COVID-19 Vaccination Responses with Different Vaccine Platforms in Patients with Inborn Errors of Immunity.

Patients with inborn errors of immunity (IEI) in Argentina were encouraged to receive licensed Sputnik, AstraZeneca, Sinopharm, Moderna, and Pfizer vaccines, even though most of the data of humoral and cellular responses combination on available vaccines comes from trials conducted in healthy individuals. We aimed to evaluate the safety and immunogenicity of the different vaccines in IEI patients in Argentina. The study cohort included adults and pediatric IEI patients (n = 118) and age-matched healthy controls (HC) (n = 37). B cell response was evaluated by measuring IgG anti-spike/receptor binding domain (S/RBD) and anti-nucleocapsid(N) antibodies by ELISA. Neutralization antibodies were also assessed with an alpha-S protein-expressing pseudo-virus assay. The T cell response was analyzed by IFN-γ secretion on S- or N-stimulated PBMC by ELISPOT and the frequency of S-specific circulating T follicular-helper cells (TFH) was evaluated by flow cytometry.No moderate/severe vaccine-associated adverse events were observed. Anti-S/RBD titers showed significant differences in both pediatric and adult IEI patients versus the age-matched HC cohort (p < 0.05). Neutralizing antibodies were also significantly lower in the patient cohort than in age-matched HC (p < 0.01). Positive S-specific IFN-γ response was observed in 84.5% of IEI patients and 82.1% presented S-specific TFH cells. Moderna vaccines, which were mainly administered in the pediatric population, elicited a stronger humoral response in IEI patients, both in antibody titer and neutralization capacity, but the cellular immune response was similar between vaccine platforms. No difference in humoral response was observed between vaccinated patients with and without previous SARS-CoV-2 infection.In conclusion, COVID-19 vaccines showed safety in IEI patients and, although immunogenicity was lower than HC, they showed specific anti-S/RBD IgG, neutralizing antibody titers, and T cell-dependent cellular immunity with IFN-γ secreting cells. These findings may guide the recommendation for a vaccination with all the available vaccines in IEI patients to prevent COVID-19 disease.

Spatiotemporal regulation of galectin-1-induced T-cell death in lamina propria from Crohn's disease and ulcerative colitis patients.

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is characterized by chronic, relapsing intestinal inflammation. Galectin-1 (Gal-1) is an endogenous lectin with key pro-resolving roles, including induction of T-cell apoptosis and secretion of immunosuppressive cytokines. Despite considerable progress, the relevance of Gal-1-induced T-cell death in inflamed tissue from human IBD patients has not been ascertained. Intestinal biopsies and surgical specimens from control patients (n = 52) and patients with active or inactive IBD (n = 97) were studied. Gal-1 expression was studied by RT-qPCR, immunoblotting, ELISA and immunohistochemistry. Gal-1-specific ligands and Gal-1-induced apoptosis of lamina propria (LP) T-cells were determined by TUNEL and flow cytometry. We found a transient expression of asialo core 1-O-glycans in LP T-cells from inflamed areas (p < 0.05) as revealed by flow cytometry using peanut agglutinin (PNA) binding and assessing dysregulation of the core-2 ß 1-6-N-acetylglucosaminyltransferase 1 (C2GNT1), an enzyme responsible for elongation of core 2 O-glycans. Consequently, Gal-1 binding was attenuated in CD3+CD4+ and CD3+CD8+ LP T-cells isolated from inflamed sites (p < 0.05). Incubation with recombinant Gal-1 induced apoptosis of LP CD3+ T-cells isolated from control subjects and non-inflamed areas of IBD patients (p < 0.05), but not from inflamed areas. In conclusion, our findings showed that transient regulation of the O-glycan profile during inflammation modulates Gal-1 binding and LP T-cell survival in IBD patients.

Toward personalization of asthma treatment according to trigger factors.

Asthma is a severe and chronic disabling disease affecting more than 300 million people worldwide. Although in the past few drugs for the treatment of asthma were available, new treatment options are currently emerging, which appear to be highly effective in certain subgroups of patients. Accordingly, there is a need for biomarkers that allow selection of patients for refined and personalized treatment strategies. Recently, serological chip tests based on microarrayed allergen molecules and peptides derived from the most common rhinovirus strains have been developed, which may discriminate 2 of the most common forms of asthma, that is, allergen- and virus-triggered asthma. In this perspective, we argue that classification of patients with asthma according to these common trigger factors may open new possibilities for personalized management of asthma.

