The stimulation of TH2 cells results in increased IL-5 and IL-13 production via the H4 receptor.

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory skin disease resulting in decreased quality of life. Histamine and specifically the H4 receptor play a key role in the inflammatory process in AD and serve as targets for novel therapeutic approaches. OBJECTIVE: In the present study we aimed to elucidate the immunopathological mechanisms with which the H4 receptor impacts TH2 cells and contributes to AD pathophysiology. METHODS: Total CD4+ T cells obtained from healthy or AD individuals and in vitro differentiated TH2 cells were cultured under different conditions and the mRNA expression or protein production of target molecules were determined using quantitative real-time PCR and ELISA. RESULTS: H4 receptor mRNA expression was upregulated concentration dependent upon IL-4 stimulation in in vitro differentiated TH2 cells progressively during the differentiation. Transcriptomic analysis of in vitro differentiated TH2 versus TH1 cells revealed that the H4 receptor among other genes represents one of the highly upregulated genes in TH2 cells. Most importantly, increased amounts of IL-5 and IL-13 mRNA expression were detected in in vitro differentiated TH2 cells as well as protein secretion in the presence of histamine or of the H4 receptor-selective-agonist when compared to the untreated control. CONCLUSION: We show for the first time an H4 receptor dependent upregulation of the pro-inflammatory cytokines IL-5 and IL-13 in human TH2 cells by histamine. This suggests that the blockade of the H4 receptor may lead to downregulation of these cytokines and amelioration of AD symptoms as reported in first clinical studies.

Polymeric Micellar Nanoparticles Enable Image-guided Drug Delivery in Solid Tumors.

We report the development of a nanotechnology to co-deliver chemocoxib A with a reactive oxygen species (ROS)-activatable and COX-2 targeted pro-fluorescent probe, fluorocoxib Q (FQ) enabling real time visualization of COX-2 and CA drug delivery into solid cancers, using a di-block PPS 135 - b -POEGA 17 copolymer, selected for its intrinsic responsiveness to elevated reactive oxygen species (ROS), a key trait of the tumor microenvironment. FQ and CA were synthesized independently, then co-encapsulated within micellar PPS 135 - b -POEGA 17 co-polymeric nanoparticles (FQ-CA-NPs), and were assessed for cargo concentration, hydrodynamic diameter, zeta potential, and ROS-dependent cargo release. The uptake of FQ-CA-NPs in mouse mammary cancer cells and cargo release was assessed by fluorescence microscopy. Intravenous delivery of FQ-CA-NPs to mice harboring orthotopic mammary tumors, followed by vital optimal imaging, was used to assess delivery to tumors in vivo . The CA-FQ-NPs exhibited a hydrodynamic diameter of 109.2 ± 4.1 nm and a zeta potential (σ) of -1.59 ± 0.3 mV. Fluorescence microscopy showed ROS-dependent cargo release by FQ-CA-NPs in 4T1 cells, decreasing growth of 4T1 breast cancer cells, but not affecting growth of primary human mammary epithelial cells (HMECs). NP-derived fluorescence was detected in mammary tumors, but not in healthy organs. Tumor LC-MS/MS analysis identified both CA (2.38 nmol/g tumor tissue) and FQ (0.115 nmol/g tumor tissue), confirming the FQ-mediated image guidance of CA delivery in solid tumors. Thus, co-encapsulation of FQ and CA into micellar nanoparticles (FQ-CA-NPs) enabled ROS-sensitive drug release and COX-2-targeted visualization of solid tumors.

The extracellular serine protease from Staphylococcus epidermidis elicits a type 2-biased immune response in atopic dermatitis patients.

