Smoking and Epstein-Barr immune response connected as MS risk factors

Having been infected with Epstein-Barr virus, being positive for the DRB1*1501 gene haplotype, and having a history of smoking are all associated with an increased risk of MS. Unfortunately, nobody knows how each of these factors relates to the actual biology of the disease. However, learning more about whether these factors interact with each other could help provide some new clues to explore.

An international study exploring this question has just been published in the journal Neurology. This study made use of blood samples and smoking histories from people with MS and controls from the US, Sweden, and Australia. Data about smoking history, DRB1 status, and the levels of antibodies to an EBV protein (EBNA) were combined and analyzed to see whether these factors act independently or work together in affecting the risk of MS. The results showed that DRB1 acts independently of smoking and EBV immune response in increasing the risk of MS. However, the immune response to EBV and smoking appear to have an interactive effect on MS risk -- that is, the effect of higher EBV antibody levels is enhanced by having a history of smoking.

The study discusses possible biological mechanisms that may be shared by EBV infection/immune response and smoking that may be involved in MS. However, not much is currently known on this topic. Seems like a good area for further research. This study also highlights again the importance of not smoking for people who want to minimize their MS risk. DRB1 status can't be changed, and EBV infection is hard to avoid, but it is possible to decide not to smoke.