Sublingual Omp16-driven redirection of the allergic intestinal response in a pre-clinical model of food allergy.

BACKGROUND: IgE-mediated food allergy remains a significant and growing worldwide problem. Sublingual immunotherapy (SLIT) shows an excellent safety profile for food allergy, but the clinical efficacy needs to be improved. This study assessed the effects of the Toll-like receptor 4 agonist outer membrane protein (Omp) 16 from Brucella abortus combined with cow´s milk proteins (CMP) through the sublingual route to modulate cow's milk allergy in an experimental model. METHODS: Mice sensitized with cholera toxin and CMP were orally challenged with the allergen to elicit hypersensitivity reactions. Then, mice were treated with a very low amount of CMP along with Omp16 as a mucosal adjuvant, and finally, animals were re-exposed to CMP. Systemic and mucosal immune parameters were assessed in vivo and in vitro. RESULTS: We found that the sublingual administration of Omp16 + CMP induced a buccal Th1 immune response that modulated the intestinal allergic response with the suppression of symptoms, reduction of IgE and IL-5, and up-regulation of IgG2a and IFN-γ. The adoptive transfer of submandibular IFN-γ-producing α4ß7+ CD4+ and CD8+ cells conferred protection against allergic sensitization. The use of Omp16 + CMP promoted enhanced protection compared to CMP alone. CONCLUSION: In conclusion, Omp16 represents a promising mucosal adjuvant that can be used to improve the clinical and immune efficacy of SLIT for food allergy.

Identification of cross-reactive B-cell epitopes between Bos d 9.0101(Bos Taurus) and Gly m 5.0101 (Glycine max) by epitope mapping MALDI-TOF MS.

Exposure to cow's milk constitutes one of the most common causes of food allergy. In addition, exposure to soy proteins has become relevant in a restricted proportion of milk allergic pediatric patients treated with soy formulae as a dairy substitute, because of the cross-allergenicity described between soy and milk proteins. We have previously identified several cross-reactive allergens between milk and soy that may explain this intolerance. The purpose of the present work was to identify epitopes in the purified αS1-casein and the recombinant soy allergen Gly m 5.0101 (Gly m 5) using an α-casein-specific monoclonal antibody (1D5 mAb) through two different approaches for epitope mapping, to understand cross-reactivity between milk and soy. The 1D5 mAb was immobilized onto magnetic beads, incubated with the peptide mixture previously obtained by enzymatic digestion of the allergens, and the captured peptides were identified by MALDI-TOF MS analysis. On a second approach, the peptide mixture was resolved by RP-HPLC and immunodominant peptides were identified by dot blot with the mAb. Finally, recognized peptides were sequenced by MALDI-TOF MS. This novel MS based approach led us to identify and characterize four peptides on α-casein and three peptides on Gly m 5 with a common core motif. Information obtained from these cross-reactive epitopes allows us to gain valuable insight into the molecular mechanisms of cross-reactivity, to further develop new and more effective vaccines for food allergy.

Use of a Collagen Membrane to Enhance the Survival of Primary Intestinal Epithelial Cells.

Intestinal epithelial cell culture is important for biological, functional, and immunological studies. Since enterocytes have a short in vivo life span due to anoikis, we aimed to establish a novel and reproducible method to prolong the survival of mouse and human cells. Cells were isolated following a standard procedure, and cultured on ordered-cow's collagen membranes. A prolonged cell life span was achieved; cells covered the complete surface of bio-membranes and showed a classical enterocyte morphology with high expression of enzymes supporting the possibility of cryopreservation. Apoptosis was dramatically reduced and cultured enterocytes expressed cytokeratin and LGR5 (low frequency). Cells exposed to LPS or flagellin showed the induction of TLR4 and TLR5 expression and a functional phenotype upon exposure to the probiotic Bifidobacterium bifidum or the pathogenic Clostridium difficile. The secretion of the homeostatic (IL-25 and TSLP), inhibitory (IL-10 and TGF-ß), or pro-inflammatory mediators (IL-1ß and TNF) were induced. In conclusion, this novel protocol using cow's collagen-ordered membrane provides a simple and reproducible method to maintain intestinal epithelial cells functional for cell-microorganism interaction studies and stem cell expansion. J. Cell. Physiol. 232: 2489-2496, 2017. © 2016 Wiley Periodicals, Inc.

