Immunohistochemical detection of PI9 in nodal and extranodal T-cell NHLs.

Tissue sections of T-ALCL (A-C,G), NK/T-cell, nasal type (D), and enteropathy-type T-cell NHL (E,F) were stained with mAb PI9-17 (A,C-E), mAb PI9-K (B), or antigranzyme B mAb GB7 (F). The section in panel G was double-stained with mAb PI9-17 (red) and GB7 (brown). The arrowhead in panel C denotes an example of a PI9⁺ dendritic cell. The arrows in panels D to F point to tumor cells positive for PI9 (D,E) and granzyme B (F). In panel G the arrows point to tumor-infiltrating CTLs positive for granzyme B and the arrowhead denotes an example of a PI9⁺ neoplastic cell. Original magnification × 630.