Polytropic MLVs Linked to CFS

The much anticipated report from a group of collaborating researchers at the Food and Drug Administration (FDA), National Institutes of Health (NIH) and Harvard Medical School (HMS) was published online on August 23, 2010, in the Proceedings of the National Academy of Sciences (PNAS). This study reports a strong association with murine leukemia virus-related viruses (MLVs), with 32 of 37 (86.5%) CFS patients testing positive for MLV sequences compared to 3 of 44 (6.8%) of healthy blood donors.

The authors state, “Our results clearly support the central argument by Lombardi et al. that MLV-related viruses are associated with CFS and are present in some blood donors.” However, the strains of MLVs detected by this research team are different from the ones reported last year in Science. The “early edition” of PNAS (Sept. 30, 2010) included letters from Erlwein et al. and Martin about the FDA/NIH/Harvard study.

A response from Lo et al. was also published. At the conclusion of the response, Lo and colleagues state, “Our recent collaborative studies with a National Cancer Institute group have shown that we can detect antibodies in most patients with CFS with positive gag sequences and not in most PCR-negative subjects; studies on virus isolation are presently in progress. As we stated in the Discussion of our study (3), these and many other studies will be needed to better understand the true nature of association between murine retroviruses and CFS.”

The full text of the following CFS-related articles appear in the August 23, 2010, PNAS issue posted online:

This package of PNAS articles is densely packed with information that will likely intensify discussion and debate about the association between CFS and this family of retroviruses, that includes XMRV. To help site visitors make sense of this material, the Solve ME/CFS Initiative has prepared the following resources:

  • Q&A With Experts: We requested answers from a range of experts familiar with the study, the emerging field of research into XMRV and other murine leukemia retroviruses, blood safety issues and the related media coverage.
  • “Another Turn of the Retrovirus Kaleidoscope” by K. Kimberly McCleary, CFIDS Association president & CEO. This article is part summary, part analysis. It describes the study’s findings and provides a history of how the collaboration unfolded across 15 years.
  • “What Should Come Next?” by Suzanne D. Vernon, PhD, CFIDS Association scientific director. In this commentary, Dr. Vernon provides her perspective about how the latest discoveries can help advance diagnosis and treatment.
  • “Comparison of XMRV/MLV Data in CFS.” This chart, published first in the spring/summer 2010 issue of SolveCFS, is updated to reflect data from the seven studies of MLVs in CFS reported in peer-reviewed publications.
September 1, 2010