The inhibition of voltage-gated H+ channel (HVCN1) induces acidification of leukemic Jurkat T cells promoting cell death by apoptosis.

Cellular energetic deregulation is widely known to produce an overproduction of acidic species in cancer cells. This acid overload must be counterbalanced with a high rate of H+ extrusion to maintain cell viability. In this sense, many H+ transporters have been reported to be crucial for cell survival and proposed as antineoplastic target. By the way, voltage-gated proton channels (Hv1) mediate highly selective H+ outward currents, capable to compensate acid burden in brief periods of time. This structure is canonically described acting as NADPH oxidase counterbalance in reactive oxygen species production. In this work, we show, for the first time in a oncohematologic cell line, that inhibition of Hv1 channels by Zn2+ and the more selective blocker 2-(6-chloro-1H-benzimidazol-2-yl)guanidine (ClGBI) progressively decreases intracellular pH in resting conditions. This acidification is evident minutes after blockade and progresses under prolonged exposure (2, 17, and 48 h), and we firstly demonstrate that this is followed by cell death through apoptosis (annexin V binding). Altogether, these results contribute strong evidence that this channel might be a new therapeutic target in cancer.

Inflammation Controls Sensitivity of Human and Mouse Intestinal Epithelial Cells to Galectin-1.

Galectins play key roles in the inflammatory cascade. In this study, we aimed to analyze the effect of galectin-1 (Gal-1) in the function of intestinal epithelial cells (IECs) isolated from healthy and inflamed mucosa. IECs isolated from mice or patients with inflammatory bowel diseases (IBD) were incubated with different pro-inflammatory cytokines, and Gal-1 binding, secretion of homeostatic factors and viability were assessed. Experimental models of food allergy and colitis were used to evaluate the in vivo influence of inflammation on Gal-1 binding and modulation of IECs. We found an enhanced binding of Gal-1 to: (a) murine IECs exposed to IL-1ß, TNF, and IL-13; (b) IECs from inflamed areas in intestinal tissue from IBD patients; (c) small bowel of allergic mice; and (d) colon from mice with experimental colitis. Our results showed that low concentrations of Gal-1 favored a tolerogenic micro-environment, whereas high concentrations of this lectin modulated viability of IECs through mechanisms involving activation of caspase-9 and modulation of Bcl-2 protein family members. Our results showed that, when added in the presence of diverse pro-inflammatory cytokines such as tumor necrosis factor (TNF), IL-13 and IL-5, Gal-1 differentially promoted the secretion of growth factors including thymic stromal lymphopoietin (TSLP), epidermal growth factor (EGF), IL-10, IL-25, and transforming growth factor (TGF-ß1 ). In conclusion, we found an augmented binding of Gal-1 to IECs when exposed in vitro or in vivo to inflammatory stimuli, showing different effects depending on Gal-1 concentration. These findings highlight the importance of the inflammatory micro-environment of mucosal tissues in modulating IECs susceptibility to the immunoregulatory lectin Gal-1 and its role in epithelial cell homeostasis.

Safety and immunogenicity of different booster vaccination schemes for COVID-19 used in El Salvador.

