Georg Stingl

Bio: Georg Stingl is an academic researcher from Medical University of Vienna. The author has contributed to research in topics: Antigen & T cell. The author has an hindex of 82, co-authored 344 publications receiving 21871 citations. Previous affiliations of Georg Stingl include University of Innsbruck & Austrian Academy of Sciences.

Efficacy and safety results from the randomized controlled comparative study of adalimumab vs. methotrexate vs. placebo in patients with psoriasis (CHAMPION).

Abstract: BACKGROUND: Biologic therapies such as adalimumab, a tumour necrosis factor antagonist, are safe and effective in the treatment of moderate to severe chronic plaque psoriasis. OBJECTIVES: To compare a biologic agent with methotrexate, a traditional systemic agent, to define clearly the role of biologics in psoriasis. METHODS: Patients with moderate to severe plaque psoriasis were randomized to adalimumab (80 mg subcutaneously at week 0, then 40 mg every other week, n=108), methotrexate (7.5 mg orally, increased as needed and as tolerated to 25 mg weekly; n=110) or placebo (n=53) for 16 weeks. The primary efficacy endpoint was the proportion of patients achieving at least a 75% improvement in the Psoriasis Area and Severity Index (PASI 75) after 16 weeks. Safety was assessed at all visits through week 16. RESULTS: After 16 weeks, 79.6% of adalimumab-treated patients achieved PASI 75, compared with 35.5% for methotrexate (P<0.001 vs. adalimumab) and 18.9% for placebo (P<0.001 vs. adalimumab). Statistically significantly more adalimumab-treated patients (16.7%) than methotrexate-treated patients (7.3%) or placebo-treated patients (1.9%) achieved complete clearance of disease. The response to adalimumab was rapid, with a 57% improvement in mean PASI observed at week 4. Adverse events were similar across treatment groups. Adverse events leading to study discontinuation were greatest in the methotrexate group, primarily because of hepatic-related adverse events. CONCLUSIONS: After 16 weeks, adalimumab demonstrated significantly superior efficacy and more rapid improvements in psoriasis compared with either methotrexate or placebo.

Immunologic functions of Ia-bearing epidermal Langerhans cells

Abstract: Langerhans cells (LC) constitute a morphologically well-characterized minor subpopulation of the mammalian epidermis whose functional role is still a matter of conjecture. The hypothesis that LC represent an epidermal equivalent to cells of the monocyte-macrophage-histiocyte series is supported by the recent observations that in humans and guinea pigs LC are the only epidermal cells that express Fc-IgG receptors, C3 receptors, and Ia antigens. Using inbred strain 2 and strain 13 guinea pigs, we investigated in this study whether LC can mediate the same immunologic functions as Ia-bearing macrophages. LC-enriched and LC-depleted epidermal cells were prepared by separation of Fc-IgG rosetting epidermal cells on density gradients. When both populations were tested for the biosynthesis of alloantigens by immunoprecipitation techniques, Ia antigen synthesis was restricted to the LC-enriched fraction. Functional studies demonstrated that antigen-pulsed LC-enriched epidermal cells induce a proliferative response in immune T cells that is comparable in magnitude to that seen with macrophages. Moreover, effective presentation of immunologically relevant antigen requires syngeneity between LC-enriched epidermal cells and responder lymphocytes. In the mixed leukocyte reaction (MLR), LC-enriched epidermal cells were as effective stimulators as macrophages. LC-depleted epidermal cells, by contrast, induced little or no stimulation in both assay systems. Both the antigen-presenting and the MLR-stimulatory capacities of LC-enriched epidermal cells could be abrogated by pretreatment with anti-Ia sera and complement. The presence in the epidermis of Ia-bearing LC, capable of mediating the immunologic functions of Ia-bearing macrophages, has important clinical implications with regard to the role of LC as sensitizing cells in both contact hypersensitivity and skin graft rejection.

Phase 3 Studies Comparing Brodalumab with Ustekinumab in Psoriasis

Abstract: BackgroundEarly clinical studies suggested that the anti–interleukin-17 receptor A monoclonal antibody brodalumab has efficacy in the treatment of psoriasis. MethodsIn two phase 3 studies (AMAGINE-2 and AMAGINE-3), patients with moderate-to-severe psoriasis were randomly assigned to receive brodalumab (210 mg or 140 mg every 2 weeks), ustekinumab (45 mg for patients with a body weight ≤100 kg and 90 mg for patients >100 kg), or placebo. At week 12, patients receiving brodalumab were randomly assigned again to receive a brodalumab maintenance dose of 210 mg every 2 weeks or 140 mg every 2 weeks, every 4 weeks, or every 8 weeks; patients receiving ustekinumab continued to receive ustekinumab every 12 weeks, and patients receiving placebo received 210 mg of brodalumab every 2 weeks. The primary aims were to evaluate the superiority of brodalumab over placebo at week 12 with respect to at least a 75% reduction in the psoriasis area-and-severity index score (PASI 75) and a static physician’s global assessment ...

