In a group of 3 068 patients with neurological diseases, CSF and serum concentrations of antithrombin III were measured simultaneously with other protein fractions: immunoglobulins (IgG, IgA, IgM), albumin, a1-microglo- bulin, complement (C3, C4), transferrin, the apolipoproteins (Apo A-I, Apo A-II, Apo B), acute phase reactants (prealbumin, a1-antitrypsin, CRP, orosomucoid, fibrinogen, haptoglobin) (Turbox-Orion analyzer). Antithrombin III 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 of specific cytological and biochemical CSF syndromes. A specific biological function of antithrombin III was observed, it behaves as a inflammatory marker and correlates with the number of erythrocytes and concentration of bilirubin in CSF.

        Key words: antithrombin III, acute phase proteins, CSF cytology.