C Ohrt

CHU de Lyon - Groupement Hospitalier Edouard Herriot, Lyons, Rhône-Alpes, France

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Publications (8)12.02 Total impact

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    ABSTRACT: The expression of blood-group antigens was studied on human epidermal cultures used as allografts in 13 non-immunosuppressed patients treated for leg ulcers. The study was carried out using monoclonal antibodies to A and B antigens by an indirect immunofluorescence technique. Blood-group antigens are weakly expressed on the suprabasal layers of the cultured epidermal sheets. After grafting, the donor's blood-group antigens were detected on a few cells of the suprabasal layers. Furthermore, scattered keratinocytes as well as acrosyringia were found to express the recipient's blood-group antigens.
    No preview · Article · Feb 1987 · Acta Dermato Venereologica
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    ABSTRACT: We have investigated on human skin the reactivity of a panel of 42 anti-thymus monoclonal antibodies (MCA) supplied by the Third International Workshop and Conference on Human Leucocyte Differentiation Antigens, Oxford, 1986. MCA of the first cluster of differentiation (CD1) define a group of surface molecules expressed by cortical thymocytes. Some of them (OKT6, M241 and Na1/34) have been shown to react in normal human skin with the epidermal Langerhans cells (LC). Twenty-two CD1 MCA were investigated in the present study. On normal human skin, 13 MCA reacted with LC in situ. This result suggests and confirms the heterogeneity of CD1 MCA. Recently, some of them were shown to recognize biochemically different molecules and/or epitopes of thymocytes. In addition, 20 anti-thymic epithelium MCA were tested on human skin. The MCA which only reacted with the thymic epithelial cell network (except Hassall's corpuscles) decorated only the epidermal basal cell layer. The MCA which reacted with all the thymic epithelial cells (including Hassall's corpuscles) decorated all the epidermal cell layers. These results confirm the heterogeneity of the thymic epithelial microenvironment and underline the antigenic similarities between the thymic epithelial structures and the different epidermal cell layers. The existence of bone-marrow-derived CD1-positive cells (thymocytes or LC) in an epithelial cell network (the thymus and the epidermis) focus the speculation around the immunological role of the epidermal basal cell layer in the T cell education and the exact lineage of the epidermal LC.
    No preview · Article · Feb 1987 · Dermatologica
  • [Show abstract] [Hide abstract]
    ABSTRACT: We have investigated on human skin the reactivity of a panel of 42 anti-thymus monoclonal antibodies (MCA) supplied by the Third International Workshop and Conference on Human Leucocyte Differentiation Antigens, Oxford, 1986. MCA of the first cluster of differentiation (CD1) define a group of surface molecules expressed by cortical thymocytes. Some of them (OKT6, M241 and Na1/34) have been shown to react in normal human skin with the epidermal Langerhans cells (LC). Twenty-two CD1 MCA were investigated in the present study. On normal human skin, 13 MCA reacted with LC in situ. This result suggests and confirms the heterogeneity of CD1 MCA. Recently, some of them were shown to recognize biochemically different molecules and/or epitopes of thymocytes. In addition, 20 anti-thymic epithelium MCA were tested on human skin. The MCA which only reacted with the thymic epithelial cell network (except Hassall’s corpuscles) decorated only the epidermal basal cell layer. The MCA which reacted with all the thymic epithelial cells (including Hassall’s corpuscles) decorated all the epidermal cell layers. These results confirm the heterogeneity of the thymic epithelial microenvironment and underline the antigenic similarities between the thymic epithelial structures and the different epidermal cell layers. The existence of bone-marrow-derived CD1-positive cells (thymocytes or LC) in an epithelial cell network (the thymus and the epidermis) focus the speculation around the immunological role of the epidermal basal cell layer in the T cell education and the exact lineage of the epidermal LC.
    No preview · Article · Jan 1987 · Dermatology
