Nomenclature of allergic diseases and hypersensitivity reactions: Adapted to modern needs: An EAACI position paper.

The exponential growth of precision diagnostic tools, including omic technologies, molecular diagnostics, sophisticated genetic and epigenetic editing, imaging and nano-technologies and patient access to extensive health care, has resulted in vast amounts of unbiased data enabling in-depth disease characterization. New disease endotypes have been identified for various allergic diseases and triggered the gradual transition from a disease description focused on symptoms to identifying biomarkers and intricate pathogenetic and metabolic pathways. Consequently, the current disease taxonomy has to be revised for better categorization. This European Academy of Allergy and Clinical Immunology Position Paper responds to this challenge and provides a modern nomenclature for allergic diseases, which respects the earlier classifications back to the early 20th century. Hypersensitivity reactions originally described by Gell and Coombs have been extended into nine different types comprising antibody- (I-III), cell-mediated (IVa-c), tissue-driven mechanisms (V-VI) and direct response to chemicals (VII). Types I-III are linked to classical and newly described clinical conditions. Type IVa-c are specified and detailed according to the current understanding of T1, T2 and T3 responses. Types V-VI involve epithelial barrier defects and metabolic-induced immune dysregulation, while direct cellular and inflammatory responses to chemicals are covered in type VII. It is notable that several combinations of mixed types may appear in the clinical setting. The clinical relevance of the current approach for allergy practice will be conferred in another article that will follow this year, aiming at showing the relevance in clinical practice where various endotypes can overlap and evolve over the lifetime.

Contact Hypersensitivity as a Murine Model of Allergic Contact Dermatitis.

Contact hypersensitivity (CHS) is an experimental model of allergic contact dermatitis (ACD) that can be studied in mice. This study aims to present an objective laboratory method that may help to study the CHS reaction in mice, which can be measured and quantified by various tests. To induce CHS, on day "0", mice were sensitized on a previously shaved spot by abdominal skin painting with the hapten 2,4,6-trinitrochlorobenzene (TNCB) in an acetone-ethanol mixture, whereas negative control mice were sham sensitized with vehicle alone-acetone-ethanol mixture. On day "4", the baseline ear thickness was measured with a micrometer prior to the elicitation of CHS (challenge) by painting both ears with diluted TNCB both in the test and control groups. After 24 h, the ear swelling was measured with a micrometer. CHS is an example of a T cell-mediated immune response that causes swelling in inflamed tissue, peaking 24 h after the skin challenge with the same hapten. An increase in ear edema correlated with augmented ear weight, myeloperoxidase (MPO) activity, pro-inflammatory cytokine concentration in the ear extracts, increased thickening of the edematous dermis in the histological examination, and ear vascular permeability. There was also an increase in the concentration of TNP-specific IgG1 antibodies in the sera of the test group when compared with the control mice. Additionally, CHS can be successfully transferred with the CHS-effector cells obtained from donors previously sensitized with TNCB. The CHS-effector cells were administered intravenously into naïve recipient mice, which were subsequently challenged with the same diluted hapten. Ear swelling was measured with a micrometer 24 h later.

Case report: Rare among ultrarare-Clinical odyssey of a new patient with Ogden syndrome.

Introduction: The definition of ultra-rare disease in terms of its prevalence varies between the sources, usually amounting to ca. 1 in 1.000.000 births. Nonetheless, there are even less frequent disorders, such as Ogden syndrome, which up to this day was diagnosed in less than 10 patients worldwide. They present typically with a variety of developmental defects, including postnatal growth retardation, psychomotor delay and hypotonia. This disorder is caused by the heterozygous mutations in NAA10 gene, which encodes N-alpha-acetyltransferase 10, involved in protein biosynthesis. Therefore, Ogden syndrome belongs to the broader group of genetic disorders, collectively described as NAA10-related syndrome. Case report: We present a case of a Polish male infant, born in 39. GW with c-section due to the pathological cardiotocography signal. Hypotrophy (2400 g) and facial dysmorphism were noted in the physical examination. From the first minute, the child required mechanical ventilation - a nasal continuous positive airway pressure. For the first 27 days, the patient was treated in a neonatal intensive care unit, where a series of examinations were conducted. On their basis, the presence of the following defects was determined: muscular ventricular septal defects, patent foramen ovale, pectus excavatum, clubfoot and axial hypotonia. Child was then consequently referred to the genetic clinic for counselling. Results of the tests allowed the diagnosis of Ogden syndrome. In the following months the patient's condition worsened due to the numerous pulmonary infections. Despite the advanced treatment including the variety of medications, the patient eventually died at the age of 10 months. Conclusion: This case report presents a tenth patient diagnosed with Ogden syndrome reported worldwide. It expands the morphologic and clinical phenotype, emphasizing the possible severity of pneumonological disorders in these patients, which may pose a greater threat to a child's life than more frequently described cardiovascular dysfunctions associated with this syndrome.

