefore, might be crucial in the pathogenesis and flare-ups of AD. OBJECTIVE: To investigate TLR-2 expression and cytokine secretion in macrophages from patients with AD compared to healthy controls upon TLR-2 stimulation with PGN, LTA and Pam3Cys. METHODS: Macrophages were cultivated from highly purified peripheral blood monocytes of AD patients and nonatopic healthy controls and stimulated with PGN, LTA and Pam3Cys in a time and dose-dependent manner. Afterwards, TLR-2 expression and cytokine secretion were measured on protein and mRNA level. TLR-1 and TLR-6 expression were investigated on the mRNA level. Immunohistochemical stainings from punch biopsies were performed to investigate TLR-2 expression in skin macrophages. RESULTS: We could clearly show that macrophages from patients with AD expressed significantly less TLR-2, whereas the expression pattern of TLR-1 and TLR-6 were not altered. Macrophages had a reduced capacity to produce pro-inflammatory cytokines such as IL-6, IL-8 and IL-1beta after stimulation with TLR-2 ligands. CONCLUSION: Our findings clearly show an impaired TLR-2 expression and functional differences of TLR-2-mediated effects on macrophages of AD patients compared to healthy controls which might contribute to the enhanced susceptibility to skin infections with S. aureus in AD.

Increased metal allergy in patients with failed metal-on-metal hip arthroplasty and peri-implant T-lymphocytic inflammation.

BACKGROUND: In 16 patients with revised metal-on-metal arthroplasty and peri-implant lymphocytic inflammation, we verified the role of metal hypersensitivity by patch testing (PT) and lymphocyte transformation test (LTT). METHODS: In the 16 patients with lymphocyte dominated periprosthetic inflammation, allergy history was obtained by a questionnaire, specific serum IgE to aeroallergens was measured to assess atopy, PT to standard and metal series was performed and metal sensitivity was further assessed by LTT using blood mononuclear cells. RESULTS: Revision surgery was performed because of pain (8/16), osteolysis (4/16), dislocation (3/16) and loosening of the stem (1/16). Histological examination showed perivascular infiltrates of T lymphocytes, high endothelial venules, fibrin exudation and accumulation of macrophages with drop-like inclusions. Five patients had a history of cutaneous metal allergy and atopy was found in 25% of the patients. In 13/16 patients (81%), systemic metal sensitivity was found based on PT and/or LTT. Patch test reactions were seen in 11/16 patients (69%; partly multiple reactions/patient): 7/16 to Cobalt (Co), 7/16 to Chromium (Cr), 4/16 to Nickel (Ni), and one each to Molybdenum (Mo) and Manganese (Mn). Ten of 16 patients (62%) showed enhanced LTT reactivity to metals: 7/16 to Ni, 7/16 to Co, 5/16 to Cr, 5/16 to Mo and 4/16 to Mn. CONCLUSIONS: The lymphocyte dominated peri-implant inflammation may well reflect an allergic hyper-reactivity in these patients, given the high rate of concomitantly found metal allergy. Despite the overall incidence of metal implant allergy being low, allergic reactions should be included as differential diagnosis in failed metal-on-metal arthroplasty.

[Giant keratoacanthoma in an immunocompetent patient with detection of HPV 11]. / Riesenkeratoakanthom bei einem immunkompetenten Patienten mit Nachweis von HPV 11.

A 47-year-old immunocompetent man presented with a nodule on the right side of the upper lip that appeared suddenly and grew rapidly. Histological examination was consistent with the diagnosis of keratoacanthoma which is often associated with immunosuppression. Low-risk HPV type 11 was detected in the PCR analysis. While formerly one often waited for spontaneous regression of keratoacanthomas, today one routinely treats them as a well-differentiated squamous cell carcinoma. Complete surgical excision was not possible in our patient because of the size of the tumor. Radiation with a cumulative dose of 30 Gray (15 sessions of 2 Gray) led to complete remission. In addition to ultraviolet exposure, trauma, genetic factors and chemical carcinogens, HPV should be considered as a possible cofactor in the etiology of keratoacanthoma.

[Severe hematogenous contact dermatitis after oral nickel exposition]. / Hämatogenes allergisches Kontaktekzem nach oraler Nickelexposition.

A 19-year-old woman with known strong contact sensitization to nickel sulfate presented with persistent periumbilical eczema even though she had been careful to avoid exposure to the allergen. She had childhood atopic dermatitis which had been latent but had flared a year previously, presenting as flexural eczema. Double-blind placebo-controlled oral challenge with 5 mg nickel revealed a hematogenous contact dermatitis, accompanied by fever and malaise. It resolved quickly after treatment with systemic steroids and antihistamines. The possibility of hematogenous contact dermatitis should be considered in patients with strong delayed-type hypersensitivity suffering from persistent or relapsing eczema.

Regulatory role of T lymphocytes in atopic dermatitis.

Eczema does not occur in the absence of T cells. Here we provide an overview on the regulatory impact which T cells have on the establishment and maintenance of atopic dermatitis. Particularly, we outline the role of different T-helper cell subsets (i.e. Th-1, Th-2, T-regulatory and Th-17 cells) and their distinct influence on the cutaneous inflammatory reaction at different stages of the disease. Eczema is characterized by epidermal inflammation and thus T-cell/ker - atinocyte interactions are of particular relevance in this condition. Alterations in innate and adaptive immunity involving T cells result in susceptibility to skin infections and in hyperreactivity reactions to environmental stimuli which in turn determine the course and severity of atopic dermatitis.

Dysregulation of toll-like receptor-2 (TLR-2)-induced effects in monocytes from patients with atopic dermatitis: impact of the TLR-2 R753Q polymorphism.

BACKGROUND: Atopic dermatitis (AD) is often complicated by an enhanced susceptibility to bacterial skin infections, especially with Staphylococcus aureus. Toll-like receptors (TLR), especially TLR-2 recognizes cell wall components of S. aureus, e.g. lipoteichoic acid (LTA) and peptidoglycan (PGN). A heterozygous TLR-2 R753Q polymorphism occurs in a frequency of 11.5% in adult AD patients and has been shown to be associated with a severe phenotype of AD. METHODS: The aim of this study was to investigate the impact of TLR-2 agonists (LTA, PGN and Pam3Cys) on cytokine production in human monocytes from AD patients with the TLR-2 R753Q polymorphism compared with that of AD patients with 'wild type' TLR-2 and control individuals to elucidate the functional role of the TLR-2 R753Q polymorphism. RESULTS: Monocytes from AD patients with the TLR-2 R753Q mutation produced significantly more IL-6 and IL-12 compared with that of AD patients with nonmutated TLR-2 upon stimulation with TLR-2 agonists. CONCLUSION: We show for the first time functional differences in TLR-2 responsiveness of monocytes from AD patients with the TLR-2 R753Q mutation compared with wild type AD patients in a ligand-dependent manner. CLINICAL IMPLICATION: Our data support the emerging concept that AD patients have a dysbalance in innate and acquired immunity. TLR-2 may be essential in the pathogenesis and maintenance of AD and may be involved in the enhanced susceptibility to skin infections with S. aureus and in a higher inflammatory response in patients with AD carrying the TLR-2 polymorphism.