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Introduction: It is still unknown whether eosinophilic esophagitis (EoE) patients with localized disease are different from those with extended disease., Methods: We evaluated prospectively included patients in the Swiss EoE cohort. Data on all patients with active disease at baseline, no concomitant gastroesophageal reflux disease, no strictures at baseline, and at least one follow-up visit were analyzed. We compared patients with histologically localized proximal versus distal versus extended (=proximal and distal) disease with regard to patient, disease characteristics, disease presentation, and development of complications., Results: We included 124 patients with a median of 2.5 years of follow-up (73.4% males, median age 35.0 years). Ten patients had proximal (8.1%), 46 patients had distal (37.1%), and 68 patients had extended disease (54.8%). Patients with proximal disease were significantly more often females (80%) compared with patients with distal (26.1%, p = 0.002) or extended disease (19.1%, p < 0.001) and reported less severe symptoms (VAS 0 vs. VAS 1, p = 0.001). Endoscopic and histological disease was less pronounced in the proximal esophagus of proximal EoE compared to extended disease (EREFS 1.0 vs. 3.0, p = 0.001; 27.0 eos/hpf vs. 52.5 eos/hpf, p = 0.008). Patients with proximal disease were less likely to undergo dilation compared to patients with distal disease in the follow-up (3.3% vs. 23.3%, p = 0.010). In a multivariate Cox regression model, proximal eosinophilia was less likely to be associated with treatment failure compared to distal eosinophilia., Conclusion: Although isolated proximal EoE is infrequent, it is associated with less severe disease and better disease outcome. Proximal disease appears to present a unique EoE phenotype., (© 2023 S. Karger AG, Basel.)

Background: An increased expression of interleukin (IL)-15, a cytokine with a key role in stimulating innate and adaptive immune cells, such as dendritic cells (DC), natural killer cells, and T cells, has been observed in infectious and inflammatory diseases, including autoimmune diseases as well as cancer. Atopic dermatitis (AD) is a common inflammatory skin disease characterized by a type 2 immune response., Objective: To explore the expression of IL-15 and its pattern in AD skin., Method: Immunofluorescence staining was performed on skin specimens of AD skin, nonlesional AD skin (AD NL), and normal skin (NS) using antibodies directed against IL-15 and CD3, mast cell tryptase, eosinophil cationic protein, CD68, CD11b, CD1a, and vimentin., Results: A significantly higher IL-15 expression in AD and AD NL was observed in both the epidermis (p = 0.0003) and the dermis (p = 0.0154) as compared to NS. Cells expressing IL-15 were mainly keratinocytes, CD1a+ DC, CD11b+ DC, CD68+ macrophages, and vimentin+ fibroblasts. In AD, an increase in the relative numbers of IL-15 expressing CD1a+ DC, macrophages, and fibroblasts was noted., Conclusion: Our results demonstrate an expression of IL-15 in AD similar to that of eosinophilic esophagitis which is also a type 2 disease. IL-15 may serve as a therapeutic target for AD., (© 2020 S. Karger AG, Basel.)

Eosinophils and their secretory mediators play an important role in the pathogenesis of infectious and inflammatory disorders. Although eosinophils are largely evolutionally conserved, their physiologic functions are not well understood. Given the availability of new eosinophil-targeted depletion therapies, there has been a renewed interest in understanding eosinophil biology as these strategies may result in secondary disorders when applied over long periods of time. Recent data suggest that eosinophils are not only involved in immunological effector functions but also carry out tissue protective and immunoregulatory functions that actively contribute to the maintenance of homeostasis. Prolonged eosinophil depletion may therefore result in the development of secondary disorders. Here, we review recent literature pointing to important roles for eosinophils in promoting immune defense, antibody production, activation of adipose tissue, and tissue remodeling and fibrosis. We also reflect on patient data from clinical trials that feature anti-eosinophil therapeutics., (© 2019 S. Karger AG, Basel.)

