Heterogeneous humoral immune responses in cerebrospinal fluid arising from inflammatory diseases of the human central nervous system. Detection of oligoclonal immunoglobulin bands after isoelectric focusing Original Research Article

Automated isoelectric focusing (IEF) with polyacrylamide micro gels (PAGs) and immune fixation in the modified PhastSystem™ proved to be more sensitive and accurate for detecting oligoclonal immunoglobulin (Ig) bands (OBs) in cerebrospinal fluid (CSF) than IEF with non-specific silver staining of bands or the calculation of intrathecal IgG production by two formulae comparing both routine OB assays and the formulae during inflammatory processes of the human central nervous system (CNS). Immune specific detection of OBs on parts of the gamma chain (Fc, CH2; Fab; Fd) and on the light chains lambda, kappa yielded different numbers of OBs of which most indicated IgG kappa and/or IgG lambda subfractions in CSF differing in pI besides a varying ground pattern of Ig in CSF and blood serum samples. In some cases more OBs on lambda (or kappa) chains than found on the gamma chain indicate other Ig subfractions and/or free light chains. Heterogeneous IgG subfractions were found in acid, neutral and alkaline regions of the PAG gel with the OB assay with immune-specific band detection; they varied with different inflammations of the CNS and during the inflammatory process. Identical OBs in CSF and serum samples were detected during chronic degradation processes of the CNS; they indicate additional heterogeneous IgG subfractions in the CSF and blood compartment, probably involved with autoimmune processes.