Background: Atopic dermatitis (AD) is a chronic, relapsing inflammatory skin disease with skin barrier defects and a misdirected type 2 immune response against harmless antigens. The skin microbiome in AD is characterized by a reduction in microbial diversity with a dominance of staphylococci, including Staphylococcus epidermidis (S. epidermidis). Objective: To assess whether S. epidermidis antigens play a role in AD, we screened for candidate allergens and studied the T cell and humoral immune response against the extracellular serine protease (Esp). Methods: To identify candidate allergens, we analyzed the binding of human serum IgG4, as a surrogate of IgE, to S. epidermidis extracellular proteins using 2-dimensional immunoblotting and mass spectrometry. We then measured serum IgE and IgG1 binding to recombinant Esp by ELISA in healthy and AD individuals. We also stimulated T cells from AD patients and control subjects with Esp and measured the secreted cytokines. Finally, we analyzed the proteolytic activity of Esp against IL-33 and determined the cleavage sites by mass spectrometry. Results: We identified Esp as the dominant candidate allergen of S. epidermidis. Esp-specific IgE was present in human serum; AD patients had higher concentrations than controls. T cells reacting to Esp were detectable in both AD patients and healthy controls. The T cell response in healthy adults was characterized by IL-17, IL-22, IFN-γ, and IL-10, whereas the AD patients' T cells lacked IL-17 production and released only low amounts of IL-22, IFN-γ, and IL-10. In contrast, Th2 cytokine release was higher in T cells from AD patients than from healthy controls. Mature Esp cleaved and activated the alarmin IL-33. Conclusion: The extracellular serine protease Esp of S. epidermidis can activate IL-33. As an antigen, Esp elicits a type 2-biased antibody and T cell response in AD patients. This suggests that S. epidermidis can aggravate AD through the allergenic properties of Esp.

Single-cell RNA sequencing reveals 2D cytokine assay can model atopic dermatitis more accurately than immune-competent 3D setup.

Modelling atopic dermatitis (AD) in vitro is paramount to understand the disease pathophysiology and identify novel treatments. Previous studies have shown that the Th2 cytokines IL-4 and IL-13 induce AD-like features in keratinocytes in vitro. However, it has not been systematically researched whether the addition of Th2 cells, their supernatants or a 3D structure is superior to model AD compared to simple 2D cell culture with cytokines. For the first time, we investigated what in vitro option most closely resembles the disease in vivo based on single-cell RNA sequencing data (scRNA-seq) obtained from skin biopsies in a clinical study and published datasets of healthy and AD donors. In vitro models were generated with primary fibroblasts and keratinocytes, subjected to cytokine treatment or Th2 cell cocultures in 2D/3D. Gene expression changes were assessed using qPCR and Multiplex Immunoassays. Of all cytokines tested, incubation of keratinocytes and fibroblasts with IL-4 and IL-13 induced the closest in vivo-like AD phenotype which was observed in the scRNA-seq data. Addition of Th2 cells to fibroblasts failed to model AD due to the downregulation of ECM-associated genes such as POSTN. While keratinocytes cultured in 3D showed better stratification than in 2D, changes induced with AD triggers did not better resemble AD keratinocyte subtypes observed in vivo. Taken together, our comprehensive study shows that the simple model using IL-4 or IL-13 in 2D most accurately models AD in fibroblasts and keratinocytes in vitro, which may aid the discovery of novel treatment options.

Italian S3-Guideline on the treatment of Atopic Eczema - Part 1: Systemic therapy, adapted from EuroGuiDerm by the Italian Society of Dermatology and STD (SIDEMAST), the Italian Association of Hospital Dermatologists (ADOI) and the Italian Society of Allergological and Environmental Dermatology (SIDAPA).

SIDeMaST (Società Italiana di Dermatologia Medica, Chirurgica, Estetica e delle Malattie Sessualmente Trasmesse) contributed to the development of the present guideline on the systemic treatment of chronic plaque psoriasis. With the permission of EuroGuiDerm, SIDeMaST adapted the guideline to the Italian healthcare context to supply a reliable and affordable tool to Italian physicians who take care of patients affected by atopic dermatitis. The evidence- and consensus-based guideline on atopic eczema was developed in accordance with the EuroGuiDerm Guideline and Consensus Statement Development Manual. Four consensus conferences were held between December 2020 and July 2021. Twenty-nine experts (including clinicians and patient representatives) from 12 European countries participated. This first part of the guideline includes general information on its scope and purpose, the health questions covered, target users and a methods section. It also provides guidance on which patients should be treated with systemic therapies, as well as recommendations and detailed information on each systemic drug. The systemic treatment options discussed in the guideline comprise conventional immunosuppressive drugs (azathioprine, ciclosporin, glucocorticosteroids, methotrexate and mycophenolate mofetil), biologics (dupilumab, lebrikizumab, nemolizumab, omalizumab and tralokinumab) and janus kinase inhibitors (abrocitinib, baricitinib and upadacitinib). Part two of the guideline will address avoidance of provocation factors, dietary interventions, immunotherapy, complementary medicine, educational interventions, occupational and psychodermatological aspects, patient perspective and considerations for pediatric, adolescent, pregnant and breastfeeding patients.

