Inmunohistoquímica de las lesiones cutáneas en la lepra y las leprorreacciones / No disponible

Objetivos: 1. Evaluar la immunohistoquimica de los granulomas de la lepra en las muestras de biopsias cutáneas de pacientes con lepra tuberculoide y lepromatosa, con respecto a la presencia y distribución de células T CD4+, CD8+ y CD28+, células CD 68+ y células CD1a+. 2. Evaluar los hallazgos inmunohistoquimicos observados en leprorreacciones. Metodología: Estudio descriptivo. Se seleccionaron para el estudio biopsias cutaneas, en las que se había diagnosticado clínica e histopatologicamente lepra entre el 1.8.2016 al 31.5.2017 en el Instituto Medico Gubernamental, Kozhikode. Se estudió la immunohistoquimica de las lesiones cutáneas en lepra y leprorreacciones, observando específicamente la distribución de células CD4/ CD8/ CD28/ CD68/ CD1a en la lepra en distintos escenarios. Resultados: En el estudio se incluyeron veintiséis casos tuberculoides y 14 lepromatosos. Todos los granulomas independientemente del tipo de enfermedad presentaron tinción positiva por CD4 y CD68. Dos de los 14 casos lepromatosos (14・3%), y 15/26 (57・7%) de las muestras tuberculoides presentaron expresion CD4 de moderada a fuerte. Se detectó negatividad CD28 en cuatro casos tuberculoides (15・4%) y en 10 lepromatosos (71・4%). La expresion CD4 moderada a fuerte se detectó en más del 70% de los T1R incremento mientras que en los demás grupos solo fue de 20%-50%. Más del 80% de las T1R estáticas e incremento presentaban positividad CD28, mayor de que el 30%-50% registrado en otros grupos. Conclusiones: Los resultados revelan que la inmunohistoquimica tiene un papel en aclarar los complejos procesos inmunológicos empleados en la lepra y las leprorreacciones

Objectives: 1. To study the immunohistochemistry of leprosy granulomas in the skin biopsy specimens of patients with tuberculoid and lepromatous leprosy, with respect to the presence and arrangement of CD4+, CD8+ and CD28+ T cells, CD 68+ cells and CD1a+ cells. 2. To study the immunohistochemistry findings observed in leprosy reactions. Design: Descriptive study. Skin biopsies in which the clinical and histopathological diagnosis of leprosy was reported between 1.8.2016 to 31.5.2017 in the Government Medical College, Kozhikode, were selected for the study. Immunohistochemistry of the skin lesions in leprosy and leprosy reactions was studied, looking specifically for the distribution of CD4/ CD8/ CD28/ CD68/ CD1a positive cells in leprosy at different scenarios. Results: Twenty-six tuberculoid and 14 lepromatous cases were included in the study. All granulomas irrespective of disease type showed positive staining for CD4 and CD68. Two of the 14 lepromatous leprosy cases (14・3%), and 15/26 (57・7%) tuberculoid specimens manifested moderate to strong CD4 expression. CD28 negativity was documented in four tuberculoid (15・4%) and 10 lepromatous cases (71・4%). Moderate to strong CD4 expression was noted in more than 70% of upgrading T1R while a similar finding was documented in only 20%-50% of other groups. More than 80% of static and upgrading T1R showed CD28 positivity, which was higher than the 30%-50% positivity recorded in other groups. Conclusions: The observations of the current study indicate a role for immunohistochemistry analysis in delineating the complex immunological processes involved in leprosy and leprosy reactions

Oral mucosa: an alternative epidermic cell source to develop autologous dermal-epidermal substitutes from diabetic subjects

