REEVALUATION OF ANTI-HTLV-I WESTERN-BLOT ASSAY USING HTLV-I AND HTLV-II SERUM PANELS

Background: Western blot assay is accepted to be a confirmatory test o f anti-HTLV-I antibodies, and several WB criteria have been proposed f or confirming HTLV-I seropositivity. There is a necessity for comprehe nsive study on the criteria. Objectives: This study was performed to e valuate anti-HTLV-I WB kits and feasibility of the WB criteria. Study design: We tested 3 commercially available WB kits: PROBLOT HTLV-I, Ei test ATL-WB and HTLV BLOT 2.2, by a standard HTLV-I serum panel which had been established in our previous study, Sensitivity and specificit y to detect each component of HTLV-I antigens were evaluated by the co rrelation coefficient, R-value. Specificity of the anti-HTLV-I WB kits and HTLV BLOT 2.3 was further evaluated by a standard HTLV-II serum p anel established from the HTLV-I/II epidemiological surveillance of Co lombian natives. Results: PROBLOT HTLV-I showed high R-values (greater than or equal to 0.980) for p28, p53 and gp46, but low R-values (< 0. 900) for p19 and p24, Eitest ATL-WB showed a high R-value for pig, but low R-values for p53, gp46 and rgp21. HTLV BLOT 2.2 showed high R-val ues for p28 and recombinant gp46-I, but low R-values for p53 and gp46. The HTLV-II serum panel showed positive reactions with p24 and p19 of HTLV-I but a little if any reactions with p28 and gp46 of HTLV-I, Alt hough these reactions could not define HTLV-II-specific WB patterns in anti-HTLV-I WB, HTLV-I- and HTLV-II-specific recombinant gp46 in HTLV BLOT 2.3 were useful to distinguish anti-HTLV-II antibodies. Conclusi ons: The currently available anti-HTLV-I WB kits are sufficient for co nfirmatory testing of anti-HTLV-I antibodies with WHO criteria using o ne gag and one env positivity, but they are inadequate for anti-HTLV-I I confirmatory testing.