High rate of severe radiation dermatitis during radiation therapy with concurrent cetuximab in head and neck cancer: results of a survey in EORTC institutes.

OBJECTIVE: Examination of the rate of grade III or grade IV radiation dermatitis during treatment of head and neck cancer (HNC) with radiotherapy (RT) and concurrent cetuximab in EORTC centres. MATERIALS AND METHOD: A questionnaire was sent to all members of the EORTC Radiation Oncology Group and Head and Neck Group (111 institutions) to evaluate the widespread use of cetuximab and radiotherapy in HNC and to estimate the frequency of grades III and IV skin reactions in the radiation portals associated with this protocol. Co-morbidities, RT schedules and co-medications were also recorded. RESULTS: We received responses from 28 institutions in 11 countries. A total of 125 HNC patients from 15 institutions were treated with cetuximab and concurrent RT. Information about the skin reactions was available from 71 patients. Of these 36 had no grade III/IV adverse effects in the RT field, 15 had a grade III and 20 had grade IV radiation dermatitis. No detectable relation of grades III and IV radiation dermatitis with co-morbidities such as liver insufficiency or renal dysfunction was found. CONCLUSION: According to the results of the questionnaire, grade III/IV radiation dermatitis is observed in 49% of HNC patients treated with cetuximab and concurrent RT. A systematic clinical monitoring of cutaneous side effects during RT plus cetuximab is advised to ensure the safety of this protocol.

Thymic stromal lymphopoietin plays divergent roles in murine models of atopic and nonatopic airway inflammation.

BACKGROUND: Thymic stromal lymphopoietin (TSLP) is a cytokine primarily produced by epithelial cells, which has been shown to be a potent inducer of T-helper 2 (Th2)-type responses. However, TSLP has pleiotropic effects upon immune cells, and although extensively studied in the context of atopic asthma, its relevance as a therapeutic target and its role in the pathogenesis of nonatopic asthma remains unknown. We sought to investigate the role of TSLP in atopic, nonatopic and viral-induced exacerbations of pulmonary inflammation. METHODS: Using stringently defined murine models of atopic, nonatopic and virally exacerbated forms of pulmonary inflammation, we compared inflammatory responses of C57BL/6 wild-type (WT) and TSLP receptor-deficient (TSLPR KO) mice. RESULTS: Thymic stromal lymphopoietin receptor (TSLPR) signaling was crucial for the development of atopic asthma. Specifically, TSLPR signaling to lung recruited CD4+ T cells enhanced eosinophilia, goblet cell hyperplasia, and overall inflammation within the airways. In contrast, the absence of TSLPR signaling was associated with strikingly exaggerated pulmonary neutrophilic inflammation in a nonatopic model of airway inflammation. The inflammation was associated with excessive levels of interleukin (IL)-17A in the lungs, indicating that TSLP negatively regulates IL-17A. In addition, in a model of influenza-induced exacerbation of atopic airway inflammation, the absence of TSLPR signaling also led to exaggerated neutrophilic inflammation. CONCLUSION: Thymic stromal lymphopoietin plays divergent roles in the pathogenesis of atopic and nonatopic asthma phenotypes by either enhancing Th2 responses or curtailing T-helper 17 responses. These findings raise important caveats for the design of therapeutic interventions targeting TSLP in asthma.

Cell death-induced activation of epidermal growth factor receptor in keratinocytes: implications for restricting epidermal damage in dermatitis.

Recent findings have implicated Fas/Fas ligand (FasL) in mediating the death of keratinocytes in spongiotic lesions. We asked whether dying keratinocytes could potentially initiate a protective response of the skin to limit the destruction of the epidermis in the spongiotic areas. In addition to apoptosis, treatment of keratinocyte cultures in vitro with FasL triggers a profound phoshorylation of the epidermal growth factor receptor (EGFR) and of its downstream effectors ERK and protein kinase B (PKB/Akt). Using a variety of inhibitors and blocking antibodies, we demonstrated that: (i) apoptosis is required for the generation of the signal(s) leading to the activation of EGFR, ERK, and Akt; (ii) the activation of EGFR, ERK, and Akt by FasL is indeed mediated by its bona fide receptor Fas; (iii) the activation of EGFR is essential for the subsequent activation of ERK and Akt; and (iv) apoptotic keratinocytes secrete soluble EGFR ligands (including amphiregulin) that are processed from membrane-bound proligand forms by metalloproteinase(s). Our findings demonstrate a potential mechanism for the restriction and repair of spongiotic damage in eczemas.

