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Background: Allergic bronchopulmonary aspergillosis (ABPA) is a pulmonary disease caused by a complex hypersensitivity reaction to colonization of the airways with various fungi. ABPA caused by Alternaria alternata, other than Aspergillus spp., is named Allergic bronchopulmonary mycosis (ABPM)., Objective: To describe the first case of ABPM caused by Alternaria alternata in East Asia., Methods: Case report., Results: A 58-year-old female visited our hospital due to an abnormal chest x-ray, following chest computed tomography (CT) revealed consolidation in the left lower lobe. On laboratory finding, eosinophil count and total IgE level were high. The skin prick test and specific IgE for Alternaria alternata were positive. After diagnosis of ABPM, the patient was treated with prednisolone without antifungal agents, and her chest image was much improved., Conclusions: Aspergillus is most common etiology of allergic pulmonary disease, however, Alternaria should be considered even though positive culture of Aspergillus spp.

Background: Type 2 innate lymphoid cells (ILC2s) are relevant players in type 2 asthma. They initiate eosinophil infiltration and airway hyperreactivity (AHR) through cytokine secretion. Leukocyte-associated immunoglobulin-like receptor 1 (LAIR-1) is an inhibitory receptor considered to be an immune checkpoint in different inflammatory diseases., Objective: Our aim here was to investigate the expression of LAIR-1 and assess its role in human and murine ILC2s., Methods: Wild-type and LAIR-1 knockout mice were intranasally challenged with IL-33, and pulmonary ILC2s were sorted to perform an ex vivo comparative study based on RNA sequencing and flow cytometry. We next studied the impact of LAIR-1 deficiency on AHR and lung inflammation by using knockout mice and adoptive transfer experiments in Rag2 -/- Il2rg -/- mice. Knockdown antisense strategies and humanized mice were used to assess the role of LAIR-1 in human ILC2s., Results: We have demonstrated that LAIR-1 is inducible on activated ILC2s and downregulates cytokine secretion and effector function. LAIR-1 signaling in ILC2s was mediated via inhibitory pathways, including SHP1/PI3K/AKT, and LAIR-1 deficiency led to exacerbated ILC2-dependent AHR in IL-33 and Alternaria alternata models. In adoptive transfer experiments, we confirmed the LAIR-1-mediated regulation of ILC2s in vivo. Interestingly, LAIR-1 was expressed and inducible in human ILC2s, and knockdown approaches of Lair1 resulted in higher cytokine production. Finally, engagement of LAIR-1 by physiologic ligand C1q significantly reduced ILC2-dependent AHR in a humanized ILC2 murine model., Conclusion: Our results unravel a novel regulatory axis in ILC2s with the capacity to reduce allergic AHR and lung inflammation., (Copyright © 2021 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Future precision medicine requires further clarifying the mechanisms of inflammation in the severe endotypes of chronic airway diseases such as asthma and chronic rhinosinusitis (CRS). The presence of neutrophils in the airways is often associated with severe airway inflammation, while their precise contribution to the severe inflammation is largely unknown. We aimed to study the role of neutrophils in BALB/c and C57BL/6 mice exposed to Alternaria alternata ( Alt ). The mice were exposed to Alt extract for twelve hours or ten days to induce allergic airway inflammation. C57BL/6 mice exposed to Alt responded with eosinophilic infiltration and the characteristic IL-5 upregulation. In contrast, the inflammatory response to Alt extract in BALB/c mice was characterized by a neutrophilic response, high levels of G-CSF, and elastase in the lungs. The lack of neutrophils affected the processing of IL-33 in BALB/c mice, as was demonstrated by depletion of neutrophils through intraperitoneal injections of anti-Ly6G antibody. Our data identifies the key role of neutrophils in airway inflammation through IL-33 cleavage in the Alt -induced airway inflammation in mice, which could potentially underline the different endotypes in human disease., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Van Nevel, van Ovost, Holtappels, De Ruyck, Zhang, Braun, Maes, Bachert and Krysko.)

