Heterochromatin and nucleolus organizer regions in cells of patients with malignant and premalignant lymphatic diseases.

Peripheral blood lymphocytes (short-term cultures) and permanent lymphoid cell lines (long-term cultures) of patients with Hodgkin disease (5), lymphoma (1), plasma cell leukemia (1), angioimmunoblastic lymphadenopathy (1), and infectious mononucleosis (3) were investigated for C-band variants and nucleolus organizer region (NOR)-activities by C-banding and silver-staining, and compared to those of healthy adults (5) and newborn children (3). Heterochromatin polymorphisms were found in malignant diseases (33%) as well as in controls (29%). In the lymphoma patients, heterochromatin of class 3 (Patil and Lubs 1977) was seen more frequently than in the controls (83%:57%). No marker C-band variants could be detected in any of the lymphatic diseases. There was no difference in the heterochromatin polymorphism between short-term cultures (predominantly T-cells) and long-term cultures (B-cells), and there was little but inconsistant difference in the NOR-activities. Silver-staining showed differences between healthy adults (8.8 AgNORs; SD:0.5) and newborn children (6.9; SD:0.4). In the lymphoma patients we found 8.3 (SD:0.7) AgNORs. Thus, using silver staining there was no detectable increase in the number of active NORs in cells of patients with malignant diseases as an expression of increased nucleolus activation in malignancies. The remarkably low NOR-activity in infectious mononucleosis (6.7; SD:1.0) may reflect an influence of acute virus infection (Epstein-Barr virus) on NOR-activity.