Abstract Oral mucosa has been highlighted as a suitable source of epidermal cells due to its intrinsic characteristics such as its higher proliferation rate and its obtainability. Diabetic ulcers have a worldwide prevalence that is variable (1%-11%), meanwhile treatment of this has been proven ineffective. Tissue-engineered skin plays an important role in wound care focusing on strategies such autologous dermal-epidermal substitutes. Objective The aim of this study was to obtain autologous dermal-epidermal skin substitutes from oral mucosa from diabetic subjects as a first step towards a possible clinical application for cases of diabetic foot. Material and Methods Oral mucosa was obtained from diabetic and healthy subjects (n=20 per group). Epidermal cells were isolated and cultured using autologous fibrin to develop dermal-epidermal in vitro substitutes by the air-liquid technique with autologous human serum as a supplement media. Substitutes were immunocharacterized with collagen IV and cytokeratin 5-14 as specific markers. A Student´s t- test was performed to assess the differences between both groups. Results It was possible to isolate epidermal cells from the oral mucosa of diabetic and healthy subjects and develop autologous dermal-epidermal skin substitutes using autologous serum as a supplement. Differences in the expression of specific markers were observed and the cytokeratin 5-14 expression was lower in the diabetic substitutes, and the collagen IV expression was higher in the diabetic substitutes when compared with the healthy group, showing a significant difference. Conclusion Cells from oral mucosa could be an alternative and less invasive source for skin substitutes and wound healing. A difference in collagen production of diabetic cells suggests diabetic substitutes could improve diabetic wound healing. More research is needed to determine the crosstalk between components of these skin substitutes and damaged tissues.

Effect of autologous platelet-rich plasma application on cutaneous wound healing in dogs

This study was conducted to identify the effectiveness of platelet-rich plasma (PRP) and efficacy of intralesional injection as a method of application to acute cutaneous wounds in dogs. Healthy adult beagles (n = 3) were used in this study. Autologous PRP was separated from anticoagulant treated whole blood in three dogs. Cutaneous wounds were created and then treated by intralesional injection of PRP in the experimental group, while they were treated with saline in the control group on days 0, 2 and 4. The healing process was evaluated by gross examination throughout the experimental period and histologic examination on day 7, 14 and 21. In PRP treated wounds, the mean diameter was smaller and the wound closure rate was higher than in the control. Histological study revealed that PRP treated wounds showed more granulation formation and angiogenesis on day 7, and faster epithelialization, more granulation formation and collagen deposition were observed on day 14 than in control wounds. On day 21, collagen deposition and epithelialization were enhanced in PRP treated groups. Overall, PRP application showed beneficial effects in wound healing, and intralesional injection was useful for application of PRP and could be a good therapeutic option for wound management in dogs.

Células madre de la piel: en la frontera entre el laboratorio y la clínica. Parte I: células madre epidérmicas / Skin Stem Cells: At the Frontier Between the Laboratory and Clinical Practice. Part 1: Epidermal Stem Cells

Las células madre son células que se caracterizan por su capacidad para autorrenovarse y diferenciarse hacia células de todos los linajes que constituyen su tejido de origen. El descubrimiento de las células madre en un organismo adulto, y la descripción de los marcadores que han permitido aislar de forma específica estas células, han abierto nuevas perspectivas y nuevos horizontes en la investigación biomédica y también nuevas esperanzas en el tratamiento de muchas enfermedades. En este artículo se revisan de forma detallada las principales características de las células madre que dan origen a las distintas células de la piel humana, incluyendo las células madre epidérmicas, mesenquimales y melanocíticas, y sus potenciales implicaciones y aplicaciones en las enfermedades cutáneas. La primera parte de este artículo revisa las células madre epidérmicas, con sus principales características y sus potenciales aplicaciones en dermatología

Stem cells are characterized by their ability to self-renew and differentiate into the different cell lineages of their tissue of origin. The discovery of stem cells in adult tissues, together with the description of specific markers for their isolation, has opened up new lines of investigation, expanding the horizons of biomedical research and raising new hope in the treatment of many diseases. In this article, we review in detail the main characteristics of the stem cells that produce the specialized cells of the skin (epidermal, mesenchymal, and melanocyte stem cells) and their potential implications and applications in diseases affecting the skin. Part I deals with the principal characteristics and potential applications of epidermal stem cells in dermatology

Stem cells in embryonic skin development

The skin is a complex stratified organ which acts not only as a permeability barrier and defense against external agents, but also has essential thermoregulatory, sensory and metabolic functions. Due to its high versatility and activity, the skin undergoes continuous self-renewal to repair damaged tissue and replace old cells. Consequently, the skin is a reservoir for adult stem cells of different embryonic origins. Skin stem cell populations reside in the adult hair follicle, sebaceous gland, dermis and epidermis. However, the origin of most of the stem cell populations found in the adult epidermis is still unknown. Far more unknown is the embryonic origin of other stem cells that populate the other layers of this tissue. In this review we attempt to clarify the emergence, structure, markers and embryonic development of diverse populations of stem cells from the epidermis, dermis and related appendages such as the sebaceous gland and hair follicle.