Purpose: The effectiveness of coronavirus disease 2019 (COVID-19) vaccination schemes and the combination of vaccines of various platforms for administering booster doses is still being studied since it will depend on the population's response to vaccines. We aimed to evaluate the safety, protection, and immunogenicity of the Salvadorean population's third dose booster COVID-19 vaccine and the potential benefit of homologous vs. heterologous regimens. Materials and Methods: This is an analytical observational cohort study in a population aged 18 to 65 years that was primarily vaccinated with AstraZeneca, Sinovac, or Pfizer/BioNTech. Volunteers were recruited (n=223) and followed up for 3 months after receiving the 3rd vaccine (BNT162b2) as a booster. Adverse reactions were monitored, serum anti-spike immunoglobulin G (IgG) was assessed by chemiluminescence, and a polymerase chain reaction was carried out when subjects developed clinical signs. Results: The cohorts finally included 199 participants, and we observed only mild adverse effects in all cohorts. A significant increase in specific IgG levels was found after the booster dose in all cohorts. The heterologous scheme with Sinovac showed the greatest increase in antibody titer, and a decrease was observed in all participants after 3 months. During the follow-up period, 30 participants showed symptomatology compatible with COVID-19, but only four were laboratory-confirmed and they showed mild clinical signs. Conclusion: These findings indicate that the booster doses used were safe and promoted an immediate increase in immunogenicity, which decreased over time. The heterologous regimen showed stronger immunogenicity compared to the messenger RNA-based homologous scheme.

Lidocaine reinforces the anti-inflammatory action of dexamethasone on myeloid and epithelial cells activated by inflammatory cytokines or SARS-CoV-2 infection.

BACKGROUND: Severe cases of Coronavirus Disease 2019 (COVID-19) that require admission to the Intensive Care Unit (ICU) and mechanical ventilation assistance show a high mortality rate with currently few therapeutic options available. Severe COVID-19 is characterized by a systemic inflammatory condition, also called "cytokine storm", which can lead to various multi-organ complications and ultimately death. Lidocaine, a safe local anesthetic that given intravenously is used to treat arrhythmias, has long been reported to have an anti-inflammatory and pro-homeostatic activity. METHODS: We studied the capacity of lidocaine to modulate cytokine secretion of mouse and human myeloid cell lines activated by different cytokines or Toll Like Receptor (TLR) ligands (flagellin (FliC), Lipopolysaccharide (LPS), Polyinosinic:polycytidylic acid (Poly I:C) and N-Palmitoyl-S- [2,3-bis(palmitoyloxy)-(2RS)-propyl]-(R)-cysteinyl-(S)-seryl-(S)-lysyl-(S)-lysyl-(S)-lysyl-(S)-lysine x 3HCl (Pam3Cys-SKKKK)) or by Severe acute respiratory syndromecoronavirus 2 (SARS-CoV-2) infection to epithelial cells. Reporter cell lines were used to study modulation of lidocaine of specific signaling pathways. RESULTS: Lidocaine used in combination with dexamethasone, had an additive effect in the modulation of cellular inflammatory response triggered by Tumoral Necrosis Factor alpha (TNFα), Interleukin 1 beta (IL-1ß) as well as different TLR ligands. We also found that lidocaine in combination with dexamethasone modulates the Nuclear factor kappa B (NF-κB) pathway, inflammasome activation as well as interferon gamma receptor (IFNγR) signaling without affecting the type I interferons (Type I IFNs) pathway. Furthermore, we showed that lidocaine and dexamethasone treatment of epithelial cells infected with SARS-CoV-2 modulated the expression of chemokines that contribute to pro-inflammatory effects in severe COVID. CONCLUSIONS: We reported for the first time in vitro anti-inflammatory capacity of lidocaine on SARS-CoV-2 triggered immune pathways. These results indicated the potential of lidocaine to treat COVID-19 patients and add tools to the therapeutic options available for these concerning cases.

Characterization of protein cargo of Echinococcus granulosus extracellular vesicles in drug response and its influence on immune response.

