Gudrun Ratzinger

Matrix Metalloproteinases 9 and 2 Are Necessary for the Migration of Langerhans Cells and Dermal Dendritic Cells from Human and Murine Skin

Dendritic cells migrate from the skin to the draining lymph nodes. They transport immunogenic MHC-peptide complexes, present them to Ag-specific T cells in the T areas, and thus generate immunity. Migrating dendritic cells encounter physical obstacles, such as basement membranes and collagen meshwork. Prior work has revealed that matrix metalloproteinase-9 (MMP-9) contributes to mouse Langerhans cell migration. In this study, we use mouse and human skin explant culture models to further study the role of MMPs in the migration and maturation of skin dendritic cells. We found that MMP-2 and MMP-9 are expressed on the surface of dendritic cells from the skin, but not from other sources. They are also expressed in migrating Langerhans cells in situ. The migration of both Langerhans cells and dermal dendritic cells is inhibited by a broad spectrum inhibitor of MMPs (BB-3103), by Abs to MMP-9 and -2, and by the natural tissue inhibitors of metalloproteinases (TIMP), TIMP-1 and TIMP-2. Inhibition by anti-MMP-2 and TIMP-2 define a functional role for MMP-2 in addition to the previously described function of MMP-9. The importance of MMP-9 was emphasized using MMP-9-deficient mice in which Langerhans cell migration from skin explants was strikingly reduced. However, MMP-9 was only required for Langerhans cell migration and not maturation, since nonmigrating Langerhans cells isolated from the epidermis matured normally with regard to morphology, phenotype, and T cell stimulatory function. These data underscore the importance of MMPs, and they may be of relevance for therapeutically regulating dendritic cell migration in clinical vaccination approaches.

Production of IL-12 by Human Monocyte-Derived Dendritic Cells Is Optimal When the Stimulus Is Given at the Onset of Maturation, and Is Further Enhanced by IL-4

Dendritic cells produce IL-12 both in response to microbial stimuli and to T cells, and can thus skew T cell reactivity toward a Th1 pattern. We investigated the capacity of dendritic cells to elaborate IL-12 with special regard to their state of maturation, different maturation stimuli, and its regulation by Th1/Th2-influencing cytokines. Monocyte-derived dendritic cells were generated with GM-CSF and IL-4 for 7 days, followed by another 3 days ± monocyte-conditioned media, yielding mature (CD83+/dendritic cell-lysosome-associated membrane glycoprotein+) and immature (CD83−/dendritic cell-lysosome-associated membrane glycoprotein−) dendritic cells. These dendritic cells were stimulated for another 48 h, and IL-12 p70 was measured by ELISA. We found the following: 1) Immature dendritic cells stimulated with CD154/CD40 ligand or bacteria (both of which concurrently also induced maturation) secreted always more IL-12 than already mature dendritic cells. Mature CD154-stimulated dendritic cells still made significant levels (up to 4 ng/ml). 2) Terminally mature skin-derived dendritic cells did not make any IL-12 in response to these stimuli. 3) Appropriate maturation stimuli are required for IL-12 production: CD40 ligation and bacteria are sufficient; monocyte-conditioned media are not. 4) Unexpectedly, IL-4 markedly increased the amount of IL-12 produced by both immature and mature dendritic cells, when present during stimulation. 5) IL-10 inhibited the production of IL-12. Our results, employing a cell culture system that is now being widely used in immunotherapy, extend prior data that IL-12 is produced most abundantly by dendritic cells that are beginning to respond to maturation stimuli. Surprisingly, IL-12 is only elicited by select maturation stimuli, but can be markedly enhanced by the addition of the Th2 cytokine, IL-4.

Acute febrile neutrophilic dermatosis: a histopathologic study of 31 cases with review of literature.