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    ABSTRACT: Yucatan mini-pig skin (Mexican hairless pig) is described as a good animal model for comparative investigations with human skin. We report the reactivity patterns of monoclonal antibodies (MCA) on both mini-pig and human skin. Of 21 MCA reacting with various human skin antigens, only six were negative with mini-pig skin.Using indirect immunofluorescence test, MCA specific for cytoplasmic or membrane antigens of human keratinocytes (glycoproteins, cytokeratins, desmosomes) gave the same reactivity patterns on mini-pig skin in the epidermis.In the dermis and at the dermal-epidermal junction, most MCA decorated the same structures on both substrates (laminin, oxytalan fibers, neurofilaments, fibroblasts). However, some of them did not stain the same cellular structures.As expected, MCA specific for HLA antigens did not show any reactivity with mini-pig skin.These MCA offer new tools for comparative investigations in various fields of experimental dermatology.
    No preview · Article · Mar 1986 · The Journal of Dermatology
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    ABSTRACT: One of the most important problems in the detection of human IgG deposits at the dermo–epidermal junction is non–specific dermo–papillary fluorescence. We describe an improved technique to decrease non–specific dermal fluorescence by using either a FITC–conjugated goat anti–human IgG–Fab or a FITC–conjugated goat anti–IgG (γ chain specific) absorbed onto normal goat serum in direct and indirect immunofluorescence tests. With this procedure, human skin was found to be a better substrate than rabbit lip for indirect immunofluorescence.
    No preview · Article · Aug 1985 · Clinical and Experimental Dermatology
  • H Barthélémy · C Ohrt · J Thivolet
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    ABSTRACT: We have studied 3 diseases: bullous pemphigoid (BP), cicatricial pemphigoid (CP) and herpes gestationis (HG). This work is at the same time prospective and retrospective. This study confirms that the most frequent pattern found in a BP is IgG + C3 in indirect immunofluorescence (IDIF), presence of circulating antibodies (AB) detected by direct fluorescence (DIF) and complement fixation (57%). In HG there is C3 in IDIF and absence of circulating AB. There is no difference in seropositivity between the only C3 type group in DIF, which is a confirmation that the BP of linear C3 type in DIF is authentic BP. HG factor is found at least as frequently in BP and in HG and consequently it is not specific to HG. This investigation allowed a decrease of the total number of seronegative patients.
    No preview · Article · Feb 1985 · Annales de Dermatologie et de Vénéréologie
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    ABSTRACT: The purpose of the present study was lo examine the phenotype of the cutaneous immunocompetent cells in lichen planus and chronic graft versus host (GVH) reaction infiltrates, by the use of monoclonal antibodies directed against T cell populations and Langerhans cells. Our results in lichen planus suggest an immunological reaction similar to the delayed hypersensitivity reaction, including all the immunocompetent cell sub-populations, with a first stage of antigenic information by Langerhans cells (OKT6 +, BL6 +, HLA-DR+) and helper cells, and a second stage mediated by suppressor/cytotoxic cells. The results from the study of GVH reaction also suggest an effect mediated by suppressor/cytotoxic cells (OKT3+, OKT4−, OK.T8+, HLA-DR+). Our results favour the existence of a lymphocytotoxic process in lichen planus and chronic GVH reaction.
    No preview · Article · Sep 1982 · Journal of Cutaneous Pathology
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    ABSTRACT: One hundred twenty skin biopsies from patients with different skin diseases were found to be positive for C3 cutaneous staining by immunofluorescence study. By the direct immunofluorescence method, we looked for C1q and C4 and immunoglobulin deposits in all those biopsies. C1q and/or C4 were only found in dermatoses with a recognised humoral immunologic mechanism; in some cases C1q and/or C4 deposits were found in the absence of immunoglobulins. The results showed that identification of C1q and C4 is important in routine immunopathologic studies, and provide interesting data of diagnostic value.
    No preview · Article · Jul 1982 · Journal of Cutaneous Pathology