Type 2 inflammation is found in most forms of asthma, which may co-exist with recurrent viral infections, bacterial colonization, and host cell death. These processes drive the accumulation of intracellular cyclic-di-nucleotides such as cyclic-di-GMP (CDG). Group 2 innate lymphoid cells (ILC2s) are critical drivers of type 2 lung inflammation during fungal allergen exposure in mice; however, it is unclear how CDG regulates lung ILC responses during lung inflammation. Here, we show that intranasal CDG induced early airway type 1 interferon (IFN) production and dramatically suppressed CD127+ST2+ ILC2s and type 2 lung inflammation during Alternaria and IL-33 exposure. Further, CD127-ST2-Thy1.2+ lung ILCs, which showed a transcriptomic signature consistent with ILC1s, were expanded and activated by CDG combined with either Alternaria or IL-33. CDG-mediated suppression of type 2 inflammation occurred independent of IL-18R, IL-12, and STAT6 but required the stimulator of interferon genes (STING) and type 1 IFN signaling. Thus, CDG potently suppresses ILC2-driven lung inflammation and promotes ILC1 responses. These results suggest potential therapeutic modulation of STING to suppress type 2 inflammation and/or increase anti-viral responses during respiratory infections., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Cavagnero, Badrani, Naji, Amadeo, Leng, Lacasa, Strohm, Renusch, Gasparian and Doherty.)

Chronic inhalation of fungi and fungal components has been linked to the development of respiratory disorders, although their role with respect to the pathogenesis of acute respiratory virus infection remains unclear. Here, we evaluate inflammatory pathology induced by repetitive administration of a filtrate of the ubiquitous fungus, Alternaria alternata , and its impact on susceptibility to infection with influenza A. We showed previously that A. alternata at the nasal mucosae resulted in increased susceptibility to an otherwise sublethal inoculum of influenza A in wild-type mice. Here we demonstrate that A. alternata -induced potentiation of influenza A infection was not dependent on fungal serine protease or ribonuclease activity. Repetitive challenge with A. alternata prior to virus infection resulted proinflammatory cytokines, neutrophil recruitment, and loss of alveolar macrophages to a degree that substantially exceeded that observed in response to influenza A infection alone. Concomitant administration of immunomodulatory Lactobacillus plantarum , a strategy shown previously to limit virus-induced inflammation in the airways, blocked the exaggerated lethal response. These observations promote an improved understanding of severe influenza infection with potential clinical relevance for individuals subjected to continuous exposure to molds and fungi.

The cyclooxygenase (COX) metabolic pathway regulates immune responses and inflammation. The effect of the COX pathway on innate pulmonary inflammation induced by protease-containing fungal allergens, such as Alternaria alternata , is not fully defined. In this study, we tested the hypothesis that COX inhibition augments Alternaria- induced pulmonary group 2 innate lymphoid cell (ILC2) responses and IL-33 release. Mice were treated with the COX inhibitors indomethacin, flurbiprofen, or vehicle and challenged intranasally with Alternaria extract for four consecutive days to induce innate lung inflammation. We found that indomethacin and flurbiprofen significantly increased the numbers of ILC2 and IL-5 and IL-13 expression by ILC2 in the lung. Indomethacin also increased ILC2 proliferation, the percentages of eosinophils, and mucus production in the lung. Both indomethacin and flurbiprofen augmented the release of IL-33 in bronchoalveolar lavage fluid after Alternaria challenge, suggesting that more IL-33 was available for ILC2 activation and that a COX product(s) inhibited IL-33 release. This is supported by the in vitro finding that the COX product PGE 2 and the PGI 2 analogs cicaprost decreased Alternaria extract-induced IL-33 release by human bronchial epithelial cells. Although contrasting effects of PGD 2 , PGE 2 , and PGI 2 on ILC2 responses have been previously reported, the overall effect of the COX pathway on ILC2 function is inhibitory in Alternaria -induced innate airway inflammation., (Copyright © 2020 by The American Association of Immunologists, Inc.)

