[Show abstract][Hide abstract] ABSTRACT: Although the pathophysiology of chronic urticaria is not fully understood, it is possible that dysfunctioning of peripheral cutaneous nerve fibres may be involved. It has also been suggested that fibromyalgia syndrome, a multi-symptomatic chronic pain condition, may be associated with alterations and dysfunctioning of peripheral cutaneous nerve fibres. The aim of this study was to determine whether patients with chronic urticaria are also affected by fibromyalgia syndrome. A total of 126 patients with chronic urticaria were investigated for fibromyalgia syndrome. An unexpectedly high proportion (over 70%) had fibromyalgia syndrome. The corresponding proportion for 50 control dermatological patients was 16%, which is higher than previously published data for the Italian general population (2.2%). It is possible that dysfunctional cutaneous nerve fibres of patients with fibromyalgia syndrome may release neuropeptides, which, in turn, may induce dermal microvessel dilatation and plasma extravasation. Furthermore, some neuropeptides may favour mast cell degranulation, which stimulates nerve endings, thus providing positive feedback. Chronic urticaria may thus be viewed in many patients, as a consequence of fibromyalgia syndrome; in fact, skin neuropathy (fibromyalgia syndrome) may trigger neurogenic skin inflammation (chronic urticaria).
Preview · Article · Feb 2009 · Acta Dermato-Venereologica
[Show abstract][Hide abstract] ABSTRACT: Although dendritic cells (DC) are well known for their immunogenic capacities, they may even induce peripheral T-cell tolerance, and such a tolerogenic potential can be exerted in mouse through the expression on the DC plasma membrane of the CD95-ligand (CD95-L) molecule, which is able to trigger apoptosis of CD95-expressing antigen-specific T cells. We therefore asked whether epidermal DC, namely Langerhans' cells (LC), either resting (i.e. within the epidermis, 'in situ') or activated (i.e. suspended from the epidermis) or both, could express the CD95-L molecule on the plasma membrane. For such a purpose, two colloidal gold-immunoelectron microscopy (IEM) double-step procedures were carried out: an 'in situ' method, able to investigate resting LC, was performed on ultrathin frozen sections obtained by ultracryomicrotomy (UCMT) of normal skin biopsies; a pre-embedding (P-E) method, able to investigate suspended LC, was performed on epidermal cells (EC) suspended from normal skin specimens. In UCMT/IEM sections, resting LC showed gold particles within the cytoplasm but very rarely within organelles and never along the plasma membrane: resting LC are therefore capable of synthesizing CD95-L but not of expressing it in a functional location, thus autoreactive phenomena against CD95-expressing EC being avoided in normal epidermis. On the other hand, in P-E/IEM preparations, suspended LC showed several gold particles along the plasma membrane: activated LC are therefore capable of expressing CD95-L in a functional location, thus bearing the potential to exert tolerogenic capabilities against CD95-expressing T cells, e.g. to prevent inflammatory/autoimmune cutaneous disorders and/or favor the resolution thereof.
No preview · Article · Nov 2003 · Experimental Dermatology
[Show abstract][Hide abstract] ABSTRACT: Fas-L molecules expressed by in vitro stimulated T cells may be critically involved in suicidal activation-induced cell death (AICD) of such cells through engagement of their Fas receptors. A similar suicide of T cells was postulated to occur even in vivo, to eliminate dangerous activated lymphocytes; however, the demonstration of suicidal AICD of T cells in healthy humans in vivo is still lacking. We therefore investigated the possible occurrence of Fas-L-linked suicidal apoptosis of T cells in normal human peripheral blood. For this purpose, we took advantage of immunoelectron microscopy, which allows simultaneous visualization of the morphological apoptotic cellular changes together with surface expression of Fas-L molecules. Very few T lymphocytes were observed showing the ultrastructural features of apoptotic lymphocytes; these occasional apoptotic T cells, together with the majority of the normal T cell population, expressed the Fas molecule on the plasma membrane, as expected. Interestingly, the apoptotic cells were also Fas-L-positive, whereas normal T cells were Fas-L-negative. Such Fas-L-associated T cell suicide operating in vivo in healthy individuals is presumably able to suppress immune responses and prevent autoreactivity, thus maintaining the homeostasis of human blood.
