Abstract
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 antiβdsDNA antibodies were significantly better adsorbed than total IgG or total protein. After a single perfusion of 21 samples, we estimated a mean antiβdsDNA antibody adsorption rate of 22.5% (Β±13.6). A group of ten responders with a medium adsorption rate of 35.4% (Β±6.5) clearly differed from a second group of eleven nonresponders (10.9% Β± 4.2). Antiβcardiolipin antibodies (ACA) were adsorbed in a wide range (IgG type, 2.5β52.7%, IgM type, 1.1β37.8%) while antiβRo (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. J. Clin. Apheresis 17:183β189, 2002. Β© 2002 WileyβLiss, Inc.