Plasma immunoglobulin responses and disease severity in chronic relapsing experimental allergic encephalomyelitis.

Plasma IgG, IgA and IgM responses in various stages of chronic relapsing experimental allergic encephalomyelitis (CR-EAE) were investigated by ELISA and rocket immunoelectrophoresis. Autoantibody levels were elevated in acute EAE but immunoglobulin responses were maximal in chronic disease. Plasma IgG and IgA specific for the whole cord, myelin and MBP correlated closely with the clinical signs of post-acute disease; in age-matched groups, levels were lower in animals in remission or with no further disease than in those in relapse or with a stable chronic disease course. Sequential sampling revealed a significant increase in neuroantigen-specific IgG (with MBP as the dominant autoantigen) during the onset of a relapse. Lipid-specific antibody levels were raised throughout CR-EAE but constituted only a small proportion of the total response against neural antigens. Determination of total immunoglobulin concentrations suggested a general suppression of IgG responses in guinea pigs in remission. The strong correlations found between antibody levels and the severity of chronic disease provide further evidence that antibody-mediated mechanisms can play a major role in the pathogenesis of CR-EAE.