Eosinophilia is a hallmark of allergic airway inflammation (AAI). Identifying key molecules and specific signaling pathways that regulate eosinophilic inflammation is critical for development of novel therapeutics. Tropomycin receptor kinase A (TrkA) is the high-affinity receptor for nerve growth factor. AAI is associated with increased expression of TrkA by eosinophils; however, the functional role of TrkA in regulating eosinophil recruitment and contributing to AAI is poorly understood. This study identifies, to our knowledge, a novel mechanism of eotaxin-mediated activation of TrkA and its role in regulating eosinophil recruitment by using a chemical-genetic approach to specifically inhibit TrkA kinase activity with 1-NM-PP1 in TrkA F592A -knock-in (TrkA-KI) eosinophils. Blockade of TrkA by 1-NM-PP1 enhanced eosinophil spreading on VCAM-1 but inhibited eotaxin-1 (CCL11)-mediated eosinophil migration, calcium flux, cell polarization, and ERK1/2 activation, suggesting that TrkA is an important player in the signaling pathway activated by eotaxin-1 during eosinophil migration. Further, blockade of matrix metalloprotease with BB-94 inhibited eotaxin-1-induced TrkA activation and eosinophil migration, additively with 1-NM-PP1, indicating a role for matrix metalloproteases in TrkA activation. TrkA inhibition in Alternaria alternata -challenged TrkA-KI mice markedly inhibited eosinophilia and attenuated various features of AAI. These findings are indicative of a distinctive eotaxin-mediated TrkA-dependent signaling pathway, which, in addition to other TrkA-activating mediators, contributes to eosinophil recruitment during AAI and suggests that targeting the TrkA signaling pathway to inhibit eosinophil recruitment may serve as a therapeutic strategy for management of eosinophilic inflammation in allergic airway disease, including asthma., (Copyright © 2020 by The American Association of Immunologists, Inc.)

The airway epithelial cell (AEC) response to allergens helps initiate and propagate allergic inflammation in asthma. CARMA3 is a scaffold protein that mediates G protein-coupled receptor-induced NF-κB activation in airway epithelium. In this study, we demonstrate that mice with CARMA3-deficient AECs have reduced airway inflammation, as well as reduced type 2 cytokine levels in response to Alternaria alternata. These mice also have reduced production of IL-33 and IL-25, and reduced numbers of innate lymphoid cells in the lung. We also show that CARMA3-deficient human AECs have decreased production of proasthmatic mediators in response to A. alternata. Finally, we show that CARMA3 interacts with inositol 1,4,5-trisphosphate receptors in AECs, and that inhibition of CARMA3 signaling reduces A. alternata-induced intracellular calcium release. In conclusion, we show that CARMA3 signaling in AECs helps mediate A. alternata-induced allergic airway inflammation, and that CARMA3 is an important signaling molecule for type 2 immune responses in the lung.

