Le Demodex, petit acarien vivant dans les follicules pilo-sébacés de tous les humains adultes, est reconnu responsable des démodécies chez l’homme mais n’est considéré dans la rosacée, au plus, que comme un facteur aggravant potentiel d’une inflammation préexistante. Toutes nos observations, depuis 1983, convergent vers la confirmation de son rôle pathogène dans la rosacée, et suggèrent des liens physiopathologiques clairs entre rosacées avec papulopustules (RPP) avec ou sans érythème permanent, rosacée érythématotélangiectasique (RET), pityriasis folliculorum et autres démodécies. (1) Dans les biopsies cutanées, le Demodex est associé à l’inflammation périfolliculaire. (2) Le concept de densité en Demodex a été introduit et une méthode de prélèvement standardisée permettant de mesurer cette densité a été développée, puis perfectionnée. (3) Elle a permis de montrer que cette densité était nettement supérieure chez les patients atteints de démodécie et de RPP, que chez ceux avec peau saine et ceux atteints d’autres dermatoses faciales, les patients avec RPP sans prolifération en Demodex étant exceptionnels. (4) Un test diagnostique hautement spécifique et sensible, utilisable facilement en consultation a été élaboré et validé. (5) Des signes cliniques discrets de ces dermatoses ont été mis en évidence, de même que la grande fréquence des démodécies en consultation de dermatologie (alors qu’elles sont très peu diagnostiquées). (6) L’effet acaricide sur le Demodex de six traitements topiques a été comparé in vivo et les meilleures molécules ont été utilisées pendant une vingtaine d’années :sur base des résultats collectés, l’efficacité du traitement a été démontrée, non seulement sur la densité en Demodex mais également sur les symptômes cliniques, tant parmi les démodécies que dans la RPP, ce qui prouve indirectement que la prolifération en parasites n’est pas un épiphénomène mais est bien la cause de la maladie. (7) Parmi les modalités comparées, les plus intenses ont une efficacité plus rapide et une meilleure compliance. (8) La RET peut correspondre à une démodécie subclinique et est probablement un facteur favorisant la prolifération des parasites, tout comme le sont probablement l’hyperplasie sébacée et l’hypothyroïdie, tandis que la cortisone semble limiter leur prolifération quand celle-ci est excessive. (9) Les similarités et les confusions nosologiques entre les démodécies et les différentes formes de rosacée ont été mises en évidence, afin de montrer que ces dermatoses ne sont vraisemblablement que des phénotypes d’une seule et même maladie :ce sont toutes des démodécies. (10) Trois systèmes d’attribution d’une cause à une maladie convergent pour confirmer le rôle pathogène du Demodex dans la RPP. Nos observations doivent être confirmées par des études longitudinales et des études contrôlées, mais d’ores et déjà, ajoutées aux données actuelles de la littérature, elles nous semblent suffisantes pour reconnaître le rôle pathogène du parasite en médecine humaine et dans la rosacée en particulier. Cette reconnaissance donnerait une définition principalement étiologique à la rosacée, la classerait parmi les démodécies, et en faciliterait la prise en charge et le traitement. Nous proposons une hypothèse physiopathologique originale où le Demodex se trouve au centre d’un réseau causal « en toile d’araignée », la RPP étant considérée comme une infection chronique s’accompagnant d’épuisement lymphocytaire. / Demodex folliculorum and Demodex brevis are small mites living in the pilosebaceous follicles of all adult humans. They are known to be responsible for demodicosis in humans but in rosacea are generally considered only as a potential aggravating factor of pre-existing inflammation. However, our observations since 1983 converge towards a pathogenic role of the Demodex mite in rosacea, and suggest clear pathophysiological links between rosacea with papulopustules (PPR) with or without persistent erythema, erythematotelangiectatic rosacea (ETR), pityriasis folliculorum and other demodicoses. Summarising our findings: (1) In skin biopsies, Demodex is statistically associated with perifollicular inflammation. (2) The concept of Demodex density was introduced and a method to measure it using two consecutive standardized skin surface biopsies was developed and refined. (3) It was shown that Demodex density was significantly higher in patients with demodicosis and PPR than in those with healthy skin and with other facial dermatoses; patients with PPR without Demodex proliferation detected are rare, and the few cases that do occur likely correspond to false negative results linked to proliferation of the mites deep in the pilosebaceous follicles, thus not detected by the sampling method. (4) A highly specific and sensitive diagnostic test based on the results from two consecutive standardized skin surface biopsies was developed and validated and can be easily used during clinical consultation. (5) Less well-known clinical signs of these dermatoses were highlighted, as well as the high frequency of demodicoses in dermatologic consultations (although they are under-diagnosed). (6) The acaricidal effect of six