Oligoclonal IgG and free light chains in the cerebrospinal fluid of patients with multiple sclerosis and infectious diseases of the central nervous system.

Conventional and crossed immunoelectrophoresis were used to characterize oligoclonal gamma-globulin bands of the cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS) or subacute sclerosing panencephalitis (SSPE) or other infections of the central nervous system. Most gamma-globulin bands were identified as IgG, but some bands were identified as kappa or lambda, or both, free light chains, Bands of IgG showed various degrees of light-chain diversity, and individual bands appeared in many instances to be derived from more than one clone of cells. Sequential changes of the oligoclonal IgG were observed in SSPE but not in MS. Oligoclonal IgG was detected in sera from most patients with SSPE and some patients with MS.