Gut Inflammation in Chronic Fatigue Syndrome

Shaheen E Lakhan; Annette Kirchgessner

Disclosures

Nutr Metab. 2010;7(1) 

In This Article

Viral Infection

Early conceptualizations of CFS focused on the role of viral infection. This is not surprising since in 60 to 80% of published reports, CFS presents with acute onset of illness, with systemic symptoms similar to influenza infection that do not subside. Numerous researchers have tried to correlate infection by several microorganisms with the onset of CFS. For example, the human parvovirus (HPV)-B19 has been the most reported CFS-associated virus.[25] Although several studies have detected parvovirus B19 DNA in the GI tract of CFS patients, it is not consistently detected in all patients.[25] Another difficulty is associating the onset of CFS with the presence of antibodies to HPV-B19.

Other studies have suggested that infection by another virus, the human herpes virus-6 (HHV-6), a neurotropic, gliotropic, and immunotropic virus, is more often found in patients with CFS than in healthy controls.[26] However, using real-time PCR, high loads of HHV-6 DNA were detected in most CFS and control biopsies.[27] Other studies attempted to show an association between Epstein-Barr virus (EBV) infection and postinfectious onset of CFS. EBV infection has been shown to cause extreme fatigue during the acute illness and to be a risk factor for developing CFS, with a prevalence rate of 8% observed at 6 months.[11,28] However, EBV was found in 15-30% of all biopsies.[25] Thus, the involvement of EBV in addition to various enteroviruses, and the human T-lymphotropic virus type 2 (HTLV-2) has not been conclusively proven.[29]

In October 2009, Lomardi et al. reported finding a gammaretrovirus in peripheral blood mononuclear cell (PBMC) DNA from about 67% of CFS patients compared to only 3.6% of healthy persons using PCR testing.[30] The agent was named xenotropic MLV-related virus (XMRV) because its env gene was nearly identical to that of xenotropic MLV, an infectious endogenous MLV that preferentially infects cells from foreign species, including humans. Almost half of the CFS patients in this study described the onset of their symptoms as related to an acute viral disease. In addition, virus isolation and antibody detection were reported in some CFS patients.

Confirmation of an association and etiologic role of XMRV in CFS is important because it could provide a useful diagnostic test and might lead to new treatment interventions. Inhibitors of XMRV such as the integrase inhibitor raltegravir, are now available. However, two recent studies from the United Kingdom using PCR testing alone or together with serologic testing reported negative XMRV results in CFS patients.[31,32] XMRV was also not found by PCR testing in CFS patients from the Netherlands,[33] China,[34] or the United States,[35] questioning the association of XMRV with CFS.

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