Anti-VDRL antibodies by ELISA in cerebrospinal fluid and its value in the differential diagnosis of abnormalities of the cerebrospinal fluid.

Enzyme-linked immunoabsorbent assay (ELISA) techniques for the detection of antibodies to the Venereal Disease Research Laboratories (VDRL) antigen as well as for the estimation of antibodies to cardiolipin (aCL) in cerebrospinal fluid (CSF) were performed in several groups of patients, including those with definite paretic neurosyphilis (DPNS, 10 patients), probable paretic neurosyphilis (PPNS, 19 patients), systemic lupus erythematosus (SLE, 71 patients), and miscellaneous neurologic disorders (30 patients), and normal subjects (11 patients). In the DPNS group, all demonstrated positive VDRL by ELISA, and 7 also had positive aCL tests, whereas only 7 of the 10 had positive CSF fluorescent treponemal antibody absorption (FTA-ABS) and Treponema pallidum hemagglutination assay (TPH A) tests. Three had positive VDRL tests by flocculation. In the PPNS group, no patients had positive FTA-ABS, TPH A, or VDRL flocculation tests in CSF. However, 18 of the 19 had positive CSF VDRL by ELISA; two of these also had positive aCL tests. Four SLE patients had positive CSF aCL tests (three with positive ELISA VDRL). Only one patient in the miscellaneous group had positive CSF aCL (Guillain-Barre syndrome), and one had positive IgM VDRL tests (bacterial meningitis). The value of VDRL ELISA in the diagnosis of neurosyphilis in the face of other negative conventional tests is established by our study and had important therapeutic consequences in patients with possible/probable neurosyphilis. The aCL test often may be positive in patients with DPNS but is less useful in the PPNS group.