Background: Respiratory fungal exposure is known to be associated with severe allergic lung inflammation. Airway epithelium is an essential controller of allergic inflammation. An innate immune recognition receptor, nucleotide-binding domain, leucine-rich-containing family, pyrin-domain-containing-3 (NLRP3) inflammasome, and phosphoinositide 3 kinase (PI3K)-δ in airway epithelium are involved in various inflammatory processes., Objectives: We investigated the role of NLRP3 inflammasome in fungi-induced allergic lung inflammation and examined the regulatory mechanism of NLRP3 inflammasome, focusing on PI3K-δ in airway epithelium., Methods: We used two in vivo models induced by exposure to Aspergillus fumigatus ( Af ) and Alternaria alternata ( Aa ), as well as an Af -exposed in vitro system. We also checked NLRP3 expression in lung tissues from patients with allergic bronchopulmonary aspergillosis (ABPA)., Results: Assembly/activation of NLRP3 inflammasome was increased in the lung of Af -exposed mice. Elevation of NLRP3 inflammasome assembly/activation was observed in Af -stimulated murine and human epithelial cells. Similarly, pulmonary expression of NLRP3 in patients with ABPA was increased. Importantly, neutralisation of NLRP3 inflammasome derived IL-1β alleviated pathophysiological features of Af -induced allergic inflammation. Furthermore, PI3K-δ blockade improved Af -induced allergic inflammation through modulation of NLRP3 inflammasome, especially in epithelial cells. This modulatory role of PI3K-δ was mediated through the regulation of mitochondrial reactive oxygen species (mtROS) generation. NLRP3 inflammasome was also implicated in Aa -induced eosinophilic allergic inflammation, which was improved by PI3K-δ blockade., Conclusion: These findings demonstrate that fungi-induced assembly/activation of NLRP3 inflammasome in airway epithelium may be modulated by PI3K-δ, which is mediated partly through the regulation of mtROS generation. Inhibition of PI3K-δ may have potential for treating fungi-induced severe allergic lung inflammation., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Group V phospholipase A 2 (Pla2g5) is a lipid-generating enzyme necessary for macrophage effector functions in pulmonary inflammation. However, the lipid mediators involved and their cellular targets have not been identified. Mice lacking Pla2g5 showed markedly reduced lung ILC2 activation and eosinophilia following repetitive Alternaria Alternata inhalation. While Pla2g5-null mice had Wt levels of immediate IL-33 release after one Alternaria dose, they failed to upregulate IL-33 in macrophages following repeated Alternaria administration. Unexpectedly, while adoptive transfer of bone marrow-derived (BM)-macrophages restored ILC2 activation and eosinophilia in Alternaria-exposed Pla2g5-null mice, exogenous IL-33 did not. Conversely, transfers of Pla2g5-null BM-macrophages reduced inflammation in Alternaria-exposed Wt mice. Mass spectrometry analysis of free fatty acids (FFAs) demonstrated significantly reduced FFAs (including linoleic acid (LA) and oleic acid (OA)) in lung and BM-macrophages lacking Pla2g5. Exogenous administration of LA or LA+OA to Wt mice sharply potentiated IL-33-induced lung eosinophilia and ILC2 expansion in vitro and in vivo. In contrast, OA potentiated IL-33-induced inflammation and ILC2 expansion in Pla2g5-null mice, but LA was inactive both in vivo and in vitro. Notably, Pla2g5-null ILC2s showed significantly reduced expression of the FFA-receptor-1 compared to Wt ILC2s. Thus, macrophage-associated Pla2g5 contributes significantly to type-2 immunity through regulation of IL-33 induction and FFA-driven ILC2 activation.

A cutaneous infection with Alternaria spp. was diagnosed in a 2-year-old male intact Irish setter dog, presenting with multifocal papules, plaques and ulcerations involving all four distal limbs, shoulder blades, scrotum, pinnae and nasal mucous membranes. The dog had been treated for inflammatory bowel disease and lymphangiectasia with immunosuppressive doses of cyclosporine and prednisolone for approximately 3 months. The diagnosis was based on clinical signs, the demonstration of fungal elements within skin biopsies, deep fungal culture and fungal PCR from a formalin-fixed tissue specimen. Complete clinical remission was achieved by tapering and cessation of the immunosuppressive medication, treatment with cold atmospheric-pressure plasma (CAPP) and topical enilconazole within 8 weeks.

Introduction: Although the mechanism of asthma is not precisely understood in humans, clinical and epidemiological studies have offered a potential relationship between exposure to environmental fungi, such as Alternaria alternata (A. alternata) and the development and exacerbation of asthma. The aim of this project is to investigate the mechanisms of Th2 responses by A. alternata as a clinically relevant model for the environmental exposure., Materials and Methods: Plastic adherent monocytes were cultured with granulocyte macrophage colony stimulating factor (GM-CSF) and interleukin-4 (IL-4) to convert these cells into Monocyte-derived Dendritic cells (MoDc) and then matured in the presence of Monocyte-Conditioned Medium (MCM) as the control group and MCM+ A. alternata extract as the inductive groups., Results: The results indicated that the expression of CD14 decreased and CD83 and anti-human leukocyte antigen-DR (HLA-DR) increased in the inductive groups in comparison with the control group. More importantly, A. alternata inhibited IL-12 production by activated dendritic cells (DCs), and the DCs exposed to A. alternata enhanced the Th2 polarisation of CD4 + T cells. The production amount of IL-10 overcame IL-12 as well as Il-23 increased significantly, and hand in T cells the production of cytokines Interferon-γ (IFN-γ) decreased. However, both IL-17 and IL-4 increased (p<0.05). Phagocytic activity in the inductive groups decreased significantly compared with the control group., Conclusion: The asthma-related environmental fungus A. alternata, with an effect on dendritic cells profile mediates TH2/TH17. Such immunodysregulation properties of causative environmental fungi may explain their strong relationship with human asthma and allergic diseases., (Copyright © 2016 SEICAP. Published by Elsevier España, S.L.U. All rights reserved.)

