Host-derived markers of Lyme disease: their discovery and diagnostic potential

Abstract

Lyme disease (LD) is a multisystem infection caused by tick-borne spirochaetes of the Borrelia burgdorferii sensu lato group. UK and US laboratory diagnosis of LD involves the two-tier serological approach. The negative predictive value of the test has been challenged, particularly in early stage LD. There is considerable interest, therefore, in the development of improved diagnostic tests. The main aim of the project is to identify new markers that could form the basis for improved tests. A mass spectrometry biomarker discovery study was undertaken on LD positive and negative residual diagnostic samples from UK LD testing by Public Health England and a cohort of patient samples from collaboration with a research group in the Czech Republic. A ‘related-disease control group’ including serum samples from syphilis, leptospirosis and chronic fatigue syndrome was also included. Several proteins were found at a significantly higher or lower in abundance in the ld-positive patients compared with ld-negative. Of particular interest was Lipocalin-2 (LCN2), a protein involved in immunity. LCN2 has previously been found in increased abundance in mice exposed to B. burgdorferi. Further analysis of LD samples using Illumina RNA sequencing revealed further markers of interest. Transcriptomic analysis including Ingenuity Pathway Analysis (IPA) gave insights into the host response to LD infection. Proteins of interest from proteomic and transcriptomic analysis were taken forward for further analysis by WB or ELISA in a larger sample set.