BIOCOMPATIBILITY EVALUATION OF POLYAMIDE HEMOFILTRATION

Introduction. Postdilution hemofiltration with a polyamide membrane is a renal replacement technique widely used, but very little informatio n is available regarding the biocompatibility of this treatment In thi s paper we report the results of an acute study of the biocompatibilit y of polyamide hemofiltration. Patients and methods. Complement activa tion such as C3a and C5a Des Arg (RIA), granulocyte degranulation like alpha 1 elastase intradialytic increase (ELISA) and the expression of high affinity membrane receptors for IL-2 (anti-TAC) were determined Beta 2-microglobulin (RIA) intradialytic decrease, as well as its conv ective removal, was evaluated The nature of protein layer adsorbed ont o the polyamide membrane, at the end of the dialytic session was inves tigated with a new immunohistochemical technique. Cell-associated cyto kine concentration (like IL-1 beta and IL-1Ra - ELISA) was determined on mononuclear cell lysates. Results. A low degree of complement activ ation was detected with the polyamide membrane when data were adjusted for hemoconcentration and for 1 m(2) of membrane surface area. An imp ortant convective removal not only of Beta 2-microglobulin (258+/-20 m g/session), but also of the activated anaphylatoxins (225+/-76 ng/ml f or C3a and 22.5+/-4 ng/ml for C5a) was revealed A marked deposition of all coagulation factors with no detectable amount of immunoglobulins and complement factors was revealed on the polyamide membrane at the e nd of the dialytic session. No intradialytic (for lL-1beta) (from 14.1 +/-3.0 to 13.5+/-2.9 pg/2.5 x 10(6) cell) and interdialytic (for IL-1R a) (from 4572+/-1076 to 5408+/-615 pg/2.5 x 10(6) cell) cell-associate d cytokine expression was induced by hemofiltration. Discussion and Co nclusion. Polyamide hemofiltration is a highly biocompatible technique due to the use of a synthetic membrane with a sterile reinfusion flui d and the convective removal of the activated anaphylatoxins and Beta 2-microglobulin.