Borrelia-specific cell-free DNA in plasma from adults with Lyme neuroborreliosis: an explorative study

Current blood-based diagnostic modalities for LNB have significant limitations. Using Next Generation Sequencing, we investigated blood samples from patients with LNB and non-LNB controls for Borrelia burgdorferi-specific cfDNA (Bb-cfDNA). Blood-samples from 61 adults suspected for LNB were analysed with amplification-free Nanopore metagenomic sequencing and detected cfDNA was cross-referenced with human and Bb-genome databases to identify Bb-specific-cfDNA. Bb-cfDNA was detected in 3 of 45 patients with LNB (6.7%) and in none of the 16 controls. Positive samples contained low levels of Borrelia-classified reads. Bb-cfDNA is unlikely to become a relevant blood-based diagnostic test for LNB in immunocompetent adults. Borrelia burgdorferi-specific cell-free DNA (Bb-cfDNA) was detected at low levels in plasma from 3/45 patients with Lyme neuroborreliosis and in none of the 16 controls. With medium-depth amplification-free, untargeted metagenomic Nanopore sequencing, plasma microbial cfDNA (mcfDNA) is unlikelyto be clinically useful as a standalone blood-based diagnostic test for Lyme neuroborreliosis.