Expression of autotaxin in lymphoid tissues. (A-B) Strong reactivity for autotaxin in HRS cells from EBV-positive primary HL tumors. (C) Lower levels of autotaxin expression in EBV-negative HRS cells despite strong labeling of nontumor cells (arrow). The difference in expression between EBV-negative and EBV-positive tumors was highly significant (see “Expression of autotaxin in primary lymphoma tissues”). In B-NHL, autotaxin expression was largely restricted to CD30⁺ ALCL (D), whereas most high-grade B-NHLs, such as BL (E) and CD30^- DLBCL (F), and low-grade B-NHLs, such as chronic lymphocytic lymphoma (CLL) (G), were negative. (F-G, arrows) Strong labeling of endothelial cells. This restricted pattern may be partly attributed to the finding that among normal B cells, autotaxin expression was absent from germinal center (GC) and mantle zone (MZ) (H) but was expressed by CD138⁺ postgerminal center B cells (I). Images were acquired using Nikon TE2000 with 60 ×/1.4 NA oil immersion lens (Nikon, Kingston-upon-Thames, United Kingdom). Cells were stained with immunoperoxidase. Images were captured with a Nikon Coolpix 2100, and Paint Shop Pro 8.0 (Jase Software, Maidenhead, United Kingdom).