Isolation and Characterization of Dermal Lymphatic and Blood Endothelial Cells Reveal Stable and Functionally Specialized Cell Lineages

Abstract: A plexus of lymphatic vessels guides interstitial fluid, passenger leukocytes, and tumor cells toward regional lymph nodes Microvascular endothelial cells (ECs) of lymph channels (LECs) are difficult to distinguish from those of blood vessels (BECs) because both express a similar set of markers, such as CD31, CD34, podocalyxin, von Willebrand factor (vWF), etc Analysis of the specific properties of LECs was hampered so far by lack of tools to isolate LECs Recently, the 38-kD mucoprotein podoplanin was found to be expressed by microvascular LECs but not BECs in vivo Here we isolated for the first time podoplanin+ LECs and podoplanin− BECs from dermal cell suspensions by multicolor flow cytometry Both EC types were propagated and stably expressed VE-cadherin, CD31, and vWF Molecules selectively displayed by LECs in vivo, ie, podoplanin, the hyaluronate receptor LYVE-1, and the vascular endothelial cell growth factor (VEGF)-C receptor, fms-like tyrosine kinase 4 (Flt-4)/VEGFR-3, were strongly expressed by expanded LECs, but not BECs Conversely, BECs but not LECs expressed VEGF-C LECs as well as BECs formed junctional contacts with similar molecular composition and ultrastructural features Nevertheless, the two EC types assembled in vitro in vascular tubes in a strictly homotypic fashion This EC specialization extends to the secretion of biologically relevant chemotactic factors: LECs, but not BECs, constitutively secrete the CC chemokine receptor (CCR)7 ligand secondary lymphoid tissue chemokine (SLC)/CCL21 at their basal side, while both subsets, upon activation, release macrophage inflammatory protein (MIP)-3α/CCL20 apically These results demonstrate that LECs and BECs constitute stable and specialized EC lineages equipped with the potential to navigate leukocytes and, perhaps also, tumor cells into and out of the tissues

Epidermal Langerhans cells bear Fc and C3 receptors.

Abstract: THE mammalian epidermis contains a system of dendritic cells, eponymously referred to as Langerhans cells, whose functions are obscure. It is, however, accepted that Langerhans cells are of mesenchymal origin and since they are known also to occur in the dermis, lymph nodes, thymus, and other organs, the concept of Langerhans cells has widened to encompass a cellular system populating the connective tissues and certain stratified squamous epithelia of mammals1. Among the many hypotheses about their biological significance they have been considered to represent immunocompetent cells or cells which might capture antigenic materials2, but there is insufficient evidence for this. Lymphocytes have been observed to be closely associated with Langerhans cells in delayed type hypersensitivity reactions to dinitrochloro-benzene in guinea pigs3; and when guinea pigs passively sensitised with lymphocytes from ferritin-hypersensitive donors, were challenged with ferritin, ferritin-containing Langerhans cells were observed in the draining lymph nodes of the challenged animals4. Metals and certain amines have an affinity for Langerhans cells in vitro5, but since they can phagocytose ferritin and other substances without previous sensitisation1, doubt remains whether they are immunologically engaged in the uptake and transport of potentially antigenic material. If Langerhans cells are indeed involved in immunological reactions, they should bear some of the surface markers characteristics of cells with known immunological functions, and we have now shown that they carry receptors for Fc and C3.

Dendritic cells and the control of immunity

Abstract: B and T lymphocytes are the mediators of immunity, but their function is under the control of dendritic cells. Dendritic cells in the periphery capture and process antigens, express lymphocyte co-stimulatory molecules, migrate to lymphoid organs and secrete cytokines to initiate immune responses. They not only activate lymphocytes, they also tolerize T cells to antigens that are innate to the body (self-antigens), thereby minimizing autoimmune reactions. Once a neglected cell type, dendritic cells can now be readily obtained in sufficient quantities to allow molecular and cell biological analysis. With knowledge comes the realization that these cells are a powerful tool for manipulating the immune system.

Immunobiology of Dendritic Cells

Abstract: Dendritic cells (DCs) are antigen-presenting cells with a unique ability to induce primary immune responses. DCs capture and transfer information from the outside world to the cells of the adaptive immune system. DCs are not only critical for the induction of primary immune responses, but may also be important for the induction of immunological tolerance, as well as for the regulation of the type of T cell-mediated immune response. Although our understanding of DC biology is still in its infancy, we are now beginning to use DC-based immunotherapy protocols to elicit immunity against cancer and infectious diseases.

