CFIDS is no stranger to controversy and the latest paper published on line by Science seems to raise more controversial thoughts. The researchers led by Judy Mikovits have implicated a contagious, rodent derived retrovirus (defn: A type of virus that contains RNA as its genetic material. The RNA of the virus is translated into DNA, which inserts itself into an infected cell’s own DNA. Retroviruses can cause many diseases, including some cancers and AIDS) named xenotropic murine leukemia virus -XMRV.
XMRV has previously been linked to an aggressive form of prostate cancer and was written up in 2006 in JAMA. This was related to an enzyme deficiency, the same enzymatic error has also been found in patients with CFIDS. Investigators then discovered that the white blood cells of CFIDS patients in two thirds of the cases had XMRV present against a lowly 4% of the controls.
XMRV it seems has an adverse effect on the function of natural killer cells (NK) a subset of the immune systems defence mechanism and important for both innate and adaptive imunity as well as providing some overall control on immune expansion and limitation of excess defence. Serum antibodies for XMRV have also been described in an unpublished work by the same authors in 95% of CFIDS patients.
Mikovits says her work “proves beyond a shadow of a doubt that CFS is a real disease.”
It may be too soon to suggest that CFIDS is a consequence of an immune response to a virus, attractive though it may seem. There remain questions on the paper – as one might expect including the demographic mix of the groups studied, their viral load and contamination risks. With such a complex illness – can causation rather than correlation really be confidently assigned to this study. Perhaps it is best at this stage to say that this study shows association and may well be a strong component of illness progression, but the proposed solution of treating CFIDS patients with AIDS anti retroviral medication is probably too early.
XMRV is a retrovirus, meaning once someone is infected, the virus permanently remains in the body; either a person’s immune system keeps it under control or drugs are needed to treat it. The virus creates an underlying immune deficiency, which might make people vulnerable to a range of diseases, said Judy Mikovits.
Further analysis of this paper is provided by John Cuffin – a molecular biologist who despite initial concerns has written a supporting article. He describes what is known and postulates that the XMRV agent may turn out to have implications in other illnesses, or it may of course reflect unique immune problems or tissue specificity related to other events in these two groups – prostate cancer and CFIDS.
So how is this virus transmitted? he goes on to say:
We do not know how the virus is transmitted, and the suggestion, based on indirect evidence, that there is sexual transmission is premature. Given that infectious virus is present in plasma and in blood cells, blood-borne transmission is a possibility. Furthermore, we do not know the prevalence or distribution of this virus in either human or animal populations, and animal models for infection and pathogenesis are badly needed.
 S. Hong et al., J. Virol. 83, 6995 (2009). View Abstract
Lombardi, V. Mikovits,J. et al. Detection of an Infectious Retrovirus, XMRV, in Blood Cells of Patients with Chronic Fatigue Syndrome Science DOI: 10.1126/science.1179052 Published Online October 8, 2009 View Abstract