DNA release and uptake associated with the development of pleomorphic cells in mammalian skin autotransplants / Liberación y absorción de ADN asociada con el desarrollo de células pleomórficas en autotrasplantes de piel en mamíferos

OBJECTIVE: Although several in vitro studies have demonstrated active release of DNA by living cells, there is still doubt. There are no such in vivo studies (1). The following experiment is an in vivo study to determine whether DNA release and uptake by cells and tissues occur and can be related to normal growth and differentiation, abnormal growth and cancer. METHODS: Epidermal and full-thickness ear-skin grafts were separately autotransplanted into two groups of mice. In a second group, host mice were labelled with tritiated thymidine and autografted separately, with unlabelled epidermal and full-thickness ear-skin grafts. Animals were sacrificed regularly in both cases. RESULTS: Full thickness grafts revealed cysts in 15 out of 16 grafts, with well-differentiated squamous epidermis, DNA labelling ofdermal fibroblasts and no DNA labelling ofepidermal cells. Epidermal grafts revealed cysts in six out of 20 grafts, with epidermal cells variable in shape and arrangement; some appeared normal but others were two to four times larger, forming solid nests ofcells. In some grafts, there were spindle-shaped pleomorphic cells loosely interconnected. DNA labelling was ob served in occasional epidermal cell. Two lung adenocarcinomas were found. CONCLUSION: These results suggest active release of DNA by host cells and DNA uptake by grafted cells. This phenomenon and the differential uptake of DNA labelling ofepidermal and dermal cells in the epidermal and full-thickness grafts suggest an association with abnormal, even pleomorphic epidermal cell behaviour due to the interference of dermal/epidermal interacting factors.

OBJETIVO: Aunque varios estudios in vitro han demostrado la liberación activa de DNA por las células vivas, todavía persisten las dudas. No existen tales estudios in vitro (1). El siguiente experimento constituye un estudio in vitro para determinar si hay liberación y absorción de ADN por parte de las células y los tejidos, y si estos procesos guardan relación con el crecimiento normal y la diferenciación, así como con el crecimiento anormal y el cáncer. MÉTODOS: Injertos de piel de la oreja, tanto de espesor total como epidérmicos fueron auto trasplantados por separado a dos grupos de ratones. En el segundo grupo, ratones huéspedes fueron etiquetados con timidina tritiada, y autoinjertados, por separado, con injertos de piel de la oreja no etiquetados, tanto de espesor total como epidérmicos. En ambos casos, fue necesario sacrificar animales de manera regular. RESULTADOS: Los injertos de espesor total revelaron quistes en 15 de cada 16 injertos, con epidermis escamosa bien diferenciada, etiquetado ADN de fibroblastos dérmicos, y no etiquetado ADN de células epidérmicas. Los injertos epidérmicos revelaron quistes en seis de 20 injertos, siendo las células epidérmicas variables en forma y ordenamiento. Algunas parecían normales, pero otras eran de dos a cuatro veces mayores, y formaban anidamientos celulares sólidos. En algunos de los injertos, se presentaron células pleomórficas en forma de huso, interconectadas con laxitud. Se observó etiquetado de DNA en células epidérmicas ocasionalmente. Se hallaron dos adenocarcinomas pulmonares. CONCLUSIÓN: Estos resultados sugieren la liberación activa de ADN por las células huéspedes y la absorción de ADN por las células injertadas. Este fenómeno y la absorción diferencial de etiquetado de ADN de células dérmicas y epidérmicas en los injertos epidérmicos y de espesor total, sugieren una asociación con el comportamiento celular anormal, e incluso pleomórfico epidérmico, debido a la interferencia de los factores dérmicos/epidérmicos interactuantes.

Nkx-2.3 gene in mouse epidemial maturation

In higher vertebrates, from amphibians to humans, epidemial maturation is a conserved developmental process. Using adult epidemial tissue and an established keratinocyte cell line, the mouse Nkx-2.3 homeobox gene was demonstrated, for the first time, to be expressed in mouse epidermal keratinocytes. Under the normal culture condition, the spontaneous aggregation phenomenon, a common initiation step of ES cell differentiation, and the induction of mouse adult K1 keratin, a marker of mature epidermal keratinocytes, were both observed in vitro when the Xenopus Nkx-2.3 gene was stably transfected into a mouse pluripotent P19 EC cell line. The induction of mouse K1 keratin by using its Xenopus orthologous gene in the mouse P19 cell implies that Nkx-2.3 may play a conserved role in the epidermal maturation of the mouse, as it does in that of the frog (Ma, 2004). However, the CAT assay study on frog adult keratin promoter could not find the induction of adult keratin. This implies there might not be a direct activation of its promoter.

