Objectives: To assess the presence of neurotropic viruses in post-mortem brains of autistic patients and matched controls.
Methods: We assessed by nested-PCR and DNA sequence analysis the presence of CMV, EBV, HSV1, HSV2, HHV6, BKV, JCV, and SV40 in genomic DNA extracted from post-mortem temporocortical tissue (Brodmann Areas 41/42) belonging to 15 autistic patients and 13 controls.
Results: BKV, JCV, and SV40 combined are significantly more frequent among autistic patients compared to controls (67% vs 23%, respectively; P<0.05). No difference is recorded for all other viruses, which are found in relatively few individuals (N≤3). Also poly-viral infections tend to occur more frequently in the brains of autistic patients compared to controls (40% vs 7.7%, respectively; P=0.08).
Conclusions: Polyomaviruses are over-represented in our sample of autistic post-mortem brains compared to controls; autistic brains also display higher frequencies of positivity to more than one virus. Hence polyomaviruses represent attractive candidates for follow-up studies exploring gene x environment interactions as possible contributors to autism pathogenesis.