High Human T Cell Leukemia Virus Type-1(HTLV-1) Provirus Load in Patients with HTLV-1 Carriers Complicated with HTLV-1-unrelated disorders | Sasaki et al. Virology Journal 2010 7 81 http content 7 1 81 VIROLOGY JOURNAL RESEARCH Open Access High Human T Cell Leukemia Virus Type-1 HTLV-1 Provirus Load in Patients with HTLV-1 Carriers Complicated with HTLV-1-unrelated disorders Daisuke Sasaki11 Yuko Doi21 Hiroo Hasegawa 1 Katsunori Yanagihara1 Kunihiro Tsukasaki2 Masako Iwanaga2 Yasuaki Yamada1 Toshiki Watanabe3 and Shimeru Kamihira 1 Abstract Background To address the clinical and virological significance of a high HTLV-1 proviral load VL in practical blood samples from asymptomatic and symptomatic carriers we simultaneously examined VL and clonal expansion status using polymerase chain reaction PCR quantification infected cell of peripheral mononuclear cells and Southern blotting hybridization SBH methods. Results The present study disclosed extremely high VL with highly dense smears with or without oligoclonal bands in SBH. A high VL of 10 or more was observed in 16 of a total of 33 samples one of 13 asymptomatic carriers 8 of 12 symptomatic carriers and 7 of 8 patients with lymphoma-type ATL without circulating ATL cells . In particular an extremely high VL of 50 or more was limited to symptomatic carriers whose band findings always contained at least dense smears derived from polyclonally expanded cells infected with HTLV-1. Sequential samples revealed that the VL value was synchronized with the presence or absence of dense smears and declined at the same time as disappearing dense smears. Dense smears transiently emerged at the active stage of the underlying disease. After disappearance of the smears several clonal bands became visible and were persistently retained explaining the process by which the clonality of HTLV-1-infected cells is established. The cases with only oligoclonal bands tended to maintain a stable VL of around 20 for a long time. Two of such cases developed ATL 4 and years later suggesting that a high VL with oligoclonal bands may be a predisposing risk .