Expression of N-terminal truncated desmoglein 3 (Delta NDg3) in epidermis and its role in keratinocyte differentiation

During a search for keratinocyte differentiation-related genes, we obtained a cDNA fragment from the 5'-untranslated region of a previously identified splicing variant of desmoglein 3 (Dg3). This transcript encodes a protein of 282 amino acids, which corresponds to the N-terminal truncated intracellular domain of Dg3 (Delta NDg3). Northern blot analysis detected a 4.6-kb transcript matching the predicted size of Delta NDg3 mRNA, and Western blot analysis with an antibody raised against the Dg3 C-terminus (H-145) detected a 31-kDa protein. Increased Delta NDg3 expression was observed in differentiating keratinocytes by RT-PCR and Western blot analysis, suggesting that Delta NDg3 is indeed a differentiation-related gene product. In immunohistochemical studies of normal and pathologic tissues, H-145 antibody detected the protein in the cytoplasm of suprabasal layer cells, whereas an antibody directed against the N-terminal region of Dg3 (AF1720) reacted with a membrane protein in the basal layer. In addition, Delta NDg3 transcript and protein were upregulated in psoriatic epidermis, and protein expression appeared to increase in epidermal tumors including Bowen's disease and squamous cell carcinoma. Moreover, overexpression of Delta NDg3 led to increased migration and weakening of cell adhesion. These results suggest that Delta NDg3 have a role in keratinocyte differentiation, and that may be related with tumorigenesis of epithelial origin.

Epidermal stem cells in skin homeostasis and cutaneous carcinomas

Skin and squamous epithelia regulate water and heat homeostasis and constitute our first barrier of protection against pathogens. Cells from the outermost layer of the skin, the cornified envelope (stratum corneum), are constantly being shed, imposing a constant demand for replenishment to maintain homeostasis. Hair follicles and sebaceous glands provide protective hair growth and skin sebum, and continuously undergo cycles of growth and regression. The outstanding ability of the epidermis, hair follicles and sebaceous glands to self-renew relies on a population of adult stem cells that are maintained throughout our life span. In this review we will provide an overview of our current knowledge about epidermal stem cells, and some of the molecular mechanisms that identify them and dictate their behaviour. We will also summarise our view on the possible link between adult epidermal stem cells and cancer stem cells within skin and squamous neoplasias. The potential of epidermal stem cells in regenerative medicine and for designing targeted antitumoral therapies will be discussed (AU)

Model for human skin reconstructed in vitro composed of associated dermis and epidermis

CONTEXTO E OBJETIVO: A técnica para obtenção de pele humana que apresente derme e epiderme, reconstruída a partir de células isoladas de pacientes, pode possibilitar a realização de enxertos autólogos de pele reconstruída em laboratório em pacientes com áreas doadoras escassas, além de permitir ensaios com substâncias químicas e drogas in vitro e não mais in vivo. O objetivo do trabalho é demonstrar um método de obtenção de pele humana reconstruída in vitro composta de derme e epiderme associadas. TIPO DE ESTUDO E LOCAL: Estudo experimental laboratorial realizado no Laboratório de Cultura de Células da Pele da Faculdade de Ciências Médicas da Universidade Estadual de Campinas, Campinas, São Paulo, Brasil. MÉTODOS: A partir da cultura de fibroblastos humanos, é possível obter um número suficiente de células que podem ser injetadas em uma matriz de colágeno bovino tipo I que, mantida imersa em meio de cultura específico para fibroblastos, permite a formação de uma derme humana reconstruída in vitro. Sobre essa derme, por meio de cultura de queratinócitos e melanócitos humanos, forma-se epiderme diferenciada, levando à formação de pele humana reconstruída in vitro, composta de derme e epiderme associadas. RESULTADOS: Demonstramos que é possível reproduzir pele humana reconstruída in vitro, composta de derme e epiderme associadas. Essa pele humana formada é, histologicamente, semelhante à pele humana in vivo. Na derme, identifica-se o tecido colágeno, com suas células, e a matriz extracelular organizados paralelamente à epiderme. Esta se desenvolve em várias camadas. CONCLUSÃO: É possível obter pele humana reconstruída in vitro, completamente diferenciada, composta de derme e epiderme, associadas, a partir da injeção de fibroblastos humanos em uma matriz de colágeno bovino tipo I e da cultura seqüencial de queratinócitos e melanócitose humanos sobre essa matriz contendo fibroblastos em seu interior.

