Cerebrospinal fluid treponemal antibodies in untreated early syphilis

C. M. Marra, C. W. Critchlow, E. W. Hook 3rd, A. C. Collier and S. A. Lukehart
Department of Medicine, University of Washington, Seattle.

OBJECTIVE: Examine prevalence and diagnostic utility of cerebrospinal fluid (CSF) treponemal antibodies in early syphilis. DESIGN: Comparison study. SETTING: Sexually transmitted diseases clinic. PATIENTS: Forty patients with untreated early syphilis who underwent lumbar puncture. Fifteen were human immunodeficiency virus seropositive. MEASUREMENTS: Cerebrospinal fluid cell count, protein, VDRL test, and antibodies to Treponema pallidum by microhemagglutination test for T pallidum (MHA-TP) and fluorescent treponemal antibody absorption test (FTA-ABS); albumin ratio; and IgG index. RESULTS: Cerebrospinal fluid cell count was not available for one sample, and this patient was excluded from analysis. Of 39 patients, eight (21%) had reactive CSF-VDRL (definite neurosyphilis). Eleven (28%) had mildly elevated cell count or protein concentration, but nonreactive CSF-VDRL (possible neurosyphilis). Twenty had normal cell count and protein concentration, and non-reactive CSF-VDRL (normal). Cerebrospinal fluid MHA-TP and CSF FTA-ABS were reactive in all eight with neurosyphilis. Cerebrospinal fluid MHA-TP was reactive in seven (70%) of 10 with possible neurosyphilis and in six (32%) of 19 with normal CSF. Cerebrospinal fluid FTA-ABS was reactive in four (36%) of 11 with possible neurosyphilis and in five (28%) of 18 with normal CSF. A reactive CSF treponemal test was associated with higher mean CSF cell count and reactive CSF-VDRL. CONCLUSION: When criteria to define neurosyphilis depend on cell count or CSF-VDRL reactivity, the sensitivity of CSF treponemal antibodies is high. Nonreactive CSF treponemal tests may help to exclude a diagnosis of neurosyphilis in patients with early syphilis.