BACKGROUND: Human endogenous retroviruses (HERVs) are suspected to play a role in the development of multiple sclerosis (MS). This suspicion has in part been based on increased expression of viral RNA or proteins or antibodies targeting retroviral products in MS patients. Recently, our group provided genetic evidence for association between the endogenous retrovirus HERV-Fc1 and MS, suggesting that HERV-Fc1 plays a role in this multifactorial disease. We have found increased expression of HERV-Fc1 in MS patients suffering from recent attack, but the underlying mechanism for association is still unknown.
FINDINGS: Evidence from animal models indicates that ERV implication in the pathogenesis of diseases can be a result of extra copies of the virus in the germ line. Therefore, we investigated the genome of 81 individuals, 74 patients with MS and 7 healthy controls, by means of Southern blotting, for presence of extra HERV-Fc1 copies. The known insertion at the Xq21.33 position was readily detectable, but no additional insertions in other genomic contexts could be identified in any studied individuals. This substantiates our previous copy-number PCR findings of a 2:1 ratio of HERV-Fc1 DNA between women and men, as expected from the X-chromosome location; there was no difference between patient and control individuals.
CONCLUSIONS: No additional germ line copies of HERV-Fc1 could be identified, precluding such copies to underlie the association between this provirus and multiples sclerosis.
You have heard that Prof Gold from Down Under has a hunch that endogenous retrovirus may be part of MS susceptibility equation. Based on some animal studies the number of copies of endogenous viral particles can influence the degree of autoimmunity. However there was no evidence that there were multiple copies of HERV in MSers although women may have more than men because some of the endogenous virus is on the X chromosome (women = XX, man =XY). Does this change the situation with regard to a role for HERV in MS susceptibility? Well No?
Maybe the Prof Gs will give update on progress with Charcot Project Soon.