Altered immune cell profiles and impaired CD4 T-cell activation in single and multi-food allergic adolescents.

BACKGROUND: Approximately 5% of adolescents have a food allergy, with peanut and tree nut allergies the most common. Having two or more food allergies in adolescence also doubles the risk of any adverse food reaction, and is associated with increased dietary and social burden. Investigations of immune function in persistently food allergic children are rare. OBJECTIVE: In the present study, we aimed to investigate the immune mechanisms that underlie food allergy in adolescence. METHODS: We used high-dimensional flow cytometry, unsupervised computational analysis and functional studies to comprehensively phenotype a range of non-antigen-specific immune parameters in a group of well-characterized adolescents with clinically defined single peanut allergy, multi-food allergy and aged-matched non-food allergic controls. RESULTS: We show that food allergic adolescents have higher circulating proportions of dendritic cells (p = .0084, FDR-adjusted p = .087, median in no FA: 0.63% live cells, in FA: 0.93%), and higher frequency of activated, memory-like Tregs relative to non-food allergic adolescents (p = .011, FDR-adjusted p = .087, median in no FA: 0.49% live cells, in FA: 0.65%). Cytokine profiling revealed that CD3/CD28 stimulated naïve CD4 T cells from food allergic adolescents produced less IL-6 (p = .0020, FDR-adjusted p = .018, median log2 fold change [stimulated/unstimulated] in no FA: 3.03, in FA: 1.92) and TNFα (p = .0044, FDR-adjusted p = .020, median in no FA: 9.16, in FA: 8.64) and may secrete less IFNγ (p = .035, FDR-adjusted p = .11, median in no FA: 6.29, in FA: 5.67) than naïve CD4 T cells from non-food allergic controls. No differences between clinical groups were observed for LPS-stimulated monocyte secretion of cytokines. CONCLUSIONS: These results have important implications for understanding the evolution of the immune response in food allergy throughout childhood, revealing that dendritic cell and T-cell signatures previously identified in early life may persist through to adolescence.

Administración satisfactoria de la vacuna triple viral mediante una prueba de provocación gradual en una paciente con anafilaxia después de una vacunación previa / Successful administration of measles-rubella-mumps vaccine by graded challenge in a case with anaphylaxis after prior vaccination

La alergia al huevo es una de las alergias alimentarias más frecuentes durante la niñez, junto con la alergia a la leche de vaca. La vacuna triple viral (VTV), contra el sarampión, la rubéola y las paperas, es parte del calendario de vacunación pediátrica y contiene proteína de huevo. La recomendación aceptada en la actualidad es que la VTV debe administrarse en una sola dosis y bajo supervisión médica en los pacientes con alergia al huevo. Si bien se ha informado que la VTV es segura para estos pacientes, algunos tuvieron anafilaxia. En general, la anafilaxia después de una vacunación previa se considera una contraindicación. En este artículo, presentamos el caso de la administración satisfactoria de la VTV mediante el incremento gradual de la dosis a una paciente que tuvo anafilaxia después de una vacunación previa.

Egg allergy is one of the most common food allergies during childhood along with cow's milk allergy. The measles-mumps-rubella (MMR) vaccine is included in the pediatric immunization schedule and contains egg protein. The currently accepted opinion is that the MMR vaccination should be done in a single dose under medical observation in patients with egg allergy. Although it is reported that the MMR vaccine is safe for that patients, there are some patients who developed anaphylaxis. Generally, the development of anaphylaxis after the previous vaccination is reported as a contraindication. We present a successful administration of MMR vaccine by gradually increased doses for a patient who developed anaphylaxis after the previous vaccination.

TRAIL deficiency and PP2A activation with salmeterol ameliorates egg allergen-driven eosinophilic esophagitis.

Food antigens are common inflammatory triggers in pediatric eosinophilic esophagitis (EoE). TNF-related apoptosis-inducing ligand (TRAIL) promotes eosinophilic inflammation through the upregulation of the E3 ubiquitin ligase Midline (MID)-1 and subsequent downregulation of protein phosphatase 2A (PP2A), but the role of this pathway in EoE that is experimentally induced by repeated food antigen challenges has not been investigated. Esophageal mucosal biopsies were collected from children with EoE and controls and assessed for TRAIL and MID-1 protein and mRNA transcript levels. Wild-type and TRAIL-deficient (Tnfsf10-/-) mice were administered subcutaneous ovalbumin (OVA) followed by oral OVA challenges. In separate experiments, OVA-challenged mice were intraperitoneally administered salmeterol or dexamethasone. Esophageal biopsies from children with EoE revealed increased levels of TRAIL and MID-1 and reduced PP2A activation compared with controls. Tnfsf10-/- mice were largely protected from esophageal fibrosis, eosinophilic inflammation, and the upregulation of TSLP, IL-5, IL-13, and CCL11 when compared with wild-type mice. Salmeterol administration to wild-type mice with experimental EoE restored PP2A activity and also prevented esophageal eosinophilia, inflammatory cytokine expression, and remodeling, which was comparable to the treatment effect of dexamethasone. TRAIL and PP2A regulate inflammation and fibrosis in experimental EoE, which can be therapeutically modulated by salmeterol.

Hypersensitivity and vaccines: an update.

Allergic reactions to vaccines can be classified as sensitivity to one of the vaccine components, pseudo-allergic reactions, often after hyperimmunization, and exacerbation of atopic symptoms or vasculitis. Pseudo-allergic reactions, some possibly due to hyperimmunization, are probably more common than true allergies. Atopic reactions should not be confused with the "flash" phenomenon, defined as an exacerbation of an allergic reaction due to a reduction in the allergic reactivity threshold following the vaccine injection. BCGitis occurs frequently, and for this reason, guidelines for Bacillus Calmette-Guérin (BCG) have been modified. The vaccine is now reserved for people at risk of exposure to Mycobacterium tuberculosis. This review provides an update on the vaccination modalities for people allergic to eggs, on the assessment that should be performed when a reaction occurs due to tetanus vaccination, on the urticaria after hepatitis vaccination, on an aluminum granuloma, which is more and more frequent in young children, and vasculitis after flu vaccination and BCGitis. The side effects associated with new, recently released vaccines, such as anti-influenza A H1N1 or anti-human papilloma virus (HPV) will also be presented.

Vacunaciones y sus problemas en el lactante / Vaccinations and their problems in the infant

En resumen, el pediatra debe manejar la información acerca de las reacciones adversas a vacunas, debe conocer la composición de las vacunas que se usan en Chile y promover su uso, y debe conocer sus contraindicaciones y sus alternativas.