Italian S3-Guideline on the treatment of Atopic Eczema - First Update, adapted from EuroGuiDerm by the Italian Society of Dermatology and STD (SIDEMAST), the Italian Association of Hospital Dermatologists (ADOI) and the Italian Society of Allergological and Occupational Dermatology (SIDAPA).

The evidence- and consensus-based guideline on atopic eczema, published in JEADV on 18 August 2022 (part 1) and 3 September 2022 (part 2) was developed in accordance with the EuroGuiDerm Guideline and Consensus Statement Development Manual. Four consensus conferences were held between December 2020 and July 2021. Twenty-nine experts (including clinicians and patient representatives) from 12 European countries participated. To reflect the most recent evidence on novel systemic medications, an update was published in October 2022. According to the purpose of the Italian Society of Dermatology and STD (SIDEMAST), the Italian Association of Hospital Dermatologists (ADOI) and the Italian Society of Allergological and Environmental Dermatology (SIDAPA) to adapt the EuroGuiDerm guideline on the treatment of atopic eczema into the Italian Healthcare setting, the original update has been supplemented by inserting notes, well highlighted by the original text, to emphasize the laws, rules, procedures and suggestions of the Italian Ministry of Health and regional Health authorities.

Italian S3-Guideline on the treatment of Atopic Eczema - Part 2: non-systemic treatments and treatment recommendations for special AE patient populations, adapted from EuroGuiDerm by the Italian Society of Dermatology and STD (SIDEMAST), the Italian Association of Hospital Dermatologists (ADOI) and the Italian Society of Allergological and Occupational Dermatology (SIDAPA).

SIDeMaST (Società Italiana di Dermatologia Medica, Chirurgica, Estetica e delle Malattie Sessualmente Trasmesse) contributed to the development of the present guideline on the systemic treatment of chronic plaque psoriasis. With the permission of EuroGuiDerm, SIDeMaST adapted the guideline to the Italian healthcare context to supply a reliable and affordable tool to Italian physicians who take care of patients affected by atopic dermatitis. The evidence- and consensus-based guideline on atopic eczema was developed in accordance with the EuroGuiDerm Guideline and Consensus Statement Development Manual. Four consensus conferences were held between December 2020 and July 2021. Twenty-nine experts (including clinicians and patient representatives) from 12 European countries participated. This second part of the guideline includes recommendations and detailed information on basic therapy with emollients and moisturizers, topical anti-inflammatory treatment, antimicrobial and antipruritic treatment and UV phototherapy. Furthermore, this part of the guideline covers techniques for avoiding provocation factors, as well as dietary interventions, immunotherapy, complementary medicine and educational interventions for patients with atopic eczema and deals with occupational and psychodermatological aspects of the disease. It also contains guidance on treatment for pediatric and adolescent patients and pregnant or breastfeeding women, as well as considerations for patients who want to have a child. A chapter on the patient perspective is also provided. The first part of the guideline, published separately, contains recommendations and guidance on systemic treatment with conventional immunosuppressive drugs, biologics and janus kinase (JAK) inhibitors, as well as information on the scope and purpose of the guideline, and a section on guideline methodology.

Modelling atopic dermatitis in healthy human skin for the characterization of topical compounds.

Suitable human models for the development and characterization of topical compounds for inflammatory skin diseases such as atopic dermatitis are not readily available to date. We describe here the development of a translational model involving healthy human skin mimicking major aspects of AD and its application for the characterization of topical Janus kinase inhibitors. Full thickness human abdominal skin obtained from plastic surgery stimulated in vitro with IL4 and IL13 shows molecular features of AD. This is evidenced by STAT6 phosphorylation assessed by immunohistochemistry and analysis of skin lysates. Broad transcriptome changes assessed by AmpliSeq followed by gene set variation analysis showed a consistent upregulation of gene signatures characterizing AD in this model. Topical application of experimental formulations of compounds targeting the JAK pathway to full thickness skin normalizes the molecular features of AD induced by IL4 and IL13 stimulation. The inhibitory effects of topical JAK inhibitors on molecular features of AD are supported by pharmacokinetic analysis. The model described here is suited for the characterization of topical compounds for AD and has the potential to be extended to other inflammatory skin diseases and pathophysiological pathways.

A comprehensive genetic map of cytokine responses in Lyme borreliosis.