Model of human epidermis reconstructed in vitro with keratinocytes and melanocytes on dead de-epidermized human dermis

CONTEXTO: Recentes progressos no campo das técnicas de cultura epitelial têm levado ao desenvolvimento de sistemas de cultura nos quais a epiderme reconstruída obtida exibe características de diferenciação morfológica semelhantes àquelas vistas in vivo. Uma epiderme humana reconstruída in vitro pode ser utilizada como melhor alternativa para testes toxicológicos e de eficácia de produtos de uso tópico in vitro e ainda no tratamento de queimaduras e úlceras crônicas de pele. OBJETIVO: Demonstrar um método de obtenção de epiderme humana reconstruída in vitro, utilizando queratinócitos e melanócitos cultivados sobre uma derme humana morta desepidermizada. TIPO DE ESTUDO: Experimental Laboratorial. LOCAL: Laboratório de Cultura de Células da Pele da Faculdade de Ciências Médicas da Universidade Estadual de Campinas, Campinas, São Paulo, Brasil. PROCEDIMENTOS: Queratinócitos e melanócitos humanos cultivados in vitro foram semeados sobre uma matriz biológica (derme humana morta desepidermizada) e o sistema foi mantido em interface ar-líquido, em meio de cultura adequado, até haver a formação de uma epiderme humana estratificada, mantendo as características histológicas da epiderme in vivo. RESULTADOS: Demonstramos, histologicamente, que é possível reproduzir uma epiderme diferenciada, a partir da cultura de queratinócitos e melanócitos sobre uma derme humana morta desepidermizada, obtendo uma epiderme humana reconstruída in vitro, com queratinócitos e melanócitos funcionais, corretamente posicionados, equivalente à epiderme in vivo. CONCLUSÕES: É possível obter uma epiderme humana reconstruída in vitro completamente diferenciada a partir da cultura de queratinócitos e melanócitos sobre uma derme humana morta desepidermizada.

Variaciones cualitativas y cuantitativas de la capa córnea epidérmica: su utilidad diagnóstica / Cualitative and quantitative variations of the epidermal horny layer: their diagnostic usefulness

Introducción: en 1978, Ackerman añadió a los tradicionales términos de hiperqueratosis ortoqueratósica y paraqueratósica tres variedades de la primera: laxa, compacta y laminar. Método: en este artículo redefinimos y matizamos tales términos llamando la atención sobre un aspecto no estudiado anteriormente: la apetencia tintorial de cada una de esas variedades de capa córnea. Resultados: la capa córnea laxa, normal o hiperqueratósica es siempre basófila. La córnea compacta, normal, hiperqueratósica o heterotópica muestra dos variantes, una basófila y otra eosinófila. La córnea laminar es siempre eosinófila igual que la córnea paraqueratósica. Conclusiones: tomando como base la apetencia tintorial de la capa córnea (basófila o eosinófila) y su estructura (laxa, compacta, laminar o paraqueratósica), se propone un algoritmo con el que efectuar una descripción objetiva de la capa córnea epidérmica de cada biopsia. Se discute la significación de cada una de esas variedades atendiendo a la localización del proceso biopsiado (AU)

Growth and differentiation of adult Mongolian gerbil epidermal cells in culture

A simple protocol for the growth and differentiation of adult Mongolian gerbil epidermal cells is reported. Insulin (8 micrograms/ml) and reduced levels of serum supplementation (2 percent) were sufficient for the maintenance of these cells in culture. Primary cultures were maintained as a proliferative monolayer in a medium with low calcium concentration (< 0.3 mM). Terminal differentiation of cultures was induced by raising the calcium concentration (1.6 mM) in the medium. These results support the concept derived from mouse epidermal cell culture that calcium is an important regulator of mammalian epidermal cell growth and differentiation. The present protocol also represents a useful tool for studies of mechanisms involved in epidermal cell growth and differentiation in a laboratory animal

