Gata3 hypermethylation and Foxp3 hypomethylation are associated with sustained protection and bystander effect following epicutaneous immunotherapy in peanut-sensitized mice.

BACKGROUND: Epicutaneous immunotherapy (EPIT) is a promising method for treating food allergies. In animal models, EPIT induces sustained unresponsiveness and prevents further sensitization mediated by Tregs. Here, we elucidate the mechanisms underlying the therapeutic effect of EPIT, by characterizing the kinetics of DNA methylation changes in sorted cells from spleen and blood and by evaluating its persistence and bystander effect compared to oral immunotherapy (OIT). METHODS: BALB/c mice orally sensitized to peanut proteins (PPE) were treated by EPIT using a PPE-patch or by PPE-OIT. Another set of peanut-sensitized mice treated by EPIT or OIT were sacrificed following a protocol of sensitization to OVA. DNA methylation was analyzed during immunotherapy and 8 weeks after the end of treatment in sorted cells from spleen and blood by pyrosequencing. Humoral and cellular responses were measured during and after immunotherapy. RESULTS: Analyses showed a significant hypermethylation of the Gata3 promoter detectable only in Th2 cells for EPIT from the 4th week and a significant hypomethylation of the Foxp3 promoter in CD62L+ Tregs, which was sustained only for EPIT. In addition, mice treated with EPIT were protected from subsequent sensitization and maintained the epigenetic signature characteristic for EPIT. CONCLUSIONS: Our study demonstrates that EPIT leads to a unique and stable epigenetic signature in specific T-cell compartments with downregulation of Th2 key regulators and upregulation of Treg transcription factors, likely explaining the sustainability of protection and the observed bystander effect.

Particulate contamination in parenteral nutrition solutions: still a cause for concern?

OBJECTIVES: In consideration of a US Federal Drug Administration recommendation that all parenteral nutrition admixtures should be administered through an in-line filtration device, this observational study examined the number, size distribution, and sources of particulate contamination in parenteral nutrition admixture infusion systems. METHODS: Samples were drawn from the terminal connection of the infusion tubing before connection to the patient. The particles were sized and counted by optical microscopy and further investigated by electron microscopy and energy disperse spectroscopy. RESULTS: Large numbers of particles were found, and information gained about their possible origin. CONCLUSIONS: This study provides further support for the adoption of this Federal Drug Administration recommendation.