GALT FRC-like FB can be detected in biopsy-based intestinal datasets and in human LN. (A) Upper panels: UMAPs showing the GALT FRC signature score (top 10 DEG) overlaid on the intestinal FB datasets of Kong et al. (2023) (left panel), Kinchen et al. (2018) (middle panel), and Elmentaite et al. (2021) (right panel). Lower panels: Spearman’s correlation plots depicting the similarities between the GALT FRC signature identified in this study (mean is set to zero) by indicated FRC clusters. (B) UMAPs showing the expression of the indicated GALT FRC subset signatures (top 10 DEG per cluster) or CD24 expression on the LN FRC dataset published by Lütge et al., as well as the original LN FRC clustering (Lütge et al., 2025). ACTA2⁺ PRC = α-smooth muscle actin–expressing PRC; PI16⁺ RC = peptidase inhibitor 16–expressing reticular cells. ADGRF5⁺ PRC = adhesion G protein–coupled receptor F5⁺ PRC; VSMC = vascular smooth muscle cells; medRC = medullary reticular cells; IFRC = interfollicular reticular cells. (C) Confocal laser microscopy images of a human mesenteric LN showing the expression of CD24 on COLVI⁺ and CR1/2⁺ FRC together with CD19⁺ B cells and CD3⁺ T cells. One representative image shown of replicates from two donors that were stained in independent experiments.