The compartmental IgM and IgA response within the central nervous system.

The diagnostic value of the locally synthesized IgA and IgM fractions in cerebrospinal fluid is described. The differentiation of the CSF immunoglobulins was performed with the help of a diagram that had been established on empirical grounds. Immunoglobulin G generally dominates the humoral immune response within the central nervous system, but in some diseases a comparatively strong participation of the other immunoglobulins was found: IgA in purulent meningitis and neurotuberculosis, IgM in tick-borne early summer meningoencephalitis. In meningopolyneuritis Bannwarth and mumps meningoencephalitis a broad three class response was found. The diagnostic significance of these findings is independent of the disease stage, since the compartmental immune response lacks the Nossal-Switch from IgM- to IgG- antibodies.