Aminopeptidases in cells of non-Hodgkin's lymphoma of varying degrees of malignancy and in lymphogranulomatosis

26 cases of lymphoproliferative diseases were studied: 8 cases of reactive follicular hyperplasia (RFH), 11 cases of non-Hodgkin's malignant lymphomas (NML), 7 cases of lymphogranulomatosis (LGM). Only gamma-glutamyl transpeptidase (GGT) was found in lymphoid cells of B- and T-dependent areas of lymph nodes with reactive changes as well as in tumor cells of NML and LGM. GGT activity was more pronounced in NML of high-grade malignancy (centroblast and immunoblast) as compared to lymphomas of lower grade of malignancy (lymphocytic, centroblast-centrocytic and in Lennert lymphoma). GGT activity in cells of Hodgkin and Berezovsky-Sterberg in some cases of LGM was high, in others low. Significant differences in GGT activity between RFH and follicular centroblast-centrocytic lymphoma were not found. Activity of aminopeptidase M was observed in histiocytes, fibroblasts, vessels and areas of connective tissue growth. Aminopeptidase A activity was observed in vessels only. Activity of dipeptidyl(amino)peptidase IV was observed in some lymphoid cells in RFH, NML and LGM. Thus, GGT activity may be considered as a differential-diagnostic marker in separating NML of high and low degree of malignancy and this may presume a different sensitivity to the therapy.