IL-33 plays an important role in the initiation of type-2 immune responses, as well as the enhancement of type 2 effector functions. Engagement of the IL-33 receptor on macrophages facilitates polarization to an alternative activation state by amplifying IL-4 and IL-13 signaling to IL-4Rα. IL-4 and IL-13 also induce macrophage proliferation but IL-33 involvement in this process has not been rigorously evaluated. As expected, in vivo delivery of IL-33 induced IL-4Rα-dependent alternative macrophage activation in the serous cavities. IL-33 delivery also induced macrophages to proliferate but, unexpectedly, this was independent of IL-4Rα signaling. In a filarial nematode infection model in which IL-4Rα-dependent alternative activation and proliferation in the pleural cavity is well described, IL-33R was essential for alternative activation but not macrophage proliferation. Similarly, during Alternaria alternata induced airway inflammation, which provokes strong IL-33 responses, we observed that both IL-4Rα and IL-33R were required for alternative activation, while macrophage proliferation in the pleural cavity was still evident in the absence of either receptor alone. Our data show that IL-33R and IL-4Rα promote macrophage proliferation independently of each other, but both are essential for induction of alternative activation., (© 2016 The Authors. European Journal of Immunology published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Fat-associated lymphoid clusters (FALC) are inducible structures that support rapid innate-like B-cell immune responses in the serous cavities. Little is known about the physiological cues that activate FALCs in the pleural cavity and more generally the mechanisms controlling B-cell activation in FALCs. Here we show, using separate models of pleural nematode infection with Litomosoides sigmodontis and Altenaria alternata induced acute lung inflammation, that inflammation of the pleural cavity rapidly activates mediastinal and pericardial FALCs. IL-33 produced by FALC stroma is crucial for pleural B1-cell activation and local IgM secretion. However, B1 cells are not the direct target of IL-33, which instead requires IL-5 for activation. Moreover, lung inflammation leads to increased IL-5 production by type 2 cytokine-producing innate lymphoid cells (ILC2) in the FALC. These findings reveal a link between inflammation, IL-33 release by FALC stromal cells, ILC2 activation and pleural B-cell activation in FALCs, resulting in local and antigen-specific IgM production.

Plants and animals perceive diverse microbe-associated molecular patterns (MAMPs) via pattern recognition receptors and activate innate immune signalling. The actin cytoskeleton has been suggested as a target for innate immune signalling and a key transducer of cellular responses. However, the molecular mechanisms underlying actin remodelling and the precise functions of these rearrangements during innate immunity remain largely unknown. Here we demonstrate rapid actin remodelling in response to several distinct MAMP signalling pathways in plant epidermal cells. The regulation of actin dynamics is a convergence point for basal defence machinery, such as cell wall fortification and transcriptional reprogramming. Our quantitative analyses of actin dynamics and genetic studies reveal that MAMP-stimulated actin remodelling is due to the inhibition of capping protein (CP) by the signalling lipid, phosphatidic acid. In addition, CP promotes resistance against bacterial and fungal phytopathogens. These findings demonstrate that CP is a central target for the plant innate immune response.

In mammalian systems RNA can move between cells via vesicles. Here we demonstrate that the gastrointestinal nematode Heligmosomoides polygyrus, which infects mice, secretes vesicles containing microRNAs (miRNAs) and Y RNAs as well as a nematode Argonaute protein. These vesicles are of intestinal origin and are enriched for homologues of mammalian exosome proteins. Administration of the nematode exosomes to mice suppresses Type 2 innate responses and eosinophilia induced by the allergen Alternaria. Microarray analysis of mouse cells incubated with nematode exosomes in vitro identifies Il33r and Dusp1 as suppressed genes, and Dusp1 can be repressed by nematode miRNAs based on a reporter assay. We further identify miRNAs from the filarial nematode Litomosoides sigmodontis in the serum of infected mice, suggesting that miRNA secretion into host tissues is conserved among parasitic nematodes. These results reveal exosomes as another mechanism by which helminths manipulate their hosts and provide a mechanistic framework for RNA transfer between animal species.

