Borrelia B-cell Diagnostics

Background: Lyme disease (LD) is the most common tick born disease in Europe. It is caused by an infection with several genospecies of the spirochaetal bacteria Borrelia burgdorferi (Bb). Although classical disease manifestations are well-known, the clinical presentation in children is often variable and inconclusive, which results in delayed diagnosis and treatment. Methods/design: The investigators are conducting an observational cohort study in children with LD. Study site is the University Children's Hospital Zurich. 502 patients will be enrolled. Children from 0-17 years of age presenting with signs and symptoms suspicious for LD are included in the study. Previously healthy children with routine blood investigation are enrolled as healthy controls. Patients will be excluded in cases of primary or secondary immunodeficiency. Clinical and routine laboratory data regarding course and outcome, as well as venous blood samples are collected at first hospital contact and follow up visits (FUP). FUPs are scheduled at 28 days, 3 months and 6 months after hospital admission. Cerebrospinal fluid (CSF) and synovial fluid (SF) will be collected for the study only if sampling is indicated due to diagnostic or therapeutic reasons. Primary objectives are to assess Bb-specific ASCs in blood using ELISpot assay, in order to develop new diagnostic tool for early LD. In addition, the investigators will examine immune response in patients with various LD manifestations using flow cytometry, ELISA assay, and ELISpot assay. Finally, the investigators will perform whole genome sequencing of causative Bb-species isolated from patients to investigate potential differences in virulence and associations with clinical presentations. Discussion: This single-centre, observational cohort study will improve the understanding of immunological response in LD in children. It will also provide new information about the virulence of distinct LD causing Bb-genospecies and will test a new approach in the diagnosis of early LD.