The incidence of Lyme borreliosis has risen, accompanied by persistent symptoms. The innate immune system and related cytokines are crucial in the host response and symptom development. We characterized cytokine production capacity before and after antibiotic treatment in 1,060 Lyme borreliosis patients. We observed a negative correlation between antibody production and IL-10 responses, as well as increased IL-1Ra responses in patients with disseminated disease. Genome-wide mapping the cytokine production allowed us to identify 34 cytokine quantitative trait loci (cQTLs), with 31 novel ones. We pinpointed the causal variant at the TLR1-6-10 locus and validated the regulation of IL-1Ra responses at transcritpome level using an independent cohort. We found that cQTLs contribute to Lyme borreliosis susceptibility and are relevant to other immune-mediated diseases. Our findings improve the understanding of cytokine responses in Lyme borreliosis and provide a genetic map of immune function as an expanded resource.

Inhibition of RNase 7 by RNase inhibitor promotes inflammation and Staphylococcus aureus growth: Implications for atopic dermatitis.

BACKGROUND: The antimicrobial ribonuclease RNase 7 is abundantly expressed in the epidermis of lesional skin of atopic dermatitis (AD). Host RNase inhibitor (RI) binds to RNase 7 and blocks its ribonuclease activity. This study aimed to evaluate the impact of RNase 7-RI interactions on AD. METHODS: Cultured human primary keratinocytes, with siRNA-mediated downregulation of RNase 7 and RI, were stimulated with the synthetic RNA polyinosinic-polycytidylic acid (poly I:C). Induction of proinflammatory mediators was analyzed by real-time PCR and ELISA. RI expression in AD non-lesional and lesional skin biopsies and healthy controls was analyzed by real-time PCR and immunostaining. RI protein release in vivo on the AD skin surface was determined by western blot. Antimicrobial and ribonuclease assays were used to investigate the functional role of RI. RESULTS: RNase 7 inhibited the RNA-induced expression of proinflammatory mediators in keratinocytes. Accordingly, downregulation of RNase 7 in keratinocytes enhanced RNA-mediated induction of proinflammatory mediators, whereas downregulation of RI had the opposite effect. RI was released by damaged keratinocytes and epidermis. In vivo expression and release of RI on the skin surface were enhanced in lesional AD skin. Rinsing solution from the surface of lesional AD skin blocked the ribonuclease activity of RNase 7. The anti-Staphylococcus aureus activity of RNase 7 was abrogated by RI. CONCLUSIONS: Our data suggest a novel role of RI as a trigger factor of inflammation in AD by blocking the ribonuclease and antimicrobial activity of RNase 7, thereby enhancing RNA-mediated inflammation and S. aureus growth.

Obesity is linked to disease severity in moderate to severe atopic dermatitis-Data from the prospective observational TREATgermany registry.

BACKGROUND: There are conflicting data on a potential association between obesity and atopic dermatitis (AD). The purpose of this study was to investigate the relationship between obesity and AD disease severity. METHODS: Patients from the TREATgermany registry cohort were divided into three groups according to their body mass index (BMI). Due to low numbers, underweight patients (BMI <18.5 kg/m2) were excluded from the analysis. Physician- and patient-reported disease severity scores as well as additional phenotypic characteristics were evaluated for association with BMI. Generalized linear mixed models and multinomial logit models, respectively, were applied to investigate the association of BMI, age, sex and current systemic AD treatment with disease severity. RESULTS: This study encompassed 1416 patients, of which 234 (16.5%) were obese (BMI ≥30 kg/m2). Obesity was associated with lower educational background and smoking. Otherwise, obese and non-obese AD patients had similar baseline characteristics. Increased BMI was associated with higher oSCORAD (adjusted ß: 1.24, 95% CI: 1.05-1.46, p = 0.013) and Patient-oriented eczema measure (POEM) (adjusted ß: 1.09, 95% CI: 1.01-1.17, p = 0.038). However, the absolute difference in the overall oSCORAD was small between obese and non-obese AD patients (Δ oSCORAD = 2.5). Allergic comorbidity was comparable between all three groups, with the exception of asthma which was more pronounced in obese patients (p < 0.001). DISCUSSION: In this large and well-characterized AD patient cohort, obesity is significantly associated with physician- and patient-assessed measures of AD disease severity. However, the corresponding effect sizes were low and of questionable clinical relevance. The overall prevalence of obesity among the German AD patients was lower than in studies on other AD cohorts from different countries, which confirms previous research on the German population and suggests regional differences in the interdependence of AD and obesity prevalence.

