Distribution of GALT FRC subsets in ileal GALT. (A) Volcano plot showing DEG between GALT FRC from PP and M-ILF. (B) Bar plot showing FRC subset abundance among GALT FRC in the individual ileal GALT samples. (C) Confocal laser microscopy images showing CD3⁺ T cells, CD19⁺ B cells (left panels), and CD24-expressing FB among all PDPN⁺ FB (right panels) in ileal PP (upper panels) and M-ILF (lower panels). (D) Confocal laser microscopy images showing the expression of CD24 on F3⁺/CR1/2⁺/COLVI⁺ FB within ileal PP (upper panels) and M-ILF (lower panels). Star marks the apical side of the epithelial layer facing the intestinal lumen. (E) Confocal laser microscopy images showing the distribution of CD3⁺ T cells, CD19⁺ B cells, and F3⁺/CR1/2⁺/COLVI⁺ FB. (F) Confocal laser microscopy images showing the expression of CXCL13 levels by FB in the SED region. (G) Confocal laser microscopy images showing the expression of HLA-DR in ileal GALT. Images in C–G show one representative GALT out of replicates from two or three patients that were stained in independent experiments. (H) Nonscaled comparison of expression profiles of the indicated GALT FRC subclusters in ileal PP (y-axis) and M-ILF (x-axis). Zero (blue) indicates no overlap of the gene signatures; one (red) indicates full overlap. (A, B, and H) Data are from five independently processed tissue donors (5× PP and SM-ILF, 3× M-ILF).