Immunity & infection
The laboratory diagnosis of Lyme disease is currently based on the detection of antibodies against Borrelia burgdorferi. Antibody assays are typically not useful indicators of treatment response, as antibody can remain elevated for months to years after infection. We previously demonstrated that IFNγ secretion is detectable in antigen-stimulated whole blood collected from patients at their initial presentation with erythema migrans (EM). The IFNγ response was reduced in paired blood samples two months after treatment, portending that monitoring cellular immunity correlates with treatment efficacy. Expanding on this initial study, we enrolled an additional 44 adults and 26 children in New York and Wisconsin in 2016-18. We incubated whole blood (1CC) overnight with mixtures of B. burgdorferi peptide antigens, and quantified plasma levels of IFNγ by ELISA. 33 adults and 19 children received a physician diagnosis of Lyme disease. 25/33 (75.7%) adults and 15/19 (78.9%) children produced significant levels of IFNγ (>3SD above the mean of controls). IFNγ production was reduced at 4 weeks and/or 6 months post-treatment in 16/25 (64%) adults and 12/13 (92.3%) children that were initially positive. By contrast, anti-B. burgdorferi antibody remained elevated at follow-up in all patients that seroconverted. Only one control patient had detectable IFNγ, and was also serologically positive by C6 and WCS ELISA. These results support the hypothesis that monitoring Borrelia-specific T cell activation through IFNγ release may be an effective method for the laboratory diagnosis of Lyme disease, and for monitoring treatment efficacy.