Background: The bacterium Propionibacterium acnes is involved in the induction and maintenance of the inflammatory phase of acne. Recent studies have found that keratinocytes express toll-like receptors (TLRs) implica...Background: The bacterium Propionibacterium acnes is involved in the induction and maintenance of the inflammatory phase of acne. Recent studies have found that keratinocytes express toll-like receptors (TLRs) implicated in immediate immunity. No studies have, to date, been carried out on the action of P. acnes upon TLR activation in keratinocytes. Objectives: Focusing on the inflammatory phase of acne, to clarify the role of P. acnes in immediate immunity by inducing expression of TLR- 2 and TLR- 4 by keratinocytes. We also studied how the secretion and expression of matrix metalloproteinase (MMP)- 9 is induced by P. acnes. Methods: The work was carried out on two levels: in vivo with the study of the expression of TLR- 2 and TLR- 4 proteins in biopsies of acne lesions and in vitro on cultured keratinocyte monolayers to study the modulating effects of P. acnes on the expression of TLR- 2 and TLR- 4 and also on the expression and secretion of MMP- 9. Results: Our findings reveal that in vivo TLR- 2 and TLR- 4 expression is increased in the epidermis of acne lesions. In vitro, an increase in TLR- 2 and TLR- 4 expression by human keratinocytes occurred in the first hours of incubatio with bacterial fractions as well as an increase of the expression and secretion by the keratinocytes of MMP- 9, which plays a role in inflammation. Conclusions: This work demonstrates that P. acnes induces TLR expression and that this mechanism could play an essential role in acnelinked inflammation. These receptors could be involved notably in acute acne.展开更多
Patients exhibiting association between vitiligo and cutaneous T-cell lymphoma (CTCL) remain rare and it is not known whether some T-cell subpopulations of CTCL in the skin are able to recognize specific melanocytic e...Patients exhibiting association between vitiligo and cutaneous T-cell lymphoma (CTCL) remain rare and it is not known whether some T-cell subpopulations of CTCL in the skin are able to recognize specific melanocytic epitopes and thus induce vitiligo. The aim of our study was to determine whether T cells specific to melanocyte differentiation antigens were detectable among tumour-infiltrating lymphocytes (TIL) in the hypopigmented skin of a patient with Sé zary syndrome (SS). A 71-year-old patient presented with SS and developed vitiligo during the course of her disease. Immunohistochemical studies showed staining with HMB45 and MelanA antibodies in the pigmented skin biopsy, whereas no staining was observed in the hypopigmented skin biopsy. To analyse responses to melanocyte differentiation antigens, we used a transient COS transfection assay that permits an estimation of CD8 T-cell responses against a- large number of HLA/antigen combinations. This technique allowed the detection of melanocyte differentiation antigen-specific T lymphocytes, directed mainly against Melan-A/MART1 antigen in the HLA-A 23 context. Our study supports the concept that vitiligo that has developed during the evolution of a CTCL is related to the presence of a T-lymphocyte subpopulation reactive against melanocyte differentiation antigens (mainly Melan-A/MART1) present in skin lesions. The role of interferon in the induction of this T-lymphocyte subpopulation is discussed.展开更多
文摘Background: The bacterium Propionibacterium acnes is involved in the induction and maintenance of the inflammatory phase of acne. Recent studies have found that keratinocytes express toll-like receptors (TLRs) implicated in immediate immunity. No studies have, to date, been carried out on the action of P. acnes upon TLR activation in keratinocytes. Objectives: Focusing on the inflammatory phase of acne, to clarify the role of P. acnes in immediate immunity by inducing expression of TLR- 2 and TLR- 4 by keratinocytes. We also studied how the secretion and expression of matrix metalloproteinase (MMP)- 9 is induced by P. acnes. Methods: The work was carried out on two levels: in vivo with the study of the expression of TLR- 2 and TLR- 4 proteins in biopsies of acne lesions and in vitro on cultured keratinocyte monolayers to study the modulating effects of P. acnes on the expression of TLR- 2 and TLR- 4 and also on the expression and secretion of MMP- 9. Results: Our findings reveal that in vivo TLR- 2 and TLR- 4 expression is increased in the epidermis of acne lesions. In vitro, an increase in TLR- 2 and TLR- 4 expression by human keratinocytes occurred in the first hours of incubatio with bacterial fractions as well as an increase of the expression and secretion by the keratinocytes of MMP- 9, which plays a role in inflammation. Conclusions: This work demonstrates that P. acnes induces TLR expression and that this mechanism could play an essential role in acnelinked inflammation. These receptors could be involved notably in acute acne.
文摘Patients exhibiting association between vitiligo and cutaneous T-cell lymphoma (CTCL) remain rare and it is not known whether some T-cell subpopulations of CTCL in the skin are able to recognize specific melanocytic epitopes and thus induce vitiligo. The aim of our study was to determine whether T cells specific to melanocyte differentiation antigens were detectable among tumour-infiltrating lymphocytes (TIL) in the hypopigmented skin of a patient with Sé zary syndrome (SS). A 71-year-old patient presented with SS and developed vitiligo during the course of her disease. Immunohistochemical studies showed staining with HMB45 and MelanA antibodies in the pigmented skin biopsy, whereas no staining was observed in the hypopigmented skin biopsy. To analyse responses to melanocyte differentiation antigens, we used a transient COS transfection assay that permits an estimation of CD8 T-cell responses against a- large number of HLA/antigen combinations. This technique allowed the detection of melanocyte differentiation antigen-specific T lymphocytes, directed mainly against Melan-A/MART1 antigen in the HLA-A 23 context. Our study supports the concept that vitiligo that has developed during the evolution of a CTCL is related to the presence of a T-lymphocyte subpopulation reactive against melanocyte differentiation antigens (mainly Melan-A/MART1) present in skin lesions. The role of interferon in the induction of this T-lymphocyte subpopulation is discussed.
