Abstract
The protein A plaque assay was used to quantitate the number of IgG-, IgA-, and IgM-producing cells per 20 × 103 lymphocytes in cerebrospinal fluid (CSF) and peripheral blood (PB) from 23 patients with aseptic meningoencephalitis (AM) in the acute stage 1–10 days after onset (group 1) and during late convalescence after 19–38 days (group II) and in PB from healthy controls. In the acute stage, IgG- and IgM-producing cells were found with significantly higher frequency in both CSF and PB than in the late convalescence. In both patient groups there were more Ig-producing cells in PB than in CSF. The predominant Ig class in PB of AM patients was IgA, just as in healthy individuals. In CSF, IgA- and IgG-producing cells predominated at similar frequencies. In the group I patients, there were positive correlations between numbers of Ig-producing cells of each class and the corresponding CSF Ig index, an indicator of intrathecal Ig synthesis. Since high numbers of Ig-producing cells could be found in CSF that was otherwise normal, enumeration of Ig-producing cells is considered a more sensitive indicator of the immune response intrathecally than measurement of free Igs