[Significance of the confirmatory test of enzyme immunoassay and western blotting method in detection of anti-HTLV-1 in sera].

In this study, we directly compared the sensitivity of the detection of anti-human T-cell leukemia virus type-1 (anti-HTLV-1) antibody in serum by enzyme immunoassay (EIA), gelatin particle agglutination method (PA), and Western blotting method (WB). Of 69 cases studied, 6 cases positive by WB were negative by both PA and EIA methods. Of these 6 cases, 5 cases were interpreted to be positive by the confirmatory test of EIA (inhibitory rates of greater than 50%). Thus, the results of the confirmatory test were most consistent with those of WB methods. We also determined the levels of anti-HTLV-1 antibody in sera from the babies born of anti-HTLV-1 positive mothers at various months of age by the above three methods. As ages progressed, a parallel decline in the levels of anti-HTLV-1 antibody was shown by the three methods. However, at the time when sera became negative by both PA and EIA methods, the antibody was still detected by WB method. The study concludes that both WB and confirmatory test of EIA are more sensitive indicators of HTLV-1 infection.