BACKGROUND: The Echinococcus granulosus sensu lato species complex causes cystic echinococcosis, a zoonotic disease of medical importance. Parasite-derived small extracellular vesicles (sEVs) are involved in the interaction with hosts intervening in signal transduction related to parasite proliferation and disease pathogenesis. Although the characteristics of sEVs from E. granulosus protoscoleces and their interaction with host dendritic cells (DCs) have been described, the effect of sEVs recovered during parasite pharmacological treatment on the immune response remains unexplored. METHODS: Here, we isolated and characterized sEVs from control and drug-treated protoscoleces by ultracentrifugation, transmission electron microscopy, dynamic light scattering, and proteomic analysis. In addition, we evaluated the cytokine response profile induced in murine bone marrow-derived dendritic cells (BMDCs) by qPCR. RESULTS: The isolated sEVs, with conventional size between 50 and 200 nm, regardless of drug treatment, showed more than 500 cargo proteins and, importantly, 20 known antigens and 70 potential antigenic proteins, and several integral-transmembrane and soluble proteins mainly associated with signal transduction, immunomodulation, scaffolding factors, extracellular matrix-anchoring, and lipid transport. The identity and abundance of proteins in the sEV-cargo from metformin- and albendazole sulfoxide (ABZSO)-treated parasites were determined by proteomic analysis, detecting 107 and eight exclusive proteins, respectively, which include proteins related to the mechanisms of drug action. We also determined that the interaction of murine BMDCs with sEVs derived from control parasites and those treated with ABZSO and metformin increased the expression of pro-inflammatory cytokines such as IL-12 compared to control cells. Additionally, protoscolex-derived vesicles from metformin treatments induced the production of IL-6, TNF-α, and IL-10. However, the expression of IL-23 and TGF-ß was downregulated. CONCLUSIONS: We demonstrated that sEV-cargo derived from drug-treated E. granulosus protoscoleces have immunomodulatory functions, as they enhance DC activation towards a type 1 pro-inflammatory profile against the parasite, and therefore support the proposal of a new approach for the prevention and treatment of secondary echinococcosis.

Food-sensitized pediatric patients show colonic cow's milk protein-specific Th2 cells.

Food allergies have become a health concern worldwide. Around 6% to 10% of children are allergic to cow's milk proteins. We have previously characterized colorectal polyps in patients sensitized to food allergens. These polyps are classified as inflammatory and present a type 2 environment, with elevated interleukin (IL)-13 and IL-4, and are a site of immunoglobulin E synthesis. In this study, we characterized and isolated cow's milk protein-specific T cell lines and T cell clones from the lamina propria of polyps from patients sensitized to these proteins. Isolated T cells responded to cow's milk proteins similarly to peripheral blood T cells, showing antigen-specific cell proliferation and Th2 cytokines release in vitro. T cell clones obtained were all CD4+ T cells and expressed the membrane TCRαß receptor and secreted higher IL-4, IL-5, and IL-13 amounts than unstimulated cells, whereas interferon γ secretion remained unchanged. Remarkably, the gut homing chemokine receptor CCR9 was augmented in cow's milk-specific peripheral and lamina propria T cells, and CCL25 was found to be expressed in the inflammatory polyp tissue and not in the adjacent mucosa. In conclusion, we isolated and characterized cow's milk-specific lamina propria CD4+ Th2 cells from colonic inflammatory polyps. CCR9 expression on these cells, along with increase secretion of CCL25 in the polyp, favors recruitment and cow's milk-specific allergic response within the inflammatory polyp tissue. Our findings may be critical to understand the underlying mechanism that promotes immunoglobulin E synthesis in the colon of cow's milk proteins allergic patients, contributing to the development of novel T cell-targeted immunotherapies.

Case report: De novo SAMD9L truncation causes neonatal-onset autoinflammatory syndrome which was successfully treated with hematopoietic stem cell transplantation.

During recent years, the identification of monogenic mutations that cause sterile inflammation has expanded the spectrum of autoinflammatory diseases, clinical disorders characterized by uncontrolled systemic and organ-specific inflammation that, in some cases, can mirror infectious conditions. Early studies support the concept of innate immune dysregulation with a predominance of myeloid effector cell dysregulation, particularly neutrophils and macrophages, in causing tissue inflammation. However, recent discoveries have shown a complex overlap of features of autoinflammation and/or immunodeficiency contributing to severe disease phenotypes. Here, we describe the first Argentine patient with a newly described frameshift mutation in SAMD9L c.2666delT/p.F889Sfs*2 presenting with a complex phenotypic overlap of CANDLE-like features and severe infection-induced cytopenia and immunodeficiency. The patient underwent a fully matched unrelated HSCT and has since been in inflammatory remission 5 years post-HSCT.

Poly(allylamine)-tripolyphosphate Ionic Assemblies as Nanocarriers: Friend or Foe?

