The intrathecal synthesis of
IgM and
IgG antibodies to Borrelia burgdorferi sonicate, to recombinant
flagellin (41 kDa) and to a tryptic
peptide of the
flagellin (14-kDa fragment) was determined by ELISA in paired cerebrospinal fluid (CSF) and serum samples from 35 patients with
Lyme neuroborreliosis (LNB) and in 10 patients with
neurosyphilis. The antibody index (AI = QBb/QIg) was calculated from the ratio between CSF/serum quotients for specific
antibodies (QBb) and total
immunoglobulins (QIg). For the examination of
IgG antibodies, the sonicate ELISA was performed with and without pre-absorption with Treponema phagedenis. Of 35 patients with LNB, 31 had intrathecal
IgG response to B. burgdorferi demonstrated by sonicate ELISA (24 after absorption of cross-reactive
antibodies), 29 had a response demonstrated by
flagellin ELISA and 21 of 35 by 14-kDa ELISA. In patients with
neurosyphilis the AI (
IgG) was elevated in the sonicate ELISA in 7 of 10 samples (none of 10 after absorption of cross-reactive
antibodies), in the
flagellin ELISA in 5 of 10 samples and in the 14-kDa ELISA in none of 10 samples. Intrathecal synthesis of
IgM antibodies to B. burgdorferi was demonstrated in patients with neuroborreliosis by sonicate ELISA in 20 of 35 samples, by
flagellin ELISA in 16 of 35 samples and by 14-kDa ELISA in 9 of 35 samples. No intrathecal synthesis of B. burgdorferi-specific
IgM could be detected by any assay in patients with
neurosyphilis.(ABSTRACT TRUNCATED AT 250 WORDS)