title: The HAF enigma: origin and clinical consequences of the appearance of high alkaline fractions on isoelectric focusing patterns of cerebrospinal fluid.
abstract: High alkaline fractions (HAF) are irregularly present on isoelectric focusing (IEF) patterns of cerebrospinal fluid (CSF). Therefore, this phenomenon was studied retrospectively in more detail. First, the appearance of HAF in time was recorded and attempts were made to discover a relationship to the biochemical parameters of CSF. No such relationship could be established, nor could any effect of age or sex of the patients or any correlation with ambient temperature or clinical diagnosis be shown. Finally, we have shown conclusively that the cause of this random appearance of HAF can be found in the collodion bags used to concentrate the CSF. This irregular feature of the collodion bags also produces a rise in the frequency of appearance of oligoclonal bands on IEF, probably by blocking the passage of proteins. We conclude that the CSF contains protein material, and that the passage of this through the collodion filters during CSF concentration depends on the regularity of composition of the filters used, occasioning the presence (or absence) of a HAF. Of even greater consequence is the observation that when HAFs do not pass a certain collodion filter, other protein-like material can also be retained, leading to the appearance of oligoclonal bands in IEF, and causing more frequent occurrence of IEF patterns containing oligoclonal bands in CSF. Also, a slight change in the spectrum of oligoclonal bands of CSF has been found when HAFs occur. This indicates that the collodion bags do not retain all protein material in the same way.
authors.affiliation: Central Clinical Chemistry Laboratory, Academic Hospital, State University, Leiden, The Netherlands.
authors.forename: J H
authors.initials: JH
authors.lastname: Souverijn
authors.forename: R
authors.initials: R
authors.lastname: Peet
authors.forename: W G
authors.initials: WG
authors.lastname: Smit
authors.forename: H M
authors.initials: HM
authors.lastname: Serrée
authors.forename: G W
authors.initials: GW
authors.lastname: Bruyn
mesh_terms: D000468:Alkalies / Q000134:cerebrospinal fluid*; D005591:Chemical Fractionation; D002623:Chemistry Techniques, Analytical / Q000295:instrumentation; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007074:Immunoglobulin G / Q000134:cerebrospinal fluid; D007136:Immunoglobulins / Q000134:cerebrospinal fluid; D007525:Isoelectric Focusing; D043025:Oligoclonal Bands; D012189:Retrospective Studies
chemical_list: D000468:Alkalies; D007074:Immunoglobulin G; D007136:Immunoglobulins; D043025:Oligoclonal Bands