Characteristic protein fractions of cerebrospinal fluid disc electrophoretic analysis

The present work was undertaken to determine characteristic proteins of normal cerebrospinal fluid (CSF) by disc electrophoresis in polyacrylamide gel, and to evaluate their usefulness as indicators of blood-brain-CSF barrier disturbance. The technique has been applied to 1280 samples of unconcentrated CSF obtained from 27 reference subjects and 847 neurological patients, with a simultaneous analysis of 361 sera. The pre-albumin content (mean +/- S.D. as a percentage of total protein, 11.0 +/- 2.3%) was higher than formerly reported. One reason for this is that preliminary concentration was not necessary, and the second is related to the principle of protein resolution. The no. 5 protein band of the post-albumin group (3.9 +/- 1.1%) was characteristic, though it has not yet been identified. The no. 3 protein band of the post-transferrin group (5.2 +/- 1.7%) was highly specific to CSF; it was found to be closely related to transferrin, and may correspond to tau fraction obtained by other methods. Barrier dysfunction was easily recognizable by the appearance of polymers of haptoglobin 2-1 or 2-2, because only haptoglobin 1-1 was detected in normal CSF. The percentage of the main region of the G-zone (13.7 +/- 2.6%) was postulated as normal content of CSF immunoglobulins.