topical treatments on Demodex was compared in vivo and the best molecules were used for about 20 years in our practice. From data collected from our patients during this time period, the efficacy of the treatment was demonstrated, not only on Demodex density but also on clinical symptoms, both in demodicosis and in PPR, indirectly showing that parasite proliferation is not an epiphenomenon, but is the cause of the disease. (7) Of the treatment modalities compared, those that were more intense worked more rapidly and had better compliance. (8) ETR may correspond to subclinical demodicosis and is probably a condition that favours parasite proliferation, as are sebaceous hyperplasia and hypothyroidism; cortisone seems initially to favour mite proliferation, but to limit it when Demodex density is very high. (9) The similarities and nosological confusion between demodicosis and the different forms of rosacea were highlighted, showing that these dermatoses are probably phenotypes of one and the same disease: they are all demodicoses. (10) Three systems used to attribute disease causality converge to confirm the pathogenic role of Demodex in PPR. Our observations need to be confirmed by longitudinal and controlled studies, but, combined with current data in the literature, they seem sufficient to recognise the pathogenic role of the parasite in human disease and in rosacea in particular. This recognition would enable a mainly aetiological definition to be given to rosacea, would classify it among the demodicoses, and would facilitate its management and treatment. We propose an original pathophysiological hypothesis in which Demodex is at the centre of a causal network, with PPR being considered a chronic infection accompanied by lymphocyte exhaustion. / Doctorat en Sciences médicales (Médecine) / info:eu-repo/semantics/nonPublished

Demodex est un genre d’acariens dont deux espèces sont connues pour coloniser la peau de l’homme : Demodex folliculorum et Demodex brevis. Leur implication dans le développement de la rosacée reste controversée. Cette maladie est caractérisée par une inflammation chronique de la peau et est définie en quatre sous-type majeurs : la rosacée érythémato-télangiectasique (ETR), la rosacée papulopustuleuse (PPR), la rosacée phymateuse et la rosacée oculaire. Certains pensent que le rôle des acariens est principalement d’exacerber une inflammation déjà enclenchée. Toutefois, l’isolation par culture d’un Bacillus oleronius à partir du broyat d’un Demodex de patient atteint de rosacée papulopustuleuse ont remis sur le devant de la scène le rôle de l’acarien en tant que vecteur de bactéries pathogènes. Le but de notre étude était de décrire le microbiote associé au Demodex par clonage du gène de l’ARN ribosomal 16S afin d’identifier par la suite d’éventuelles différences en fonction du statut de l’hôte (ETR, PPR ou sain). Le microbiote décrit présentait une diversité jusqu’alors insoupçonnée. Une partie des espèces identifiées n’avaient jamais été rapportées chez l’homme, pouvant donc correspondre au microbiote spécifique de l’acarien. Il serait composé comme d’une majorité de Protéobactéries. De manière intéressante, les proportions des phyla majeurs étaient différentes en fonction du groupe étudié. De plus, il semblerait que certaines espèces soient spécifiques des Demodex collectés chez des patients atteints de rosacée. Par exemple, Bartonella quintana n’a été détectée qu’à partir de Demodex d’une patiente atteinte de rosacée érythémato-télangiectasique. / Demodex is a genus of mites comprising two species known to colonize human skin: Demodex folliculorum and Demodex brevis. Their role in the pathogenesis of rosacea remains controversial. Rosacea is defined by a chronic inflammation of the skin and four main subtypes are defined : erythematotelangiectasic rosacea (ETR), papulopustular rosacea (PPR), phymatous rosacea and ocular rosacea. Mites are thought to be only involved in the exacerbation of a pre-existing inflammation. The growth of Bacillus oleronius from a crushed Demodex mite collected on a PPR patient gave rise to a new hypothesis that the mite is actually the vector of pathogenic bacteria. Present study aimed at describing the microbiote associated with Demodex mites by a 16S rRNA clone library approach. This allowed us to compare the obtained bacterial communities according to the group of patients the mites were collected from (erythematotelangiectasic rosacea, papulopustular rosacea or healthy subjects). The microbiota described here revealed an unexpected diversity. Part of the identified species had never been reported on human beings and could thus represent the microbiota specific to Demodex. As in many arthropods, this microbiota was predominantly composed of Proteobacteria. Interestingly, the proportion of the main phyla Proteobacteria, Firmicutes and Actinobacteria differed according to the host status. Though, some species appeared to be specific to Demodex collected from patients with erythematotelangiectasic rosacea or papulopustular rosacea. Among them, we identified Bartonella quintana only from a mite collected on a patient with erythematotelangiectasic rosacea.

