Proteome Serological Determination of Tumor-Associated Antigens in Melanoma

Proteome serology may complement expression library-based approaches as strategy utilizing the patients' immune responses for the identification pathogenesis factors and potential targets for therapy and markers for diagnosis. Melanoma is a relatively immunogenic tumor and antigens recognized by melanoma-specific T cells have been extensively studied. The specificities of antibody responses to this malignancy have been analyzed to some extent by molecular genetic but not proteomics approaches. We screened sera of 94 melanoma patients for anti-melanoma reactivity and detected seropositivity in two-thirds of the patients with 2–6 antigens per case detected by 1D and an average of 2.3 per case by 2D Western blot analysis. For identification, antigen spots in Western blots were aligned with proteins in 2-DE and analyzed by mass spectrometry. 18 antigens were identified, 17 of which for the first time for melanoma. One of these antigens, galectin-3, has been related to various oncogenic processes including metastasis formation and invasiveness. Similarly, enolase has been found deregulated in different cancers. With at least 2 of 18 identified proteins implicated in oncogenic processes, the work confirms the potential of proteome-based antigen discovery to identify pathologically relevant proteins

Large-scale, prospective, observational studies in patients with psoriasis and psoriatic arthritis: A systematic and critical review

<p>Abstract</p> <p>Background</p> <p>Observational studies, if conducted appropriately, play an important role in the decision-making process providing invaluable information on effectiveness, patient-reported outcomes and costs in a real-world environment. We conducted a systematic review of large-scale, prospective, cohort studies with the aim of (a) summarising design characteristics, the interventions or aspects of the disease studied and the outcomes measured and (b) investigating methodological quality.</p> <p>Methods</p> <p>We included prospective, cohort studies which included at least 100 adults with psoriasis or psoriatic arthritis. Studies were identified through searches in electronic databases (Pubmed, Medline, Cochrane library, Centre for Reviews and Dissemination). Information on study characteristics were extracted and tabulated and quality assessment, using a checklist of 18 questions, was conducted.</p> <p>Results</p> <p>Thirty five papers covering 16 cohorts met the inclusion criteria. There were ten treatment-related studies, only two of which provided a comparison between treatments, and six non-treatment studies which examined a number of characteristics of the disease including mortality, morbidity, cost of illness and health-related quality of life. All studies included a clinical outcome measure and 11 included patient-reported outcomes, however only two studies reported information on patient utilities and two on costs. The quality of the assessed studies varied widely. Studies did well on a number of quality assessment questions including having clear objectives, documenting selection criteria, providing a representative sample, defining interventions/characteristics under study, defining and using appropriate outcomes, describing results clearly and using appropriate statistical tests. The quality assessment criteria least adhered to involved questions regarding sample size calculations, describing potential selection bias, defining and adjusting for confounders and losses to follow-up, and defining and describing a comparison group.</p> <p>Conclusion</p> <p>The review highlights the need for well designed prospective observational studies on the effectiveness, patient-reported outcomes and economic impact of treatment regimes for patients with psoriasis and psoriatic arthritis in a real-world environment.</p

Mechanisms of allergic contact dermatitis

Allergenicity depends on several factors determined by the very physicochemical nature of the molecules themselves, i.e., their capacity to penetrate the horny layer, lipophilicity, and chemical reactivity. The sensitizing property of the majority of contact allergens could be predicted from these characteristics (Patlewicz et al., Contact Dermatitis 50:91-97, 2004; Gerberick et al., Altern Lab Anim 36(2):215-242, 2008). Two other factors, however, further contribute to the allergenicity of chemicals, namely, their pro-inflammatory activity and capacity to induce maturation of LC. These issues will be dealt with in more detail in the following sections. Along with their migration and settling within the draining lymph nodes, haptenized LC further mature, as characterized by their increased expression of costimulatory and antigen-presentation molecules (Cumberbatch et al., Arch Dermatol Res 289:277-284, 1997; Heufler et al. J Exp Med 167:700-705, 1988). In addition, they adopt a strongly veiled, interdigitating appearance, thus maximizing the chances of productive encounters with naive T lymphocytes and recognition of altered self (Steinman et al., J Invest Dermatol 105:2S-7S, 1995; Furue et al., Br J Dermatol 135:194-198, 1996; Schuler and Steinman, J Exp Med 161:526-546, 1985). The intricate structure of lymph node paracortical areas, the differential expression of chemokines and their receptors, the characteristic membrane ruffling of IDC, and the predominant circulation of naive T lymphocytes through these lymph node areas provide optimal conditions for T-cell-receptor binding, i.e., the first signal for induction of T-cell activation (Banchereau and Steinman, Nature 392:245-252, 1998). Intimate DC-T-cell contacts are further strengthened by secondary signals, provided by sets of cellular adhesion molecules, and growth-promoting cytokines (reviewed in Hommel, Immunol Cell Biol 82:62-66, 2004; Cella et al., Curr Opin Immunol 9:10-16, 1997). In healthy individuals, primary skin contacts with contact allergens lead to differentiation and expansion of allergen-specific effector T cells displaying Th1, Th2, and/or Th17 cytokine profiles. The same allergens, if encountered along mucosal surfaces, favor the development of allergen-specific Th2 and Th17 effector cells, and/or Th3 and Tr1 allergen-specific regulatory T cells. Whereas the first two subsets may assist or replace Th1 cells in pro-inflammatory effector functions, the latter two subsets are mainly known for downregulating immune responsiveness. For most, if not all allergens, along with prolonged allergenic contacts, the role of Th2 cells as effector cells gradually increases given reduced longevity of Th1 responses. The respective contributions of similar subsets of allergen-specific CD8 + T cells are still unknown, but distinct effector roles of allergen-specific Tc1 and Tc2 have been postulated. Priming via the skin results in CLA positive T cells, which upon inflammatory stimuli preferentially enter the skin; on the other hand, gut homing T cells have been primed and generated along mucosal surfaces. Upon priming, T cells loose much of their capacity to recirculate via the lymph nodes, but gain the capacity to enter the tissues. In particular recently activated T cells will enter skin inflammatory sites. ACD reactions are primarily infiltrated by CD4 and/or CD8 pro-inflammatory cells, later reactions may be dominated by Th2 cells and regulatory T cells. Skin infiltation by T cells is fine-tuned by sets of adhesion molecules and chemokine receptors, whose expression is not rigid, but can be modulated by micro-environmental factors. After antigenic activation the progeny of primed T cells is released via the efferent lymphatics into the bloodstream. Circulating allergen-specific cells can be challenged in vitro to provide diagnostic parameters for contact hypersensitivity. At least for water-soluble allergens, like metal salts, the degree of allergen-specific proliferation and cytokine production, in particular type-2 cytokines, correlate with clinical allergy. For routine application of a broad spectrum of allergens, culture conditions still need to be improved. For mechanistic in vitro studies in ACD, however, with selected sets of relatively nontoxic allergens, peripheral blood provides an excellent source of lymphocytes and antigen-presenting cells. ACD reactions can be mediated by classical effector cells, i.e., allergen-specific CD4+ type-1 T cells which, upon triggering by allergen-presenting cells, produce IFN-? to activate nonspecific inflammatory cells like macrophages. However, CD8 + T cells, and other cytokines, including IL-4, IL-17, and IL-22 can also play major roles in ACD. The conspicuous difference with DTH reactions induced by intradermal administration of protein antigens, i.e., the epidermal infiltrate, can largely be attributed to hapten-induced chemokine release by keratinocytes