Sweet syndrome is a neutrophilic dermatosis defined by diagnostic criteria that include the lack of evidence for leukocytoclastic vasculitis. Because of the clinicopathological similarities on the one hand and the strict exclusion on the other hand, we were interested in a systematic evaluation of the relationship between these two diseases. We investigated the clinical and histopathological characteristics of 31 patients with Sweet syndrome, comparing our cases with 32 cases of leukocytoclastic vasculitis (including seven cases of urticarial vasculitis) and tried to place them in the background of published cases. There is a close relationship between Sweet syndrome and leukocytoclastic vasculitis in terms of clinical appearance, histopathological pattern, triggers, disease course, and response to treatment. The majority of the cases (23/31; 74%) showed histologic evidence of vasculitis, including nuclear dust, extravasation of erythrocytes, fibrin in and around vessel walls, and degeneration of collagen. Although one original criterion for Sweet syndrome is the absence of vasculitis, we propose that vasculitic changes should not exclude the diagnosis of Sweet syndrome. In contrast, Sweet syndrome can demonstrate vasculitis and may, similarly to urticarial vasculitis, be regarded a variant of leukocytoclastic vasculitis. Clinicopathologic characteristics with acute onset of juicy papules, plaques mostly on the face, shoulder, and trunk, and prominent edema probably reflect modifications of the pathogenetic process based on location and disease acuity.

Wells syndrome and its relationship to Churg-Strauss syndrome.

Background  Wells syndrome has been described as an inflammatory disorder based on typical clinical appearance combined with the histopathological presence of eosinophilic infiltrates and flame figures in the absence of vasculitis. Churg–Strauss syndrome, on the other hand, is primarily a diffuse, necrotizing vasculitis but is also typically displaying eosinophils and flame figures. Despite several parallels, the present understanding of these two diseases excludes any pathogenetic relationship.

Conditioning of the Injection Site With Cpg Enhances the Migration of Adoptively Transferred Dendritic Cells and Endogenous Cd8+ T-cell Responses

The efficiency of immunotherapy using tumor–antigen-loaded dendritic cells (DCs) is severely limited by the impaired migration of injected cells from the application site to the draining lymph nodes. As described earlier, pretreatment of the injection site with inflammatory cytokines enhances DC migration. We wanted to test whether toll-like receptor (TLR) ligands can improve migration of murine bone marrow-derived DC (BMDC) and the subsequent T-cell responses. For this purpose, we established an experimental setup closely resembling human vaccination protocols that served to investigate DC migration from the skin to the draining lymph nodes. We observed that BMDC, matured with a cytokine cocktail (tumor necrosis factor-α, interleukin-β, interleukin-6, prostaglandin E2), strongly expressed CCR7. The migration efficiency of adoptively transferred mature BMDCs was determined by the number of cells injected and the application site. We decided to inject DC intradermally into the ear skin and investigated the effects of pretreatment of the injection site with various TLR ligands. Conditioning of the skin site with the TLR ligands CpG and Peptidoglycan increased the number of DCs arriving in the lymph node. Mechanical stress applied to the skin, such as tape stripping of the skin was equally effective. Importantly, only pretreatment with CpG enhanced responses of endogenous CD8+ T cells. Thus, conditioning of the injection site with the TLR ligand CpG could be a new promising way to improve the outcome of DC immunotherapy.

Vasculitic wheel - an algorithmic approach to cutaneous vasculitides.

Previous classifications of vasculitides suffer from several defects. First, classifications may follow different principles including clinicopathologic findings, etiology, pathogenesis, prognosis, or therapeutic options. Second, authors fail to distinguish between vasculitis and coagulopathy. Third, vasculitides are systemic diseases. Organ‐specific variations make morphologic findings difficult to compare. Fourth, subtle changes are recognized in the skin, but may be asymptomatic in other organs. Our aim was to use the skin and subcutis as a model and the clinicopathologic correlation as the basic process for classification.

Eosinophilic leukocytoclastic vasculitis — a spectrum ranging from Wells’ syndrome to Churg-Strauss syndrome?

