Atopic dermatitis is associated with an increased risk of cardiovascular diseases: A large-scale, propensity-matched US-based retrospective study.

BACKGROUND: Atopic dermatitis is a chronic relapsing inflammatory skin disease characterized by intense itch impacting heavily on patients' and caregivers' quality of life. Its clinical presentation is accompanied by a variety of type 2 comorbidities, e.g. asthma, hay fever, food allergies. However, current data on cardiovascular comorbidities are inconsistent. OBJECTIVES: To identify risk of cardiovascular diseases in patients with atopic dermatitis. METHODS: Data from Electronic Health Records (EHRs) of 1,070,965 atopic dermatitis patients and equally propensity score matched controls were retrieved from the US Collaborative Network part of the federated TriNetX network. Hazard ratios for risk of onset of cardiovascular diseases with a prevalence of ≥1% in both cohorts within 20 years after diagnosis were determined. RESULTS: A total of 55 cardiovascular diseases belonging to 8 major cardiovascular groups were identified. Of those, 53 diagnoses displayed a significantly increased risk in atopic dermatitis patients. Different diagnoses of heart failure and heart disease were found most often, followed by valve insufficiencies, arrhythmia, tachycardia, atrial fibrillation, flutter, but also MACE and venous thromboembolism. The individual diagnoses venous insufficiency, atherosclerosis of native arteries of the extremities, and unspecified diastolic (congestive) heart failure displayed highest hazard ratios. CONCLUSION: Atopic dermatitis is associated with an increased risk for multiple cardiovascular diseases.

Risk and timing of isotretinoin-related laboratory disturbances: a population-based study.

INTRODUCTION: Uncertainty surrounds the optimal routine laboratory monitoring in acne patients treated with isotretinoin. OBJECTIVE: Our aim was to evaluate the risk of mild and severe laboratory abnormalities in patients with acne starting isotretinoin versus oral antibiotic treatment. METHODS: A global population-based retrospective cohort study assigned two groups of patients with acne-prescribed isotretinoin (n = 79,012) and oral antibiotics (n = 79,012). Comprehensive propensity-score matching was conducted. RESULTS: Compared to acne patients treated with oral antibiotics, those under isotretinoin demonstrated an increased risk of grade ≥3 hypertriglyceridemia (hazard ratio [HR], 7.85; 95% confidence interval [CI], 5.58-11.05; P < 0.001) and grade ≥3 elevated aspartate transaminase (AST) levels (HR, 1.45; 95% CI, 1.13-1.85; P = 0.003) within the initial 3 months of treatment. The absolute risk of these abnormalities among isotretinoin initiators was 0.4% and 0.2%, respectively. The risk difference of these findings was clinically marginal: 3 and 1 additional cases per 1,000 patients starting isotretinoin, respectively. There was no significant risk of grade ≥3 impairment in cholesterol, alanine transaminase, gamma-glutamyl transferase, or creatinine levels under isotretinoin. Most laboratory abnormalities were documented 1-3 months after drug initiation in time-stratified analysis. CONCLUSION: Isotretinoin is associated with a clinically marginal increased risk of severe hypertriglyceridemia and hypertransaminasemia. Routine blood testing should be performed 1-3 months after commencing therapy.

Hydroxy-Functionalized Ionic Liquids under Pressure: The Influence on Hydrogen Bonding between Ions of Opposite and Like Charges.

Hydroxy functionalization of cations in ionic liquids (ILs) can lead to formation of hydrogen bonds between their OH groups, resulting in so-called (c-c) H-bonds. Thereby, the (c-c) H-bonds compete with regular H-bonds (c-a) between the OH groups and the anions. Polarizable cations, weakly interacting anions, and long alkyl chains at the cation support the propensity for the formation of (c-c) H-bonds. At low temperatures, the equilibrium between (c-c) and (c-a) H-bonds is strongly shifted in favor of the cation-cation interaction. Herein, we clarify the pressure dependence on (c-c) and (c-a) H-bond distributions in the IL 1-(2-hydroxyethyl)-3-methylimidazolium hexafluorophosphate [HOC2C1Im][PF6], in mixtures of [HOC2C1Im][PF6] with the nonhydroxy-functionalized IL 1-propyl-3-methylimidazolium hexafluorophosphate [C3C1Im][PF6] and in [HOC2C1Im][PF6] including trace amounts of water. The infrared (IR) spectra provide clear evidence that the (c-c) H-bonds diminish with increasing pressure in favor of the (c-a) H-bonds. Adding trace amounts of water results in enhanced (c-c) clustering due to cooperative effects. At ambient pressure, the water molecules are involved in the (c-c) H-bond motifs. Increasing pressure leads to squeezing them out of H-bond clusters, finally resulting in demixing of water and the IL at the microscopic level.