Designing effective drug nanocarriers that are easy to synthesize, robust, and nontoxic is a significant challenge in nanomedicine. Polyamine-multivalent molecule nanocomplexes are promising drug carriers due to their simple and all-aqueous manufacturing process. However, these systems can present issues of colloidal instability over time and cellular toxicity due to the cationic polymer. In this study, we finely modulate the formation parameters of poly(allylamine-tripolyphosphate) complexes to jointly optimize the robustness and safety. Polyallylamine was ionically assembled with tripolyphosphate anions to form liquid-like nanocomplexes with a size of around 200 nm and a zeta potential of -30 mV. We found that nanocomplexes exhibit tremendous long-term stability (9 months of storage) in colloidal dispersion and that they are suitable as protein-loading agents. Moreover, the formation of nanocomplexes induced by tripolyphosphate anions produces a switch-off in the toxicity of the system by altering the overall charge from positive to negative. In addition, we demonstrate that nanocomplexes can be internalized by bone-marrow-derived macrophage cells. Altogether, these nanocomplexes have attractive and promising properties as delivery nanoplatforms for potential therapies based on the immune system activation.

In vivo evidence of cross-reactivity between cow's milk and soybean proteins in a mouse model of food allergy.

BACKGROUND: Cow's milk allergy (CMA) is an important problem worldwide and the development of an in vivo system to study new immunotherapeutic strategies is of interest. Intolerance to soybean formula has been described in CMA patients, but it is not fully understood. In this work, we used a food allergy model in BALB/c mice to study the cross-reactivity between cow's milk protein (CMP) and soy proteins (SP). METHODS: Mice were orally sensitized with cholera toxin and CMP, and then challenged with CMP or SP to induce allergy. Elicited symptoms, plasma histamine, humoral and cellular immune response were analyzed. Th1- and Th2-associated cytokines and transcription factors were assessed at mucosal sites and in splenocytes. Cutaneous tests were also performed. RESULTS: We found that the immediate symptoms elicited in CMP-sensitized mice orally challenged with SP were consistent with a plasma histamine increase. The serum levels of CMP-specific IgE and IgG1 antibodies were increased. These antibodies also recognized soy proteins. Splenocytes and mesenteric lymph node cells incubated with CMP or SP secreted IL-5 and IL-13. mRNA expression of Th2-associated genes (IL-5, IL-13, and GATA-3) was upregulated in mucosal samples. In addition, sensitized animals exhibited positive cutaneous tests after the injection of CMP or SP. CONCLUSIONS: We demonstrate that CMP-sensitized mice, without previous exposure to soy proteins, elicited hypersensitivity signs immediately after the oral administration of SP, suggesting that the immunochemical cross-reactivity might be clinically relevant. This model may provide an approach to further characterize cross-allergenicity phenomena and develop new immunotherapeutic treatments for allergic patients.

Federation of Clinical Immunology Societies Goes South 2021: advanced course on molecular and cellular translational immunology.

The Federation of Clinical Immunology Societies (FOCIS) regularly organizes scientific meetings to foster advances in immunology. A new event of this type is FOCIS Goes South, a course and workshop organized by FOCIS Centers of Excellence (FCEs) from across Latin America, which consists of a course on advanced immunology, a flow cytometry workshop and seminars on cutting-edge research in autoimmunity, tolerance, cancer, infectious diseases and vaccines. Due to the COVID-19 pandemic, the second version of FOCIS Goes South, hosted by the Millennium Institute on Immunology and Immunotherapy in Chile, took place virtually from 15 to 18 November 2021, with more than 950 registered participants. The present article summarizes the key findings and insights discussed at FOCIS Goes South 2021.

Volcanic ash-driven worsening of mucosal inflammation in an experimental colitis model.

