Paolo Amerio

Eotaxins and CCR3 Receptor in Inflammatory and Allergic Skin Diseases: Therapeutical Implications

Cell migration is mediated by a group of chemotactic cytokines called chemokines: low molecular weight molecules that have been shown as important leukocyte chemical attractants to sites of inflammation and infection. Eotaxin-1, also called CCL11, was first described in 1994, as a highly specific eosinophils chemokine. Many cell types including lymphocytes, macrophages, bronchial smooth muscle cells, endothelial cells and eosinophils, are able to produce this chemokine, predominantly after cytokine stimulation, however little is known about its expression in human skin in vivo. Eotaxin-1 also regulates the chemiotaxis and, in some conditions, activation of basophils, mast cells and T lymphocytes. Chemokine receptors are named from their ligand families, thus the CC chemokine eotaxin-1 binds to the CCR3 receptor which is expressed on eosinophis, mast cells, Th2 type lymphocytes and even on keratinocytes. It seems that eotaxin-1 is one of the most important cytokines involved in tissue inflammation playing a central role in the pathogenesis of allergic airway diseases (asthma and rhinitis), in inflammatory bowel disease and gastrointestinal allergic hypersensitivity and recently it has been proposed as a therapeutical target for these conditions. Our group has studied the role of eotaxin-1 in the pathogenesis of two skin conditions: dermatitis herpetiformis and AIDS-associated eosinophilic folliculitis, demonstrating that this chemokine, together with Th2 type cytokines (IL-13 and IL-4) is important in cell recruitment, inflammation and tissue damage; moreover eotaxin has proven to paly an important role in other skin conditions such as, bullous pemphigoid, pemphigoid gestationis, atopic dermatitis and allergic drug reactions Recent advances in the understanding of eotaxin-1-mediated mechanisms of chemotaxis in allergic and inflammatory conditions may predict that therapeutic antagonism is achievable. This paper will focus on the role that eotaxin and its receptor play in the pathogenetical mechanism in a number of dermatologic diseases, some of which, like atopic dermatitis, may benefit from the introduction of novel and more selective therapeutic options.

EGFR regulates the expression of keratinocyte-derived granulocyte/macrophage colony-stimulating factor in vitro and in vivo.

Recent advances in the knowledge of the EGFR pathway have revealed its contribution to distinct immune/inflammatory functions of the epidermis. The purpose of our study was to evaluate the role of EGFR in the regulation of keratinocyte GM-CSF expression. In cultured human keratinocytes, proinflammatory cytokines synergized with TGF-alpha to induce GM-CSF expression. Accordingly, high epidermal levels of EGFR activation are associated with enhanced expression of GM-CSF in lesional skin of patients with psoriasis or allergic contact dermatitis. In cultured keratinocytes, pharmacological inhibition of EGFR activity reduced GM-CSF promoter transactivation, whereas genetic inhibition of AP-1 reduced expression of GM-CSF. Furthermore, EGFR activation enhanced TNF-alpha-induced c-Jun phosphorylation and DNA binding, whereas c-Jun silencing reduced GM-CSF expression. Using two different mouse models, we showed that the lack of a functional EGFR pathway was associated with reduced cytokine-induced phosphorylation of ERK1/2, JNK1/2, c-Jun and reduced keratinocyte-derived GM-CSF expression both in vitro and in vivo. Finally, the analysis of GM-CSF expression in the skin of cancer patients treated with anti EGFR drugs showed an association between ERK activity, c-Jun phosphorylation, and epidermal GM-CSF expression. These data demonstrate that the EGFR pathway is critical for the upregulation of keratinocyte GM-CSF expression under conditions of cytokine stimulation.

