Local immunity in mumps meningitis.

Titers of antibodies to mumps and measles virus and interferon activity were measured in sera and CSF obtained from 15 children with mumps meningitis. Antibody to mumps virus was found in 11 of 15 CSF samples. Evaluation of the CSF-serum ratio for antibodies to both viruses showed a substantially higher ratio for antibody to mumps virus. The ratio of IgG/IgM antibody activity to mumps virus was greater in CSF than in sera. These results could be attributed to antibody synthesis, particularly IgG, in the CNS. Titers of antibodies to mumps virus in CSF increased rapidly, reaching a peak four to ten days from onset of meningitis, and swiftly decreased thereafter. During the acute phase, interferon activity was found in almost all cases ranging from 16 to 128 IU/mL in sera, and 4 to 16 IU/mL in CSF. In cases of mumps meningitis that followed the usual clinical course, interferon disappeared within a week, whereas it persisted in the CSF in cases of persistent pleocytosis.