Spectroscopic Evidence for Doubly Hydrogen-Bonded Cationic Dimers in the Solid, Liquid, and Gaseous Phases of Carboxyl-Functionalized Ionic Liquids.

Intermolecular interactions determine whether matter sticks together, gases condense into liquids, or liquids freeze into solids. The most prominent example is hydrogen bonding in water, responsible for the anomalous properties in the liquid phase and polymorphism in ice. The physical properties are also exceptional for ionic liquids (ILs), wherein a delicate balance of Coulomb interactions, hydrogen bonds, and dispersion interactions results in a broad liquid range and the vaporization of ILs as ion pairs. In this study, we show that strong, local, and directional hydrogen bonds govern the structures and arrangements in the solid, liquid, and gaseous phases of carboxyl-functionalized ILs. For that purpose, we explored the H-bonded motifs by X-ray diffraction and attenuated total reflection (ATR) infrared (IR) spectroscopy in the solid state, by ATR and transmission IR spectroscopy in the liquid phase, and by cryogenic ion vibrational predissociation spectroscopy (CIVPS) in the gaseous phase at low temperature. The analysis of the CO stretching bands reveals doubly hydrogen-bonded cationic dimers (c═c), resembling the archetype H-bond motif known for carboxylic acids. The like-charge doubly hydrogen-bonded ion pairs are present in the crystal structure of the IL, survive phase transition into the liquid state, and are still present in the gaseous phase even in (2,1) complexes wherein one counterion is removed and repulsive Coulomb interaction increased. The interpretation of the vibrational spectra is supported by quantum chemical methods. These observations have implications for the fundamental nature of the hydrogen bond between ions of like charge.

Inhibition of interferon gamma impairs induction of experimental epidermolysis bullosa acquisita.

Epidermolysis bullosa acquisita (EBA) is a muco-cutaneous autoimmune disease characterized and caused by autoantibodies targeting type VII collagen (COL7). The treatment of EBA is notoriously difficult, with a median time to remission of 9 months. In preclinical EBA models, we previously discovered that depletion of regulatory T cells (Treg) enhances autoantibody-induced, neutrophil-mediated inflammation and blistering. Increased EBA severity in Treg-depleted mice was accompanied by an increased cutaneous expression of interferon gamma (IFN-γ). The functional relevance of IFN-γ in EBA pathogenesis had been unknown. Given that emapalumab, an anti-IFN-γ antibody, is approved for primary hemophagocytic lymphohistiocytosis patients, we sought to assess the therapeutic potential of IFN-γ inhibition in EBA. Specifically, we evaluated if IFN-γ inhibition has modulatory effects on skin inflammation in a pre-clinical EBA model, based on the transfer of COL7 antibodies into mice. Compared to isotype control antibody, anti-IFN-γ treatment significantly reduced clinical disease manifestation in experimental EBA. Clinical improvement was associated with a reduced dermal infiltrate, especially Ly6G+ neutrophils. On the molecular level, we noted few changes. Apart from reduced CXCL1 serum concentrations, which has been demonstrated to promote skin inflammation in EBA, the expression of cytokines was unaltered in the serum and skin following IFN-γ blockade. This validates IFN-γ as a potential therapeutic target in EBA, and possibly other diseases with a similar pathogenesis, such as bullous pemphigoid and mucous membrane pemphigoid.

Comparing the risk of death, major adverse cardiac events, and relapse in bullous pemphigoid patients treated with systemic or topical corticosteroids.

