Sequential change of virus markers in seroconverters with community-acquired infection of human T lymphotropic virus type I

Twenty-three human T lymphotropic virus type I (HTLV-I) seroconverters were identified among 1120 HTLV-I-seronegative adults followed up for 11 years in an area of Japan endemic for HTLV-I. The geometric mean titer of anti-HT LV-I was 1: 453 in the first year after seroconversion; the titer of each s ubject did not change significantly during 2-10 years of followup. HTLV-I p roviral DNA load was quantified in 15 seroconverters, and a broad range of levels was observed-from <10 to >1000 copies/10(5) peripheral blood mononuc lear cells. However, there was no obvious change in HTLV-I proviral DNA loa d over several years within individual subjects. Therefore, both proviral D NA load and humoral response in adult HTLVI seroconverters were shown to st abilize within a few years after initial infection. In addition, 1 subject tested positive for HTLV-I proviral DNA before antibody seroconversion, whi ch suggests the existence of a window period in community-acquired infectio n.