Preview · Article · Mar 2001 · American Journal Of Pathology
[Show abstract][Hide abstract] ABSTRACT: Forty patients with rosacea were entered into a study comparing clarithromycin with doxycycline in the systemic treatment of mild and severe rosacea. The patients, 25 women and 15 men, aged from 26 to 62 years, were subdivided into two homogeneous groups with regard to age, sex, and disease severity. The first group of 23 patients, 14 women and 9 men, was treated with 250 mg of clarithromycin for 4 weeks twice daily, and then with 250 mg once daily for the following 4 weeks. The second group of 17 patients, 11 women and 6 men was treated with 100 mg of doxycycline for 4 weeks twice daily, and then with 100 mg once a day for the following 4 weeks. Both objective and subjective evaluations of the dermatosis were performed prior to therapy and after 4, 6, and 8 weeks of treatment. Forty patients with rosacea were entered into a study comparing clarithromycin with doxycycline in the systemic treatment of mild and severe rosacea. The patients, 25 women and 15 men, aged from 26 to 62 years, were subdivided into two homogeneous groups with regard to age, sex, and disease severity. The first group of 23 patients, 14 women and 9 men, was treated with 250 mg of clarithromycin for 4 weeks twice daily, and then with 250 mg once daily for the following 4 weeks. The second group of 17 patients, 11 women and 6 men was treated with 100 mg of doxycycline for 4 weeks twice daily, and then with 100 mg once a day for the following 4 weeks. Both objective and subjective evaluations of the dermatosis were performed prior to therapy and after 4, 6, and 8 weeks of treatment.
No preview · Article · Jan 1998 · International Journal of Dermatology
[Show abstract][Hide abstract] ABSTRACT: Thrombospondin (TSP) is an adhesive protein with multiple binding sites, which is able to mediate several cell-to-cell and cell-to-matrix interactions, particularly through its cell membrane receptor (TSP-R). Because human keratinocytes are able to synthesize and express TSP, and as TSP is also localized at the dermal-epidermal junction in normal human skin, we questioned whether epidermal cells are able to bind available TSP, that is, to express TSP-R. To investigate this, we employed gold immunoelectron microscopy on epidermal cells freshly isolated from normal human skin; the TSP-R was detected by OKM5 monoclonal antibody. Epidermal cells showing ultrastructural characteristics of melanocytes were gold-stained on their plasma membrane, whereas keratinocytes, Langerhans cells and lymphocytes were unstained. Although functional studies are clearly necessary to clarify the role(s) played by the TSP-R on the cell surface of melanocytes, it is tempting to speculate that the TSP-R may be important for melanocyte adhesion to the dermal-epidermal junction and to keratinocytes. Such adhesion may not only subserve the steric localization of melanocytes, but also have important implications for those functional activities of melanocytes which have been shown to require close contact between these cells and adjacent keratinocytes and/or basement membrane components.
No preview · Article · Sep 1993 · British Journal of Dermatology
[Show abstract][Hide abstract] ABSTRACT: In previous studies, IgE molecules were detected along the cell membrane of Langerhans cells (LC) in atopic dermatitis involved skin. However, the exact nature of the receptor still remains obscure. Moreover, large subsets of leukocytes have been recently shown to express the low affinity receptor for the Fc portion of IgE (Fc epsilon RII/CD23). Since LC are epidermal leukocytes the present study was intended in order to verify if LC of normal human subjects express the Fc epsilon RII/CD23. An anti-CD23 monoclonal antibody (MoAb) was used in a double step gold immunoelectron microscopical (IEM) procedure, carried out on Ficoll-Hypaque LC-enriched epidermal cell suspensions, freshly isolated from midly trypsinized normal human skin. Cells with LC features showed gold particles on their surface. Up to now LC from normal human epidermis, investigated using MoAb against human IgE, apparently were IgE-negative. Here we inequivocally demonstrate that the Fc epsilon RII/CD23 is constitutively expressed by normal human LC. It is well known that LC play an important role in antigen presentation. Further, it has been previously described the existence of a steric relationship between CD23 and HLA-DR molecules. Therefore, the present data add further strength to the hypothesis that FC epsilon RII/CD23 could participate to antigen presentation phenomena.
No preview · Article · Feb 1992 · Acta bio-medica: Atenei Parmensis
[Show abstract][Hide abstract] ABSTRACT: The intercellular adhesion molecule-1 (ICAM-1) is a cell membrane glycoprotein displaying a pivvtal role in cell-cell interactions in the immune system, and is a ligand for LFA-1, which is expressed on leukocytes. ICAM-1 is expressed in different cell types, including epithelial cells in a number of organs; the universal feature on all these cells is ICAM-1 induction from very low ICAM-1 constitutive levels on unstimulated resting cells to very high ICAM-1 levels triggered by mediators released at sites of inflammation. Therefore, since a strong expression of ICAM-1 on keratinocyte (KC) surface was recently demonstrated in various inflammatory skin lesions, in this investigation we asked whether very low ICAM-1 levels might be present on the plasma membrane of unstimulated KC in normal skin. Crude epidermal cell suspensions, freshly isolated from normal human skin, were immunolabeled by anti-ICAM-1 monoclonal antibody and stained by two highly sensitive ultrastructural detection systems, namely, the immunogold (5-nm-sized particles) method and the immunogold-silver-enhancement method. The quantitative analysis of 1000 KC scrutinized under the electron microscope revealed that 17.2% KC were ICAM-1-positive, although a density per KC section (midplane) of merely 18.92 +/- 13.02 5 nm-sized particles was scored (n = 100), indicating that the amounts of ICAM-1 moieties on this KC subset are presumably low. The ICAM-1 expression on a subset of KC in normal skin might account for the trafficking to and from normal epidermis of LFA-1-positive cells, including migrating Langerhans cells and occasional leukocytes.