Particulate matter exposure and related chemical changes in drinking water have been associated with health problems and inflammatory disorders. This study aimed to examine the effect of orally administered ash-water dilution on the gut of mice under normal and inflammatory conditions. Balb/c mice received ash-released soluble and dust-suspended components in the drinking water for 14 days. On day 7, animals were intrarectally instilled with TNBS in ethanol or flagellin from Salmonella typhimurium in PBS. At sacrifice, colon segments were collected and histologic damage, mRNA expression and cytokine levels in tissue were evaluated. In addition, these parameters were also evaluated in IL-10 null mice. We found that mice that received 5% w. fine-ash dilution in the drinking water worsened colitis signs. Weight loss, shortening of the colon, tissue edema with mucosa and submucosa cell infiltration and production of pro-inflammatory cytokines and chemokines were enhanced compared to control mice. A more pronounced inflammation was observed in IL-10 null mice. In addition, markers of NLRP3-dependent inflammasome activation were found in animals exposed to ash. In conclusion, ingestion of contaminated water with dust-suspended particulate matter enhanced the inflammatory response in the gut, probably due to alteration of the gut barrier and promoting an intense contact with the luminal content. This study critically appraises the response for fine particulate matter in uncommon illnesses reported for volcanic ash pollution. We suggest actions to enable better prediction and assessment the health impacts of volcanic eruptions.

Carbonylation induced by antibiotic and pesticide residues on casein increases its IgE binding and allergenicity.

This work aimed to evaluate the effect of carbonylation induced by tetracyclines, ß-lactams, fluoroquinolones, and pyrethroids in caseins of bovine origin on their immunoreactivity and allergenicity. Using a spectrophotometric method, ELISA, dot-blot, and an IgE-mediated milk allergy mouse model, we confirmed that antibiotics and pesticides at their maximum residue limit, promoted the in vitro carbonylation of caseins (among 5.0 ± 0.01 and 67.5 ± 0.70 nmol of carbonyl/mg of protein); furthermore, carbonylations greater than 19 nmol significantly increase the in vitro IgE immunoreactivity of caseins (average OD among 0.63-1.50) regarding the negative control (average OD: 0.56). On the other hand, sensitized mice exposed to oxidized caseins showed increased clinical scores (2-5), positive skin tests, and footpad swelling (0.28-0.59 mm) compared to the negative control (1-2; negative skin tests; 0.1 mm, respectively), denoting increased allergenicity. These results suggest that casein carbonylation increases their IgE immunoreactivity and allergenicity, a fact that could be explained by the resistance to the digestion promoted by carbonylation and by conformational changes in the random coil casein structure, which can expose cryptic epitopes or neoepitopes.

Type-2 Cytokines Promote the Secretion of the Eosinophil-Attractant CCL26 by Intestinal Epithelial Cells in Food-Sensitized Patients.

Several inflammatory processes of the bowel are characterized by an accumulation of eosinophils at inflammation sites. The mechanisms that govern mucosal infiltration with eosinophils are not fully understood. In this work, we studied the colorectal polyp-confined tissue containing eosinophils and we hypothesized that intestinal epithelial cells are the cell source of eotaxin-3 or CCL26, a potent chemoattractant for eosinophils. We analyzed colorectal polyps (n=50) from pediatric patients with rectal bleeding by H&E staining and eosin staining, and different pro-inflammatory cytokines were assessed by RT-qPCR and ELISA. IgE and CCL26 were investigated by RT-qPCR, ELISA and confocal microscopy. Finally, the intracellular signaling pathway that mediates the CCL26 production was analyzed using a kinase array and immunoblotting in human intestinal Caco-2 cell line. We found a dense cell agglomeration within the polyps, with a significantly higher frequency of eosinophils than in control adjacent tissue. IL-4 and IL-13 were significantly up-regulated in polyps and CCL26 was elevated in the epithelial compartment. Experiments with Caco-2 cells showed that the type-2 cytokine IL-13 increased STAT3 and STAT6 phosphorylation and eotaxin-3 secretion. The addition of the blocking antibody Dupilumab or the inhibitor Ruxolitinib to the cytokine-stimulated Caco-2 cells diminished the CCL26 secretion to basal levels in a dose-dependent manner. In conclusion, our findings demonstrate a high frequency of eosinophils, and elevated levels of type-2 cytokines and eotaxin-3 in the inflammatory stroma of colorectal polyps from pediatric patients. Polyp epithelial cells showed to be the main cell source of CCL26, and IL-13 was the main trigger of this chemokine through the activation of the STAT3/STAT6/JAK1-2 pathway. We suggest that the epithelial compartment actively participates in the recruitment of eosinophils to the colonic polyp-confined inflammatory environment.