This update on chronic urticaria (CU) focuses on the prevalence and pathogenesis of chronic spontaneous urticaria (CSU), the expanding spectrum of patient-reported outcome measures (PROMs) for assessing CU disease activity, impact, and control, as well as future treatment options for CU. This update is needed, as several recently reported findings have led to significant advances in these areas. Some of these key discoveries were first presented at past meetings of the Collegium Internationale Allergologicum (CIA). New evidence shows that the prevalence of CSU is geographically heterogeneous, high in all age groups, and increasing. Several recent reports have helped to better characterize two endotypes of CSU: type I autoimmune (or autoallergic) CSU, driven by IgE to autoallergens, and type IIb autoimmune CSU, which is due to mast cell (MC)-targeted autoantibodies. The aim of treatment in CU is complete disease control with absence of signs and symptoms as well as normalization of quality of life (QoL). This is best monitored by the use of an expanding set of PROMs, to which the Angioedema Control Test, the Cholinergic Urticaria Quality of Life Questionnaire, and the Cholinergic Urticaria Activity Score have recently been added. Current treatment approaches for CU under development include drugs that inhibit the effects of signals that drive MC activation and accumulation, drugs that inhibit intracellular pathways of MC activation and degranulation, and drugs that silence MCs by binding to inhibitory receptors. The understanding, knowledge, and management of CU are rapidly increasing. The aim of this review is to provide physicians who treat CU patients with an update on where we stand and where we will go. Many questions and unmet needs remain to be addressed, such as the development of routine diagnostic tests for type I and type IIb autoimmune CSU, the global dissemination and consistent use of PROMs to assess disease activity, impact, and control, and the development of more effective and well-tolerated long-term treatments for all forms of CU., (© 2020 The Author(s) Published by S. Karger AG, Basel.)

A vaccine to protect against COVID-19 is urgently needed. Such a vaccine should efficiently induce high-affinity neutralizing antibodies which neutralize SARS-CoV-2, the cause of COVID-19. However, there is a concern regarding both vaccine-induced eosinophilic lung disease and eosinophil-associated Th2 immunopotentiation following infection after vaccination. Here, we review the anticipated characteristics of a COVID-19 vaccine to avoid vaccine-associated eosinophil immunopathology., (© 2020 S. Karger AG, Basel.)

Atopic dermatitis (AD) is a chronic inflammatory skin disease presenting with recurrent eczematous lesions and intense pruritus. It is common and affects both children and adults, often beginning in infancy. Due to the unpredictable disease course, its visible skin lesions, itching and scratching followed by sleeplessness, other associated atopic diseases, and behavioral and psychiatric disorders, AD is an immense burden for patients and caregivers. AD is determined by a genetic predisposition characterized by an impaired skin barrier and a T-helper-2-predominant inflammation. Restoration of the skin barrier is the main approach for treating and preventing AD. In order to cope with acute flares, usually topical corticosteroids (TCS) are applied, while topical calcineurin inhibitors (TCI) are used mainly for maintenance therapy. There is a small group of patients who are refractory to TCS and TCI and require systemic immunosuppressive drugs such as ciclosporin. Novel, targeted therapies are under clinical investigation, among which an anti-IL-4/IL-13 receptor antibody has recently been approved in several countries. As we learn to understand the pathomechanisms of AD, the characteristics of the different patient subgroups, and the effectiveness of various targeted therapies, a personalized treatment ensuring the best efficacy and safety and, probably, a disease-modifying effect will result., (© 2019 S. Karger AG, Basel.)

Limited evidence is available regarding the effect of partially hydrolyzed whey-based formula (pHF-W) on growth and atopic dermatitis (AD) risk reduction in infants within the general infant population, and without a familial history of allergy as an inclusion or exclusion criterion. We reviewed the current evidence available from studies using pHF-W in the general population and summarized the data on safety (growth) and efficacy outcomes (reduction of AD), comparing the studies side by side. A total of 8 clinical trials were identified from the literature search, 7 of which used the same pHF-W. Six out of 8 studies indicated a reduction of atopic manifestations using a specific pHF-W versus cow's milk formula (CMF) in the first years of life. Data were summarized and compared side by side for growth (3 studies) and efficacy (5 studies). In these diverse general populations, the results on growth and AD were consistent with the previous findings reported on infants with a family history of allergy, but numerous limitations to these studies were identified. This literature review confirms that pHF-W supports normal growth in infants, and suggests that the risk of AD may be reduced in not-fully breastfed infants from the general population when supplemented with a specific pHF-W when compared to CMF during the first 4-6 months of life. Further studies are warranted to confirm these results., (© 2018 The Author(s) Published by S. Karger AG, Basel.)

