Zusammenfassung Die vorliegende S3‐Leitlinie wurde auf der Basis der europäischen englischsprachigen S3‐Leitlinie unter besonderer Berücksichtigung der medizinischen Gegebenheiten im deutschsprachigen Raum und mit Ergänzungen der deutschsprachigen Vorgängerversion, entsprechend den Kriterien der AWMF, erstellt. Dieser zweite Teil der Leitlinie behandelt die systemische Therapie der atopischen Dermatitis (AD). Eingegangen wird unter anderem auf die Indikationsstellung für eine Systemtherapie bei Kindern, Jugendlichen und erwachsenen Patienten mit AD. Darüber hinaus werden alle für die AD zugelassenen Medikamente wie die Biologika Dupilumab und Tralokinumab, die Januskinase‐Inhibitoren Abrocitinib, Baricitinib und Upadacitinib sowie die konventionellen immunsuppressiven Therapien mit systemischen Glukokortikosteroiden und Ciclosporin adressiert. Systemische Off‐Label ‐Therapien werden ebenfalls behandelt. Der separat publizierte erste Teil der Leitlinie umfasst die Definition und diagnostischen Aspekte der AD, beschreibt die topische Therapie sowie nichtmedikamentöse Therapieverfahren und geht auf Aspekte bei besonderen Patientengruppen ein.

ZusammenfassungDiese S3‐Leitlinie wurde auf der Basis der europäischen S3‐Leitlinie unter besonderer Berücksichtigung der medizinischen Gegebenheiten im deutschsprachigen Raum und mit Ergänzungen der deutschsprachigen Vorgängerversion erstellt. Die interdisziplinäre Leitlinienkommission bestand aus Vertretern der Deutschen Dermatologischen Gesellschaft, dem Berufsverband der Deutschen Dermatologen, der Österreichischen Gesellschaft für Dermatologie und Venerologie, der Schweizerischen Gesellschaft für Dermatologie und Venerologie, der Deutschen Gesellschaft für Allergologie und Klinische Immunologie, der Deutschen Gesellschaft für Kinder‐ und Jugendmedizin, dem Berufsverband der Kinder‐ und Jugendärzte, der Gesellschaft für Pädiatrische Allergologie und Umweltmedizin, der Deutschen Gesellschaft für Pädiatrische Rehabilitation und Prävention, der Deutschen Gesellschaft für Psychosomatische Medizin und Ärztliche Psychotherapie, dem Deutschen Netzwerk Versorgungsforschung, dem Deutschen Neurodermitis Bund und dem Deutschen Allergie‐ und Asthmabund. Dieser erste Teil der Leitlinie geht auf die Definition und die diagnostischen Aspekte der atopischen Dermatitis (AD) ein, behandelt die topische Therapie sowie die nichtmedikamentösen Therapieverfahren wie die UV‐Therapie, die psychoedukative Therapie, diätische Interventionen bei AD, die Allergen‐spezifische Immuntherapie bei AD und die Komplementärmedizin. Auch behandelt dieser Teil der Leitlinie die besonderen Aspekte der AD bei Kindern und Jugendlichen, in der Schwangerschaft und in der Stillzeit sowie bei Kinderwunsch. Außerdem wird auf berufsbezogene Aspekte der AD eingegangen und die Perspektive der Patienten hervorgehoben. Der zweite, separat publizierte Teil der Leitlinie adressiert die systemische Therapie der AD.

Microbiome next-generation sequencing data are distorted by multiple laboratory and bioinformatic biases. Extraction bias, sequence errors and contamination are major factors blurring true biological signals, and could potentially be corrected by jointly optimizing experimental and computational workflows. We compared dilution series (10⁸-10⁴ bacteria) of 3 mock communities with an even or staggered composition. DNA was extracted with 8 different extraction protocols (2 buffers, 2 extraction kits, 2 lysis conditions). Extracted DNA was sequenced (V1-V3 16S) together with corresponding DNA mocks. Sequences were denoised using DADA2, and annotated by exact matching against reference genomes. Independent of the extraction protocol, contamination increased with less input cells, but interestingly, chimera formation increased with higher input cells. Microbiome composition was significantly different between extraction kits and lysis conditions, but not between buffers. Differences in the skin microbiome between two participants were more pronounced than any difference between extraction protocols. Bias in microbiome composition compared to corresponding DNA mocks revealed that extraction protocols favored specific groups of bacteria. Strikingly, this extraction bias per groups of species was predictable by bacterial cell morphology. We provide novel explanations that higher DNA density increases chimera formation during PCR amplification, and present a robust link between cell morphology and extraction bias. These findings pave the road for bioinformatic correction of biases in microbiome data.