Introdução: Rosácea é uma doença inflamatória cutânea crônica relativamente comum, com incidência que varia de 2 a 10%. Caracteriza-se pelo surgimento de pápulas e pápulo-pustulas, eritema e telangiectasias precedidas por episódios de flushing. Apesar de não ser doença que comprometa o estado geral dos doentes, por ter acometimento preferencial da face, representa problema estético acentuado que interfere na socialização e qualidade de vida dos doentes. A etiologia da rosácea permanece incerta. A participação da imunidade inata tem sido implicada recentemente. Objetivo: Este estudo avaliou o envolvimento da imunidade inata na patogenia da rosácea através de pesquisa de células de Langerhans, células plasmocitóides (PDC), receptores \"toll-like\" (TLR) e expressão da forma induzida da enzima óxido nítrico sintase (iNOS) em biopsias de pele de pacientes com diagnóstico de rosácea. Métodos: Biopsias de 28 pacientes com diagnóstico clínico e histopatológico de Rosácea foram classificadas de acordo com características histopatológicas em Rosácea Granulomatosa (RG) (n = 10) e Rosácea Não Granulomatosa (RNG) (n = 18), e submetidas à técnica imunoistoquímica para demonstração de células de Langerhans (anticorpo anti-CD1a) (n = 26), PCD (anticorpo anti- CD123) (n = 24) e expressão dos receptores toll-like 2 e 4, bem como da forma induzida da óxido nítrico sintase (iNOS) (n = 28). Todos foram comparados com controles de pele normal (n = 15). Resultados: A população de células de Langerhans epidérmicas foi menor no grupo rosácea. Foram encontradas PDC dérmicas isoladas ou agrupadas no grupo rosácea, representando um novo dado no estudo da sua etiopatogenia. A expressão de TLR 2, TLR 4 e iNOS foi maior no grupo rosácea do que no grupo controle, estando distribuída com forte predominância na epiderme e anexos. Não houve diferença dos achados entre os grupos RG e RNG. Conclusão: Demonstrou-se, pela primeira vez, a presença de PDC nas lesões de rosácea. Juntamente com os outros marcadores estudados, os resultados apresentados confirmam a participação da imunidade inata na patogênese da rosácea através de mecanismos interdependentes e associados / Introduction: Rosacea is a common, chronic inflammatory condition with a reported prevalence between 2 and 10%. The disease has a variety of clinical manifestations that include flushing, persistent erythema, papules, pustules and telangiectasia. Because the facial skin is the predominant site of involvement, many patients sense that rosacea alters their social interactions affecting quality of life. The etiology of rosacea remains unknown. Recent studies have suggested that aberrant innate immunity is central to this disease. Objective: The aim of the present study was to examine the presence of Langerhans cells, plasmacytoid dentritic cells (PDC), and the expression of toll-like receptors (TLR) and inducible oxide nitric synthase (iNOS) in skin of patients with rosacea, in order to highlight the participation of innate immunity in the pathogenesis of this disease. Methods: 28 biopsy specimens were taken from patients with clinical and histopathological findings of rosacea. The samples were classified as Granulomatous rosacea (GR) (n= 10) or Non-Granulomatous rosacea (NGR) (n =18) according to histopathological features. Immunohistochemical demonstration of Langerhans cells (anti-CD1a antibody) (n = 24), PDC (anti-CD 123 antibody) (n = 26), TLR 2, TLR 4 and iNOS (n = 28) was performed in skin samples. The results were compared to normal skin control group (n = 15). Results: The number of Langerhans cells was lower in rosacea group than in control group. PDC were found in skin samples of rosacea as isolated cells and forming small clusters which represents a new contribution to the researches of its etiology. Expression of TLR2, TLR4 and iNOS was higher in rosacea samples than in normal skin controls, predominatly located in epidermal and adnexal structures. The comparison between GR and NGR groups did not show significant statistical difference. Conclusion: This research demonstrates, for the first time, the presence of PDC in lesions of rosacea, which together with the other results of this study, ratifies the existence of an altered innate immunity in pathogenesis of rosacea

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 5 uppsatser.

