Analysis of HTLV-I proviral load in 202 HAM/TSP patients and 243 asymptomatic HTLV-I carriers: High proviral load strongly predisposes to HAM/TSP
Abstract
P135 OBJECTIVE: In order to examine the effect of HTLV-I proviral load (HPL) on the pathogenesis of HAM/TSP, we measured the HPL in peripheral blood mononuclear cells (PBMC) from a large number of HAM/TSP patients and asymptomatic HTLV-I carriers. METHODS: To measure the HPL, we used an accurate and reproducible quantitative PCR method using a dual-labeled fluorogenic probe (ABI PRISM 7700™ Sequence Detection System). RESULTS: The mean ± standard error of mean (SEM) HPL copy number per 1×104 PBMC was 798 ± 51 (median 544) in 202 HAM/TSP patients; 120 ± 17 (median 34) in 200 non HAM-related (general) asymptomatic HTLV-I carriers (RC); and 496 ± 82 (median 321) in 43 asymptomatic HTLV-I carriers genetically related to HAM/TSP patients (FA). The prevalence of HAM/TSP rises exponentially once HPL exceeds 1% PBMC. The HPL of female patients with HAM/TSP was significantly higher than that of male patients, however there was no significant difference in HPL between sexes in RC. There was a significant correlation between HPL and the concentration of neopterin in CSF of HAM/TSP patients. CONCLUSIONS: These results indicate that the HPL in PBMC may be related to the inflammatory process in the spinal cord lesion. The increased HPL in FA suggests the existence of genetic factors contributing to the replication of HTLV-I in vivo.