Proliferating IgD^– AID⁺ cells and CD30⁺ B-cell partially overlap. (A) AID (green) and IgD are mutually exclusive. Original magnification ×4. (B) AID⁺ cells (green) are IgD^– (red) and proliferate (Ki-67⁺, blue). Note nuclear AID⁺ extrafollicular cell (arrow). Original magnification ×40. (C) AID (green) and CD30 (red) are partially overlapping subsets. (D) Occasionally, AID⁺ (green) and CD30⁺ (red) double-positive cells can be seen outside and at the periphery of the GC. The areas marked by white rectangles are enlarged and colors are split below. Double-positive cells are indicated (arrows). Original magnification × 40. (E) Two representative nuclear AID⁺ (green) and CD30⁺ (red) extrafollicular cells are shown (arrows). Merged images show orange color where coexpressed. Original magnification × 40. Scale bar: 1 μm at ×40, 4 μmat ×10, and 10 μmat ×4.