Characterization of the effects on pruritus by novel treatments for atopic dermatitis

Chronic pruritus is a common and debilitating symptom in patients with atopic dermatitis and contributes to impairment of quality of life. Effective treatment of pruritus should therefore be one of the main treatment goals in patients with atopic dermatitis. Pathophysiologically, the histamine-independent pruritogens interleukin-31, interleukin-13, and interleukin-4, have been shown to play a major role in atopic dermatitis. All three cytokines can mediate chronic pruritus via Janus kinase 1/2 signaling pathways. Novel drugs target these pathways and have shown rapid and sustained reduction of pruritus in patients with atopic dermatitis in clinical use and in phase II and III clinical trials. Here we summarize the published data on the effects of these drugs on itch parameters such as overall reduction in pruritus intensity and percent of patients with atopic dermatitis achieving a relevant reduction in itch. Each of the novel drugs shows very good effects on pruritus. These data offer hope for an even better and possibly more specific treatment of pruritus in patients with atopic dermatitis in the future. In addition, the different pharmacological approaches give us the chance to learn more about the pathophysiology of pruritus in atopic dermatitis

Pathomechanismen, Klinik und Therapie chronischer urtikarieller Hauterkrankungen

Ergebnisse zu pathomechanistischen, klinischen und therapeutischen Aspekten von chronischen urtikariellen Hauterkrankungen werden in vorliegender Arbeit dargestellt und diskutiert

Skin and Systemic Inflammation in Schnitzler's Syndrome Are Associated With Neutrophil Extracellular Trap Formation

Schnitzler's syndrome is a rare autoinflammatory disorder characterized by interleukin-1ß-mediated and neutrophil-dominated inflammation. Neutrophil extracellular traps (NETs) are web-like structures of decondensed chromatin, histones, and antimicrobial peptides released by neutrophils. NETs were initially described in the context of pathogen defense but are also involved in autoimmune-mediated skin diseases. Here, we assessed the role of neutrophil extracellular trap formation (NETosis) in Schnitzler's syndrome. Immunofluorescence co-staining of myeloperoxidase and subnucleosomal complex was performed on lesional skin samples from patients with Schnitzler's syndrome, other neutrophilic dermatoses (cryopyrin-associated periodic syndrome, Sweet syndrome, and pyoderma gangrenosum), urticarial vasculitis and chronic spontaneous urticaria as well as healthy control skin. Blood neutrophils from patients with Schnitzler's syndrome and controls were isolated, and NETosis was induced by phorbol 12-myristate 13-acetate (PMA). Also, NETosis of control neutrophils induced by symptomatic Schnitzler's syndrome sera, cytokines and sub-threshold PMA doses was studied. Immunofluorescence co-staining revealed widespread and substantial NET formation in lesional skin of Schnitzler's syndrome patients but absence of NETs in chronic spontaneous urticaria and control skin. Neutrophils undergoing NETosis were observed in the skin of other neutrophilic diseases too. Correspondingly, blood neutrophils from Schnitzler's syndrome patients showed significantly elevated NETosis rates compared to control neutrophils following stimulation with PMA. Increased NETosis correlated well with high levels of C-reactive protein (CRP). SchS patients with the lowest NETosis rates had persistent joint and bone pain despite IL-1 blockade. Stimulation of control neutrophils and sub-threshold PMA with sera of symptomatic Schnitzler's syndrome patients disclosed enhanced NETosis as compared to control sera. Our results suggest that the induction of NET formation by neutrophils contributes to skin and systemic inflammation and may support the resolution of local inflammation in Schnitzler's syndrome.</p

Skin and Systemic Inflammation in Schnitzler's Syndrome Are Associated With Neutrophil Extracellular Trap Formation