Observational data revealed correlations between the birch pollen season and the prevalence of viral infections, including airway infections,1 and the reactivation of latent herpesviruses.2 One reason might be a pollen-induced disturbance of the integrity of epithelial tissues that would cause defects in its barrier function and thus allow for easier viral invasion. Importantly, the pollen matrix also contains compounds that can modulate immunity, irrespective of the allergenic traits of pollen.3 This raises the question of whether birch pollen can directly affect antiviral immunity, to which dendritic cells (DC) critically contribute to. Therefore, here we addressed whether treatment of human DC with birch pollen affects their gene expression profiles, their innate antiviral responses, and their susceptibility to viral infection. In accordance with earlier studies,3 treatment of monocyte-derived DC (moDC) with aqueous pollen extract (APE) downregulated LPS induced IL-12p70 responses in a dose-dependent manner (Figure S1A). The strongest inhibition was detected at a concentration of 3 mg/ml APE, which we also used in the subsequent experiments. APE stimulation of moDC for 24 h moderately induced the surface expression of the DC maturation markers CD40, HLA-ABC, and HLA-DR (Figure 1A, B). Bulk RNA sequencing of moDC after APE treatment for 6 and 24 h revealed ample transcriptional changes (Figure S1B). Protein–protein interaction (PPI) network analysis of the combined differentially expressed genes (DEG) from both time points highlighted genes involved in pro-inflammatory innate immune functions such as type I interferon (IFN) signaling and IL-6 expression (Figure 1C). The transcription factors NF-κB and RELA were identified as potential upstream controllers of APE-regulated genes (Figure 1D). At the protein level, APE-treated moDC did not produce any measurable IFN-α, and they did not significantly increase IL-6 production (Figure S1C, D). Thus, our results indicate that APE treatment of moDC promotes a pro-inflammatory prone status at the transcriptional level, but has mild effects on the expression of pro-inflammatory cytokines at the protein level. To investigate whether APE treatment enhances pro-inflammatory cytokine responses upon virus infection, we utilized the β-herpesvirus human cytomegalovirus expressing the fluorescent marker GFP (HCMV). This virus is known to infect various different subsets of the myeloid cell lineage, including moDC.4 Upon exposure of moDC with HCMV together with APE (APE + HCMV) (Figure 2A), protein secretion of IFN-α and IL-6 was significantly enhanced compared to moDC treated with HCMV alone (Figure 2B, C). Interestingly, pre-incubation with APE for 24 h followed by HCMV exposure (preAPE + HCMV) did not have an impact on IFN-α production, whereas it still augmented IL-6 expression (Figure 2A, D, E and S2A, B). Notably, upon the various treatments, moDC did not produce detectable levels of anti-inflammatory cytokines, such as IL-10, TGF-β, or IL-23 (Figure S2C). Thus, APE treatment of moDC promotes a pro-inflammatory milieu upon HCMV infection. To address whether APE affects viral infection, we quantified percentages of GFP expressing moDC by flow cytometry. Upon exposure of moDC to APE + HCMV, percentages of GFP-positive moDC, that is, cells that support viral gene expression, were significantly enhanced (Figure 2F, G) and the release of viral progeny was increased (Figure S2E). PreAPE + HCMV treatment further increased the percentage of GFP-positive moDC and the amount of viral progeny (Figures 2F, G, S2D, F). Thus, APE-driven changes in gene signatures of moDC provide a favorable environment for HCMV infection and replication, despite an enhancement in pro-inflammatory cytokine responses. NF-κB signaling, which was induced by APE treatment of moDC, was reported to enhance HCMV infection.5 Pharmacological inhibition of NF-κB by BMS-345541 (BMS) treatment reduced percentages of GFP expressing moDC after HCMV exposure (Figure 2H, upper panel), suggesting that NF-κB signaling is important for efficient HCMV infection of moDC. Moreover, BMS treatment prevented the increase of GFP expressing cells in APE + HCMV treated moDC, but not in preAPE + HCMV treated moDC when compared with HCMV treatment alone (Figure 2H, lower panel). Thus, our results indicate that APE + HCMV treatment augments HCMV infection in an NF-κB-dependent manner. Warmer temperatures and expanding urbanization increase the release of birch pollen into the air and also enhance the amount of immune stimulatory mediators contained in pollen.3 This in turn could increase the risk of herpesvirus infection and reactivation in sensitized and non-sensitized individuals. A recent study demonstrated that HCMV and Epstein–Barr virus were the two most abundant viruses in the lung of asthma patients and that the presence of these viruses correlated with the severity of the disease.6 As asthma patients are especially sensitive to the effects of pollen, the pollen-induced enhancement of HCMV infection that we report here might have even more severe implications for such high-risk patients than for healthy individuals. We are grateful to Berenike Lange and Kira Baumann for excellent technical assistance, to Christian Sinzger and Kerstin Laib-Sampaio for generating and providing recombinant human cytomegalovirus expressing GFP, to Firas Fneish for assistance with data analysis in R and to Matthias Bruhn for his assistance in performing endotoxin detection in birch pollen extract. We thank the DRK-Blutspendedienst NSTOB gGmbH (Germany) for the provision of blood samples. This study was supported by funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation; Project ID 398367752 – FOR 2830, to UK; Project ID 158989968 – SFB 900-B2, to UK, Project ID 398066876 – GRK 2485, to UK), by funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy—EXC 2155 “RESIST”—Project ID 39087428 to UK, and by funding from the Helmholtz Association [Zukunftsthema “Immunology & Inflammation” (ZT-0027)] to CT-H and UK. Open Access funding enabled and organized by Projekt DEAL. VS is employed by AYOXXA Biosystems GmbH, BioCampus Cologne, 50.829 Köln, Germany. UK is advisor of AYOXXA Biosystems GmbH, BioCampus Cologne, 50.829 Köln, Germany. The other authors declare no conflict of interest. Appendix S1 Figure S1 Figure S2 Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Identification of microbial species is essential for the generation of meaningful results from microbiome analysis. However, annotation of 16S microbial sequences down to the species level presents a challenge because most available databases of 16S sequences are not well curated. AnnotIEM is a new tool for species level annotation of sequences derived from 16S rRNA sequencing. A novel hit selection algorithm is used to combine the alignment results from multiple databases. Benchmarking using mock community control datasets proved that AnnotIEM annotation precision is greater than 80% on species level, better than any currently available annotation tool. Benchmarking using a number of real microbiome studies demonstrated that annotation by AnnotIEM gave rise to higher fraction of sequences annotated on species level (60-80%), as compared to any other currently available tool. In conclusion, AnnotIEM significantly improves microbiome annotation, which can greatly enhance the results of any microbiome analysis study, and can be potentially used also for other organisms ### Competing Interest Statement The authors have declared no competing interest.

