T and B lymphocytes and plasma cells within tertiary lymphoid organs. Double immunofluorescence was performed for CD3 (green) (A), CD45RO (red) (B), double-positive (yellow) (C), CD27 (green) (D), CD20 (red) (E), double-positive (yellow) (F), IgG (green) (G), CD138 (red) (H), double-positive (yellow) (I), IgM (green) (J), CD138 (red) (K), and double-positive (yellow) (L) cells. CD45RO and CD27 are markers of memory T cells and memory B cells, respectively. G–L suggest that plasma cells have the ability to produce antibodies. Bar, 100 μm.