BACKGROUND: According to current guidelines, systemic or topical corticosteroids are recommended as first-line treatments for bullous pemphigoid (BP). There is evidence suggesting that topical application may be associated with a lower risk of mortality. However, there is a lack of comprehensive large-scale data comparing mortality rates, as well as the risk of major adverse cardiac events (MACE), infections, and relapse, between systemic and topical corticosteroid treatments. OBJECTIVES: To evaluate the risk of death, MACE, infections, and relapse in BP patients treated with systemic or topical corticosteroids. METHODS: A population-based retrospective cohort study was performed in the TriNetX US Collaborative Network. As a measure against bias, propensity-score matching for age, sex, ten diseases and six medications, and three sensitivity analyses were conducted. RESULTS: All-time risk of death was increased in US BP patients exposed to any dose of systemic corticosteroids (n=2,917) compared to topical clobetasol propionate treated patients (n=2,932, hazard ratio [HR], 1.43, 95% confidence interval [CI] 1.28-1.58, p<0.0001). This was consistent in time-stratified analysis (1- and 3-year mortality rates), and in analysis contrasting prednisone (equivalent) does of 1-10 mg (low) or 30-100 mg (medium-high) systemic corticosteroid to topical treatment. The increased risk of death in US BP patients exposed to any dose of systemic corticosteroids compared to topical treatment was accompanied by increased risks for MACE (HR 1.33, CI 1.08-1.64, p=0.0075) and infections (HR 1.33, CI 1.15-1.54, p=0.0001). The risk of continued disease or relapse was decreased in patients treated with systemic as opposed to topical corticosteroid (HR 0.85, CI 0.77-0.94, p=0.0016). Results regarding mortality and continued disease or relapse persisted in three of three sensitivity analyses. Potential limitations are the retrospective data collection, bias for treatment selection and miscoding. CONCLUSION: Pending validation in prospective studies, where feasible, and despite the heightened risk of relapse, topical corticosteroid treatment may be advantageous compared to systemic corticosteroid treatment due to its significantly lower risk of death.

EGFR Inhibition by Erlotinib Rescues Desmosome Ultrastructure and Keratin Anchorage and Protects Against Pemphigus Vulgaris IgG-Induced Acantholysis in Human Epidermis.

Pemphigus is a severe blistering disease caused by autoantibodies primarily against the desmosomal cadherins desmoglein (DSG)1 and DSG3 which impair desmosome integrity. Especially for the acute phase, additional treatment options allowing to reduce corticosteroids would fulfill an unmet medical need. Here, we provide evidence that epidermal growth factor receptor (EGFR) inhibition by erlotinib ameliorates pemphigus vulgaris immunoglobulin G (PV-IgG) -induced acantholysis in intact human epidermis. PV-IgG caused phosphorylation of EGFR (Y845) and SRC in human epidermis. In line with that, a phosphotyrosine kinome analysis revealed a robust response associated with EGFR and SRC family kinase signaling in response to PV-IgG but not pemphigus foliaceus autoantibodies. Erlotinib inhibited PV-IgG-induced epidermal blistering and EGFR phosphorylation, loss of desmosomes as well as ultrastructural alterations of desmosome size, plaque symmetry, keratin filament insertion and restored the desmosome midline considered as hallmark of mature desmosomes. Erlotinib enhanced both single molecule DSG3 binding frequency and strength and delayed DSG3 fluorescence recovery supporting that EGFR inhibition increases DSG3 availability and cytoskeletal anchorage. Our data indicate that EGFR is a promising target for pemphigus therapy due to its link to several signaling pathways known to be involved in pemphigus pathogenesis.

Increased cardiovascular risks and mortality in prurigo nodularis: a global cohort study.