Schnitzler's syndrome is a rare autoinflammatory disorder characterized by interleukin-1ß-mediated and neutrophil-dominated inflammation. Neutrophil extracellular traps (NETs) are web-like structures of decondensed chromatin, histones, and antimicrobial peptides released by neutrophils. NETs were initially described in the context of pathogen defense but are also involved in autoimmune-mediated skin diseases. Here, we assessed the role of neutrophil extracellular trap formation (NETosis) in Schnitzler's syndrome. Immunofluorescence co-staining of myeloperoxidase and subnucleosomal complex was performed on lesional skin samples from patients with Schnitzler's syndrome, other neutrophilic dermatoses (cryopyrin-associated periodic syndrome, Sweet syndrome, and pyoderma gangrenosum), urticarial vasculitis and chronic spontaneous urticaria as well as healthy control skin. Blood neutrophils from patients with Schnitzler's syndrome and controls were isolated, and NETosis was induced by phorbol 12-myristate 13-acetate (PMA). Also, NETosis of control neutrophils induced by symptomatic Schnitzler's syndrome sera, cytokines and sub-threshold PMA doses was studied. Immunofluorescence co-staining revealed widespread and substantial NET formation in lesional skin of Schnitzler's syndrome patients but absence of NETs in chronic spontaneous urticaria and control skin. Neutrophils undergoing NETosis were observed in the skin of other neutrophilic diseases too. Correspondingly, blood neutrophils from Schnitzler's syndrome patients showed significantly elevated NETosis rates compared to control neutrophils following stimulation with PMA. Increased NETosis correlated well with high levels of C-reactive protein (CRP). SchS patients with the lowest NETosis rates had persistent joint and bone pain despite IL-1 blockade. Stimulation of control neutrophils and sub-threshold PMA with sera of symptomatic Schnitzler's syndrome patients disclosed enhanced NETosis as compared to control sera. Our results suggest that the induction of NET formation by neutrophils contributes to skin and systemic inflammation and may support the resolution of local inflammation in Schnitzler's syndrome

A novel histopathological scoring system to distinguish urticarial vasculitis from chronic spontaneous urticaria

Background: Urticarial vasculitis (UV) is defined by long-lasting urticarial lesions combined with the histopathologic findings of leukocytoclastic vasculitis. As one of the major unmet needs in UV, diagnostic criteria are rather vague and not standardized. Moreover, there seems to be considerable overlap with chronic spontaneous urticaria (CSU), particularly for the normocomplementemic variant of UV. Therefore, this study aimed to develop a diagnostic scoring system that improves the histopathologic discrimination between UV and CSU. Methods: Lesional skin sections of patients with clinical and histopathologic diagnosis of UV (n = 46) and CSU (n = 51) were analyzed (blinded to the diagnosis) for the following pre-defined criteria: presence of leukocytoclasia, erythrocyte extravasation, fibrin deposits, endothelial cell swelling, ectatic vessels, blurred vessel borders, dermal edema, intravascular neutrophil, and eosinophil numbers and numbers of dermal neutrophils, macrophages and mast cells. Results: The greatest differences between UV and CSU samples were observed for leukocytoclasia (present in 76% of UV vs. 3.9% of CSU samples; p < 0.0001), erythrocyte extravasation (present in 41.3% of UV vs. 2.0% of CSU samples; p < 0.0001), and fibrin deposits (present in 27.9% of UV vessels vs. 9.7% of CSU vessels; p < 0.0001). Based on these findings, we developed a diagnostic score, the urticarial vasculitis score (UVS), which correctly assigned 37 of 46 cases of UV and 49 of 51 cases of CSU to the previously established diagnosis. Conclusion: Our results suggest that the UVS, a combined quantitative assessment of the three criteria leukocytoclasia, fibrin deposits and extravasated erythrocytes, distinguishes UV from CSU in skin histopathology. The UVS, if validated in larger patient samples, may help to improve the diagnostic approach to UV

Topical inflammasome inhibition with disulfiram prevents irritant contact dermatitis

