Therapeutic immunoadsorption increases the level of circulating soluble HLA molecules

Background and Objectives: Immunoadsorption (IA) is an established procedur e to remove Igs and immune complexes from peripheral blood. Since Igs repor tedly bind to human leucocyte antigen (HLA) molecules, we were interested t o know whether removal of Ig will also influence the plasma concentration o f soluble HLA (sHLA). Patients and Methods: Nine patients suffering from se vere autoimmune disease and undergoing 17 single courses of IA treatment we re monitored for their sHLA class I (sHLA-I) and sHLA-DR plasma levels. Pla sma was separated by a hollow-fiber-type separator. Plasma samples were tak en before therapy, after 15 min of recirculation (without operating the ads orber), after 1 and 2 liters of plasma adsorption, and 24 and 48 h after th e end of IA. Results: Before treatment the mean levels of sHLA-I and sHLA-D R were 0.37 (+/-0.06 SEM) and 0.32+/-0.05 mu g/ml, respectively. After 2 li ters of plasma filtration, an increase in sHLA-DR (0.80+/-0.10 mu g/ml) was observed (p<0.001), whereas sHLA-I was only slightly affected (mean: 0.45/-0.06 mu g/ml). sHLA concentrations returned to initial levels after 24 h. Conclusion: The significant increase in sHLA-DR may contribute to the immu nomodulatory effect of IA. Copyright (C) 2000 S. Karger AG, Basel.