BACKGROUND: Prurigo nodularis (PN) presents with intensely itchy hard nodules. Despite being limited to the skin, PN was noted to be associated with systemic diseases including diabetes and chronic renal failure. In previous smaller retrospective studies, several cardiac and vascular diseases were found more frequently in patients with PN. However, small cohort sizes, partially discrepant outcomes, missing data, and incomplete risk assessment limit these findings. METHODS: Electronic health records (EHR)s of 64,801 patients (59.44% females) with PN and an equal sized propensity-matched control group were retrieved. In these cohorts, the risks to develop cardiac and vascular diseases and mortality following the diagnosis of PN were determined. Sub-analyses included stratification for sex, ethnicity, and treatments. FINDINGS: PN was associated with a higher risk for a broad range of acute cardiac events including heart failure and myocardial infarction. For example, the hazard ratio of myocardial infarction was 1.11 (95%-CI: 1.041-1.184, p = 0.0015) following PN diagnosis. Also, all-cause mortality was higher in patients with PN. Further, chronic vascular as well as structural heart diseases, e.g., peripheral arterial disease, chronic ischaemic heart disease and valval disorders were found more frequently following a PN diagnosis. Risks were more pronounced in white and female patients. Having established an increased risk for death and cardiovascular disease, we next addressed if dupilumab that has been recently licenced for use in this indication can modulate these risks. The risk of death but not of any cardiovascular disease was slightly reduced in patients with PN treated with dupilumab as opposed to those treated with systemic therapies other than dupilumab. The study is limited by retrospective data collection and reliance on ICD10-disease classification. INTERPRETATION: PN is associated with higher mortality and an increased risk for the development of a wide range of cardiac and vascular diseases. Health care professionals should take this into account when managing patients with PN. FUNDING: This work was supported by the University of Lübeck, the Deutsche Forschungsgemeinschaft and the State of Schleswig-Holstein.

C3d-Targeted factor H inhibits tissue complement in disease models and reduces glomerular injury without affecting circulating complement.

Complement-mediated diseases can be treated using systemic inhibitors. However, complement components are abundant in circulation, affecting systemic inhibitors' exposure and efficacy. Furthermore, because of complement's essential role in immunity, systemic treatments raise infection risk in patients. To address these challenges, we developed antibody fusion proteins combining the alternative-pathway complement inhibitor factor H (fH1-5) with an anti-C3d monoclonal antibody (C3d-mAb-2fH). Because C3d is deposited at sites of complement activity, this molecule localizes to tissue complement while minimizing circulating complement engagement. These fusion proteins bind to deposited complement in diseased human skin sections and localize to activated complement in a primate skin injury model. We further explored the pharmacology of C3d-mAb-2fH proteins in rodent models with robust tissue complement activation. Doses of C3d-mAb-2fH >1 mg/kg achieved >75% tissue complement inhibition in mouse and rat injury models while avoiding circulating complement blockade. Glomerular-specific complement inhibition reduced proteinuria and preserved podocyte foot-process architecture in rat membranous nephropathy, indicating disease-modifying efficacy. These data indicate that targeting local tissue complement results in durable and efficacious complement blockade in skin and kidney while avoiding systemic inhibition, suggesting broad applicability of this approach in treating a range of complement-mediated diseases.

Computing the frequency-dependent NMR relaxation of 1H nuclei in liquid water.

We present a computational framework for reliably determining the frequency-dependent intermolecular and intramolecular nuclear magnetic resonance (NMR) dipole-dipole relaxation rates of spin 1/2 nuclei from Molecular Dynamics (MD) simulations. This approach avoids the alterations caused by the well-known finite-size effects of translational diffusion. Moreover, a procedure is derived to control and correct for effects caused by fixed distance-sampling cutoffs and periodic boundary conditions. By construction, this approach is capable of accurately predicting the correct low-frequency scaling behavior of the intermolecular NMR dipole-dipole relaxation rate and thus allows for the reliable calculation of the frequency-dependent relaxation rate over many orders of magnitude. Our approach is based on the utilization of the theory of Hwang and Freed for the intermolecular dipole-dipole correlation function and its corresponding spectral density [L.-P. Hwang and J. H. Freed, J. Chem. Phys. 63, 4017-4025 (1975)] and its combination with data from MD simulations. The deviations from the Hwang and Freed theory caused by periodic boundary conditions and sampling distance cutoffs are quantified by means of random walker Monte Carlo simulations. An expression based on the Hwang and Freed theory is also suggested for correcting those effects. As a proof of principle, our approach is demonstrated by computing the frequency-dependent intermolecular and intramolecular dipolar NMR relaxation rates of 1H nuclei in liquid water at 273 and 298 K based on the simulations of the TIP4P/2005 model. Our calculations are suggesting that the intermolecular contribution to the 1H NMR relaxation rate of the TIP4P/2005 model in the extreme narrowing limit has previously been substantially underestimated.

