USE OF A GENERIC POLYMERASE CHAIN-REACTION ASSAY DETECTING HUMAN T-LYMPHOTROPIC VIRUS (HTLV) TYPE-I, TYPE-II AND DIVERGENT SIMIAN STRAINS IN THE EVALUATION OF INDIVIDUALS WITH INDETERMINATE HTLV SEROLOGY

In countries with a low prevalence of human T-lymphotropic virus (HTLV ) infection, indeterminate HTLV serologies are a major problem in bloo d bank screening because of the uncertainties about infection in these cases. The recent discovery of two new types of simian T-lymphotropic viruses (STLV), which give an HTLV-indeterminate serology, raises the question whether indeterminate serologies in humans may be linked to new types of HTLV. Starting from a Tax sequence alignment of all avail able primate T-cell lymphotropic virus strains (PTLV), including the t wo new types STLV-PH969 and STLV-PP1664, we developed generic and type -specific nested polymerase chain reactions (PCRs). The generic PCR pr oved to be highly sensitive and cross-reactive for all four types of P TLV, while the discriminatory PCRs had a high sensitivity and a specif icity of 100%. There was no crossreactivity with human immunodeficienc y virus (HIV), ensuring correct interpretation of results from coinfec ted patients. Among the 77 serologically indeterminate samples tested, 6 were found to be HTLV-I PCR positive and 1 was HTLV-II PCR positive . Sequencing of one of the HTLV-I PCR positives excluded PCR contamina tion, and revealed a divergent type of HTLV-I. The majority of the ser oindeterminate samples (91%) were however HTLV-PCR negative, and no ne w types of HTLV were found. This new assay can identify otherwise unde tected HTLV-I or HTLV-II infections and is a useful tool of screening for new types of HTLV among seroindeterminate samples. (C) 1997 Wiley- Liss, Inc.