Sequential Change of Virus Markers in Seroconverters with Community‐Acquired Infection of Human T Lymphotropic Virus Type I

Abstract

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–HTLV-I was 1:453 in the first year after seroconversion; the titer of each subject did not change significantly during 2–10 years of follow-up. HTLV-I proviral DNA load was quantified in 15 seroconverters, and a broad range of levels was observed—from 1000 copies/10⁵ peripheral blood mononuclear cells. However, there was no obvious change in HTLV-I proviral DNA load over several years within individual subjects. Therefore, both proviral DNA load and humoral response in adult HTLV-I seroconverters were shown to stabilize within a few years after initial infection. In addition, 1 subject tested positive for HTLV-I proviral DNA before antibody seroconversion, which suggests the existence of a window period in community-acquired infection