Use of a generic polymerase chain reaction assay detecting human T-lymphotropic virus (HTLV) types I, II and divergent simian strains in the evaluation of individuals with indeterminate HTLV serology

Abstract

In countries with a low prevalence of human T-lymphotropic virus (HTLV) infection, indeterminate HTLV serologies are a major problem in blood 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 available primate T-cell lymphotropic virus strains (PTLV), including the two new types STLV-PH969 and STLV-PP1664, we developed generic and type-specific nested polymerase chain reactions (PCRs). The generic PCR proved to be highly sensitive and cross-reactive for all four types of PTLV, while the discriminatory PCRs had a high sensitivity and a specificity of 100%. There was no cross-reactivity with human immunodeficiency virus (HIV), ensuring correct interpretation of results from coinfected patients. Among the 77 serologically indeterminate samples tested, 6 were found to be HTLV-1 PCR positive and 1 was HTLV-II PCR positive. Sequencing of one of the HTLV-I PCR positives excluded PCR contamination, and revealed a divergent type of HTLV-I. The majority of the seroindeterminate samples (91%) were however HTLV-PCR negative, and no new types of HTLV were found. This new assay can identify otherwise undetected HTLV-I or HTLV-II infections and is a useful tool of screening for new types of HTLV among seroindeterminate samples.

Simian T-Cell Leukemia Virus (STLV) Infection in Wild Primate Populations in Cameroon: Evidence for Dual STLV Type 1 and Type 3 Infection in Agile Mangabeys ( Cercocebus agilis )

“…DNA was isolated from whole blood or peripheral blood mononuclear cells using Qiagen DNA extraction kits (Qiagen, Courtaboeuf, France). To confirm the presence of PTLVs in samples with HTLV-cross-reactive antibodies, a previously described diagnostic tax-rex PCR allowing generic as well as typespecific detection of PTLVs was done (38). The generic PCR proved to be highly sensitive in detecting PTLV strains, and the discriminatory PCRs had high sensitivities and specificities.…”

High Prevalence of Simian T-Lymphotropic Virus Type L in Wild Ethiopian Baboons

“…The nucleotide sequences of the oligonucleotide primers, the positions in the prototype strains and the expected fragment sizes are shown in Table 1 (34). Oligonucleotide primers for amplification of type L strains were designed based on the reported STLV-L strain (PH969) (30). The nested-PCR conditions are described elsewhere (18,33).…”

Serological, Epidemiological, and Molecular Differences between Human T-Cell Lymphotropic Virus Type 1 (HTLV-1)-Seropositive Healthy Carriers and Persons with HTLV-I Gag Indeterminate Western Blot Patterns from the Caribbean

“…Stringent HTLV WB criteria require that an HTLV-1-infected individual have an antibody response to the complete range of the core bands (p19, p24, and pr53), in addition to the respective recombinant glycoprotein (gd21) and to type-specific synthetic peptide MTA-1 (HTLV-1). However, especially in tropical areas, indeterminate HTLV serologic test results (i.e., WB patterns reactive to only part of the viral proteins) appear commonly, leading to difficulties in interpretation and counseling (2,6,11,12,13,15,16,18,19,20,23,26,28,31,37,38,44). Previous epidemiological studies, particularly in Cameroon (central Africa), have reported that indeterminate WB patterns (notably those exhibiting p19, p26, p28, p32, p36, and pr53, which have been termed the HTLV-1 Gag indeterminate profile [HGIP]) were not associated with true HTLV-1 infection (26,28).…”