Immune Modulation in Pemphigus Vulgaris: Role of CD28 and IL-10

Pemphigus vulgaris (PV) is an autoimmune bullous skin disease characterized by Abs to the desmosomal cadherin desmoglein-3. Although the autoantibodies have been shown to be pathogenic, the role of the cellular immune system in the pathology of pemphigus-induced acantholysis is unclear. To further delineate the potential role of T cell-signaling pathways in the pathogenesis of PV, we performed passive transfer experiments with PV IgG in gene-targeted mutant mice. Our results demonstrated that CD28-deficient mice (lacking a costimulatory signal for T cell activation) are 5-fold more sensitive to the development of PV than wild-type mice. To evaluate whether the higher incidence of disease was due to an impairment in intercellular adhesion of keratinocytes, we performed an in vitro acantholysis, using CD28−/− mice keratinocytes. No alteration in in vitro adhesion was detected in CD28−/−-type keratinocytes. Because the CD28 molecule plays a pivotal role in the induction of Th2 cytokines, we examined the levels of a prototypic Th2 cytokine (IL-10) in CD28−/− mice. Lower levels of IL-10 mRNA were found in lesions from CD28−/− mice. To determine whether pemphigus susceptibility in CD28−/− was related to IL-10 deficiency, we performed passive transfer experiments in IL-10−/− mice that demonstrated increased blisters compared with controls. To confirm that IL-10 is involved in the pathogenesis, rIL-10 was given with PV IgG. IL-10 significantly suppressed the disease activity. These data suggest a potential role of IL-10 in PV.

Immunogenicity of anti-TNFα therapy in psoriasis: a clinical issue?

Introduction: Immunogenicity of antitumor necrosis factor-alpha (TNFα) agents has been proven to play a significant role in the variability of clinical responses among patients with chronic inflammatory diseases. However, its clinical impact on the outcome of patients with psoriasis and psoriatic arthritis receiving anti-TNFα treatment is not yet fully clear. Despite the high rates of efficacy of anti-TNFα agents in psoriasis, a substantial proportion of patients remain who experience a primary or secondary failure or significant side effects, which are potentially ascribable to immunogenicity. Areas covered: Topics include immunologic response elicited by anti-TNFα agents, the impact of immunogenicity on treatment response to anti-TNFα and the role played by immunogenicity in the lack of efficacy of anti-TNFα agents (infliximab, adalimumab and etanercept) in psoriasis. Expert opinion: Based on data available in the literature and the clinical experience of the authors, this article suggests the optimal approach to drug monitoring and antidrug antibody assay and the most effective use of biologic immunotherapies in this setting. Immunogenicity should be taken into account in the adoption of therapeutic choices in psoriatic patients, such as anti-TNFα agent intensification, or switching to another anti-TNFα agent or a drug with a different mechanism of action.

Vitiligo associated with other autoimmune diseases: polyglandular autoimmune syndrome types 3B + C and 4

Vitiligo is a common skin disease characterized by depigmented maculae resulting from a reduction of the number and function of melanocytes. Many studies suggest that vitiligo might be an autoimmune disease. Vitiligo has been frequently described in association with other autoimmune diseases. Among the diseases described in association with vitiligo are the so‐called autoimmune polyglandular syndromes (APS). Vitiligo can be present in all types of APS but the most frequent association appears to be in APS‐3. APS‐3 was defined as the association between autoimmune thyroiditis and another autoimmune disease. Here we report one patient with thyroiditis, vitiligo and autoimmune gastritis (APS‐3B + C), one patient with chronic autoimmune thyroiditis, vitiligo and alopecia (APS‐3C), and one case of a young patient with type 1 diabetes mellitus and vitiligo (APS‐4), according to the newest classification. We stress the importance of a thorough assessment for autoimmune diseases in selected patients with vitiligo.

Cytokines and T cells in atopic dermatitis

Atopic dermatitis (AD) is an inflammatory disorder of the skin characterized by an impaired immune response. Several effector T cell subsets, such as pro-inflammatory cells like Th9, Th17 and Th22 cells, expressing high levels of IL-9, IL-17 and IL-22, together with the anti-inflammatory, immuno-modulating Treg cells constitutively producing IL-10, seem to play a role in this condition. IL-9 and IL-9 receptors are significantly increased in lesional AD skin compared to normal control skin. In addition, some polymorphisms in IL-9 and IL-9r genes have been associated with AD. The role of IL-17 and IL-17-producing T cells remains under debate and conflicting data are available. IL-22-producing T-cells seem to correlate with the severity of the AD. The number and function of Treg cells, producing IL-10, have been widely investigated in AD with conflicting results. Other studies suggest that high levels of IL-31 or low levels of IL-21 might be involved in the pathogenesis of AD. This review was undertaken in order to provide a better understanding of the relevance of certain cytokines in AD. We have analysed the new insight into the pathogenesis of AD, with special attention to those cytokines produced by the different T cell subpopulations.

