Identification of granzyme B-expressing CD-8-positive T cells in lymphocytic inflammatory infiltrate in cutaneous lupus erythematosus and in dermatomyositis.

BACKGROUND: Lupus erythematosus (LE) and dermatomyositis (DM) are interface dermatitis, histologically characterized by formation of colloid bodies and a CD4+ CD8+ lymphocyte infiltrate. Colloid bodies are examples of intraepidermal apoptosis. Granzyme (Gr)B, synthesized by activated cytotoxic lymphocytes, is a serine protease able to prime apoptosis. GrB+ lymphocytes have been previously found in infiltrates in skin lesions from other types of interface dermatitis. AIM: To evaluate, on histological skin specimens from patients with LE and DM, GrB expression as a mediator of keratinocyte apoptosis in lymphocyte infiltrate. METHODS: In total, 22 patients with cutaneous LE [9 with discoid lupus erythematosus (DLE), 9 with subacute lupus erythematosus (SCLE) and 4 with systemic lupus erythematosus (SLE)] and 20 patients with DM were studied. Skin specimens underwent immunohistochemical staining with antibodies to CD3, CD4, CD8 and GrB. RESULTS: Immunohistochemical study with GrB was positive in 17 of the 22 patients with LE but only 2 of the 20 patients with DM. In LE, in systemic and subacute forms of LE, the median obtained was < 10 (+) whereas in the chronic forms, the median was 10-50% (++). Patients with DM were negative for GrB. CONCLUSIONS: In LE, a correlation between GrB+ lymphocyte and the presence of DLE form was found, but in DM, GrB is poorly expressed. GrB labels a subpopulation of effector cells involved in ongoing cytotoxic action and should be considered as a specific marker showing the extent of the direct local cytotoxic damage. GrB could play a role in the induction of skin apoptosis mechanisms in LE.

A tridimensional view of the organization of actin filaments in the central nervous system by use of fluorescent photooxidation

Cellular and subcellular organization and distribution of actin filaments have been studied with various techniques. The use of fluorescence photo-oxidation combined with phalloidin conjugates with eosin has allowed the examination of the precise cellular and subcellular location of F-actin. Correlative fluorescence light microscopy and transmission electron microscopy studies of F-actin distribution are facilitated with this method for morphological and physiological studies. Because phalloidin-eosin is smaller than other markers, this method allows the analysis of the three-dimensional location of F-actin with high-resolution light microscopy, three-d serial sections reconstructions, and electron tomography. The combination of selective staining and three-dimensional reconstructions provide a valuable tool for revealing aspects of the synaptic morphology that are not available when conventional electron microscopy is used. By applying this selective staining technique and three-dimensional imaging, we uncovered the structural organization of actin in the postsynaptic densities in physiological and pathological conditions.

A tridimensional view of the organization of actin filaments in the central nervous system by use of fluorescent photooxidation

Cellular and subcellular organization and distribution of actin filaments have been studied with various techniques. The use of fluorescence photo-oxidation combined with phalloidin conjugates with eosin has allowed the examination of the precise cellular and subcellular location of F-actin. Correlative fluorescence light microscopy and transmission electron microscopy studies of F-actin distribution are facilitated with this method for morphological and physiological studies. Because phalloidin-eosin is smaller than other markers, this method allows the analysis of the three-dimensional location of F-actin with high-resolution light microscopy, three-d serial sections reconstructions, and electron tomography. The combination of selective staining and three-dimensional reconstructions provide a valuable tool for revealing aspects of the synaptic morphology that are not available when conventional electron microscopy is used. By applying this selective staining technique and three-dimensional imaging, we uncovered the structural organization of actin in the postsynaptic densities in physiological and pathological conditions.(AU)