UCSF

Purpose of review

We highlight how metagenomics and proteomics-based approaches are being applied to the problem of diagnosis in idiopathic encephalitis.

Recent findings

Low cost, high-throughput next-generation sequencing platforms have enabled unbiased sequencing of biological samples. Rapid sequence-based computational algorithms then determine the source of all the nonhost (e.g., pathogen-derived) nucleic acids in a sample. This approach recently identified a case of neuroleptospirosis, resulting in a patient's dramatic clinical improvement with intravenous penicillin. Metagenomics also enabled the discovery of a neuroinvasive astrovirus in several patients. With regard to autoimmune encephalitis, advances in high throughput and efficient phage display of human peptides resulted in the discovery of autoantibodies against tripartite motif family members in a patient with paraneoplastic encephalitis. A complementary assay using ribosomes to display full-length human proteins identified additional autoantibody targets.

Summary

Metagenomics and proteomics represent promising avenues of research to improve upon the diagnostic yield of current assays for infectious and autoimmune encephalitis, respectively.