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Development of an in vitro miniature model to simulate immunoadsorption in patients with systemic lupus erythematosus
Birgit Avenhaus1, Wolfgang Avenhaus, Matthias Schneider
1Department of Medicine B, University of Muenster, Muenster, Germany. avenhaw@mednet.uni-muenster.de
In SLE, immunoadsorption is used as an adjuvant therapy; however, adsorption profiles and binding mechanisms have not yet been completely investigated. Using a minicolumn filled with the sorbent IMPH with or without the ligand phenylalanine, we developed a model simulating clinical conditions in a reduced scale with a constant ratio of plasma to column volume and a constant plasma flow at room temperature. By desorbing the column, the adsorption efficacy for different antibodies could be measured directly. We demonstrate that the adsorption rate can be increased by a low plasma flow and by covering the column surface. Double perfusion of the same column did not increase the amount of adsorbed antibodies. We further demonstrate that the carrier material without a ligand is unable to bind antibodies or protein. In the IMPH sorbent anti-dsDNA antibodies were significantly better adsorbed than total IgG or total protein. After a single perfusion of 21 samples, we estimated a mean anti-dsDNA antibody adsorption rate of 22.5% (+/-13.6). A group of ten responders with a medium adsorption rate of 35.4% (+/-6.5) clearly differed from a second group of eleven nonresponders (10.9% +/- 4.2). Anti-cardiolipin antibodies (ACA) were adsorbed in a wide range (IgG type, 2.5-52.7%, IgM type, 1.1-37.8%) while anti-Ro (SSA) antibody adsorption was negligible. This in vitro minimodel provides a precise simulation of therapeutic immunoadsorption and helps to analyze the binding characteristics of the sorbent IMPH and shows its effectiveness in several antibody subsets of different patients.
In SLE, immunoadsorption is used as an adjuvant therapy; however, adsorption profiles and binding mechanisms have not yet been completely investigated. Using a minicolumn filled with the sorbent IMPH with or without the ligand phenylalanine, we developed a model simulating clinical conditions in a reduced scale with a constant ratio of plasma to column volume and a constant plasma flow at room temperature. By desorbing the column, the adsorption efficacy for different antibodies could be measured directly. We demonstrate that the adsorption rate can be increased by a low plasma flow and by covering the column surface. Double perfusion of the same column did not increase the amount of adsorbed antibodies. We further demonstrate that the carrier material without a ligand is unable to bind antibodies or protein. In the IMPH sorbent anti-dsDNA antibodies were significantly better adsorbed than total IgG or total protein. After a single perfusion of 21 samples, we estimated a mean anti-dsDNA antibody adsorption rate of 22.5% (+/-13.6). A group of ten responders with a medium adsorption rate of 35.4% (+/-6.5) clearly differed from a second group of eleven nonresponders (10.9% +/- 4.2). Anti-cardiolipin antibodies (ACA) were adsorbed in a wide range (IgG type, 2.5-52.7%, IgM type, 1.1-37.8%) while anti-Ro (SSA) antibody adsorption was negligible. This in vitro minimodel provides a precise simulation of therapeutic immunoadsorption and helps to analyze the binding characteristics of the sorbent IMPH and shows its effectiveness in several antibody subsets of different patients.