LIPS detection of anti-HTLV-I Gag antibodies. Each symbol represents individual samples from normal control, asymptomatic HTLV-infected, ATLL, and HAM/TSP patients. Antibody titers in LU are plotted on the Y-axis using a log10 scale. The dashed line represents the cut-off level for determining sensitivity and specificity for the particular antigen and is derived from the mean plus 5 SD of the antibody titer of the 42 normal volunteer samples. P values were calculated using the Mann Whitney U test. The solid line indicates the mean antibody titer per group.