Serum and cerebrospinal fluid antibodies to single-stranded and double-stranded nucleic acids in neurological diseases.

Two different subpopulations of IgG antibodies to nucleic acids may be demonstrated: (1) IgG directed against single-stranded (ss) nucleic acids: they are found in normal human serum and increased in sera in subacute sclerosing panencephalities, multiple sclerosis and in other neurological diseases. Absent from normal cerebrospinal fluid, they can be synthetized inside the central nervous system during these diseases. Their only common antigenic determinant seems to be the polymeric single-stranded structure. No correlation can be demonstrated between their increase in sera and their local synthesis (inside the central nervous system) and between these data and the clinical stage. These facts suggest a "non-specific" reaction and not a pathogenic mechanism. (2) IgG antibodies directed against double-stranded (ds) nucleic acids: they were detected in cerebrospinal fluid during 3 neurological diseases only, all of proved viral etiology: subacute sclerosing panencephalitis, herpes meningoencephalitis and B hepatitis polyradiculoneuritis. These antibodies are also synthetized inside the central nervous system, and are distinct from antibodies to ss nucleic acids. The mechanism of production and the signification of these antibodies remains unknown, and their scarcity in MS patients must be stressed.