Interferon Gamma Targeted Therapy: Is It Justified in Primary Sjögren's Syndrome?

Background: The pathomechanism of primary Sjögren syndrome (pSS) is multifactorial. Many cytokines take part in this process, including interferon. The study aimed to quantify certain cytokines involved in the pathomechanism of primary Sjögren syndrome (IL2, IL5, IL6, IL10, IL13, TNFα, IFNγ) and determine their common clinical correlation. On this basis, we discuss the potential use of anti-cytokine drugs in pSS therapy. Methods: The study group consisted of adult patients with a confirmed diagnosis of pSS. Results: The most frequently detected cytokines were IFNγ (82% of patients), TNFα (70%), IL6 (50%), and IL2 (42.5%). In all patients, except for one patient, IFNγ was found in the presence of other specific cytokines. There was no difference in clinical symptoms, age, and laboratory test results between the group of patients with IL-6 + TNFα + IFNγ positive cytokine, and the group of patients in whom they were not detected. There was no correlation between the presence of IL5, IL13, IL2, IL6, IL10, TNFα and musculoskeletal symptoms, skin lesions, glandular domains, pulmonary neurological, lymphadenopathy, biological and hematological domains in ESSDAI (p > 0.05). Conclusions: IFNγ most likely plays a central role in the pathomechanism of the disease. We have not noticed a clinical correlation between the three most common cytokines (IL6, IFNγ and TNFα), preliminary research results open up the possibility of searching for new treatments for pSS. The lower percentage of patients with detectable levels of TNFα and IL6 may explain the ineffectiveness of drugs targeting cytokines in clinical trials to date.

The Clinical and Immunological Activity Depending on the Presence of Interferon γ in Primary Sjögren's Syndrome-A Pilot Study.

The upregulation of IFN pathways and their stimulated genes is associated with primary Sjögren's syndrome (pSS). The recent studies also indicate the involvement of interferon γ (IFNγ) in the pathogenesis of pSS. The study aimed to assess the clinical and immunological activity depending on the concentration of IFNγ in the peripheral blood in pSS patients. METHODS: The study group consisted of patients over 18 years of age with a confirmed diagnosis of pSS. Based on the collected data, disease activity was assessed using the EULAR Sjögren's syndrome disease activity index (ESSDAI) and the EULAR Sjögren's syndrome patient reported index (ESSPRI). RESULTS: Among 40 pSS patients, 33 (82%) showed increased levels of IFNγ. The group with positive IFNγ was younger (43 years) than the group with negative IFNγ (57 years) (p < 0.05). In the positive IFNγ group, the time to diagnosis was shorter (p < 0.05). There was a difference in ESSDAI among patients with and without IFNγ (p < 0.05). There were no differences between the groups in ESSPRI and the presence of cryoglobulins, specific anti-SSA, and anti-SSB antibodies and in C3 and C4 hypocomplementemia. RF occurred in both groups with a similar frequency (p = 0.6), but in patients with IFNγ presence, significantly higher RF titers were observed (34.9 vs. 10.5; p < 0.05). CONCLUSION: In the group of patients with positive IFNγ, the mean value of RF and ESSDAI was higher. This group was also younger than patients with pSS without IFNγ.

Obesity and disease severity magnify disturbed microbiome-immune interactions in asthma patients.

In order to improve targeted therapeutic approaches for asthma patients, insights into the molecular mechanisms that differentially contribute to disease phenotypes, such as obese asthmatics or severe asthmatics, are required. Here we report immunological and microbiome alterations in obese asthmatics (n = 50, mean age = 45), non-obese asthmatics (n = 53, mean age = 40), obese non-asthmatics (n = 51, mean age = 44) and their healthy counterparts (n = 48, mean age = 39). Obesity is associated with elevated proinflammatory signatures, which are enhanced in the presence of asthma. Similarly, obesity or asthma induced changes in the composition of the microbiota, while an additive effect is observed in obese asthma patients. Asthma disease severity is negatively correlated with fecal Akkermansia muciniphila levels. Administration of A. muciniphila to murine models significantly reduces airway hyper-reactivity and airway inflammation. Changes in immunological processes and microbiota composition are accentuated in obese asthma patients due to the additive effects of both disease states, while A. muciniphila may play a non-redundant role in patients with a severe asthma phenotype.