Introdução: Rosácea é uma doença inflamatória cutânea crônica relativamente comum, com incidência que varia de 2 a 10%. Caracteriza-se pelo surgimento de pápulas e pápulo-pustulas, eritema e telangiectasias precedidas por episódios de flushing. Apesar de não ser doença que comprometa o estado geral dos doentes, por ter acometimento preferencial da face, representa problema estético acentuado que interfere na socialização e qualidade de vida dos doentes. A etiologia da rosácea permanece incerta. A participação da imunidade inata tem sido implicada recentemente. Objetivo: Este estudo avaliou o envolvimento da imunidade inata na patogenia da rosácea através de pesquisa de células de Langerhans, células plasmocitóides (PDC), receptores \"toll-like\" (TLR) e expressão da forma induzida da enzima óxido nítrico sintase (iNOS) em biopsias de pele de pacientes com diagnóstico de rosácea. Métodos: Biopsias de 28 pacientes com diagnóstico clínico e histopatológico de Rosácea foram classificadas de acordo com características histopatológicas em Rosácea Granulomatosa (RG) (n = 10) e Rosácea Não Granulomatosa (RNG) (n = 18), e submetidas à técnica imunoistoquímica para demonstração de células de Langerhans (anticorpo anti-CD1a) (n = 26), PCD (anticorpo anti- CD123) (n = 24) e expressão dos receptores toll-like 2 e 4, bem como da forma induzida da óxido nítrico sintase (iNOS) (n = 28). Todos foram comparados com controles de pele normal (n = 15). Resultados: A população de células de Langerhans epidérmicas foi menor no grupo rosácea. Foram encontradas PDC dérmicas isoladas ou agrupadas no grupo rosácea, representando um novo dado no estudo da sua etiopatogenia. A expressão de TLR 2, TLR 4 e iNOS foi maior no grupo rosácea do que no grupo controle, estando distribuída com forte predominância na epiderme e anexos. Não houve diferença dos achados entre os grupos RG e RNG. Conclusão: Demonstrou-se, pela primeira vez, a presença de PDC nas lesões de rosácea. Juntamente com os outros marcadores estudados, os resultados apresentados confirmam a participação da imunidade inata na patogênese da rosácea através de mecanismos interdependentes e associados / Introduction: Rosacea is a common, chronic inflammatory condition with a reported prevalence between 2 and 10%. The disease has a variety of clinical manifestations that include flushing, persistent erythema, papules, pustules and telangiectasia. Because the facial skin is the predominant site of involvement, many patients sense that rosacea alters their social interactions affecting quality of life. The etiology of rosacea remains unknown. Recent studies have suggested that aberrant innate immunity is central to this disease. Objective: The aim of the present study was to examine the presence of Langerhans cells, plasmacytoid dentritic cells (PDC), and the expression of toll-like receptors (TLR) and inducible oxide nitric synthase (iNOS) in skin of patients with rosacea, in order to highlight the participation of innate immunity in the pathogenesis of this disease. Methods: 28 biopsy specimens were taken from patients with clinical and histopathological findings of rosacea. The samples were classified as Granulomatous rosacea (GR) (n= 10) or Non-Granulomatous rosacea (NGR) (n =18) according to histopathological features. Immunohistochemical demonstration of Langerhans cells (anti-CD1a antibody) (n = 24), PDC (anti-CD 123 antibody) (n = 26), TLR 2, TLR 4 and iNOS (n = 28) was performed in skin samples. The results were compared to normal skin control group (n = 15). Results: The number of Langerhans cells was lower in rosacea group than in control group. PDC were found in skin samples of rosacea as isolated cells and forming small clusters which represents a new contribution to the researches of its etiology. Expression of TLR2, TLR4 and iNOS was higher in rosacea samples than in normal skin controls, predominatly located in epidermal and adnexal structures. The comparison between GR and NGR groups did not show significant statistical difference. Conclusion: This research demonstrates, for the first time, the presence of PDC in lesions of rosacea, which together with the other results of this study, ratifies the existence of an altered innate immunity in pathogenesis of rosacea

Tetínské skály Nature Reserve is one of the major sites for the presence of protected species, which are Dianthus gratianopolitanus, Saxifraga rosacea subsp. Sponhemica and Saxifraga paniculata. My goal was a field survey and data collection about the incidence of these species on the surfaces of rock walls, followed by identification of key environmental factors and description of their impact on the species. Such survey has not been conduncted so far. I used mainly multivariate analysis, PCA and RDA and One-way ANOVA to determine the interrelationships. The analysis results showed significant differences in species abundances influenced by different combinations of environmental factors. The factors with significant influence include cardinal direction. The highest proportion of species abundances showed areas of eastern orientation. Another important factor was shading from vegetation, which proved to have strong negative impact on abundace, especially for species S.rosacea subsp. sponhemica and D. gratianopolitanus. These two variables indicate a preference for sunny areas. Other factors with a significant influence on the occurrence of species are also a presence of soil surface rock wall and a presence of gardens in the area over the rock wall, which greatly increased the proportion of...