Adult gerbil epidermal cells resistant to terminal differentiation associated with initiation of carcinogenesis

In order to identify the cellular basis of the gerbil skin unresponsiveness to two-stage carcinogenesis, it was studied the effect of an initiating dose of carcinogen on the biological behaviour of gerbil skin. Treatment of adult gerbil epidermal cells either in vivo or in vitro with 3-methylcholanthrene yielded cells which were resistant to terminal differentiation induced by calcium. These results support the concept derived from the mouse model system of skin carcinogenesis in which initiation is associated with an altered program of epidermal differentiation. The results also suggest that relative resistance of gerbil skin to two-stage carcinogenesis is related to promotion stage

Moléculas de adhesión celular y piel / Adhesion molecules and skin

Las moléculas de adhesión celular tienen un papel importante en múltiples fenómenos biológicos, tanto normales (generación de la respuesta inmune, coagulación, cicatrización, órgano-génesis) como patológicos (inflamación, trombosis, metástasis de células tumorales). En el presente trabajo se revisan los aspectos básicos de las moléculas de adhesión celular y su papel en diversas condiciones patológicas que afectan a la piel

Células dendríticas epidérmicas Thy-1 positivas un nuevo grupo celular asociado con inmunovigilancia cutánea / Dendritic epidermal cells thy-1 positives. A new cell group asociated with cutaneous immune surveillance

Las células dendríticas epidérmicas Thy-1 positivas (CDE Thy-1) son un tipo celular recientemente descubierto en la epidermis de ratones. Estás células se caracterizan por presentar en su superficie el antígeno Thy-1, que hasta 1975 se había encontrado sólo en timocitos y células nerviosas. Las CDE Thy-1 expresan las glicoproteínas CD3 y gamma delta (* *) del receptor antígenico de linfocitos T, lo cual las relaciona consistentemente con este grupo celular. Hasta el presente se desconoce la función específica de este nuevo tipo celular. Sin embargo, experimentos in vitro han demostrado que estas células presentan citotoxicidad frente a los grupos de células tumorales. Por otra parte, pruebas in vivo demuestran que las CDE Thy-1 ejercen una función derreguladora en las repuestas de hipersensibilidad por contacto. Además su ubicación en el epitelio y la expresión del receptor antigénico **, han permitido asociarlas a mecanismos de vigilancia inmunológica de la integridad cutánea a través del reconocimiento antigénico de proteínas de stress

Técnicas para la identificación y aislamiento de las células de Langerhans de la epidermis / Techniques for identification and isolation of Langerhans cells of the epidermis

Mediante técnicas de realización sencilla se pueden identificar las Células de Langerhans (CL), componentes importantes de la epidermis por su intervención en la respuesta inmune de la piel. Luego de separar la epidermis de la dermis se utiliza la coloración con ATP, mediante la cual se pueden observar las células de Langerhans en la epidermis "in toto", evaluar su número y morfología. Se ha observado que las CL aumentan su número, se presentan "activadas" desarrollando numerosos procesos dendríticos en diversas patologías humanas. Aislando células epidérmicas se puede lograr una población casi pura de CL, debido a que las mismas presentan en su superficie receptores para Fc. Roseteandolas, se las puede separar de los queratinocitos y utilizarlas en distintas experiencias "in vitro"

Técnicas para la identificación y aislamiento de las células de Langerhans de la epidermis / Techniques for identification and isolation of Langerhans cells of the epidermis

Mediante técnicas de realización sencilla se pueden identificar las Células de Langerhans (CL), componentes importantes de la epidermis por su intervención en la respuesta inmune de la piel. Luego de separar la epidermis de la dermis se utiliza la coloración con ATP, mediante la cual se pueden observar las células de Langerhans en la epidermis "in toto", evaluar su número y morfología. Se ha observado que las CL aumentan su número, se presentan "activadas" desarrollando numerosos procesos dendríticos en diversas patologías humanas. Aislando células epidérmicas se puede lograr una población casi pura de CL, debido a que las mismas presentan en su superficie receptores para Fc. Roseteandolas, se las puede separar de los queratinocitos y utilizarlas en distintas experiencias "in vitro" (AU)