PROTEIN LAYER ON HEMODIALYSIS MEMBRANES - A NEW IMMUNOHISTOCHEMISTRY TECHNIQUE

In order to investigate the nature of the protein layer deposited on hemodialysis membranes we developed a direct immunohistochemical technique using fluoresceinated antibodies to plasma proteins. Fifteen patients on regular dialytic treatment were dialyzed with CU, HE, PAN, PS and PMIMA and the dialyzers analyzed at the end of a standard dialytic session. Snap frozen sections of hollow fiber devices were treated with flourescein-isothiocyanate conjugated antibodies for IgG, IgA, IgM, C3c, fibrinogen, factor VIII, factor XIIIa-s, antithrombin III, fibrinogen degradation products (PDF) and plasminogen. Protein deposits were evaulated by a quantitative criteria, which evaluates the intensity of fluorescence and the area of the capillary wall occupied by this fluorescence by using an image analysis software. The coagulation cascade is activated by all membranes and similar deposits of these proteins were revealed, whereas important differences in C3c deposition were found.