Immunoglobulin binding to brain in autoimmune mice.

Brain-reactive autoantibodies (BRAA) are thought to play an important role in central nervous system (CNS) manifestations of systemic lupus erythematosus (SLE). Previous studies have shown the existence of BRAA in human and murine SLE. This study was undertaken to establish and characterize the presence of autoantibody binding to brain of autoimmune mice. Laser confocal microscopy was performed on frozen brain sections to detect the presence of immunoglobulin (Ig) in the brain of MRL/lpr and BXSB mice and compare that to control strains of MRL/mp and C57BL/6 mice. There was a dramatic increase in fluorescence in the brains of MRL/lpr and BXSB at 4 months of age. There was little or no Ig detected in the brains of control mice. This increase in presence of Ig in the autoimmune mouse brain was paralleled by an increase in the serum titers of BRAA and anti-DNA autoantibodies as determined by ELISA. These studies provide another link between the existence of brain-reactive autoantibodies and altered CNS functioning.