Testing combo helps diagnose neurosyphilis in HIV patients
Source : Neurology 2004;63:85-88.
Last Updated: 2004-07-29

NEW YORK (Reuters Health) – The use of cerebrospinal fluid fluorescent treponemal antibody (CSF-FTA) reactivity testing combined with characterization of CSF lymphocytes can help diagnose neurosyphilis in HIV-infected patients, researchers report in the July 13th issue of Neurology.

The diagnosis of neurosyphilis is not excluded by standard nonreactive CSF-Venereal Disease Research Laboratory (VDRL) testing "and in some cases is based solely on an elevated CSF white blood count," lead investigator Dr. Christina Marra of the University of Washington School of Medicine in Seattle told Reuters Health.

"Establishing the diagnosis of neurosyphilis can be especially difficult in HIV-infected individuals because HIV itself causes mild elevations in CSF white blood cells that can be indistinguishable from the elevations seen in neurosyphilis."

To investigate alternative approaches, the researchers used CSF-FTA testing and measurement of the percentage of CSF lymphocytes that were B cells in fresh and frozen serum samples from 47 HIV patients with syphilis and 26 HIV-infected controls.

Different CSF-FTA approaches were 100% sensitive for diagnosis. An elevated percentage of CSF B cells was 100% specific, but only about 40% sensitive.

However, used together, the tests allowed 16% of cases with pleocytosis, but nonreactive CSF-VDRL, to be confirmed as neurosyphilis and 26% to be diagnosed as not being neurosyphilis.

"Our results suggest that the combination of the CSF-FTA test and assessment of the percent of CSF lymphocytes that are B cells can be used to identify syphilis patients with and without neurosyphilis when the CSF-VDRL is nonreactive," Dr. Marra concluded.

Source : Neurology 2004;63:85-88.