Background: The fungal allergen Alternaria alternata is implicated in severe asthma and rapid onset life-threatening exacerbations of disease. However, the mechanisms that underlie this severe pathogenicity remain unclear., Objective: We sought to investigate the mechanism whereby Alternaria was capable of initiating severe, rapid onset allergic inflammation., Methods: IL-33 levels were quantified in wild-type and ST2(-/-) mice that lacked the IL-33 receptor given inhaled house dust mite, cat dander, or Alternaria, and the effect of inhibiting allergen-specific protease activities on IL-33 levels was assessed. An exacerbation model of allergic airway disease was established whereby mice were sensitized with house dust mite before subsequently being challenged with Alternaria (with or without serine protease activity), and inflammation, remodeling, and lung function assessed 24 hours later., Results: Alternaria, but not other common aeroallergens, possessed intrinsic serine protease activity that elicited the rapid release of IL-33 into the airways of mice through a mechanism that was dependent upon the activation of protease activated receptor-2 and adenosine triphosphate signaling. The unique capacity of Alternaria to drive this early IL-33 release resulted in a greater pulmonary inflammation by 24 hours after challenge relative to the common aeroallergen house dust mite. Furthermore, this Alternaria serine protease-IL-33 axis triggered a rapid, augmented inflammation, mucus release, and loss of lung function in our exacerbation model., Conclusion: Alternaria-specific serine protease activity causes rapid IL-33 release, which underlies the development of a robust TH2 inflammation and exacerbation of allergic airway disease., (Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.)

Alternaria species are a group of dematiaceous fungi that are ubiquitous in nature and are becoming an increasingly important cause of disease in immunocompromised patients. We present a case of a 70 year old renal transplant recipient with multiple areas of cutaneous Alternaria infections likely introduced during local trauma. Treatment has required a combination of systemic therapy and surgical excision. This case illustrates the importance of recognizing fungal infections with cutaneous manifestations, such as alternariosis, in immunosuppressed patients.

We report a case of Alternaria alternata cutaneous and pulmonary infection in a 62-year-old man after heart transplantation treated by azole antifungals. Alternaria spp. belong to a group of opportunistic dematiaceous fungi with worldwide distribution. The cutaneous form of the infection in human is very rare and occurs predominantly among immunosuppressed patients. Therefore, diagnosis is often delayed or not reached at all. Appropriate treatment is not standardized and remains a matter of discussion. According to current studies, the best results are obtained with systemic azole antifungal therapy combined with surgical intervention., (© 2013 Wiley Periodicals, Inc.)

Organ transplant recipients under immunosuppressive therapy have a highly increased risk of opportunistic fungal infections. Cutaneous infection caused by Alternaria species are relatively rare in humans and most cases reported in the literature are in immunocompromised individuals. We report here on a 33-year old male renal transplant patient with diabetes mellitus who presented with cutaneous alternariosis caused by Alternaria infectoria, two years after the transplant. The diagnosis was performed by real-time polymerase chain reaction assay and histopathologic examination. The extension of the lesion under itraconazole treatment required treatment consisting of a combination of surgical excision and liposomal amphotericin B.

