Immunoadsorption in systemic connective tissue diseases and primary vasculitis

Immunoadsorption offers some advantages over plasmapheresis; until recently the primary advantage has been avoidance of substitution fluids. In collagen vascular disorders, immunoadsorption is performed for the same indications as plasma exchange; most often adsorbers with binding capacities for IgG and circulating immune complexes are used. Tested ligands are protein A, anti-IgG antibodies, Clq, phenylalanine, and tryptophan. Human IgG was utilized to adsorb rheumatoid factor and dextran sulfate, DNA, or specific anti-idiotypes for anti-DNA antibodies in systemic lupus erythematous (SLE). Most applications have used immunoadsorbent columns in pretransplantation treatment of patients with high panel reactivity and in patients with idiopathic thrombocytopenic purpura (ITP). For these indications, as for systemic connective tissue diseases, randomized trials have yet to be conducted. SLE controlled trials have been completed for IMPH-350 and Ig-Therasorb. Results indicated excellent biocompatibility and good clinical responses. Using protein A in primary systemic vasculitis, histologically proven inactivation of renal involvement was demonstrated, but the patients were also treated with immunosuppressive drugs. Randomized controlled trials are mandatory to provide continued support to the therapeutical opportunities offered only by immunoadsorption.