The K (+) battery-regulating Arabidopsis K (+) channel AKT2 is under the control of multiple post-translational steps.

Potassium (K (+) ) is an important nutrient for plants. It serves as a cofactor of various enzymes and as the major inorganic solute maintaining plant cell turgor. In a recent study, an as yet unknown role of K (+) in plant homeostasis was shown. It was demonstrated that K (+) gradients in vascular tissues can serve as an energy source for phloem (re)loading processes and that the voltage-gated K (+) channels of the AKT2-type play a unique role in this process. The AKT2 channel can be converted by phosphorylation of specific serine residues (S210 and S329) into a non-rectifying channel that allows a rapid efflux of K (+) from the sieve element/companion cells (SE/CC) complex. The energy of this flux is used by other transporters for phloem (re)loading processes. Nonetheless, the results do indicate that post-translational modifications at S210 and S329 alone cannot explain AKT2 regulation. Here, we discuss the existence of multiple post-translational modification steps that work in concert to convert AKT2 from an inward-rectifying into a non-rectifying K (+) channel.

Calcium-dependent modulation and plasma membrane targeting of the AKT2 potassium channel by the CBL4/CIPK6 calcium sensor/protein kinase complex.

Potassium (K(+)) channel function is fundamental to many physiological processes. However, components and mechanisms regulating the activity of plant K(+) channels remain poorly understood. Here, we show that the calcium (Ca(2+)) sensor CBL4 together with the interacting protein kinase CIPK6 modulates the activity and plasma membrane (PM) targeting of the K(+) channel AKT2 from Arabidopsis thaliana by mediating translocation of AKT2 to the PM in plant cells and enhancing AKT2 activity in oocytes. Accordingly, akt2, cbl4 and cipk6 mutants share similar developmental and delayed flowering phenotypes. Moreover, the isolated regulatory C-terminal domain of CIPK6 is sufficient for mediating CBL4- and Ca(2+)-dependent channel translocation from the endoplasmic reticulum membrane to the PM by a novel targeting pathway that is dependent on dual lipid modifications of CBL4 by myristoylation and palmitoylation. Thus, we describe a critical mechanism of ion-channel regulation where a Ca(2+) sensor modulates K(+) channel activity by promoting a kinase interaction-dependent but phosphorylation-independent translocation of the channel to the PM.

Potassium (K+) gradients serve as a mobile energy source in plant vascular tissues.

The essential mineral nutrient potassium (K(+)) is the most important inorganic cation for plants and is recognized as a limiting factor for crop yield and quality. Nonetheless, it is only partially understood how K(+) contributes to plant productivity. K(+) is used as a major active solute to maintain turgor and to drive irreversible and reversible changes in cell volume. K(+) also plays an important role in numerous metabolic processes, for example, by serving as an essential cofactor of enzymes. Here, we provide evidence for an additional, previously unrecognized role of K(+) in plant growth. By combining diverse experimental approaches with computational cell simulation, we show that K(+) circulating in the phloem serves as a decentralized energy storage that can be used to overcome local energy limitations. Posttranslational modification of the phloem-expressed Arabidopsis K(+) channel AKT2 taps this "potassium battery," which then efficiently assists the plasma membrane H(+)-ATPase in energizing the transmembrane phloem (re)loading processes.

A minimal cysteine motif required to activate the SKOR K+ channel of Arabidopsis by the reactive oxygen species H2O2.