Background: Although allergic mechanisms appear to be important, the pathogenesis of both extrinsic and intrinsic forms of atopic dermatitis (AD) is unknown., Methods: We compared the cytokine production of peripheral blood mononuclear cells of extrinsic AD (EAD) and intrinsic AD (IAD) patients and normal control individuals after stimulation with anti-CD3 and/or anti-CD28 monoclonal antibodies (mAbs) in the presence or absence of anti-CD2-blocking mAb. The cytokine production was measured by immunoassays in supernatants of 24-hour cultures., Results: EAD patients showed a decreased capacity to synthesize interferon gamma and granulocyte-macrophage colony-stimulating factor upon anti-CD3 mAb stimulation as compared with IAD patients. Both EAD and IAD patients demonstrated an increased production of interleukin (IL)-5 and IL-13. As expected, interferon gamma, granulocyte-macrophage colony-stimulating factor, and IL-5 levels were reduced in the presence of anti-CD2-blocking mAbs. CD28 costimulation restored the release in cultures with anti-CD2 mAbs added, suggesting that CD2 and CD28 have redundant functions in T cell activation and subsequent cytokine production. Strikingly, the IL-13 production was not blocked by anti-CD2 mAbs and also not increased by agonistic anti-CD28 mAb, in particular within the EAD patient group., Conclusion: The signalling pathway initiated by the T cell receptor complex leading to increased IL-13 production in AD patients appears to be highly sensitive and is largely independent on CD2 costimulatory signals., (Copyright 2003 S. Karger AG, Basel)

Plant extracts are causing an increased interest in the treatment of many chronic diseases, including asthma and other allergic diseases. Several laboratories characterized petasins (petasin, isopetasin, and neopetasin) isolated from extracts of butterbur (Petasites hybridus) as pharmacologically active components, which inhibit leukotriene synthesis in leukocytes. The molecular mechanisms by which petasins abrogate inflammatory effector cell functions have, at least partially, been identified. In vitro studies revealed that petasins may have several intracellular targets and this may depend on the stereoisomer used. In an open clinical trial in patients suffering from allergic rhinitis, a reduction of leukotriene and histamine levels in nasal fluids was associated with the butterbur extract administration. To better evaluate the clinical value in this particular allergic disease, the clinical efficacy of the drug was compared with an established antihistamine treatment scheme in a double-blind study; no significant difference was observed between the two treatment groups. In this article, we critically review recently published work and summarize the current stage in the pharmacological characterization of butterbur extracts., (Copyright 2002 S. Karger AG, Basel)

Background: Apoptosis is a necessary process to control cell numbers in multicellular organisms. In many chronic inflammatory diseases, reduced cell death of different types of granulocytes is one important mechanism for cell accumulation. Here, we studied the role of caspases in neutrophil and eosinophil apoptosis in the presence or absence of granulocyte-macrophage stimulating factor and anti-CD95 monoclonal antibodies, respectively., Methods: Granulocytes were isolated from human blood using standard protocols. Immunoblot and functional studies with cell-permeable specific peptide inhibitors were performed to analyze caspase involvement. Fas receptor and Fas ligand expression was analyzed by RT-PCR, flow cytometry, and immunoblotting. Cell death was analyzed by ethidium bromide exclusion test., Results: Caspases 3 and 8 are critically involved in the regulation of neutrophil apoptosis in vitro. In contrast, these two caspases did not appear to play a major role in the regulation of eosinophil apoptosis. However, the broad-range caspase inhibitor VAD prevented eosinophil death, indicating that caspases are also involved within the apoptotic machinery of eosinophils. Functional inhibitor studies suggested that caspase 9 is crucial for both caspase 3 and 8 activation, at least in neutrophils. In contrast, spontaneous apoptosis of neutrophils or eosinophils is unlikely to be the consequence of Fas ligand/Fas receptor molecular interactions., Conclusion: The data of this study indicate differences in the usage of caspases between neutrophils and eosinophils., (Copyright 2001 S. Karger AG, Basel)