Unraveling the role of superalkalis in modulating the static and dynamic hyperpolarizabilities of emerging calix[4]arenes.

Calixarenes, as novel organic materials, can play a pivotal role in the development of high-performance nonlinear optical materials due to the ease of design and fabrication. In this study, DFT simulations were employed to investigate the geometric, electronic, and NLO responses of calix[4]arene doped with Li3O, Na3O, and K3O superalkalis. The computed values of the vertical ionization energies and interaction energies indicate the chemical and thermodynamic stabilities of the targeted M3O@calix[4]arene complexes. The corresponding energy gaps (2.01 to 3.49 eV) are notably reduced, indicating the semiconductor nature of the materials. Surprisingly, the M3O@calix[4]arene complexes exhibit transparency in the UV/visible range as the absorption peaks are shifted in the near infrared (NIR) region. The highest values of 5.9 × 105 a.u. and 2.3 × 108 a.u. for the respective first and second hyperpolarizabilities are observed for Na3O@calix[4]arene. Furthermore, the Na3O@calix[4]arene complex exhibits maximum values of 2.3 × 105 a.u. for second harmonic generation (SHG) and (K3O@calix[4]arene) 2.3 × 106 a.u. for the electro-optical Pockels effect (EOPE) at 1064 nm. Similarly, approximations are made for the dynamic second hyperpolarizability coefficients (EOKE and EFISHG) at different wavelengths. Notably, the Na3O@calix[4]arene complex demonstrates the highest quadratic nonlinear refractive index (n2) of 9.5 × 10-15 cm2 W-1 at 1064 nm. This research paves the way for the development of stable calix[4]arenes doped with superalkalis, leading to an improved nonlinear optical (NLO) response.

Corrigendum: Blocking soluble Fas Ligand ameliorates pemphigus: PC111 efficacy in ex-vivo human pemphigus models.

[This corrects the article DOI: 10.3389/fimmu.2023.1193032.].

The Clinical Features of Hereditary Alpha-Tryptasemia­Implications for Interdisciplinary Practice.

BACKGROUND: Hereditary alpha-tryptasemia (HAT) is a genetic predisposition of autosomal dominant inheritance that leads to a high normal (≥ 8-11.4 µg/L) or pathologically elevated (>11.4 µg/L) basal serum tryptase (BST) concentration. Its prevalence in the United Kingdom and France is reportedly 5%-6%; its prevalence in Germany is unknown. Symptomatic persons with HAT suffer from a complex constellation of symptoms. As described in this review, HAT is an important differential diagnosis in interdisciplinary practice. METHODS: This review is based on publications about HAT retrieved by a selective search in PubMed, on relevant presentations at scientific meetings, and on our clinical experience. We also collected our own data on the prevalence and clinical manifestations of HAT. RESULTS: According to the literature, HAT is very common among patients in medical centers with BST values of 8 µg/L or above (64-74%). HAT is most commonly associated with neuropsychiatric symptoms such as exhaustion (85%), depressive episodes (59%), sleep disturbances (69%), and memory impairment (59%-68%), followed by gastrointestinal symptoms such as irritable bowel (30%-60%), nausea (51%), and reflux (49%-77%). Typical mast cell-mediated symptoms, such as flushing (47%), itch (69%), urticaria (37%), and anaphylaxis (14%-28%), are reported as well. Less commonly reported are cardiovascular manifestations, such as hypotonia, dizziness, and tachycardia (34%), and joint hypermobility (28%). HAT is more common among patients with sytemic mastocytosis (SM; 12%-21%). It is often associated with severe anaphylaxis induced by insect toxins or unknown triggers. The therapeutic options include treatment with antihistamines, mast-cell stabilizers, or IgE antibodies. CONCLUSION: A diagnosis of hereditary alpha-tryptasemia can be strongly suspected on the basis of thorough history-taking and BST measurement and then confirmed by molecular genetic testing.

