1. From the Translational Immunology Research Program (J.L., K.N., M.A., J.K.N., L.J., S.M.L., K.K.E., P.J.T.), University of Helsinki; Departments of Neurology (J.L., J.K.N., L.J., S.M.L., P.J.T.), Neurocenter, and Rheumatology (K.N., M.A., K.K.E.), Helsinki University Hospital; Research and Development (J.C.), Finnish Red Cross Blood Service, Helsinki; and Department of Virology (H.V., A.V., T.S.), Medicum, University of Helsinki, Finland.