Background: The pathogenesis of contact dermatitis, a common inflammatory skin disease with limited treatment options, is held to be driven by inflammasome activation induced by allergens and irritants. We here aim to identify inflammasome-targeting treatment strategies for irritant contact dermatitis. Methods: A high content screen with 41,184 small molecules was performed using fluorescent Apoptosis associated speck-like protein containing a CARD (ASC) speck formation as a readout for inflammasome activation. Hit compounds were validated for inhibition of interleukin (IL)-1β secretion. Of these, the approved thiuramdisulfide derivative disulfiram was selected and tested in a patch test model of irritant contact dermatitis in 25 healthy volunteers. Topical application of disulfiram, mometasone or vehicle was followed by application of sodiumdodecylsulfate (SDS) for 24 h each. Eczema induction was quantified by mexameter and laser speckle imaging. Corneocyte sampling of lesional skin was performed to assess inflammasome-mediated cytokines IL-1β and IL-18. Results: Disulfiram induced a dose-dependent inhibition of ASC speck formation and IL-1β release in cellular assays in vitro. In vivo, treatment with disulfiram, but not with vehicle and less mometasone, inhibited SDS-induced eczema. This was demonstrated by significantly lower erythema and total perfusion values assessed by mexameter and laser speckle imaging for disulfiram compared to vehicle (p < 0.001) and/or mometasone (p < 0.001). Also, corneocyte IL-18 levels were significantly reduced after application of disulfiram compared to vehicle (p < 0.001). Conclusion: We show that disulfiram is a dose-dependent inhibitor of inflammasome pathway activation in vitro and inhibitor of SDS-induced eczema in vivo. Topical application of disulfiram represents a potential treatment option for irritant contact dermatitis

The Number of MRGPRX2-Expressing Cells Is Increased in Skin Lesions of Patients With Indolent Systemic Mastocytosis, But Is Not Linked to Symptom Severity

BackgroundRecently, the expression of the mast cell (MC) receptor Mas-related G protein–coupled receptor X2 (MRGPRX2) has been detected in lesional skin of adult patients with cutaneous mastocytosis. As of yet, little is known about the clinical relevance of MRGPRX2 and its agonists in patients with mastocytosis, including indolent systemic mastocytosis (ISM).MethodsMRGPRX2 and MRGPRX2 agonists, cortistatin (CST), and major basic protein (MBP) were analyzed in lesional and non-lesional skin of patients with ISM and skin of healthy controls by immunohistochemistry. Co-localization of MRGPRX2 and MRGPRX2-mRNA with the MC marker tryptase was assessed by immunofluorescence microscopy and in situ hybridization, respectively. We assessed clinical, demographic, and laboratory data, including mastocytosis activity score (MAS), serum tryptase, and KIT D816V allele burden.ResultsThe number of MRGPRX2-expressing (MRGPRX2+) cells, MRGPRX2-mRNA+ MCs, and CST-expressing (CST+) and MBP-expressing (MBP+) cells was significantly higher in lesional skin as compared to non-lesional skin and/or skin of healthy controls (all p &lt; 0.05). Increased numbers of MRGPRX2+ cells, MRGPRX2-mRNA+ MCs, and CST+ and MBP+ cells were not associated with clinical and laboratory features of ISM, including disease burden, symptom severity, evidence of anaphylaxis, and tryptase levels.ConclusionsSkin lesions of patients with ISM showed high numbers of MRGPRX2+ cells, although they were not linked to symptom severity. Clinical relevance of the MRGPRX2-mediated pathway of MC activation in ISM remains unclear and should be investigated in further studies

The global impact of the COVID-19 pandemic on the management and course of chronic urticaria

