C6 peptide test may indicate Borrelia miyamotoi infection

Koetsveld and colleagues examined C6 reactivity in sera from both mice infected with Borrelia miyamotoi and from 46 patients with PCR-positive Borrelia miyamotoi disease (BMD). Their results support the use of the C6 peptide test used for for Lyme disease as an indication of borrelia miyamotoi test

They found, “Cross-reactivity against the C6-peptide was confirmed in 21 out of 24 mice experimentally infected with B. miyamotoi.” And a C6 antibody response was present in 39 of 46 patients. ¹

Interestingly, another recent study “showed that in a set of 43 sera from 24 patients with [Borrelia miyamotoi disease] from the United States the C6 ELISA was also positive in the vast majority (>90%) of convalescent phase serum samples.” ²

Koetsveld warns, however, that since “BMD [Borrelia miyamotoi disease] and Lyme borreliosis are found in the same geographical locations, caution should be used when relying solely on C6-reactivity testing.”

[bctt tweet=”According to a new study, the C6 peptide test used to diagnose Lyme disease may also be helpful in identifying Borrelia miyamotoi. ” username=”DrDanielCameron”]

They recommend further testing if the Western blot is negative.

“We propose that a positive C6 EIA with negative immunoblot, especially in patients with fever several weeks after a tick bite, warrants further testing for B. miyamotoi.”

Testing for the glycerophosphodiester phosphodiesterase (GlpQ) gene may be helpful in detecting B. miyamotoi infection.

“Our results demonstrate that cross-reactive antibodies against the C6 peptide regularly occur in patients with [Borrelia miyamotoi disease],” writes Koetsveld.

He adds, “with as much as 90% (95% CI 68.3–98.8) of patients being C6-reactive in samples taken 10 to 19 days after onset of disease.”

Editor’s note: It is also possible that the patients could have seronegative Lyme disease concurrent with B. miyamotoi. In fact, 10 of their 39 patients were reactive by Western blot for Lyme disease.