Apolipoproteins in human cerebrospinal fluid.

The presence of apolipoproteins A-I, E, C-II, and C-III and the absence of apolipoprotein B was demonstrated in human cerebrospinal fluid. The concentration of apolipoproteins was measured by electroimmunoassay. Apolipoproteins E, C-II, and C-III were present in cerebrospinal fluid at 3--5% of their concentration in plasma; the cerebrospinal fluid level of apolipoprotein A-I was 0.4%. Most of the cerebrospinal fluid apolipoproteins were present in the rho less than 1.21 g/ml lipoprotein fraction. The major apolipoporteins of cerebrospinal fluid are E and A-I. The possible mechanism of transfer and the physiological and pathophysiological role of apolipoproteins in cerebrospinal fluid are postulated.