a Overlays of fluorescence images obtained from one single FOV of a tonsil, where ILCs are shown as white arrows. Panel A: CD19 (red), CD20 (green), CD21 (blue), and Pax5 (Cyan) stain for B cells and depict two B cell follicles. Panel B: CD3 (red), CD4 (green), CD8 (blue), and Foxp3 (cyan) stain for T cells and depict the T cell zone. Panel C: CD138 (red), IgG (green), CD38 (blue), and IRF4 (cyan) stain for plasma cells and depict a plasma cell-rich area. Panel D: Fbn (fibronectin, red), CD31 (green), SMA (smooth muscle actin blue), and CD49a (cyan) stain for extracellular matrix (ECM) proteins and endothelial cells, and depict the connective tissue septum. Scale bars: 100 µm. See also Supplementary Fig. 2. b Three distinct functional areas in the tonsil (B cell follicles in magenta, T cell zone in blue, and connective tissue septum in yellow) are shown as segmented tissue compartments. Scale bar: 100 µm. c Box plot showing the distribution of ILCs within each tonsil compartment, as segmented in (b). Data are shown as mean ± SD and analyzed by one-way ANOVA (F = 19.01 and 3 df) with Bonferroni´s multiple comparison test, where *p < 0,05, **p < 0,01, ***p < 0,001 and ****p < 0,0001. a–c (n = 5). Source data are provided as a Source Data file.