Session: 039. Diagnostics: Sequencing & Typing, Thursday, 12:15-1:30 p.m.
Background : Diagnosing Lyme disease often involves laboratory evaluation, yet available tests have limitations. Serology remains negative for weeks after infection occurs, and may then remain positive for years. Borrelia burgdorferi blood PCR testing has low sensitivity, rendering it unhelpful. We sought to determine if an emerging technology, next generation sequencing (NGS) of microbial cell-free DNA (mcfDNA), can detect B. burgdorferi DNA in the plasma of pediatric patients with erythema migrans (EM).
Methods : Patients 1-17 years old with a clinically-identified single or multiple EM were enrolled. Two clinical investigators were required to agree on the EM finding, with no evidence of an alternative diagnosis. Subjects were excluded if they previously had Lyme disease, had received antibiotics within 30 days prior to enrollment, or if the rash had resolved before the first blood draw. Three blood samples were taken during the study period: one before antibiotics were administered, then 1-3 weeks and 2-3 months later. At enrollment, plasma was tested for Lyme disease using C6 antibody with reflex to Western Blot and mcfDNA sequencing (Karius, Inc, Redwood City, CA). Briefly, mcfDNA was extracted from plasma and NGS performed. Human reads were removed and remaining sequences were aligned to a curated microbial database. Only mcfDNA testing was performed at follow-up visits.
Results : We enrolled 5 subjects (ages 4-15 years old, median age 4). Four subjects had a single EM and negative Lyme serology. One subject had approximately 20 EMs and positive serology (C6-antibody=7.52 (Positive > 1.09), 3/3 IgM, 2/10 IgG). All fourteen plasma samples, including five pre- and nine post-antibiotic samples, were negative for B. burgdorferi DNA by mcfDNA sequencing. No other infections, including other tick-borne infections, were detected.
Conclusion : NGS of mcfDNA did not identify B. burgdorferi DNA in the plasma of pediatric patients with active EM rashes. This approach is unlikely to be helpful in diagnosing early localized Lyme disease. This may be because spirochetes are localized to the periphery of the rash in EM and spirochetemia likely occurs at later stages of infection. Follow-up studies are planned to investigate how NGS of mcfDNA performs during early and late disseminated Lyme disease.
Andrew Handel– Pediatric Infectious Disease Fellow, Stony Brook Children's Hospital, Stony Brook, NY
Carine Ho– Clinical Research Associate, Karius, Inc, Redwood City, CA
Desiree Hollemon– Head of Clinical Affairs, Karius, Inc, Redwood City, CA
David Hong– Vice President, Medical Affairs and Clinical Development, Karius, Inc., Redwood City, CA
Christy Beneri– Associate Professor of Pediatrics, Stony Brook Children's Hospital, Stony Brook, NY