No preview · Article · Jan 1992 · Regional immunology
[Show abstract][Hide abstract] ABSTRACT: Large subsets of leucocytes were recently shown to express the low affinity receptor for the Fc portion of IgE. Because Langerhans cells (LC) are epidermal leucocytes, we investigated whether LC of normal human subjects might express this receptor. Whereas conventional immunofluorescence on epidermal sheets gave negative results, highly sensitive immunoelectron microscopy revealed that a subset (about one-third) of freshly isolated LC express the CD23 molecule.
No preview · Article · Jul 1991 · British Journal of Dermatology
[Show abstract][Hide abstract] ABSTRACT: It is now becoming clear that a collection of adhesion molecules is required on the surface of epidermal cells (EC) to establish the cell interactions that are necessary for skin immunologic reactions. In previous studies, we showed that human resting Langerhans cells (LC) express at least two members of the "integrins" family of adhesive molecules, as well as the intercellular adhesion molecule-1, which is a member of the immunoglobulin-related superfamily of molecules. This latter family includes another adhesive moiety, namely, the lymphocyte function-associated antigen-3 (LFA-3), which is the ligand for the T-lymphocyte-associated CD2 molecule, and has a broad tissue and organ distribution. In the present investigation the colloidal gold-immunoelectronmicroscopy immunostaining system and a quantitative analysis of the labeling provided decisive evidence for the weak but clear LFA-3 expression on virtually all keratinocytes (KC) and LC freshly isolated from normal human skin. Such constitutive expression of LFA-3 molecule on EC may be relevant for a number of functional interactions between LFA-3-positive EC and CD2-positive T lymphocytes within the cutaneous environment.
Preview · Article · May 1991 · Journal of Investigative Dermatology
[Show abstract][Hide abstract] ABSTRACT: The potential of an immunogold-silver staining for the study of human suspended Langerhans cells at the transmission electron microscopic level was evaluated. Cells were labeled, by using a preembedding technique, with 5-nm colloidal gold particles followed by silver enhancement. The use of small colloidal gold particles permits a detection of small quantities of antigen; the metallic silver deposition around gold granules gives rise to a large electron-dense marker which can be easily detected even at low magnification. Ultrastructural details were well preserved, and the background was not significant. The major advantage of the present immunogold-silver staining is that it enables to detect labeled cells easily, even when limited amounts of antigenic moieties are present on a low percentage of cells. Therefore, a rapid and simultaneous evaluation of both immunophenotype and ultrastructural details of investigated cells is allowed.
[Show abstract][Hide abstract] ABSTRACT: The present study demonstrates that a consistent percentage (over 30%) of freshly isolated human Langerhans cells express the CD23 moiety. This was achieved employing a pre-embedding immunoelectronmicroscopy, using the peroxidase reaction product as a marker, assay on suspended trypsinized epidermal cells isolated from normal human skin. The possibility that the CD23 molecule on the surface of Langerhans cells could play a role in the antigen-presentation function of dendritic epidermal cells to T lymphocytes is proposed.
No preview · Article · Oct 1990 · Archivio italiano di anatomia e di embriologia. Italian journal of anatomy and embryology
[Show abstract][Hide abstract] ABSTRACT: We examined morphometric as well as functional characteristics of CD16-positive human peripheral blood lymphocytes on the basis of the coexpression of the CD2 antigen. For morphometric analyses, nuclear area and cellular area were determined by counting line cross-points of a superimposed quadratic lattice test system overlying nuclei and the whole cell, respectively. Moreover, to evaluate the cellular villousity degree, the maximum inscrible circle and an irregular polygon were inscribed within cell profiles. The cytoplasm fraction included between the plasmalemma and the traced irregular polygon was considered as the villous portion of the cell. Finally, the NK capability was measured in a 6-hr 51Cr-release assay with human K-562 myeloid cells as targets. Within the CD16-positive cell population, the CD16-positive/CD2-negative cells seem to represent the most efficient NK cell subset. To the higher NK capability correspond a higher villousity degree and a lower nuclear area/cellular area ratio of the CD2-negative/CD16-positive subset, when compared with CD2-positive/CD16-positive cells.
No preview · Article · Jul 1990 · Cellular Immunology