Urticarial skin reactions are one of the most frequent problems seen by allergists and clinical immunologists in daily practice. The most common reason for recurrent wheals is spontaneous urticaria. There are, however, several less common diseases that present with urticarial rash, such as urticarial vasculitis and autoinflammatory disorders. The latter include cryopyrin-associated periodic syndrome and Schnitzler's syndrome, both rare and disabling conditions mediated by increased interleukin-1 secretion. Apart from the urticarial rash, patients are suffering from a variety of systemic symptoms including recurrent fever attacks, arthralgia or arthritis and fatigue. Autoinflammatory diseases are often associated with a diagnostic delay of many years and do not respond to antihistamines and other treatments of urticaria. Also, the chronic inflammation may lead to long-term complications such as amyloidosis. It is therefore important not to miss these diseases when diagnosing and treating patients with chronic recurrent urticarial rash. Here, we present clinical clues and tips that can help to identify autoinflammatory disorders in patients presenting with chronic urticarial rash and discuss their clinical picture and management.

The primary site of exposure to pollen grains is the epithelium of the upper respiratory tract, which is densely populated by immature dendritic cells as link between the innate and adaptive immune system. We recently demonstrated that pollen grains not only function as allergen carriers but are also a rich source of bioactive lipid mediators. Aqueous extracts from phleum pratense and betula alba pollen (APE) contained predominantly monohydroxylated derivatives of linoleic and linolenic acid. In addition, GC-MS analysis of betulla alba APE demonstrated the presence of phytoprostanes E1, F1, A1/B1. Since DC critically influence the outcome of the ensuing T cell polarization, we investigate the biological activity of APE on immature DC. Human pB monocytes-derived DC (GM-CSF, IL-4) displayed morphology and phenotype of immature DC (CD1a+, MHC IImed, mannose receptor+, CD14neg., CD83neg., CD86neg.). Exposure to phleum pratense or betula alba APE induced DC maturation as documented by upregulation of MHC class II, CD83, CD86 and increased allostimulatory activity. APE induced DCs to release significantly less IL-12 p40 and p70, as compared to LPS. In addition, APE inhibited dose-dependently the LPS-induced IL-12 p70 release and IL-12 p40 (but not p35) mRNA levels (real time PCR), while no effect on LPS induced IL-6 release was observed. Consistent with that, APE-activated DCs induced significant less IFN-g production in allogeneic naïve CD45RA+, CD4+ T cells. These results suggest that pollen associated lipid molecules (PALMs) act as important regulatory signals that modulate DC function in a fashion that favours a reduced Th1 polarization