Recent work suggests that in some patients with the hypereosinophilic syndrome, a clone of abnormal T cells produces large amounts of interleukin-5. In this study, we examined 60 patients with idiopathic eosinophilia. Sixteen patients had circulating T cells with an aberrant immunophenotype that, in most cases, were associated with different forms of skin inflammation. The abnormal T cells produced large amounts of interleukin-5, which may have increased eosinophil differentiation in the bone marrow of these patients., (Copyright 2001 S. Karger AG, Basel)

Background: In allergic inflammations of the skin, the pivotal role of CD45RO+ (memory/effector) T cells expressing the cutaneous lymphocyte-associated antigen (CLA) was demonstrated. In both atopic dermatitis (AD) and contact dermatitis (CD), T cells specific to skin-related allergens were confined to the CLA+ T cell population. Our research was aimed to further characterize these T cells in AD., Methods: CD4+ and CD8+ subsets of CLA+ CD45RO+ T cells were purified from peripheral blood of AD patients and healthy control individuals. We studied, in vivo activation patterns, cytokine profiles, immunoglobulin isotype regulation and the influence of these cells on eosinophil survival and apoptosis., Results: The CLA+ CD45RO+ T cells represent an in- vivo-activated memory/effector T cell subset as shown by surface expression of activation markers, spontaneous proliferation and a lower activation threshold via TCR/CD3 triggering. These cells contain and spontaneously release high amounts of preformed IL-5 and IL-13 but only very little IL-4 and IFN-gamma in their cytoplasm, as demonstrated by intracellular cytokine staining immediately after purification. Moreover, CLA+ memory/ effector T cells induce IgE production in B cells and enhance eosinophil survival by inhibiting eosinophil apoptosis in AD. In comparison, the CLA- population represents a resting memory T cell fraction, induces rather IgG4 in B cells and does not show any effect on eosinophil survival and apoptosis., Conclusion: Our results indicate that in-vivo-activated both CD4+ and CD8+ memory/effector T cells with skin-homing property play a specific and decisive role in the pathogenesis and exacerbation of AD. In contrast, resting memory T cells of atopic individuals retain normal, nonallergic immune functions.

Apoptosis is a necessary process to maintain correct cell numbers in a multicellular organism. Defects in this process may contribute to the pathogenesis of a number of human diseases. We have suggested that inhibition of apoptosis in eosinophils by cytokines such as IL-5 and GM-CSF may play an important role in the pathogenesis of allergic disorders. Here, we review our recent progress in understanding the processes regulating eosinophil apoptosis.

Inhibition of apoptosis in eosinophils by cytokines such as IL-5 and GM-CSF may play an important role in the pathogenesis of allergic and parasitic disorders. Recently, there has been some progress in the understanding of the signal transduction pathways activated by these cytokines in eosinophils. The IL-3, IL-5 and GM-CSF receptors share a common signal transducer that possesses no intrinsic kinase domain. It has been shown that eosinophil stimulation by these cytokines is associated with increases in tyrosine phosphorylation of several cellular substrates. In the past few years, there has been some progress in defining the tyrosine kinases that are activated by the IL-3/IL-5/GM-CSF receptor beta-subunit in eosinophils. This review will concentrate on this topic and on its role for the regulation of eosinophil apoptosis.

Eosinophils can synthesize various cytokines. We demonstrate that interleukin-8 (IL-8) mRNA and protein are constitutively expressed by freshly isolated resting human eosinophils. Most of the patients with bronchial asthma or atopic dermatitis show evidence for up-regulated IL-8 protein expression in eosinophils but not in neutrophils, suggesting that an eosinophil-specific cytokine may act in these patients. To investigate whether the intracellular IL-8 can be released, eosinophils were stimulated by different cytokines and platelet-activating factor (PAF). Priming with granulocyte/macrophage-colory-stimulating factor and a subsequent 25-min stimulation with RANTES or PAF resulted in release of IL-8 from highly purified human eosinophils in vitro.