PD-L1–coexpressing MCs aggregate near the PALS structure in MCL. Splenic tissue was stained for expression of tryptase (red), PD-L1 (light green), and nuclei (DAPI, blue). (Top panel) Seven regions of interest acquired by confocal microscopy were stitched together to provide a larger field of view. Images are the maximum projection of 3 z-sections. Total field of view is 184.52 µm × 1290.24 µm; scale bar, 50 µm. (1-4) Magnification of corresponding boxes in top panel. Scale bar, 10 µm. Note that PD-L1⁺ MCs are more frequently found near the PALS.