Dipeptidyl aminopeptidase-IV as a histochemical marker of differential diagnosis of large cell anaplastic CD30+-lymphoma and Hodgkin's disease

Using histochemical methods, we studied distribution of dipeptidylaminopeptidase-IV (DPP-IV) in tumor cells of 16 patients with non-Hodgkin's malignant lymphomas (NHL) including B-cell NHL (10 cases), pleomorphic T-cell lymphoma (1 case), CD30+ anaplastic large cell lymphoma (ALCL) of T-cell (1 case) and ALCL of null-cell type (4 cases) and of 13 patients with Hodgkin's disease (HD). The results indicate that tumour cells of pleomorphic T-cell NHL and ALCL of T- and null-cell type showed DPP-IV activity. In contrast, no DPP-IV activity was seen in the tumor cells of B-cell NHL (lymphocytic, centroblastic/centrocytic, centroblastic, immunoblastic), in Berezovsky-Reed-Sternberg and Hodgkin's cells of different HD variants. These results demonstrate that difference in DPP-IV activity between tumor cells of ALCL and HD may be diagnostically important for separation of ALCL from HD and moreover may be used in verification of the borderline between HD-like ALCL and ALCL-like HD. It is possible that DPP-IV activity contributes to pathogenesis of ALCL and may determine clinical behaviour of this NHL being involved in autocrine and paracrine regulation of tumor cell growth of ALCL.