Measles-virus-specific immunoglobulin-M response in subacute sclerosing panencephalitis.

Measles-virus specific IgM and IgG responses in sera and cerebrospinal fluid (C.S.F.) of 20 patients with subacute sclerosing panencephalitis (S.S.P.E.) and of two control groups were examined by indirect radioimmunoassay. All S.S.P.E. patients, regardless of the stage of the disease, had high titres of anti-measles antibodies in sera and C.S.F. The antibody activity was associated with both the IgM and the IgG classes of immunoglobulins. In 7 (35%) of the S.S.P.E. cases the specific IgM response was more pronounced in the C.S.F. than in the serum, suggesting IgM production within the central nervous system. The two control groups did not have a specific IgM response in C.S.F. or serum. It is assumed that the continuing release of measles antigen in S.S.P.E., as the result of the persistence of virus virus in the central nervous system, pevents the shut-off of IgM synthesis and is responsible for the specific IgM activity. It is proposed that the detection of virus-specific IgM antibodies in the C.S.F. of patients with chronic diseases of the central nervous system can be taken as an indication of persistence of virus.