Characterization of immune complexes in progressive rubella panencephalitis

In two patients with the slow virus disease progressive rubella panencephalitis, high levels of immune complexes were found in serum and, in one case, spinal fluid. These complexes contained immunoglobulin G. Serum complexes sedimented over a wide density range compared with the more homogeneous spinal fluid complexes. Complexes from both serum and spinal fluid contained antibody directed against rubella virus. Serum complexes were also shown to contain rubella antigen (or antigens) that appeared to differ between the two patients.