DIFFERENTIAL SEROLOGICAL DIAGNOSIS OF HTLV-I AND HTLV-II INFECTION BYEXTERNAL MEMBRANE-PROTEIN PEPTIDE-BASED ENZYME IMMUNOASSAYS

Background: HTLV antibody screening assays detect both antibodies to t he etiological agent of adult T-cell leukemia and tropical spastic par aparesis HTLV-I and to the less pathogenic HTLV-II. It is critical to make a differential diagnosis of the two viruses. Objectives: To desig n and evaluate synthetic core and envelope-derived peptide enzyme immu noassays (EIA) for serological differential diagnosis. Study design: P eptide EIAs were evaluated with a panel of 202 plasma samples comprise d of HTLV antibody positive, serologically classified as confirmed, in determinate, or non confirmed, characterized as HTLV-I, HTLV-II or nei ther by genomic amplification. The peptide EIA with the best performan ce was further used to differentiate between HTLV-I and HTLV-II antibo dies in 807 samples from 18 countries in four continents and to provid e ratios between the two infections. Results: The gp46 peptide EIA cor rectly identified 96.5% of HTLV-I and 98.6% of HTLV-II antibody-confir med samples. HTLV-I was found exclusively in Japan and Caribbean count ries; almost exclusively in Africa. HTLV-II represented 10-25% of samp les from Canada, Chile and Venezuela and was predominant in the US. Co nclusions: Differential diagnosis between HTLV-I and HTLV-II can be re liably performed using specific peptides from the gp46 envelope protei n of each virus. (C) 1997 Elsevier Science B.V.