Immunopathogenesis of Asthma and Atopic Diseases – The specific Role of a selected Panel of Genes in human T helper Cell Differentiation

T helper cell (Th) functions are crucial for proper immune defence against various intra- and extracellular pathogens. According to the specific immune responses, Th cells can be classified into subtypes, Th1 and Th2 cells being the most frequently characterized classes. Th1 and Th2 cells interact with other immune cells by regulating their functions with specific cytokine production. IFN, IL-2 and TNF- are the cytokines predominantly produced by Th1 cells whereas Th2 cells produce Th2-type cytokines, such as IL-4, IL-5 and IL-13. Upon TCR activation and in the presence of polarizing cytokines, Th cells differentiate into effector subtypes from a common precursor cell. IFN and IL-12 are the predominant Th1 polarizing cytokines whereas IL-4 directs Th2 polarization. The cytokines mediate their effects through specific receptor signalling. The differentiation process is complex, involving various signalling molecules and routes, as well as functions of the specific transcription factors. The functions of the Th1/Th2 cells are tightly regulated; however, knowledge on human Th cell differentiation is, as yet, fairly poor. The susceptibility for many immune-mediated disorders often originates from disturbed Th cell responses. Thus, research is needed for defining the molecular mechanisms involved in the differentiation and balanced functions of the Th cells. Importantly, the new information obtained will be crucial for a better understanding of the pathogenesis of immune-mediated disorders, such as asthma or autoimmune diseases. In the first subproject of this thesis, the role of genetic polymorphisms in the human STAT6, GATA3 and STAT4 genes were investigated for asthma or atopy susceptibility in Finnish asthma families by association analysis. These genes code for key transcription factors regulating Th cell differentiation. The study resulted in the identification of a GATA3 haplotype that associated with asthma and related traits (high serum IgE level). In the second subproject, an optimized method for human primary T cell transfection and enrichment was established. The method can be utilized for functional studies for the selected genes of interest. The method was also utilized in the third subproject, which aimed at the identification of novel genes involved in early human Th cell polarization (0-48h) using genome-wide oligonucleotide arrays. As a result, numerous genes and ESTs with known or unknown functions were identified in the study. Using an shRNA knockdown approach, a panel of novel IL-4/STAT6 regulated genes were identified in the functional studies of the genes. Moreover, one of the genes, NDFIP2, with a previously uncharacterized role in the human Th differentiation, was observed to promote IFN production of the differentiated Th1 cells. Taken together, the results obtained have revealed potential new relevant candidate genes serving as a basis for further studies characterizing the detailed networks involved in the human Th cell differentiation as well as in the genetic susceptibility of Th-mediated immune disorders.

Malassezia yeasts activate the NLRP3 inflammasome in antigen-presenting cells via Syk-kinase signalling.

Although being a normal part of the skin flora, yeasts of the genus Malassezia are associated with several common dermatologic conditions including pityriasis versicolour, seborrhoeic dermatitis (SD), folliculitis, atopic eczema/dermatitis (AE/AD) and dandruff. While Malassezia spp. are aetiological agents of pityriasis versicolour, a causal role of Malassezia spp. in AE/AD and SD remains to be established. Previous reports have shown that fungi such as Candida albicans and Aspergillus fumigatus are able to efficiently activate the NLRP3 inflammasome leading to robust secretion of the pro-inflammatory cytokine IL-1β. To date, innate immune responses to Malassezia spp. are not well characterized. Here, we show that different Malassezia species could induce NLRP3 inflammasome activation and subsequent IL-1β secretion in human antigen-presenting cells. In contrast, keratinocytes were not able to secrete IL-1β when exposed to Malassezia spp. Moreover, we demonstrate that IL-1β secretion in antigen-presenting cells was dependent on Syk-kinase signalling. Our results identify Malassezia spp. as potential strong inducers of pro-inflammatory responses when taken up by antigen-presenting cells and identify C-type lectin receptors and the NLRP3 inflammasome as crucial actors in this process.