Introduction: The COVID-19 pandemic dramatically disrupts health care around the globe. The impact of the pandemic on chronic urticaria (CU) and its management are largely unknown. Aim: To understand how CU patients are affected by the COVID-19 pandemic; how specialists alter CU patient management; and the course of CU in patients with COVID-19. Materials and Methods: Our cross-sectional, international, questionnaire-based, multicenter UCARE COVID-CU study assessed the impact of the pandemic on patient consultations, remote treatment, changes in medications, and clinical consequences. Results: The COVID-19 pandemic severely impairs CU patient care, with less than 50% of the weekly numbers of patients treated as compared to before the pandemic. Reduced patient referrals and clinic hours were the major reasons. Almost half of responding UCARE physicians were involved in COVID-19 patient care, which negatively impacted on the care of urticaria patients. The rate of face-to-face consultations decreased by 62%, from 90% to less than half, whereas the rate of remote consultations increased by more than 600%, from one in 10 to more than two thirds. Cyclosporine and systemic corticosteroids, but not antihistamines or omalizumab, are used less during the pandemic. CU does not affect the course of COVID-19, but COVID-19 results in CU exacerbation in one of three patients, with higher rates in patients with severe COVID-19. Conclusions: The COVID-19 pandemic brings major changes and challenges for CU patients and their physicians. The long-term consequences of these changes, especially the increased use of remote consultations, require careful evaluation

An immunohistological characterization of potential diagnostic biomarkers in urticarial vasculitis and autoinflammatory skin diseases

