Identification of the kappa and lambda light chains within the CSF immunoglobulin region in multiple sclerosis and subacute sclerosing panencephalitis by immunofixation after isoelectric focusing.

The distribution of the kappa and lambda light chains within the cerebrospinal fluid (CSF) IgG oligoclonal bands of 15 multiple sclerosis (MS) and 3 subacute sclerosing panencephalitis (SSPE) patients has been studied by isoelectric focusing (IF) followed by direct immunofixation. The oligoclonal bands demonstrated by IF were both homogeneous and heterogeneous with regard to the light chain type; in the MS patients there was a prevalence of heterogeneous bands and of homogeneous bands of lambda type, while in SSPE a slight prevalence of kappa homogeneous bands was found. The kappa homogeneous bands were preferentially disposed in a more cathodal position in respect to lambda IgG bands; in some cases bands probably constituted only of free light chains of lambda type were found. Finally, in some cases, the oligoclonal IgG pattern was more distinct after immunofixation than after basal IF.