Digital dermatitis of the accessory digits of dairy cows

This report characterizes the digital dermatitis (DD) lesions in the accessory digits of dairy cows and presents data on the applied therapy. Fifteen Holstein cattle with DD affecting the accessory digits of the hindlimbs from four dairy farms with previous history of DD were evaluated. Lesions were excised, the wounds were sutured, and a topical application of oxytetracycline powder covered by bandaging was associated with a single parenteral administration of long acting oxytetracycline IM (20mg/kg). Tissue samples were obtained for histopathology and transmission electronic microscopy (TEM). Lesions from all the animals were recuperated 15 days after surgical procedure. Overal, most DD lesions were papillomatous epidermal projections or wartlike verrucous lesions. Histopathologically, samples revealed hyperplasia of epidermis with hyperkeratosis, several mitoses in the stratum basale and elongated rete ridges in the superficial and middle dermis. TEM revealed long, thin spirochete-like bacteria. Morphologic features of lesions and its response to therapy were comparable to those described for DD.

Atypical actinobacillosis in bulls in Argentina: granulomatous dermatitis and lymphadenitis

Actinobacillosis is a common cause of sporadic infection in cattle. It was mostly characterized as a pyogranulomatous inflammation of the tongue, but also soft tissues as lymph nodes, other digestive tract localization and skin. The aim of this study was to describe an episode of granulomatous dermatitis and lymphadenitis affecting a bull herd in Argentina during 2010. Actinobacillus lignieresii was isolated from samples collected from one of the affected bulls, and characteristic lesions were observed. Lesions other than 'wooden tongue' are usually uncommon; however, actinobacillosis should be included as a differential diagnosis for cutaneous diseases.

The Impact of Neonatal Antibiotic Exposure on Atopic Sensitisation by the Age of 12 Months

Varhaislapsuuden antibioottialtistuksen vaikutus atooppiseen herkistymiseen 12 kuukauden ikään mennessä Bakteerien vaikutus terveyteen on merkittävä: ne ovat toisaalta hengenvaarallisten infektioiden aiheuttajia, mutta samanaikaisesti niiden läsnäolo on välttämätöntä terveen immuunipuolustuksen kehittymiseksi. Ensimmäisen elinvuoden aikana suoliston bakteerikanta on altis ulkoisten tekijöiden vaikutuksille. Varhaislapsuuden antibioottihoidolla voi olla tuhoisat seuraukset eri bakteerilajien suhteille, ja sen tiedetään altistavan erilaisille immuunivälitteisille sairauksille, kuten atopialle. Ei ole kuitenkaan selvitetty, onko tämä vaikutus johtunut käynnissä olevan infektion aiheuttamista muutoksista kehittyvään immuunijärjestelmään vai onko siihen ollut syynä infektioon aloitettu antibioottihoito. Tässä tutkimuksessa selvitettiin eroja kahden, varhaista antibioottihoitoa saaneen ryhmän välillä ja päätetapahtumaksi katsottiin myöhemmin lapsuudessa ilmenevä atopiataipumus. Toinen ryhmä sai antibioottihoitoa kliinisesti todistettuun bakteeri-infektioon (varhaiseen sepsikseen). Toinen ryhmä taas sai antibioottihoidon pelkästään infektioepäilyyn eli ns. empiirisen hoidon, joka lopetettiin alle viiden vuorokauden kuluessa kun katsottiin, ettei oireiden taustalla ollutkaan bakteeri-infektiota. Mukana vertailussa oli lisäksi ryhmä, joka ei saanut lainkaan varhaista antibioottihoitoa. Antibioottihoidon pitkäaikaisvaikutusta arvioitiin ihon prick-testillä, joka kertoo atopiaan liittyvästä IgE-välitteisestä herkistymisestä. Varhaisella antibioottihoidolla tarkoitetaan tässä alle 72 tunnin sisällä syntymästä alkanutta hoitoa G-penisilliinin ja gentamysiinin yhdistelmällä. Tutkimuksen aineisto koostui 755 vastasyntyneen lapsen seurantadatasta, joka saatiin neljän käynnissä olevan allergian ehkäisytutkimuksen aineistosta. Tutkimuksen mukaanottokriteereinä pidettiin sitä, että saatavilla oli tiedot sekä mahdollisen antibioottialtistuksen kestosta että ihon prick-testituloksesta joko 6 tai 12 kuukauden iässä. Tulokset analysoitiin logistisella regressioanalyysillä huomioiden mahdolliset sekoittavat tekijät: äidin allergia, ennenaikaisuus, tutkimusprobiootti, imetyksen kesto, äidin raskauden aikainen tupakointi ja synnytystapa. Potilasryhmässä, joka sai antibioottihoitoa ilman samanaikaista infektiota, nähtiin tilastollisesti merkittävästi vähemmän positiivisia prick-testituloksia verrattuna lapsiin, jotka eivät altistuneet antibiooteille. Tulos on merkittävä, sillä se osoittaa, että varhaisella antibioottihoidolla on kauaskantoisia vaikutuksia kehittyvään immuunijärjestelmään.

