Interleukin 7 from Maternal Milk Crosses the Intestinal Barrier and Modulates T- Cell Development in Offspring

Background Breastfeeding protects against illnesses and death in hazardous environments, an effect partly mediated by improved immune function. One hypothesis suggests that factors within milk supplement the inadequate immune response of the offspring, but this has not been able to account for a series of observations showing that factors within maternally derived milk may supplement the development of the immune system through a direct effect on the primary lymphoid organs. In a previous human study we reported evidence suggesting a link between IL-7 in breast milk and the thymic output of infants. Here we report evidence in mice of direct action of maternally-derived IL-7 on T cell development in the offspring. Methods and Findings  We have used recombinant IL-7 labelled with a fluorescent dye to trace the movement in live mice of IL-7 from the stomach across the gut and into the lymphoid tissues. To validate the functional ability of maternally derived IL- 7 we cross fostered IL-7 knock-out mice onto normal wild type mothers. Subsets of thymocytes and populations of peripheral T cells were significantly higher than those found in knock-out mice receiving milk from IL-7 knock-out mothers. Conclusions/Significance Our study provides direct evidence that interleukin 7, a factor which is critical in the development of T lymphocytes, when maternally derived can transfer across the intestine of the offspring, increase T cell production in the thymus and support the survival of T cells in the peripheral secondary lymphoid tissue

Harmonization of Reporting for Detection of ALK Genetic Alterations in Neuroblastoma: A SIOPEN Biology Study

\ua9 2026 Association for Molecular Pathology and American Society for Investigative Pathology. In high-risk neuroblastoma, identification of ALK activating genetic alterations is considered for clinical decision-making at relapse or more recently in frontline treatment. The accurate diagnosis of genetic alterations requires harmonization of molecular techniques and reporting, especially when these concern inclusion criteria for clinical trials. Analysis and validation of 14 DNA samples harboring distinct ALK alterations were performed across the 21 SIOPEN (International Society of Paediatric Oncology Europe Neuroblastoma) molecular diagnostic laboratories. These included ALK mutations at or outside hotspots in the tyrosine kinase domain with variant allele frequencies (VAFs) of 1% to 91% or ALK genomic amplification. Each laboratory used their own techniques: ALK amplifications were detected by pan-genomic copy number techniques or fluorescence in situ hybridization, and ALK mutations were characterized by next-generation sequencing techniques. All laboratories correctly identified high-level ALK amplification and ALK mutations within the known hotspots with VAF >5%, with the exception of two cases. Differences in interpretation and reporting were apparent for samples harboring mutations with a VAF <5% or outside known hotspots. These results highlight the importance of standard operating procedures, standardized reporting, and the robustness of ALK genetic testing in the SIOPEN laboratories, and the need for expert discussions regarding atypical ALK alterations, to validate eligibility for ALK targeted treatment in clinical trials