Reactive oxygen species (ROS) are essential for development and stress signaling in plants. They contribute to plant defense against pathogens, regulate stomatal transpiration, and influence nutrient uptake and partitioning. Although both Ca(2+) and K(+) channels of plants are known to be affected, virtually nothing is known of the targets for ROS at a molecular level. Here we report that a single cysteine (Cys) residue within the Kv-like SKOR K(+) channel of Arabidopsis thaliana is essential for channel sensitivity to the ROS H(2)O(2). We show that H(2)O(2) rapidly enhanced current amplitude and activation kinetics of heterologously expressed SKOR, and the effects were reversed by the reducing agent dithiothreitol (DTT). Both H(2)O(2) and DTT were active at the outer face of the membrane and current enhancement was strongly dependent on membrane depolarization, consistent with a H(2)O(2)-sensitive site on the SKOR protein that is exposed to the outside when the channel is in the open conformation. Cys substitutions identified a single residue, Cys(168) located within the S3 α-helix of the voltage sensor complex, to be essential for sensitivity to H(2)O(2). The same Cys residue was a primary determinant for current block by covalent Cys S-methioylation with aqueous methanethiosulfonates. These, and additional data identify Cys(168) as a critical target for H(2)O(2), and implicate ROS-mediated control of the K(+) channel in regulating mineral nutrient partitioning within the plant.

Distributed structures underlie gating differences between the kin channel KAT1 and the Kout channel SKOR.

The family of voltage-gated (Shaker-like) potassium channels in plants includes both inward-rectifying (K(in)) channels that allow plant cells to accumulate K(+) and outward-rectifying (K(out)) channels that mediate K(+) efflux. Despite their close structural similarities, K(in) and K(out) channels differ in their gating sensitivity towards voltage and the extracellular K(+) concentration. We have carried out a systematic program of domain swapping between the K(out) channel SKOR and the K(in) channel KAT1 to examine the impacts on gating of the pore regions, the S4, S5, and the S6 helices. We found that, in particular, the N-terminal part of the S5 played a critical role in KAT1 and SKOR gating. Our findings were supported by molecular dynamics of KAT1 and SKOR homology models. In silico analysis revealed that during channel opening and closing, displacement of certain residues, especially in the S5 and S6 segments, is more pronounced in KAT1 than in SKOR. From our analysis of the S4-S6 region, we conclude that gating (and K(+)-sensing in SKOR) depend on a number of structural elements that are dispersed over this approximately 145-residue sequence and that these place additional constraints on configurational rearrangement of the channels during gating.

Distinct roles of the last transmembrane domain in controlling Arabidopsis K+ channel activity.

The family of voltage-gated potassium channels in plants presumably evolved from a common ancestor and includes both inward-rectifying (K(in)) channels that allow plant cells to accumulate K(+) and outward-rectifying (K(out)) channels that mediate K(+) efflux. Despite their close structural similarities, the activity of K(in) channels is largely independent of K(+) and depends only on the transmembrane voltage, whereas that of K(out) channels responds to the membrane voltage and the prevailing extracellular K(+) concentration. Gating of potassium channels is achieved by structural rearrangements within the last transmembrane domain (S6). Here we investigated the functional equivalence of the S6 helices of the K(in) channel KAT1 and the K(out) channel SKOR by domain-swapping and site-directed mutagenesis. Channel mutants and chimeras were analyzed after expression in Xenopus oocytes. We identified two discrete regions that influence gating differently in both channels, demonstrating a lack of functional complementarity between KAT1 and SKOR. Our findings are supported by molecular models of KAT1 and SKOR in the open and closed states. The role of the S6 segment in gating evolved differently during specialization of the two channel subclasses, posing an obstacle for the transfer of the K(+)-sensor from K(out) to K(in) channels.

External K+ modulates the activity of the Arabidopsis potassium channel SKOR via an unusual mechanism.

Plant outward-rectifying K+ channels mediate K+ efflux from guard cells during stomatal closure and from root cells into the xylem for root-shoot allocation of potassium (K). Intriguingly, the gating of these channels depends on the extracellular K+ concentration, although the ions carrying the current are derived from inside the cell. This K+ dependence confers a sensitivity to the extracellular K+ concentration ([K+]) that ensures that the channels mediate K+ efflux only, regardless of the [K+] prevailing outside. We investigated the mechanism of K+-dependent gating of the K+ channel SKOR of Arabidopsis by site-directed mutagenesis. Mutations affecting the intrinsic K+ dependence of gating were found to cluster in the pore and within the sixth transmembrane helix (S6), identifying an 'S6 gating domain' deep within the membrane. Mapping the SKOR sequence to the crystal structure of the voltage-dependent K+ channel KvAP from Aeropyrum pernix suggested interaction between the S6 gating domain and the base of the pore helix, a prediction supported by mutations at this site. These results offer a unique insight into the molecular basis for a physiologically important K+-sensory process in plants.