TELOMERASE ACTIVITY IN REACTIVE AND NEOPLASTIC LYMPHOID-TISSUES - INFREQUENT DETECTION OF ACTIVITY IN HODGKINS-DISEASE

We used the recently described sensitive and rapid detection assay cal led telomeric repeat amplification protocol (TRAP) to detect telomeras e activity in lymphoblastoid (n = 5) and lymphoma cell lines (n = 7), hyperplastic lymph nodes (n = 6) and tonsils (n = 5), and tissues invo lved by non-Hodgkin's lymphoma (NHL) (n = 43) and Hodgkin's disease (H D) (n = 14). Clearly evident telomerase activity was found in all lymp hoblastoid and lymphoma cell lines, and in 34 of 43 cases (80%) of NHL . These results were expected because of the proliferative and immorta l nature of the cell lines and most malignant cells. However, positive results were obtained with the TRAP assay in all hyperplastic lymph n odes and tonsils, which raises the issue of derepression of telomerase activity during an immune response. Telomerase activity alone therefo re does not distinguish malignant lymphoid proliferations from reactiv e states. Telomerase activity was detected in only 1 of 14 cases (7%) of lymphoid tissues involved by HD, Eight of the 13 negative cases wer e considered to be interpretable because of the lack (3 of 13 cases) o r tow level (5 of 13 cases) of telomerase inhibition. The five remaini ng cases could not be evaluated because of their telomerase inhibitor content, The findings imply either transient or very low levels of tel omerase activity in HD or that HD for the greater part is a telomerase -independent neoplasm. Microdissection studies are needed to identify subsets of cells carrying telomerase activity in both reactive and neo plastic lymphoid tissues. (C) 1997 by The American Society of Hematolo gy.