Figure 4.

B cells and IL-33R⁺ CD3⁻ cells localize to the collecting lymphatic vessel walls associated with creeping fat. A: Portion of the small bowel bearing relocalized, or creeping, fat from a patient receiving ileal resection because of Crohn disease complications. Adipose tissue was cut so as to bisect lobes of the fat, in the opposite orientation to the usual direction we cut the tissue (Figure 1). B and C: Hematoxylin and eosin sections from these lobes showed the presence of collecting lymphatic vessels. The two parts show the same vessel at different points. D and E: Adjacent sections from the block used in C were stained to identify nucleated cells, podoplanin (Podo), and α-smooth muscle actin (α-SMA; D) or CD3, CD20, and IL-33R (E). F and G: Analysis of a tertiary lymphoid organ from different patient as above. Seven-color confocal scanning was performed with the display of data in two parts. Scale bars = 50 μm.