Hand eczema symptoms, exposures and skin care in orthodontics : A national, cross-sectional questionnaire-based survey.

OBJECTIVES: Occupational hand eczema is a common inflammatory skin condition among healthcare professionals. Orthodontists are frequently exposed to a variety of irritating and allergenic substances, and therefore they belong to a predisposed group to develop hand eczema. However, current data on the prevalence and predisposing factors among orthodontists to provide adequate prophylaxis are lacking. METHODS: An anonymous online survey was conducted in Germany between January and February 2023 and distributed to 2402 orthodontists. The questionnaire addressed general information on current skin status, as well as occupational skin exposure and skin care. RESULTS: A total of 209 orthodontists responded to the survey. Seventy-four percent reported experiencing hand eczema-specific symptoms within the last 12 months, with 24% describing moderate and 10% describing severe symptoms. The average daily glove wearing time was stated to be 6 ± 2 h. The most frequently reported triggers at work were frequent hand washing (62.7%) and hand disinfection (59.1%). Among all the respondents, 22.6% stated not using either barrier cream or moisturizer. CONCLUSIONS: This study showed a high prevalence of hand eczema symptoms among orthodontists, which is probably due to frequent disinfection, hand washing, and contact with allergens such as acrylates. In this professional group especially, against a background of future increasing acrylate and epoxy resin exposures due to in-office three-dimensional printing processes, timely education and skin protection could decisively counteract the pathogenesis of hand eczema.

Postpolymerization Modification of Poly(2-vinyl-4,4-dimethyl azlactone) as a Versatile Strategy for Drug Conjugation and Stimuli-Responsive Release.

Postpolymerization modification of highly defined "scaffold" polymers is a promising approach for overcoming the existing limitations of controlled radical polymerization such as batch-to-batch inconsistencies, accessibility to different monomers, and compatibility with harsh synthesis conditions. Using multiple physicochemical characterization techniques, we demonstrate that poly(2-vinyl-4,4-dimethyl azlactone) (PVDMA) scaffolds can be efficiently modified with a coumarin derivative, doxorubicin, and camptothecin small molecule drugs. Subsequently, we show that coumarin-modified PVDMA has a high cellular biocompatibility and that coumarin derivatives are liberated from the polymer in the intracellular environment for cytosolic accumulation. In addition, we report the pharmacokinetics, biodistribution, and antitumor efficacy of a PVDMA-based polymer for the first time, demonstrating unique accumulation patterns based on the administration route (i.e., intravenous vs oral), efficient tumor uptake, and tumor growth inhibition in 4T1 orthotopic triple negative breast cancer (TNBC) xenografts. This work establishes the utility of PVDMA as a versatile chemical platform for producing polymer-drug conjugates with a tunable, stimuli-responsive delivery.

Symptom severity reflected by NYHA grade is independently associated with pruritus in chronic heart failure patients.

BACKGROUND: Pruritus is a symptom profoundly impairing patients' quality of life (QoL). It is a common symptom in chronic heart failure (CHF) patients of yet unknown nature. The aim of this study was to evaluate the risk factors of pruritus in CHF patients. METHODS: For this monocentric, prospective cohort study, CHF patients were recruited and CHF symptoms, comorbidities and drug intake were assessed using a structured report. Additionally, a questionnaire evaluated pruritus symptoms. Detailed medical histories including laboratory test results were retrieved from patient files for all participants. RESULTS: We evaluated data from 550 CHF patients. Of those, 25.3% reported pruritus to occur frequently (3-5 times per week), often (1-2 times per week) or daily. Patients of higher NYHA classes (NYHA III + IV) experienced significantly more pruritus (31.2%) than lower NYHA classes (NYHA I + II) (21.1%, p = 0.024). Patients with pruritus reported disproportionately often concomitant stasis dermatitis (p = 0.026) and chronic lung disease (p = 0.014). Other parameters reflecting cardiac, liver, kidney and thyroid function, as well as medical therapies showed no significant differences between patients with and without pruritus. In the multivariate logistic regression analysis, only NYHA class (p = 0.016, OR 1.55, 95% confidence interval (CI): [1.09; 2.20]) and elevated leukocyte count (p = 0.007, OR 1.11, CI [1.03; 1.21]) remained significantly associated with pruritus in CHF patients. CONCLUSIONS: NYHA class is an independent predictor for pruritus in CHF patients. Besides NYHA class, leukocyte count was also associated with increased pruritus. Pruritus may impair QoL in CHF patients and should thus be included in the assessment of those patients. We suggest that providing best care for CHF patients can be achieved through an interdisciplinary approach of cardiologists and dermatologists and should include a pruritus assessment.

