TELOMERASE ACTIVITY AND TELOMERES IN PERIPHERAL BLOOD MONONUCLEAR CELLS FROM PATIENTS WITH ATL AND HAM/TSP

Abstract

P134 Telomeres and telomerase are known to be important in chromosome function and cell proliferation. We investigated the effect of infection of HTLV-I on telomerase activity, telomere length and human telomerase RNA (hTR) of the peripheral blood mononuclear cells from donors infected with HTLV-I. Ten patients with ATL and 10 patients with HAM/TSP were examined. As controls, 11 asymptomatic controls were examined; 6 of these were infected with HTLV-I and the other 5 were not. The telomerase activity was assayed by a non-radioisotope quantitative system from a telomeric repeat amplification protocol (TRAP), and it was detected using a fluorescence-based TRAP method. We measured the telomere length as the terminal restriction fragment length. The amount of hTR was measured using the real-time PCR system. The telomerase activity was significantly increased in the samples from patients with acute type of ATL (n=4, mean ± SEM 206.24 ± 22.44 units/μg) compared with asymptomatic controls (11.29 ± 2.60) (p<0.01). It was also slightly increased in the other types of ATL (n=6, 29.06 ± 9.09) (p<0.05), but not in HAM/TSP (13.32 ± 3.49). Both telomere length and the amount of hTR showed no specific association with the type of diseases, although the decrease of telomere length was observed with aging (p<0.05). Infections with HTLV-I themselves cause no significant effect on the telomerase activity and telomere length, although telomerase may play an important role in the process of tumorigenesis of some types of ATL.