The skin microbiome in pediatric atopic dermatitis and food allergy.

The skin microbiome is an extensive community of bacteria, fungi, mites, viruses and archaea colonizing the skin. Fluctuations in the composition of the skin microbiome have been observed in atopic dermatitis (AD) and food allergy (FA), particularly in early life, established disease, and associated with therapeutics. However, AD is a multifactorial disease characterized by skin barrier aberrations modulated by genetics, immunology, and environmental influences, thus the skin microbiome is not the sole feature of this disease. Future research should focus on mechanistic understanding of how early-life skin microbial shifts may influence AD and FA onset, to guide potential early intervention strategies or as microbial biomarkers to identify high-risk infants who may benefit from possible microbiome-based biotherapeutic strategies. Harnessing skin microbes as AD biotherapeutics is an emerging field, but more work is needed to investigate whether this approach can lead to sustained clinical responses.

Study protocol: The role of milk matrix lipids in programming the immunoreactivity of proteins derived from lactic acid bacteria.

Food allergy is widely recognized as a significant health issue, having escalated into a global epidemic, subsequently giving rise to the development of numerous additional complications. Currently, the sole efficient method to curb the progression of allergy is through the implementation of an elimination diet. The increasing number of newly identified allergens makes it harder to completely remove or avoid them effectively. The immunoreactivity of proteins of bacterial origin remains an unexplored topic. Despite the substantial consumption of microbial proteins in our diets, the immunologic mechanisms they might induce require thorough validation. This stands as the primary objective of this study. The primary objective of this study was to evaluate the effects of bacterial proteins on the intestinal barrier and immune system parameters during hypersensitivity induction in both developing and mature organisms. The secondary objective was to evaluate the role of lipids in the immunoreactivity programming of these bacterial proteins. Notably, in this complex, comprehensively designed in vitro, in vivo, and ex vivo trial, the immunoreactivity of various bacterial proteins will be examined. In summary, the proposed study intends to address the knowledge gaps regarding the effects of Lactobacillus microbial proteins on inflammation, apoptosis, autophagy, and intestinal barrier integrity in a single study.

Zebrafish gut microbiota composition in response to tick saliva biomolecules correlates with allergic reactions to mammalian meat consumption.

The α-Gal syndrome (AGS) is an IgE-mediated tick borne-allergy that results in delayed anaphylaxis to the consumption of mammalian meat and products containing α-Gal. Considering that α-Gal-containing microbiota modulates natural antibody production to this glycan, this study aimed to evaluate the influence on tick salivary compounds on the gut microbiota composition in the zebrafish (Danio rerio) animal model. Sequencing of 16 S rDNA was performed in a total of 75 zebrafish intestine samples, representing different treatment groups: PBS control, Ixodes ricinus tick saliva, tick saliva non-protein fraction (NPF), tick saliva protein fraction (PF), and tick saliva protein fractions 1-5 with NPF (F1-5). The results revealed that treatment with tick saliva and different tick salivary fractions, combined with α-Gal-positive dog food feeding, resulted in specific variations in zebrafish gut microbiota composition at various taxonomic levels and affected commensal microbial alpha and beta diversities. Metagenomics results were corroborated by qPCR, supporting the overrepresentation of phylum Firmicutes in the tick saliva group, phylum Fusobacteriota in group F1, and phylum Cyanobacteria in F2 and F5 compared to the PBS-control. qPCRs results at genus level sustained significant enrichment of Plesiomonas spp. in groups F3 and F5, Rhizobium spp. in NPF and F4, and Cloacibacterium spp. dominance in the PBS control group. This study provides new results on the role of gut microbiota in allergic reactions to tick saliva components using a zebrafish model of AGS. Overall, gut microbiota composition in response to tick saliva biomolecules may be associated with allergic reactions to mammalian meat consumption in AGS.

Inulin has a beneficial effect by modulating the intestinal microbiome in a BALB/c mouse model.

