22 February is World Encephalitis Day. Founded by The Encephalitis Society four years ago, it aims to help raise awareness of the disease on an international scale.
In a nutshell, encephalitis refers to the inflammation of the brain. Up until recently, it was thought that encephalitis was simply either a viral or bacterial infection. However, in 2005, research described a new version of the disease: auto-immune or ‘anti-NMDAR encephalitis’, which is caused by antibodies that attack the brain tissue. In all its forms, encephalitis is incredibly rare: herpes simplex encephalitis (HSE), for instance, affects approximately one in 1,000,000 children. Although there are clear treatment routes available, viral encephalitis is incredibly destructive. The virus can cause irreversible damage in the brain, which will continue to impact upon a patient’s quality of life well after their short-term recovery from the disease itself.
Despite its often devastating consequences, the rarity of encephalitis might raise some important questions for those hearing about the disease for the first time, namely: why should we spend our time researching something that affects so few people?
It’s crucial to acknowledge that just because something is rare, it doesn’t mean that it’s not important. I started working on herpes simplex encephalitis during my time as a postdoc, because it’s an incredibly useful paradigm for studying genetic disorders, and human genetics in general. Looking at cases of encephalitis can also tell us so much about human immune responses to infection. By investigating what has gone wrong in the body in these rare cases of encephalitis, we also learn more about which immune responses are essential to fighting diseases in the average person. Not only does our research into encephalitis allow us to better combat the disease itself, it also give us insights into the mechanisms at work in our body that help to protect the brain from infection and inflammation. We’re beginning to see that our findings have far-reaching implications for other neurological disorders that may be linked to encephalitis via a crossover of immune mechanisms.
With the relatively recent discovery of anti-NMDAR encephalitis, the field of autoimmune encephalitis has blossomed. Although my primary research is rooted in the viral, infectious type of the disease, we’re beginning to investigate its relationship to this newer form. I’m now working with Dr Ming Lim at the Evelina’s Children Hospital at King’s College London, and Dr Yael Hacohen at the Great Ormond Street Institute of Child Health at UCL, to try and pinpoint whether there is a link between the two. More specifically, I’m interested in finding out if suffering from HSE means that a patient is more predisposed to developing autoimmune encephalitis further down the line. (more…)