Immunohistology of CCR7.

Immunohistochemical detection on paraffin-embedded sections using the 3D12/CCR7 (A-E) monoclonal antibody. In a case of dermatopathic lymphadenopathy, the dendritic cells in the interfollicular zone are strongly positive, whereas the follicles remain unlabeled (A). In a case of follicular lymphoma, CCR7 expression is restricted to dendritic cells, whereas the neoplastic cells are negative (B). The neoplastic cells of 2 cases of cHD are strongly positive for CCR7 (C,D). In contrast, the neoplastic cells in NLPHD (arrowheads) are negative, whereas a single cell (probably a dendritic cell) is stained (E). (F-J) Radioactive in situ hybridization with a probe specific for ELC or SLC transcripts. In a hyperplastic tonsil, ELC is observed only in the interfollicular zone (F). In cHD, reactive cells within the tumor infiltrate express ELC (G) and SLC (H). The nodules in NLPHD are negative for both chemokines (I,J), but SLC-specific signals (I) are found in the internodular areas and ELC-specific signals are observed outside the nodules (J). All chemokines are expressed in either the nonneoplastic leukocytic infiltrates of HD or stromal cells, but not in the HRS cells (arrows). Original magnification, × 20 (F, I), × 40 (A), × 100 (B, D), × 200 (C, E, G, H, J).