On HERV-H, autism, ADHD and methylphenidate?

Today's post is a bit of a mash-up including two paper: the first from Emanuela  Balestrieri and colleagues [1] (open-access available here) talking about "increased HERV-H [Human Endogenous Retroviruses - H] transcriptional activity in all autistic patients" included in their cohort (author's words not mine) and the second from D'Agati and colleagues [2] (open-access available here) describing "the reduction of HERV-H expression and the significant improvement of ADHD [attention-deficit hyperactivity disorder] symptoms after 6 months of methylphenidate treatment."

Taken together, both papers provide some potentially important information on how those fossil viruses that litter the human genome might not be as redundant as we might have first thought. Also how some of the commonly used medications to treat/manage certain psychiatric labels might have quite a few more effects than those listed on the package insert. A shocker indeed.

I've covered HERVs a few times on this blog in relation to quite a few labels (see here and see here and see here). If you've clicked on that first link, you'll know that this is not the first time that Balestrieri et al have talked about HERVs with autism in mind [2]. On that first occasion, they even went as far as proposing that "HERV-H expression be explored in larger samples of individuals with autism spectrum in order to determine its utility as a novel biological trait of this complex disorder." This time around "the transcriptional activity of three human endogenous retrovirus (HERV) families, in peripheral blood mononuclear cells (PBMCs)" was examined in 30 children diagnosed with autism spectrum disorder (ASD) and 30 asypmtomatic controls. Quantitative real-time PCR was the analytical weapon of choice, as "transcriptional levels of env of HERV families were quantitatively evaluated." As I've already mentioned, HERV-H expression showed some interesting trends compared to the not-autism controls. The authors note that this data from Albanian children is pretty much the same as what they found in Italian children diagnosed with autism.

The D'Agati findings - also including Balestrieri on the authorship list - although discussing a case report on what happened to HERV-H expression following use of methlyphenidate (MPH) in relation to ADHD, might also have some implications for [some] autism. Reiterating that this was a case report where both before and after HERV-H expression levels were measured, it potentially offers a road map for how HERV-H expression might be 'affected' by the use of certain medicines. Yes, I know that researchers only measured one variable (HERV-H) and one variable/measurement does not a link make. But given the quite significant overlap between ADHD and autism (see here) and the insinuation that over-expression of HERV-H might not necessarily be a 'good thing', one could see how further [independent] studies might be informative in this area.

Although slightly complicated by the fact that we are only beginning to realise how important HERVs might be to things like stem cells for example or even potentially being involved in the process of genetic deletion (see here), what is becoming clear is that these fossil viruses might be something to watch when it comes to health and wellbeing at different times of development. I've tried not to be too enthusiastic about HERVs and autism / ADHD / other (delete as appropriate) on this blog given our lack of understanding on any connection, specifically the hows and whys of any effect on either aetiology or symptoms. But it is getting harder not to wonder what role these and other mobile elements might play in development and behaviour, particularly in the context of HERVs being implicated in autoimmunity [3] (yes, that might also show a connection to some autism) and a possible role for the still emerging science of epigenetics in both HERV expression [4] and also [some] autism. There is lots more research to be done on this topic.

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[1] Balestrieri E. et al. Transcriptional activity of human endogenous retrovirus in Albanian children with autism spectrum disorders. New Microbiol. 2016 Sep;39(3):228-31.

[2] D'Agati E. et al. First evidence of HERV-H transcriptional activity reduction after methylphenidate treatment in a young boy with ADHD. New Microbiol. 2016 Sep;39(3):237-9.

[3] Tugnet N. et al. Human Endogenous Retroviruses (HERVs) and Autoimmune Rheumatic Disease: Is There a Link? The Open Rheumatology Journal. 2013;7:13-21.

[4] Lavie L. et al. CpG methylation directly regulates transcriptional activity of the human endogenous retrovirus family HERV-K(HML-2). J Virol. 2005 Jan;79(2):876-83.

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Balestrieri E, Cipriani C, Matteucci C, Capodicasa N, Pilika A, Korca I, Sorrentino R, Argaw-Denboba A, Bucci I, Miele MT, Coniglio A, Alessandrelli R, & Sinibaldi Vallebona P (2016). Transcriptional activity of human endogenous retrovirus in Albanian children with autism spectrum disorders. The new microbiologica, 39 (3), 228-31 PMID: 27602423


D'Agati E, Pitzianti M, Balestrieri E, Matteucci C, Sinibaldi Vallebona P, & Pasini A (2016). First evidence of HERV-H transcriptional activity reduction after methylphenidate treatment in a young boy with ADHD. The new microbiologica, 39 (3), 237-9 PMID: 27602426