Elevated 8-isoprostane levels in basal cell carcinoma and in UVA irradiated skin.

Isoprostanes are prostaglandin isomers produced from the peroxidation of polyunsaturated fatty acids from the cellular membrane. They have been used as a specific index of cellular lipoperoxidation and as an indirect measure of oxidative stress. However, these molecules also present several biological activities. An oxidative environment measured as the presence of other indirect measurements of reactive oxygen species lipoperoxidation has recently been described in basal cell carcinoma, the most frequent type of non-melanoma skin cancer. This study aims to measure the levels of 8-isoprostaglandin F2α, an isoprostane widely studied in other models as a by-product of ROS-induced lipid peroxidation, in basal cell carcinoma and in UVA irradiated healthy skin. We found that 8-iso-PGF2α is present in higher levels in BCC specimens compared to healthy non sun-exposed skin, confirming previous studies on the production of lipoperoxidation in this tumor. Moreover, we demonstrated that topical pre-treatment with a compound containing vitamin E is capable of reducing 8-iso-PGF2α formation in UV irradiated skin suggesting a role for isoprostanes in UV induced inflammation and eventually carcinogenesis and confirming the function of vitamin E as an antioxidant in this model.

Cutaneous carcinomas and preinvasive neoplastic lesions. Role of MMP-2 and MMP-9 metalloproteinases in neoplastic invasion and their relationship with proliferative activity and p53 expression.

Background: Metalloproteinases (MMPs) are thought to be involved in the process of destruction of basement membranes and stromal invasion by neoplastic epithelial cells.

In vitro C3 mRNA expression in pemphigus vulgaris : Complement activation is increased by IL-1α and TNF-α

Background: Pemphigus vulgaris (PV) is a potentially life-threatening disease, characterized immunohistologically by IgG deposits and complement activation on the surface of keratinocytes. Complement activation has been implicated in the pathogenesis with C3 deposits in about 90% of patients. Objective: In order to further elucidate the role of complement in PV and to define which cytokines play a role in C3 mRNA expression, we performed an in vitro study in human keratinocytes. Methods: Normal human epidermal keratinocytes (NHuK) were incubated with PV serum and C3 mRNA was measured. We previously had shown that IL-1α and TNF-α are expressed in PV in vivo and in vitro. Since cytokines are able to modulate complement activation, mRNA expression was evaluated in a similar experiment after pretreatment using antibodies against IL-1α and TNF-α. Results: Incubation of NHuK with PV sera caused their detachment from the plates after 20–30 minutes with a complete acantholysis within 12 hours. An early C3 mRNA expression was seen after 30 minutes with a peak level after 1 hour. Blocking studies, using antibodies against human IL-1α and TNF-α in NHuK together with PV-IgG, showed reduction of in vitro induced acantholysis and inhibition of C3 mRNA expression. Conclusions: This study supports the hypothesis that complement C3 is important in PV acantholysis and that complement activation is increased by IL-1α and TNF-α.

Treatment of Cutaneous Calciphylaxis with Sodium Thiosulfate

Cutaneous calciphylaxis is a potentially fatal condition characterized by calcium deposition in dermal arterioles and the subsequent development of livedo reticularis, plaques, and extremely painful ulcers. This condition may be present in up to 4% of end-stage renal disease patients. Several treatments, which mainly attempt to control calcium phosphate metabolism, are available for this condition.We describe two patients treated with sodium thiosulfate with good results. Moreover, we also performed a PubMed literature search of sodium thiosulfate treatment for calciphylaxis. We found 41 cases of which most (>90%) presented a rapid and sustained resolution, indicating this drug is a very good candidate for the treatment of this condition.