Staying IgD positive in a challenging environment.

The nasopharyngeal tissues provide a frontline defense against airborne exposure to viruses, bacteria, and allergens. In this issue of JEM, Tachó-Piñot et al. (https://doi.org/10.1084/jem.20251752) show that mutated IgD+ B cell subsets populate epithelial areas of nasopharyngeal mucosa, ready to tackle a multitude of antigenic targets.