In a group of 3 625 patients with neurological diseases, CSF and serum concentrations of apolipoprotein Apo A-II were measured simultaneously with the other protein fractions: immunoglobulins (IgG, IgA, IgM), albumin, a1-microglobulin, complement (C3, C4), antithrombin III, the other apolipoproteins (Apo A-I, Apo B), acute phase reactants (prealbumin, a1-antitrypsin, CRP, orosomucoid, fibrinogen, transferrin, haptoglobin) (Turbox-Orion analyzer). Apo A-II concentrations were compared with concentrations of the other CSF protein fractions using linear regression analysis both in the group of patients with normal biochemical and cytological CSF findings and after division of the group according to the presence or absence of lipophagic elements in the cytological count. These macrophagic elements mediate scavenger reaction after onset of destructive CNS lesions; they enable the detection of CNS tissue lesions in the CSF cytological count. In the presence of lipophages in CSF, elevation of CSF Apo A-II concentrations can be observed. The probable function of Apo A-II in CSF is transport of lipoid substance formed during degradation of CNS structural lipids by macrophages. A similar mechanism has been described in apolipoprotein Apo A-I. Assessment of CSF Apo A-II concentration can be used in routine practice for evidence of structural CNS lesions.

        Key words: Apo A-II, apolipoproteins, lipophages, foam cells, CSF cytology.