BackgroundWells’ syndrome is defined as an inflammatory disorder with the histopathological presence of eosinophilic infiltrates and flame figures in the absence of vasculitis. Eosinophilic leukocytoclastic vasculitis shows eosinophilic infiltrates in combination with vasculitic changes. And Churg Strauss Syndrome comprises all three characteristics — eosinophilic infiltrates, vasculitis and flame figures.ObjectiveTo determine whether these three diseases are distinct entities or different manifestations of a similar clinicopathologic process.MethodHistopathological samples and clinical courses of 17 patients with eosinophilic infiltrates, flame figures and clinical features of Wells’ syndrome were re-evaluated. Histopathologically, we focused on the presence or absence of vasculitic features. Clinically, we included only patients who were diagnosed with Wells’ syndrome at least once in the course of their disease.Results4 patients were finally diagnosed with Wells’ syndrome, 5 with eosinophilic leukocytoclastic vasculitis and 6 with Churg Strauss syndrome. Further, we had one case of an overlap between Wells’ syndrome and eosinophilic vasculitis and one case of Wegener granulomatosis. Vasculitic features were found in the samples of all patients.ConclusionsHistologically, we find vasculitic features in typical presentations of Wells’ syndrome. Clinically, we find typical features of Wells’ syndrome in patients finally diagnosed with eosinophilic leukocytoclastic vasculitis or Churg Strauss syndrome. Furthermore, we have observed and formerly reported 3 patients with progression from Wells’ syndrome to Churg Strauss syndrome. Thus, we assume that eosinophilic leukocytoclastic vasculitis might form a bridge between Wells’ syndrome and Churg Strauss syndrome.

Lebensqualität und Behandlungsziele bei Psoriasis aus Patientensicht: Ergebnisse eines österreichweiten Querschnitt-Survey: Lebensqualität österreichischer Psoriasispatienten

Patienten mit Psoriasis sind mit einer krankheitsbedingten Einschränkung ihrer Lebensqualität konfrontiert, weshalb einer hochqualitativen dermatologischen Versorgung ein besonderer Stellenwert zukommt.

Das Vaskulitis-Rad – ein algorithmischer Ansatz für kutane Vaskulitiden

Ältere Klassifikationen für Vaskulitiden weisen verschiedene Mängel auf. Erstens kann die Klassifikation unterschiedlichen Prinzipien folgen, wie klinisch‐pathologischen Befunden, Ätiologie, Pathogenese, Prognose oder therapeutischen Optionen. Zweitens unterscheiden die Autoren nicht zwischen Vaskulitis und Koagulopathie. Drittens sind Vaskulitiden systemische Erkrankungen. Aufgrund organspezifischer Variationen sind morphologische Befunde schwierig zu vergleichen. Viertens sind geringfügige Veränderungen zwar an der Haut erkennbar, verursachen jedoch an anderen Organen möglicherweise keine Symptome. Unser Ziel war es, die Haut und die Subkutis als Modell und die klinisch‐pathologische Korrelation als Grundlage für die Klassifikation zu verwenden.

Migration of dendritic cells into the lymphatics: the Langerhans cell example

Dendritic cells, including Langerhans cells of the epidermis and the mucous membranes, are key leukocytes for the initiation of adaptive immune responses as well as for the maintenance of peripheral tolerance. In the former regard they may well play an important, but as yet unrecognized role in the pathogenesis of Behcets disease. Epidermal Langerhans cells may serve as a paradigm for their counterparts in the mucosae. These cells efficiently take up (microbial) antigens, they process them into immunogenic MHC–peptide complexes, and they transport this form of antigen to the lymph nodes via lymphatic vessels. Depending on the milieu where Langerhans cells have encountered antigen (inflammatory versus non-inflammatory/steady-state), they make T cells proliferate and acquire effector functions (immunity) or render them unresponsive or even delete them (tolerance), respectively. In addition, plasmacytoid dendritic cells, a recently characterized type of dendritic cells, may also directly trigger innate responses (e.g. by secretion of type I interferons in response to virus). Studying the pathways and the regulation of dendritic cell migration might help to unravel a possible involvement of dendritic cells in Behcets disease. We present observations on the physical obstacles that dendritic cells migrating in the skin have to overcome until they reach dermal lymphatic vessels. Furthermore, we show that migration is critically dependent on the function of matrix metalloproteinases, in particular MMP-2 and MMP-9. It becomes evident that Langerhans cells indeed carry antigens (including self antigens such as melanosomes or apoptotoic bodies or tumor antigens such as particular cytokeratins) through the lymphatics. Given these observations it may be worth studying Langerhans cells and dermal dendritic cells in Behcets disease.