DEPENDENCY OF ANTIBODY TITER ON PROVIRUS LOAD IN HUMAN T-LYMPHOTROPICVIRUS TYPE-I CARRIERS - AN INTERPRETATION FOR THE MINOR POPULATION OFSERONEGATIVE CARRIERS

To evaluate the prevalence of seronegative carriers of human T lymphot ropic virus type I (HTLV-I), buffy coat samples from 1015 Okinawan hig h school students were tested by immunoassays and nested polymerase ch ain reaction (PCR). Among 17 HTLV-I carriers, 1 person who was seroneg ative and 1 who was PCR-negative were identified, gag and tax/rex PCR titers correlated with each other (r = .92; P < .001). Of the 17 carri ers, 14 (82%) had high virus loads (geometric averages, 522 gag and 70 3 tax/rex copies/mu g of DNA; 95% confidence intervals, 38-7260 and 75 -6594, respectively). Carriers with low virus loads had less than or e qual to 2.2 gag copies. In the high-virus-load group, the gag PCR tite rs correlated with the antibody titers (r = 0.88; P < .001). The regre ssion line intersected the minimum antibody detection level at 35 gag copies/mu g of DNA. These results suggest that a small percentage of c arriers may be seronegative.