S3 Guideline Atopic dermatitis: Part 1 - General aspects, topical and non-drug therapies, special patient groups.

This S3 guideline was created based on the European S3 guideline, with special consideration of the medical conditions in the German-speaking region and incorporating additions from the previous German-language version. The interdisciplinary guideline commission consisted of representatives from the German Dermatological Society, the Professional Association of German Dermatologists, the Austrian Society of Dermatology and Venereology, the Swiss Society of Dermatology and Venereology, the German Society for Allergology and Clinical Immunology, the German Society for Pediatric and Adolescent Medicine, the Professional Association of Pediatricians and Adolescent Medicine, the Society for Pediatric Allergology and Environmental Medicine, the German Society for Pediatric Rehabilitation and Prevention, the German Society for Psychosomatic Medicine and Medical Psychotherapy, the German Network for Health Services Research, the German Eczema Association and the German Allergy and Asthma Association. This first part of the guideline focuses on the definition and diagnostic aspects of atopic dermatitis (AD), addressing topical therapy as well as non-pharmacological treatment approaches such as UV therapy, psychoeducational therapy, dietary interventions for AD, allergen immunotherapy for AD, and complementary medicine. This part of the guideline also covers specific aspects of AD in children and adolescents, during pregnancy and lactation, and in the context of family planning. Additionally, it addresses occupational aspects of AD and highlights the perspective of the patients. The second part of the guideline, published separately, addresses the systemic therapy of AD.

Protein-Functionalized Gold Nanospheres with Tunable Photothermal Efficiency for the Near-Infrared Photothermal Ablation of Biofilms.

Temperature-responsive nanostructures with high antimicrobial efficacy are attractive for therapeutic applications against multidrug-resistant bacteria. Here, we report temperature-responsive nanospheres (TRNs) engineered to undergo self-association and agglomeration above a tunable transition temperature (Tt). The temperature-responsive behavior of the nanoparticles is obtained by functionalizing citrate-capped spherical gold nanoparticles (AuNPs) with elastin-like polypeptides (ELPs). Using protein design principles, we achieve a broad range of attainable Tt values and photothermal conversion efficiencies (η). Two approaches were used to adjust this range: First, by altering the position of the cysteine residue used to attach ELP to the AuNP, we attained a Tt range from 34 to 42 °C. Then, by functionalizing the AuNP with an additional small globular protein, we could extend this range to 34-50 °C. Under near-infrared (NIR) light exposure, all TRNs exhibited reversible agglomeration. Moreover, they showed an enhanced photothermal conversion efficiency in their agglomerated state relative to the dispersed state. Despite their spherical shape, TRNs have a photothermal conversion efficiency approaching that of gold nanorods (η = 68 ± 6%), yet unlike nanorods, the synthesis of TRNs requires no cytotoxic compounds. Finally, we tested TRNs for the photothermal ablation of biofilms. Above Tt, NIR irradiation of TRNs resulted in a 10,000-fold improvement in killing efficiency compared to untreated controls (p < 0.0001). Below Tt, no enhanced antibiofilm effect was observed. In conclusion, engineering the interactions between proteins and nanoparticles enables the tunable control of TRNs, resulting in a novel antibiofilm nanomaterial with low cytotoxicity.

S3 guideline Atopic dermatitis: Part 2 - Systemic treatment.

The present S3 guideline was created based on the European English-language S3 guideline, with special consideration given to the medical conditions in the German-speaking region, and with additions from the previous German-language version, in accordance with the criteria of the AWMF. This second part of the guideline addresses the systemic therapy of atopic dermatitis (AD). It covers topics such as the indication for systemic therapy in children, adolescents, and adult patients with AD. Furthermore, it addresses all medications approved for AD, such as the biologics dupilumab and tralokinumab, the Janus kinase inhibitors abrocitinib, baricitinib, and upadacitinib, as well as conventional immunosuppressive therapies with systemic glucocorticosteroids and ciclosporin. Additionally, it discusses systemic off-label therapies. The first part of the guideline, published separately, includes the definition and diagnostic aspects of AD, describes topical therapy, non-drug therapy approaches, and addresses aspects related to special patient groups.