Early Life Intestinal Microbiota in Health and in Atopic Eczema

Decrease in microbial contacts in affluent societies is considered to lie behind the rise in allergic and other chronic inflammatory diseases during the last decades. Indeed, deviations in the intestinal microbiota composition and diversity have been associated with several diseases, such as atopic eczema. However, there is no consensus yet on what would constitute a beneficial or harmful microbiota. The aim of this thesis was to study the microbiota development in healthy infants and to characterize intestinal microbiota signatures associated with disease status and severity in infants with atopic eczema. The methodological aim was to compare and optimize methods for DNA extraction from fecal samples to be used in high-throughput microbiota analyses. It was confirmed that the most critical step in successful microbial DNA extraction from fecal samples is the mechanical cell lysis procedure. Based on this finding, an efficient semi-automated extraction process was developed that can be scaled for use in high-throughput platforms such as phylogenetic microarray used in this series of studies. By analyzing a longitudinal motherchild cohort for 3 years it was observed that the microbiota development is a gradual process, where some bacterial groups reach the degree of adult-type pattern earlier than others. During the breast-feeding period, the microbiota appeared to be relatively simple, while major diversification was found to start during the weaning process. By the age of 3 years, the child’s microbiota composition started to resemble that of an adult, but the bacterial diversity has still not reached the full diversity, indicating that the microbiota maturation extends beyond this age. In addition, at three years of age, the child’s microbiota was more similar to mother’s microbiota than to microbiota of nonrelated women.In infants with atopic eczema, a high total microbiota diversity and abundance of butyrate-producing bacteria was found to correlate with mild symptoms at 6 months. At 18 months, infants with mild eczema had significantly higher microbiota diversity and aberrant microbiota composition when compared to healthy controls at the same age. In conclusion, the comprehensive phylogenetic microarray analysis of early life microbiota shows the synergetic effect of vertical transmission and shared environment on the intestinal microbiota development. By the age of three years, the compositional development of intestinal microbiota is close to adult level, but the microbiota diversification continues beyond this age. In addition, specific microbiota signatures are associated with the existence and severity of atopic eczema and intestinal microbiota seems to have a role in alleviating the symptoms of this disease.