Bullous pemphigoid induced by IgG targeting type XVII collagen non-NC16A/NC15A extracellular domains is driven by Fc gamma receptor- and complement-mediated effector mechanisms and is ameliorated by neonatal Fc receptor blockade.

Bullous pemphigoid (BP) is an autoimmune blistering disease characterized by autoantibodies targeting type XVII collagen (Col17) with the noncollagenous 16A (NC16A) ectodomain representing the immunodominant site. The role of additional extracellular targets of Col17 outside NC16A has not been unequivocally demonstrated. In this study, we showed that Col17 ectodomain-reactive patient sera depleted in NC16A IgG induced dermal-epidermal separation in a cryosection model indicating the pathogenic potential of anti-Col17 non-NC16A extracellular IgG. Moreover, injection of IgG targeting the murine Col17 NC14-1 domains (downstream of NC15A, the murine homologue of human NC16A) into C57BL/6J mice resulted in erythematous skin lesions and erosions. Clinical findings were accompanied by IgG/C3 deposits along the basement membrane and subepidermal blistering with inflammatory infiltrates. Disease development was significantly reduced in either Fc-gamma receptor (FcγR)- or complement-5a receptor-1 (C5aR1)-deficient mice. Inhibition of the neonatal FcR (FcRn), an atypical FcγR regulating IgG homeostasis, with the murine Fc fragment IgG2c-ABDEG, a derivative of efgartigimod, reduced anti-NC14-1 IgG levels, resulting in ameliorated skin inflammation compared with isotype-treated controls. These data demonstrate that the pathogenic effects of IgG targeting the Col17 domain outside human NC16A/murine NC15A are partly attributable to antibody-mediated FcγR- and C5aR1 effector mechanisms while pharmacological inhibition of the FcRn represents a promising treatment for BP. The mouse model of BP will be instrumental in further investigating the role of Col17 non-NC16A/NC15A extracellular epitopes and validating new therapies for this disease. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Are interleukin 17 and interleukin 23 inhibitors associated with malignancies?-Insights from an international population-based study.

BACKGROUND: Cancer risk after long-term exposure to interleukin (IL)-23 inhibitors (IL-23i) and IL-17 inhibitors (IL-17i) remains to be delineated. OBJECTIVE: To evaluate the risk of malignancies in patients with psoriasis treated with IL-23i and IL-17i relative to those prescribed tumour necrosis factor inhibitors (TNFi) during the first 5 years following drug initiation. METHODS: A global population-based cohort study included two distinct analyses comparing patients with psoriasis under different therapeutic modalities; (i) new users of IL-17i(n = 15,331) versus TNFi (n = 15,331) and (ii) new users of IL-23i (n = 5832) versus TNFi (n = 5832). RESULTS: Patients prescribed IL-17i experienced a decreased risk of non-Hodgkin lymphoma (NHL; HR, 0.58; 95% CI, 0.40-0.82; p = 0.002), colorectal cancer (HR, 0.68; 95% CI, 0.49-0.95; p = 0.024), hepatobiliary cancer (HR, 0.68; 95% CI, 0.58-0.80; p < 0.001), ovary cancer (HR, 0.48; 95% CI, 0.29-0.81; p = 0.005), melanoma (HR, 0.52; 95% CI, 0.37-0.73; p < 0.001), and basal cell carcinoma (BCC; HR, 0.57; 95% CI, 0.48-0.67; p < 0.001). IL-23i was associated with a reduced risk of NHL (HR, 0.39; 95% CI, 0.19-0.78; p = 0.006), hepatobiliary cancer (HR, 0.44; 95% CI, 0.31-0.62; p < 0.001) and BCC (HR, 0.76; 95% CI, 0.57-0.99; p = 0.046). In a sensitivity analysis comparing patients managed by IL-17i and IL-23i with their biologic-naïve counterparts, these classes were associated with decreased risk of several malignancies. CONCLUSION: IL-17i and IL-23i are associated with decreased risk of several malignancies. These findings should be considered prior to the prescription of biologics.

