Absence of detectable xenotropic murine leukemia virus-related virus in plasma or peripheral blood mononuclear cells of human immunodeficiency virus type 1-infected blood donors or individuals in Africa

Abstract

Background: Since the identification of xenotropic murine leukemia virus-related virus (XMRV) in prostate cancer patients in 2006 and in chronic fatigue syndrome patients in 2009, conflicting findings have been reported regarding its etiologic role in human diseases and prevalence in general populations. In this study, we screened both plasma and peripheral blood mononuclear cells (PBMNCs) collected in Africa from blood donors and human immunodeficiency virus Type 1 (HIV-1)-infected individuals to gain evidence of XMRV infection in this geographic region.

Study design and methods: A total of 199 plasma samples, 19 PBMNC samples, and 50 culture supernatants from PBMNCs of blood donors from Cameroon found to be infected with HIV-1 and HIV-1 patients from Uganda were screened for XMRV infection using a sensitive nested polymerase chain reaction (PCR) or reverse transcription (RT)-PCR assay.

Results: Using highly sensitive nested PCR or RT-PCR and real-time PCR assays capable of detecting at least 10 copies of XMRV plasmid DNA per reaction, none of the 268 samples tested were found to be XMRV DNA or RNA positive.

Conclusions: Our results failed to demonstrate the presence of XMRV infection in African blood donors or individuals infected with HIV-1. More studies are needed to understand the prevalence, epidemiology, and geographic distribution of XMRV infection worldwide.

Fig. 1

PCR for XMRV detection. (A) Primer sets for nested PCR and (q)PCR are indicated or numbered according to the XMRV vp62 sequence (GenBank Accession Number EF185282). The primer sequences have been previously published.^, (B) PCR products. Left panel shows XMRV gag gene products. The first and second PCR products are 612 and 413 nucleotides, respectively. Right panel shows PCR products for XMRV env gene. The first and second PCR products are 325 and 259 nucleotides, respectively. The detection limits of first and second PCR for both XMRV gag and env gene were 10 and 1 copy, respectively. (C) (q)PCR. XMRV plasmid was serially diluted 1:10 from 10⁴ to 0.1 fg and tested. The curves show the sensitivity of the assay, which was 0.1 fg or 6.7 copies in this experiment.

Fig. 2

PCR screening for XMRV and HIV-1. (A) RT-PCR products of 11 plasma samples (Lanes 1–11) collected in South Africa with XMRV gag gene primer pair (top panel) and HIV-1 gp41 primer pair (bottom panel). Lanes 12 and 13 = negative and positive controls of XMRV, respectively. (B) PCR products of 12 PBMNC samples (Lane 1–12) collected in Cameroon with XMRV gag (top panel), HIV-1 gp41 (middle panel), and hGAPDH gene (bottom panel). Lane 13 and 14 = negative and positive controls of XMRV, respectively.