Food allergy is an important health problem that affects human quality of life and socioeconomic development, and its treatment requires improvement. Intestinal flora dysbiosis is closely associated with food allergies. A sensitised mouse model was established by the intraperitoneal injection of ovalbumin (OVA). The mice were randomly divided into four groups: control, model, high-dose (H), and low-dose (L) inulin. The mice were administered water containing different concentrations of inulin four weeks before the OVA injection. Body weight changes were monitored. After the last OVA injection, the mice were scored for allergic reactions. The levels of total immunoglobulin E (IgE) and diamine oxidase (DAO) in the serum and secretory IgA (sIgA) in the small intestinal mucus were measured, and 16S rRNA sequencing of the faecal flora was performed to evaluate microbial parameters. The intestinal flora biomarkers, correlations between them, and biochemical indicators were analysed. Inulin treatment had no effect on the body weight of OVA-sensitised mice but attenuated allergic reactions and intestinal injury in mice. Compared with the control group, the model group had significantly higher levels of serum DAO and IgE and significantly lower levels of intestinal mucus IgA. IgA levels in the intestinal mucus of mice treated with inulin prior to OVA sensitisation were higher than those in non-inulin-treated OVA-sensitised mice. Furthermore, analysis of operational taxonomic units showed that inulin treatment decreased the abundance of Alloprevotella, Rikenellaceae RC9, Eubacterium siraeum, and Eubacterium xylanophilum, and increased the abundance of Blautia and Lachnospiraceae. Serum DAO levels were positively associated with Eubacterium siraeum, Alloprevotella, Eubacterium xylanophilum, and Odoribacter and negatively associated with Blautia, Tyzzerella, Alistipes, Desulfovibrionaceae, and Ruminococcaceae UCG005. In addition, IgE levels were positively associated with Eubacterium siraeum, Alloprevotella, Eubacterium xylanophilum, Odoribacter, and Citrobacter and negatively associated with Blautia, unclassified Ruminococcaceae, and Alistipes. IgA exhibited significant positive correlation with Blautia, norank_f_Eubacterium coprostanoligenes, Alistipes, norank Desulfovibrionaceae, Muribaculum, and Ruminococcaceae U C G 005 and significant negative correlation with Eubacterim siraeum, Eubacterium xylanophilum, Odoribacter, and Citrobacter. Inulin exerts a protective effect against food allergies in mice, which is partially mediated by alterations in the gut microbiota.

Entendiendo la relación entre la infección por Helicobacter pylori y enfermedades alérgicas en niños y adultos / Understanding the relationship between Helicobacter pylori infection and allergies in children and adults

La infección por Helicobacter pylori afecta a más del 50 por ciento de la población mundial, asociándose a gastritis histológica, úlcera duodenal y gástrica, así como también a cáncer gástrico. Abundante literatura reciente sugiere una relación entre H. pylori y las enfermedades alérgicas, las cuales han presentado un sostenido aumento en su incidencia en los últimos años. Considerando que ambas enfermedades (H. pylori y alergias), presentan respuestas Th polarizadas y opuestas, se revisan los aspectos claves de esta infección y su respuesta inmune polarizada a Th1, la cual, siendo inefectiva para erradicar H. pylori, es el elemento característico subyacente de la gastritis crónica histológica. Junto con ésto se analiza la respuesta inmune de tipo Th2 sistémica asociada a alergias cutáneas, respiratorias y alimentarias, para así comprender mejor su posible interacción. Algunos estudios plantean que la erradicación de H. pylori beneficiaría la remisión de enfermedades tales como urticaria crónica,asma y alergias alimentarias entre otras. Por el contrario, una fuerte línea de investigación se apoyanen la teoría de higiene y plantean que la erradicaciónde microrganismos como H. pylori, Toxoplasma gondii y virus de hepatitis A aumentaría la incidencia de alergias por un desbalance hacia Th2. En la mayoría de los estudios, la falta de grupo control o protocolos ciegos dificultan la posibilidad de llegar a una conclusión.

Helicobacter pylori’s infection affects more than 50% of the world’s population, inducing a histologic chronic gastritis, which can develop to a duodenal and gastric ulceration, as well as gastric cancer. Recent literature suggests a possible relationship between H. pylori and allergic diseases, which have also shown an increase in their incidence these last years. Considering that both diseases, H. pylori and allergies, have polarized and opposite immune responses, we wanted to examine the important aspects of this infection and it’s immune response (Th1), which is ineffective in eradicating H. pylori, and is a characteristic element in the histologic chronic gastritis. We also wanted to review the immune response linked to skin, food and respiratory allergies (Th2) so we can understand the interaction between allergic diseases and H. pylori. Many of the studies conclude that the eradication of H. pylori would benefit the remission of chronic urticaria, asthma and food allergies among others. However, other studies mention the hygiene hypothesis where the eradication of microrganisms such as H. pylori, Toxoplasma gondii and hepatitis A virus could increase the incidence of allergic diseases due to a polarized response towards Th2. The lack of control groups and blind studies make difficult to establish a final conclusion