Combined Spectroscopic, Thermodynamic, and Theoretical Approach for Detecting and Quantifying Hydrogen Bonding and Dispersion Interaction in Ionic Liquids.

ConspectusIonic liquids (ILs) are attracting increasing interest in science and engineering due to their unique properties that can be tailored for specific applications. Clearly, a better understanding of their behavior on the microscopic scale will help to elucidate macroscopic fluid phenomena and thereby promote potential applications. The advantageous properties of these innovative fluids arise from the delicate balance of Coulomb interactions, hydrogen bonding, and dispersion forces. The development of these properties requires a fundamental understanding of the strength, location, and direction of the different types of interactions and their contribution to the overall phase behavior. Contrary to expectations, hydrogen bonding and dispersion interactions have a significant influence on the structure, dynamics, and phase behavior of ILs.The synergy between experimental and theoretical methods has now advanced to a stage where hydrogen bonds and dispersion effects as well as the competition between the two can be studied in detail. In this account, we demonstrate that a suitable combination of spectroscopic, thermodynamic, and theoretical methods enables the detection, dissection, and quantification of noncovalent interactions, even in complex systems such as ionic liquids. This approach encompasses far-infrared vibrational spectroscopy (FIR), various thermodynamic methods for determining enthalpies of vaporization, and quantum chemical techniques that allow us to switch dispersion contributions on or off when calculating the energies and spectroscopic properties of clusters.We briefly discuss these experimental and theoretical methods, before providing various examples illustrating how the mélange of Coulomb interaction, hydrogen bonds, and dispersion forces can be analyzed, and their individual contributions quantified. First, we demonstrated that both hydrogen bonding and dispersion interactions are manifested in the FIR spectra and can be quantified by observed shifts of characteristic spectral signatures. Through the selection of suitable protic ionic liquids (PILs) featuring anions with varying interaction strengths and alkyl chain lengths, we were able to demonstrate that dispersion interactions can compete with hydrogen bonding. The resultant transition enthalpy serves as a measure of the dispersion interaction. Contrary to expectations, PILs possess lower enthalpies of vaporization compared with aprotic ILs (AILs). The reason for this is simple: In protic ILs, ion pairs carry both the hydrogen bond and attractive dispersion between the cation and anion into the gas phase. By utilizing a well-curated set of protic ILs and molecular analogues, we successfully disentangled Coulomb interaction, hydrogen bonding, and dispersion interaction through purely thermodynamic methods.

C-type lectin receptor expression is a hallmark of neutrophils infiltrating the skin in epidermolysis bullosa acquisita.

Introduction: Inflammatory epidermolysis bullosa acquisita (EBA) is characterized by a neutrophilic response to anti-type VII collagen (COL7) antibodies resulting in the development of skin inflammation and blistering. The antibody transfer model of EBA closely mirrors this EBA phenotype. Methods: To better understand the changes induced in neutrophils upon recruitment from peripheral blood into lesional skin in EBA, we performed single-cell RNA-sequencing of whole blood and skin dissociate to capture minimally perturbed neutrophils and characterize their transcriptome. Results: Through this approach, we identified clear distinctions between circulating activated neutrophils and intradermal neutrophils. Most strikingly, the gene expression of multiple C-type lectin receptors, which have previously been reported to orchestrate host defense against fungi and select bacteria, were markedly dysregulated. After confirming the upregulation of Clec4n, Clec4d, and Clec4e in experimental EBA as well as in lesional skin from patients with inflammatory EBA, we performed functional studies in globally deficient Clec4e-/- and Clec4d-/- mice as well as in neutrophil-specific Clec4n-/- mice. Deficiency in these genes did not reduce disease in the EBA model. Discussion: Collectively, our results suggest that while the upregulation of Clec4n, Clec4d, and Clec4e is a hallmark of activated dermal neutrophil populations, their individual contribution to the pathogenesis of EBA is dispensable.