Background: Exposure to the fungal allergen Alternaria alternata as well as ryegrass pollen has been implicated in severe asthma symptoms during thunderstorms. We have previously shown that Alternaria extract induces innate type 2 lung inflammation in mice. We hypothesized that the innate eosinophilic response to Alternaria extract may enhance lung inflammation induced by ryegrass., Methods: Mice were sensitized to ryegrass allergen and administered a single challenge with A. alternata extract before or after final ryegrass challenges. Levels of eosinophils, neutrophils, Th2 cells, innate lymphoid cells (ILC2), interleukin (IL)-5 and IL-13 in bronchoalveolar lavage (BAL) as well as inflammation and mucus were assessed., Results: Mice receiving ryegrass sensitization and challenge developed an eosinophilic lung response. A single challenge with Alternaria extract given 3 days before or 3 days after ryegrass challenges resulted in increased eosinophils, peribronchial inflammation and mucus production in the airways compared with ryegrass-only challenges. Type 2 ILC2 and Th2 cell recruitment to the airways was increased after Alternaria extract exposure in ryegrass-challenged mice. Innate immune challenges with Alternaria extract induced BAL eosinophilia, Th2 cell recruitment as well as ILC2 expansion and proliferation., Conclusions: A single exposure to Alternaria extract in ryegrass-sensitized and -challenged mice enhances the type 2 lung inflammatory response, including airway eosinophilia, peribronchial infiltrate, and mucus production, possibly through Th2 cell recruitment and ILC2 expansion. If translated to humans, exposure to both grass pollen and Alternaria may be a potential cause of thunderstorm-related asthma.

Asthma exacerbations can be caused by a number of factors, including the fungal allergen Alternaria, which is specifically associated with severe and near-fatal attacks. The mechanisms that trigger lung responses are unclear and might vary between allergens. A comparison between Alternaria, Aspergillus, Candida, and house dust mite, all allergens in humans, showed that only Alternaria promoted immediate innate airway eosinophilia within 12 h of inhalation in nonsensitized mice. Alternaria, but not the other allergens, induced a rapid increase in airway levels of IL-33, accompanied by IL-33 receptor (IL-33R)-positive natural helper cell (NHC) production of IL-5 and IL-13. NHCs in the lung and bone marrow constitutively expressed transcription factors [GATA-3 and E26 transformation-specific sequence-1 (ETS-1)] that could allow for rapid induction of T helper type 2 (Th2) cytokines. Lung NHC numbers and proliferation (%Ki-67), but not IL-5 or GATA-3 expression, were significantly reduced in STAT6-deficient mice 3 days after one challenge with Alternaria. Alternaria induced NHC expression of the EGF receptor ligand amphiregulin (partially dependent on STAT6), as well as EGF receptor signaling in the airway epithelium. Finally, human peripheral blood NHCs (CRTH2(+)CD127(+) lineage-negative lymphocytes) from allergic individuals highly expressed GATA-3 and ETS-1, similar to lung NHCs in mice. In summary, Alternaria-induced lung NHC proliferation and expression of amphiregulin are regulated by STAT6. In addition, NHCs in mouse and humans are primed to express Th2 cytokines through constitutive expression of GATA-3 and ETS-1. Thus several transcription factor pathways (STAT6, GATA-3, and ETS-1) may contribute to NHC proliferation and Th2-type responses in Alternaria-induced asthma.

The fungal allergen, Alternaria, is specifically associated with severe asthma, including life-threatening exacerbations. To better understand the acute innate airway response to Alternaria, naive wild-type (WT) mice were challenged once intranasally with Alternaria. Naive WT mice developed significant bronchoalveolar lavage eosinophilia following Alternaria challenge when analyzed 24 h later. In contrast to Alternaria, neither Aspergillus nor Candida induced bronchoalveolar lavage eosinophilia. Gene microarray analysis of airway epithelial cell brushings demonstrated that Alternaria-challenged naive WT mice had a >20-fold increase in the level of expression of found in inflammatory zone 1 (FIZZ1/Retnla), a resistin-like molecule. Lung immunostaining confirmed strong airway epithelial FIZZ1 expression as early as 3 h after a single Alternaria challenge that persisted for ≥5 d and was significantly reduced in STAT6-deficient, but not protease-activated receptor 2-deficient mice. Bone marrow chimera studies revealed that STAT6 expressed in lung cells was required for epithelial FIZZ1 expression, whereas STAT6 present in bone marrow-derived cells contributed to airway eosinophilia. Studies investigating which cells in the nonchallenged lung bind FIZZ1 demonstrated that CD45(+)CD11c(+) cells (macrophages and dendritic cells), as well as collagen-1-producing CD45(-) cells (fibroblasts), can bind to FIZZ1. Importantly, direct administration of recombinant FIZZ1 to naive WT mice led to airway eosinophilia, peribronchial fibrosis, and increased thickness of the airway epithelium. Thus, Alternaria induces STAT6-dependent acute airway eosinophilia and epithelial FIZZ1 expression that promotes airway fibrosis and epithelial thickness. This may provide some insight into the uniquely pathogenic aspects of Alternaria-associated asthma.

