Editor’s Note: The purpose of this study was to determine if autoimmunity is a factor in some subgroups of patients with ME/CFS. Human endogenous retroviruses, known as HERVs, are ancient retroviruses that are part of the human genome. (They are estimated to comprise about 8% of human DNA.) Because HERVs are part of our DNA, they do not normally provoke immune reactions. Plasmacytoid dendritic cells (pDCs), which are present in the gut, are a part of the innate immune system. They act to simulate the immune system against antigens. When pDCs react to antibodies against HERV proteins, an underlying autoimmune process may be implicated. Read full article HERE.
Plasmacytoid dendritic cells in the duodenum of individuals diagnosed with myalgic encephalomyelitis are uniquely immunoreactive to antibodies to human endogenous retroviral proteins.
~Source: In Vivo. March, 2013.
By K.L. De Meirleir et al.
Myalgic encephalomyelitis (ME) is a debilitating illness of unknown etiology characterized by neurocognitive dysfunction, inflammation, immune abnormalities and gastrointestinal distress. An increasing body of evidence suggests that disruptions in the gut may contribute to the induction of neuroinflammation. Therefore, reports of human endogenous retroviral (HERV) expression in association with neuroinflammatory diseases prompted us to investigate the gut of individuals with ME for the presence of HERV proteins. In eight out of 12 individuals with ME, immunoreactivity to HERV proteins was observed in duodenal biopsies. In contrast, no immunoreactivity was detected in any of the eight controls. Immunoreactivity to HERV Gag and Env proteins was uniquely co-localized in hematopoietic cells expressing the C-type lectin receptor CLEC4C (CD303/BDCA2), the co-stimulatory marker CD86 and the class II major histocompatibility complex HLA-DR, consistent with plasmacytoid dendritic cells (pDCs). Although the significance of HERVs present in the pDCs of individuals with ME has yet to be determined, these data raise the possibility of an involvement of pDCs and HERVs in ME pathology. To our knowledge, this report describes the first direct association between pDCs and HERVs in human disease.
Source: In Vivo. 2013 Mar;27(2):177-87. De Meirleir KL, Khaiboullina SF, Frémont M, Hulstaert J, Rizvanov AA, Palotás A, Lombardi VC.