Seroreactivity to the C6 Peptide in Borrelia Miyamotoi Infections Occurring in the Northeastern United States

Abstract

Background

There are no Food and Drug Administration (FDA) approved diagnostic tests for Borrelia miyamotoi infection, an emerging tick-borne illness in the United States. The purpose of this study was to evaluate whether the FDA-approved C6 peptide ELISA currently used to diagnose Lyme disease may potentially serve as a diagnostic test for B. miyamotoi infections.

Methods

Serum specimens from 30 patients from the Northeastern United States with B. miyamotoi infection established by a polymerase chain reaction assay of a blood specimen were tested using the C6 ELISA. To reduce confounding with B. burgdorferi co-infection, 6 sera were excluded: 3 from patients with a positive Western immunoblot for antibodies to B. burgdorferi and 3 from patients for whom immunoblot testing had not been performed.

Results

Twenty-two (91.7%; (95% C.I. 73.0%-98.8%) of 24 evaluable B. miyamotoi patients were C6 ELISA reactive, principally on a convalescent phase serum specimen. C6 ELISA index values were often well above the positive cut-off value of 1.1, exceeding 4 in 11 (50.0%) of the 22 C6 ELISA reactive patients.

Conclusions

Although previously regarded as a highly specific test for Lyme disease, the C6 ELISA is also regularly positive on convalescent phase serum samples of patients from the Northeastern United States with B. miyamotoi infection.