Herpes Infections May Be Linked to Rheumatoid Arthritis

Herpes viruses are associated with rheumatoid arthritis (RA), according to a study published in the September 2005 issue of Annals of Rheumatic Diseases. Viral infections have long been suspected to have a role in the development of RA. Despite the results of this study, the team from the Hospital Clinico San Carlos in Madrid, lead by R. çlvarez-Lafuente, are still unsure whether the viruses play a causal role. Nonetheless, the researchers think it may be worthwhile to monitor herpes virus DNA levels in RA patients.

Herpes is the broad name given to certain diseases caused by members of the herpes simplex family. There are two main kinds of herpes simplex virus, type 1 (HSV-1) and type 2 (HSV-2). Although HSV-1 is generally considered to be associated with orofacial infection (i.e. oral infection, leading to blisters on the lips), and HSV-2 with genital infection, both types can affect any region of the body. There are some differences, however, in the infectivity and severity of infection Ñ HSV-1 infections are more easily acquired and infections are more severe in the orofacial region and similar with HSV-2 in the genital region. Despite these differences, neither kind of herpes is curable.

For this study, the researchers assessed the level of various herpes viruses in peripheral blood mononuclear cells (PBMC) and serum samples obtained from 61 individuals with RA and 75 healthy controls. The three forms of the herpes virus studied in particular were cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human herpesvirus 6 (HHV-6). The samples obtained from the test subjects were analysed by quantitative real time polymerase chain reaction for DNA prevalence and viral load for these three viruses. Analysis of the PBMC samples revealed that the Ebstein-Barr virus DNA was more commonly found in RA patients than in controls and reached higher levels. Similar results were obtained for human herpesvirus 6.

Due to the lack of evidence of a causal link between RA and herpes, not much else can be said about the relationship between RA and herpes just yet. The researchers speculated in their report that the impaired cellular immunity found in RA patients may simply lead to higher levels of these viruses than is seen in healthy subjects. Also, RA could make patients prone to infection or reactivation with these viruses. It would be useful to know if bumps in the viral load correlate with exacerbations of RA, and therefore the group suggests that further investigation is necessary.

Article References
http://ard.bmjjournals.com/cgi/content/abstract/64/9/1357, site accessed on 08/21/05

"Herpes may play role in rheumatoid arthritis", site accessed on 08/21/05

http://en.wikipedia.org/wiki/Herpes_simplex_virus, site accessed on 07/31/05