We evaluated occurrence and levels of intrathecal synthesis of
IgG,
IgM,
IgA and
IgD by calculating corresponding index values in 8 patients with definite and 4 with suspected or possible
neurosyphilis, prior to, during and after high-dose intravenous
penicillin therapy. Four patients with active
neurosyphilis displayed intrathecal synthesis of
IgG,
IgM and
IgA. Only 2 of them showed elevated
IgD index, and both had taboparesis,
pleocytosis and positive VDRL in CSF, and simultaneous elevation of the
IgG,
IgA and especially of the
IgM indices. This suggests that intrathecal synthesis of
IgD may occur in patients with severe CNS
inflammation in response to diffuse CNS treponemal damage.
Penicillin therapy incited transitory elevation of one or more of the
immunoglobulin index values in most patients, possibly in response to massive treponemal lysis inside the CNS. Thereafter, the values became mostly normalized but exceptions occurred, including one patient who had elevated
IgG and
IgM index which persisted 31 months after
therapy. Our data indicate that determinations of
immunoglobulin indices performed on consecutive specimens from individual patients with
neurosyphilis may be helpful in the evaluation of treatment.