OLIGOCLONAL IGG IN CEREBROSPINAL-FLUID DETECTED BY ISOELECTRIC-FOCUSING USING PHASTSYSTEM(TM)

Identification of oligoclonal immunoglobulin G (IgG) in cerebrospinal fluid (CSF) is one of the major laboratory signs in multiple sclerosis (MS). Oligoclonal IgG can also be seen in other immunostimulating cen tral nervous system diseases, e.g. meningitis caused by Borrelia spiro chetes. A convenient isoelectric focusing (IEF) method combined with p olyethyleneglycol-enhanced (PEG) immunofixation and silverstaining usi ng PhastSystem(TM) for detection of oligoclonal IgG bands in serum and unconcentrated spinal fluid was developed. Serum and cerebrospinal fl uid samples earlier investigated using agarose IEF combined with immun oblotting and avidin-biotin amplified double-antibody peroxidase stain ing (= A-IEF) were blindly re-analysed using PhastGel IEF 3-9 modified with addition of Pharmalyte 8-10.5 followed by immunofixation and sil ver staining (= PhastIEF). PhastSystem IEF using PhastGel had the same capability to separate and visualize oligoclonal IgG bands as the con ventional agarose IEF. However, PhastIEF was more convenient and less time-consuming than A-IEF. PhastIEF combined with immunofixation and s ilver staining using application of standardized amounts of IgG for bo th the serum and CSF samples (40-60 ng IgG /lane is fast, well-standar dized and reproducible. The method is sensitive and uses only a minute volume of unconcentrated cerebrospinal fluid for the investigation of CSF IgG pattern.