Humoral and cellular immune responses to Blomia tropicalis and concanavalin A-binding fractions in atopic patients

Blomia tropicalis, Dermatophagoides pteronyssinus and D. farinae are prevalent house dust mites. Concanavalin A-binding components derived from B. tropicalis (Bt-ConA extract) are highly immunogenic in allergic diseases. The aim of the present study was to evaluate the humoral and cellular immune responses to B. tropicalis in mite-sensitized patients. A total of 137 patients with allergic rhinitis with/without asthma and 109 non-atopic subjects were selected and analyzed by the skin prick test, and for total serum IgE and specific IgE levels to both Bt-total and Bt-ConA extracts, their proliferative response and cytokine (IFN-γ and IL-5) production by peripheral blood mononuclear cells (PBMC) stimulated with both extracts. Skin prick test showed that 70% of the patients were sensitized to Bt (Bt+) and similar levels of specific IgE to Bt-total and Bt-ConA extracts were demonstrable in Bt+ patients. Significant PBMC proliferation was observed in response to Bt-total extract in Bt+, but not in Bt- patients and non-atopic subjects (P < 0.001). Bt-ConA extract induced increased proliferative responses in all patient groups compared to medium alone (P < 0.05), but these responses were significantly decreased in the presence of the mannopyranoside ConA inhibitor (P < 0.05). Significant IFN-γ production was observed after Bt-ConA stimulation of Bt+ patients (P < 0.05), while Bt-total extract had no effect. IL-5 production was consistently detected in Bt+ patients after allergen-specific stimulation or with no stimulus, indicating that PBMC from allergic patients are prone to produce Th2 profile cytokines, spontaneously or inductively by allergen restimulation. These data showed that ConA-binding components isolated from B. tropicalis may contain relevant antigens that are involved in both humoral and cellular immune responses. However, without an additional purification procedure to eliminate the residual contamination with ConA, its use in immunotherapeutic procedures cannot be recommended.

High HTLV-1 proviral load, a marker for HTLV-1 associated myelopathy/tropical spastic paraparesis, is also detected in patients with infective dermatitis associated with HTLV-1

Salvador (BA, Brazil) is an endemic area for human T-cell lymphotrophic virus type 1 (HTLV-1). The overall prevalence of HTLV-1 infection in the general population has been estimated to be 1.76%. HTLV-1 carriers may develop a variety of diseases such as adult T-cell leukemia/lymphoma, HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and infective dermatitis associated with HTLV-1 (IDH). IDH is a chronic and severe form of childhood exudative and infective dermatitis involving mainly the scalp, neck and ears. It has recently been observed that 30% of patients with IDH develop juvenile HAM/TSP. The replication of HTLV-1 has been reported to be greater in adult HAM/TSP patients than in asymptomatic HTLV-1 carriers. In the current study, the proviral load of 28 children and adolescents with IDH not associated with HAM/TSP was determined and the results were compared to those obtained in 28 HTLV-1 adult carriers and 28 adult patients with HAM/TSP. The proviral load in IDH patients was similar to that of patients with HAM/TSP and much higher than that found in HTLV-1 carriers. The high levels of proviral load in IDH patients were not associated with age, duration of illness, duration of breast-feeding, or activity status of the skin disease. Since proviral load is associated with neurological disability, these data support the view that IDH patients are at high risk of developing HAM/TSP.

Prevalencia de síntomas cutáneos asociados a dermatitis de contacto y su relación con factores sociodemográficos y ocupacionales en el personal asistencial de un laboratorio clínico de la ciudad de Bogotá en el año 2012

El objetivo fue determinar la prevalencia de síntomas cutáneos asociados a Dermatitis de Contacto y su relación con factores socios demográficos y ocupacionales, en el personal asistencial de un laboratorio clínico de la ciudad de Bogotá en el año 2012. Es un estudio descriptivo observacional de corte transversal (n= 100) se estimo la prevalencia de síntomas cutáneos de Dermatitis de Contacto y sus factores asociados socio demográficos y ocupacionales en el personal asistencial de un laboratorio clínico de la ciudad de Bogotá en Se usó como instrumento el cuestionario Nórdico para Enfermedades profesionales de la piel (NOQS) en su versión larga validada al español. La sensibilidad y especificidad del cuestionario aplicado en lo referente a las preguntas sobre eczema fue del 96 y 75% respectivamente. Los resultados encontrados fueron que la prevalencia de la sintomatología cutánea de Dermatitis de contacto en la población estudiada fue de 30% para manos y de 16 % para muñecas o antebrazos.