Evaluation of the nontreponemal IgM antibodies in syphilis serofast patients: A new serologic marker for active syphilis.

BACKGROUND

Serofast status is challenging to interpret in clinical work, and distinguishing active syphilis in serofast patients can provide a reference for clinical diagnosis and treatment. However, effective serologic markers for active syphilis are still lacking.

OBJECTIVES

We aimed to explore the possibility of nontreponemal IgM antibodies in distinguishing active syphilis in serofast patients.

METHODS

A total of 1501 clinical serum samples were collected from 301 serofast patients, and nontreponemal IgM antibodies were detected by chemiluminescence immunoassay.

RESULTS

The results showed that a total of 29 samples (9.63%) of 301 serofast patients were positive for nontreponemal IgM antibodies, and our limited follow-up data showed that 66.67% (2/3) of the serofast patients progressed to neurosyphilis and cardiovascular syphilis.

CONCLUSION

These findings demonstrate that most serofast patients with positive nontreponemal IgM antibodies have evidence of progressive syphilis, and nontreponemal IgM antibodies can be used as a new serologic marker for the activity of syphilis. Nontreponemal IgM antibodies may play a role in the management of serofast patients.