Urtikariavaskulitis (UV) und autoinflammatorische Erkrankungen der Haut (AIH), wie Cryopyrin-assoziiertes periodisches Syndrom (CAPS), Schnitzler-Syndrom (SchS) und adulter Morbus Still (AOSD), sind seltene Erkrankungen. Das dabei charakteristische urtikarielle Exanthem unterscheidet sich klinisch oft nicht von den Urticae der deutlich häufigeren chronischen spontanen Urtikaria (csU). Ziel der Arbeit ist die Untersuchung läsionaler Haut bei AIH und UV auf potentielle diagnostische Biomarker zur Abgrenzung gegen csU. Es wurden histologische (HE, Toluidinblau als Mastzell-Marker), immunhistologische (Myeloperoxidase [MPO] als Neutrophilen-Marker, Interleukine [IL-1β, IL-6, IL-17, IL-18], Vascular Endothelial Growth Factor [VEGF] und die Inflammasommarker Nucleotide-binding Domain-like Receptor Protein 3 [NLRP3], Apoptosis Speck Protein [ASC] und Caspase-1) sowie Immunfluoreszenz- (MPO, Histon H2A, Cathelicidin, DAPI, Interleukine, Avidin-FITC) Färbungen an formalin-fixiertem Hautgewebe durchgeführt. Die Untersuchungen erfolgten an läsionaler Haut von Patienten mit SchS (n=9), CAPS (n=3), AOSD (n=1), UV (n=18) und csU (n=10) sowie an gesunden Kontrollen (n=10) und wurden mithilfe (semi-)quantitativer Histomorphometrie analysiert. Eine Proteinkonzentrationsbestimmung erfolgte mittels ELISA für Interleukine und Caspase-1 an kryo-konservierten Hautproben bei SchS (n=6), UV (n=10), csU (n=5) und Gesunden (n=11). Die immunhistologischen Untersuchungen an läsionaler Haut zeigten eine Erhöhung von IL-1β, IL-6, IL-18, ASC und Caspase-1 sowie VEGF bei AIH und UV im Vergleich zu csU und Gesunden. Der Unterschied von SchS gegenüber csU (p≤0,05) und Gesunden (p≤0,001) war für IL-6 und ASC signifikant. Bestätigend hierzu fand sich im ELISA- Proteinnachweis für die Interleukine sowie Caspase-1 eine signifikante Erhöhung bei SchS vergleichend zu csU (p≤0,05). Durch Immunfluoreszenz- Kolokalisationsfärbungen wurden Mastzellen (IL-1β, IL-6) und neutrophile Granulozyten (IL-1β, IL-18) als Interleukin-Produzenten identifiziert. Hinsichtlich der Mastzelldichte bestand kein signifikanter Unterschied. Ein erhöhtes dermales MPO-positives Infiltrat wurde bei AIH und UV im Vergleich zu csU und Gesunden beobachtet, mit signifikantem Unterschied zwischen SchS zu csU und Gesunden (p≤0,05). Läsionale Haut von AIH, nicht aber von csU, zeigte Hinweise für das Vorhandensein von Neutrophil Extracellular Traps (NETs). IL-1-assoziierte Zytokine und Inflammasomkomponenten sind in läsionaler Haut bei AIH aufreguliert und werden von Mastzellen (IL-1β, IL-6) und Neutrophilen (IL-6, IL-18) produziert. IL-1β und IL-6 wurden neben IL-18, Caspase-1, ASC sowie MPO im Sinne eines Biomarker-Profils als besonders robuste Marker zur Differenzierung der AIH von csU identifiziert. Die UV nahm eine Stellung zwischen den AIH und der csU ein, hinweisend auf eine mögliche autoinflammatorische Komponente in einer UV-Subpopulation. Diese Ergebnisse sollten an größeren Patientenzahlen weiter untersucht werden.Urticarial vasculitis (UV) and autoinflammatory skin diseases (AISD) i.e. Cryopyrin-associated periodic syndrome (CAPS), Schnitzler’s syndrome (SchS) and Adult Onset Still’s Disease (AOSD) are rare diseases. Thereby it is often difficult to distinguish their characteristic urticarial exanthema from hives caused by the more frequent chronic spontaneous urticaria (csU). Aim of this study is to examine lesional skin of patients with AISD and UV for potential diagnostic biomarkers allowing to differentiate these patients from csU patients. Histological (HE, toluidine blue for mast cells), immunohistological (myeloperoxidase [MPO] for neutrophils, interleukins [IL-1β, IL-6, IL-17, IL-18], vascular endothelial growth factor [VEGF] and the inflammasome markers nucleotide-binding domain-like receptor protein 3 [NLRP3], apoptosis speck protein [ASC] and caspase-1) as well as immunofluorescence (MPO, histone H2A, cathelicidin, DAPI, interleukins, Avidin-FITC) stainings of formalin-fixed lesional skin were performed. Lesional skin of patients with SchS (n=9), CAPS (n=3), AOSD (n=1), UV (n=18) and csU (n=10) as well as healthy controls (n=10) was examined and analyzed by (semi-)quantitative histomorphometry. Determination of protein concentration was performed by ELISA for interleukins and caspase-1 in cryo-preserved skin samples for SchS (n=6), UV (n=10), csU (n=5) and controls (n=11). Immunohistological examination of lesional skin showed an increase of IL-1β, IL-6, IL-18, VEGF, ASC and caspase-1 for AISD and UV compared to csU and controls. There was a significant difference for IL-6 and ASC between SchS and both csU (p≤0,05) and healthy controls (p≤0,001). ELISA confirmed a significant difference for interleukins and caspase-1 between SchS and csU (p≤0,05). Immunofluorescence-colocalization identified mast cells (IL-1β, IL-6) and neutrophils (IL-1β, IL-18) as interleukin producers. No statistical significance was observed for mast cell numbers. High neutrophilic infiltration in AISD and UV compared to csU and healthy controls was demonstrated with significant difference between SchS and both csU and controls (p≤0.05). AISD lesional skin showed structures indicative for neutrophil extracellular traps (NETs) while csU did not. IL-1-related cytokines and inflammasome components are upregulated in lesional AISD skin and produced by mast cells (IL-1β, IL-6) and neutrophils (IL-6, IL-18). We identified IL-1β and IL-6 as especially robust markers besides IL-18, caspase-1, ASC and MPO as a biomarker profile to differentiate AISD from csU. UV took an intermediate position between AIH and csU, indicating a possible autoinflammatory component in a UV-subpopulation. These results should be further explored in larger patient numbers