Friday, 23 September 2016

Epilepsy and systemic autoimmune diseases: birds of a feather?

A couple of years back on this blog I talked about some rather intriguing research suggesting that epilepsy and autoimmune disease might not be unstrange diagnostic bedfellows (see here) and that a "potential role of autoimmunity must be given due consideration in epilepsy." [1]

Today, I'm continuing that research theme as the findings from Zhang Lin and colleagues [2] caught my eye concluding that: "There is an association between epilepsy and SAD [systemic autoimmune diseases], which was shown to be stronger at a young age."

Relying on that rather important methodological tool called a meta-analysis, where various study findings are lumped together and conclusions (hopefully) derived from the whole, Lin et al included data from some 25 studies where epilepsy and SAD had been examined together "which included 10,972 patients with epilepsy (PWE) and 2,618,637 patients with SAD."

Aside from those with epilepsy showing "more than a 2.5-fold increased risk of SAD" the authors also observed the opposite too: "patients with SAD were also shown to have a more than 2.5-fold increased risk of epilepsy." When it came to specifics, those diagnosed with epilepsy were observed to show "a 2.6-fold increased risk of celiac disease" and those "patients with systemic lupus erythematosus had a 4.5-fold increased risk of epilepsy."

I remain intrigued about this topic. Appreciating that within the peer-reviewed literature there is such a thing as autoimmune epilepsy [3] and that even in cases of epilepsy seemingly without the autoimmune encephalitis element to it, there may be antibodies to neuronal tissue involved [4], there are perhaps some further important clinical studies to be done in this area. It is for example, not uncommon to see more than one autoimmune condition appearing at the same time (see here) as various autoimmune overlaps have been noted in the quite voluminous science literature on this topic. The implications perhaps being that if one could find some of the 'causes' behind such autoimmune issues (be that related to molecular mimicry or the presence of a superantigen for examples) one may potentially be able to treat/manage quite a few conditions.

Wearing my autism research blogging hat and extending the possibility of an 'autism link' discussed on my previous post on this topic, I'd like to think there may be some scope for further inquiry with autism in mind too. Not only because epilepsy is one of the prime comorbidites attached to a diagnosis of autism (see here) but also that for some people on the autism spectrum, autoimmunity is also potentially something to contend with (see here). Should we therefore be so surprised at the possibility that autism, epilepsy and autoimmunity could form an important clinical triad for some?

And with full caveats in action about not giving medical or clinical advice on this blog, there is a body of evidence out there supporting immunotherapy for certain types of epilepsy [5] where other interventions have failed. Mmm, I also wonder...

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[1] Ong MS. et al. Population-level evidence for an autoimmune etiology of epilepsy. JAMA Neurol. 2014 May;71(5):569-74.

[2] Lin Z. et al. Association between epilepsy and systemic autoimmune diseases: A meta-analysis. Seizure. 2016 Aug 23;41:160-166.

[3] Britton J. Autoimmune epilepsy. Handb Clin Neurol. 2016;133:219-45.

[4] Wright S. et al. Neuronal antibodies in pediatric epilepsy: Clinical features and long-term outcomes of a historical cohort not treated with immunotherapy. Epilepsia. 2016 May;57(5):823-31.

[5] Bello-Espinosa LE. et al. Efficacy of intravenous immunoglobulin in a cohort of children with drug-resistant epilepsy. Pediatr Neurol. 2015 May;52(5):509-16.

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ResearchBlogging.org Lin Z, Si Q, & Xiaoyi Z (2016). Association between epilepsy and systemic autoimmune diseases: A meta-analysis. Seizure, 41, 160-166 PMID: 27592469