QUANTIFICATION OF HTLV-II PROVIRAL COPIES BY COMPETITIVE POLYMERASE CHAIN-REACTION IN PERIPHERAL-BLOOD MONONUCLEAR-CELLS OF ITALIAN INJECTING DRUG-USERS, CENTRAL AFRICANS, AND AMERINDIANS

To better correlate the burden of human T cell leukemia virus type I ( HTLV-I) and type II (HTLV-II) infection with diagnostic and prognostic markers, we developed a new competitive polymerase chain reaction (PC R) assay for the quantitative determination of proviral copy numbers i n infected cells. A competitive plasmid was constructed that carried a 112-bp fragment from a highly conserved region of the HTLV tax gene a nd that was further modified by inserting a sequence of 24 bp. This co mpetitive PCR assay system can be used for the quantification of HTLV- I and HTLV-II proviral DNA as demonstrated by using HTLV-I- and HTLV-I I-infected cell lines and/or patient material. We determined the HTLV- II proviral load in peripheral blood mononuclear cells (PBMCs) of 11 I talian injecting drug users (IDUs) infected by this virus and in PBMCs of 10 seropositive Amerindian and Central African individuals from en demically infected ethnic groups. A great variation was observed in th e number of HTLV-II proviral sequences in the PBMCs of Italian drug ab users, ranging from 5-10 to 16,239 copies/10(5) cells. There was no cl ear-cut correlation between proviral load, CD8 count, stage of HIV-1 i nfection, and therapy. A considerable variation in HTLV-II proviral lo ad was also observed in PBMCs of Amerindians and Central Africans with no correlation between the amount of HTLV-II provirus and the geograp hic origin of the infected individuals.