Presence of murine leukemia virus (MLV)-related virus gene sequences in a commercial RT-PCR reagent.

BACKGROUND The recent identification of murine leukemia virus (MLV)-related viruses in patients with chronic fatigue syndrome (CFS) has aroused much interest, not least among sufferers. However, other studies failed to detect these viruses in CFS patients. METHODS We wanted to establish a MLV-related virus real-time PCR for routine diagnostics. RESULTS Our study identified false positive MLV-related virus results due to a contamination of Superscript III Platinum One-Step Quantitative RT-PCR System (Invitrogen). CONCLUSIONS This observation may be helpful to elucidate discrepant results for the detection of MLV-related virus like xenotropic MLV-related virus (XMRV) in recently published studies.