In this study, three different rat hybridoma cell lines secreting monoclonal antibodies (mAbs) recognizing the spores from Alternaria alternata, a plant pathogenic fungus, contaminant of food products and important cause of both allergic rhinitis and asthma, have been characterized. These three mAbs are all of IgM isotype. Two antibodies, A1 and F10, were cross-reactive antibodies recognizing spores from Alternaria, Cladosporium, Penicillium, Aspergillus and Stachybotrys genera, but not the yeasts Saccharomyces cerevisiae or Candida albicans. Competitive and sandwich assays demonstrated that these two mAbs were directed against the same or very close repetitive(s) epitope(s). A1-based sandwich ELISA efficiently detected this epitope in various mould (but not yeast)-soluble extracts prepared from strains grown in the laboratory. Moreover, this A1-based sandwich ELISA detected its cognate epitope in air and dust samples obtained from dwellings. The third antibody, E5, recognized only the spores of Alternaria and the phylogenetically very close Ulocladium botrytis. This E5 antibody is directed against a repetitive epitope found in Alternaria and Ulocladium laboratory extracts and can be used in a sandwich assay for the quantification of these moulds. Therefore, E5 antibody is a promising tool for the development of Alternaria-Ulocladium-specific immunoassays, while A1 and F10 could be interesting tools for the quantification of the total mould biomass.

Background: Rhinitis is a very common disease, frequently caused by sensitisation to inhalant allergens. Negative results from skin prick tests (SPT) and in vitro IgE tests generally lead to a diagnosis of non-allergic rhinitis. However, it is possible, as indicated by studies addressed with dust mites or pollens that the production of specific IgE occurs exclusively at nasal level., Methods: We measured specific nasal IgE in children suffering from rhinitis in the periods when Alternaria spores were present in the air. All subjects underwent SPT with a standard panel of aeroallergens (Stallergenes, Milan, Italy) and, in the same session, to nasal IgE test (NT). Nasal provocation test (NPT) with Alternaria was used as reference., Results: Fifty-six subjects were included in the study. Of them, 20 (37.5%) were positive to SPT and 45 (80.3%) were positive to NT. In particular, 11 subjects (19.6%) had a positive SPT and a negative NT; 36 (64.3%) had a negative SPT and a positive NT; and 9 (16.1%) were positive to both tests. Positivity of NT and NPT was observed in 36 patients (69.6%), while positivity of SPT and NPT was observed in 15 patients (26.8%). This difference was highly significant (p<0.0001)., Conclusions: These findings suggest that sensitisation to Alternaria is frequently expressed by exclusive production of specific IgE in the nasal mucosa. Thus, measuring nasal IgE in children with rhinitis and negative SPT during the period of presence of Alternaria spores seems helpful to avoid a mistaken diagnosis of non-allergic rhinitis., (Copyright © 2011 SEICAP. Published by Elsevier Espana. All rights reserved.)

The genus Alternaria is one of the most common black moulds and appears to be increasing as a causative agent of subcutaneous phaeohyphomycosis, particularly among immunosuppressed patients. A 53-year-old patient who had received a kidney transplant presented with multiple verrucous lesions on the distal extremities. Positive histopathology and cultures, in addition to rDNA ITS region sequencing, identified the fungal isolate as Alternaria infectoria. Oral itraconazole was administered for 10 months. A follow-up at 15 months demonstrated no signs of infection. Clinical manifestations of cutaneous alternariosis vary significantly and only a few cases have been described in the literature. Although optimal treatment options remain controversial, this case of phaeohyphomycosis was successfully treated with itraconazole monotherapy., (Copyright © 2010 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.)