Re-epithelialization and immune cell behaviour in an ex vivo human skin model.

Abstract: A large body of literature is available on wound healing in humans. Nonetheless, a standardized ex vivo wound model without disruption of the dermal compartment has not been put forward with compelling justification. Here, we present a novel wound model based on application of negative pressure and its effects for epidermal regeneration and immune cell behaviour. Importantly, the basement membrane remained intact after blister roof removal and keratinocytes were absent in the wounded area. Upon six days of culture, the wound was covered with one to three-cell thick K14+Ki67+ keratinocyte layers, indicating that proliferation and migration were involved in wound closure. After eight to twelve days, a multi-layered epidermis was formed expressing epidermal differentiation markers (K10, filaggrin, DSG-1, CDSN). Investigations about immune cell-specific manners revealed more T cells in the blister roof epidermis compared to normal epidermis. We identified several cell populations in blister roof epidermis and suction blister fluid that are absent in normal epidermis which correlated with their decrease in the dermis, indicating a dermal efflux upon negative pressure. Together, our model recapitulates the main features of epithelial wound regeneration, and can be applied for testing wound healing therapies and investigating underlying mechanisms.

Immunologic self-tolerance maintained by activated T cells expressing IL-2 receptor alpha-chains (CD25). Breakdown of a single mechanism of self-tolerance causes various autoimmune diseases.

Abstract: Approximately 10% of peripheral CD4+ cells and less than 1% of CD8+ cells in normal unimmunized adult mice express the IL-2 receptor alpha-chain (CD25) molecules. When CD4+ cell suspensions prepared from BALB/c nu/+ mice lymph nodes and spleens were depleted of CD25+ cells by specific mAb and C, and then inoculated into BALB/c athymic nude (nu/nu) mice, all recipients spontaneously developed histologically and serologically evident autoimmune diseases (such as thyroiditis, gastritis, insulitis, sialoadenitis, adrenalitis, oophoritis, glomerulonephritis, and polyarthritis); some mice also developed graft-vs-host-like wasting disease. Reconstitution of CD4+CD25+ cells within a limited period after transfer of CD4+CD25- cells prevented these autoimmune developments in a dose-dependent fashion, whereas the reconstitution several days later, or inoculation of an equivalent dose of CD8+ cells, was far less efficient for the prevention. When nu/nu mice were transplanted with allogeneic skins or immunized with xenogeneic proteins at the time of CD25- cell inoculation, they showed significantly heightened immune responses to the skins or proteins, and reconstitution of CD4+CD25+ cells normalized the responses. Taken together, these results indicate that CD4+CD25+ cells contribute to maintaining self-tolerance by down-regulating immune response to self and non-self Ags in an Ag-nonspecific manner, presumably at the T cell activation stage; elimination/reduction of CD4+CD25+ cells relieves this general suppression, thereby not only enhancing immune responses to non-self Ags, but also eliciting autoimmune responses to certain self-Ags. Abnormality of this T cell-mediated mechanism of peripheral tolerance can be a possible cause of various autoimmune diseases.

The dendritic cell system and its role in immunogenicity

Abstract: Dendritic cells are a system of antigen presenting cells that function to initiate several immune responses such as the sensitization of MHC-restricted T cells, the rejection of organ transplants, and the formation of T-dependent antibodies. Dendritic cells are found in many nonlymphoid tissues but can migrate via the afferent lymph or the blood stream to the T-dependent areas of lymphoid organs. In skin, the immunostimulatory function of dendritic cells is enhanced by cytokines, especially GM-CSF. After foreign proteins are administered in situ, dendritic cells are a principal reservoir of immunogen. In vitro studies indicate that dendritic cells only process proteins for a short period of time, when the rate of synthesis of MHC products and content of acidic endocytic vesicles are high. Antigen processing is selectively dampened after a day in culture, but the capacity to stimulate responses to surface bound peptides and mitogens remains strong. Dendritic cells are motile, and efficiently cluster and activate T cells that are specific for stimuli on the cell surface. High levels of MHC class-I and -II products and several adhesins, such as ICAM-1 and LFA-3, likely contribute to these functions. Therefore dendritic cells are specialized to mediate several physiologic components of immunogenicity such as the acquisition of antigens in tissues, the migration to lymphoid organs, and the identification and activation of antigen-specific T cells. The function of these presenting cells in immunologic tolerance is just beginning to be studied.