Successful management of paraprotein‐associated peripheral polyneuropathies by immunoadsorption of plasma with staphylococcal protein A

Abstract

Two patients with paraprotein-associated peripheral polyneuropathy were treated successfully using immunoadsorption of patient's plasma with staphylococcal protein A. Both had previously been treated with immunosuppressive agents or plasma exchange, and were rapidly relapsing at the time of their protein A immunoadsorption therapy. One patient was treated "on-line" with a blood cell separator, and one was treated "off-line." Both responded well to therapy with minimal toxicity. Serum levels of circulating immune complexes were elevated in one patient and remained so during and after therapy. Immunoadsorption with protein A should be investigated as a therapeutic option for patients with paraprotein-associated peripheral polyneuropathy. The therapy is relatively easy to administer, particularly "off-line," and was well tolerated by our patients. More experience, including formal clinical trials, will be required to properly define the indications for, and mechanism of response to, this therapy.

Response of patients with IgM and IgA-associated peripheral polyneuropathies to ?off-line? immunoadsorption treatment using the Prosorba� protein A column

“…Our patients who have responded to Prosorba column treatment [12] have had mainly demyelinating sensorimotor peripheral polyneuropathies without prominent axonal signs or denervation. The associated monoclonal paraproteins have been of all major immunoglobulin classes.…”

“…The response of two of our three patients to Prosorba treatment suggests that removal of pathogenetic IgG paraproteins cannot be the sole mechanism of action in these patients given that their paraproteins were of the IgM and IgA class respectively. Previous reported experience with polyneuropathies treated using Prosorba columns suggested that activation of complement and/or enhanced clearance of soluble immune complexes from the plasma may occur [12,22].…”

“…Immunoadsorption procedures using Prosorba columns (Cypress Bioscience, Inc., San Diego, CA) were performed "off-line" as previously described [12]. In brief, peripheral vein access was established using an 18-gauge IV catheter fitted with a heparin lock.…”

“…Response to treatment was assessed and documented by the referring neurologist. Functional scores before and after treatments were assigned according to a "modified Hughes" scale as previously described [12,18].…”

“…The association between MGUS and polyneuropathy is generally considered to be causal [reviewed in 10]. Based on this consideration, and the reported effectiveness of plasma exchange in the treatment of IgG-associated peripheral polyneuropathies [11], we have previously reported successful treatment of two patients with IgG-associated peripheral polyneuropathy using the Prosorba protein A immunoadsorption column [12]. Despite our original assumption regarding the benefit of removing IgG paraproteins using the Prosorba column, it seemed unlikely that physical removal of a relatively small quantity of IgG with each procedure could explain the clinical response of our patients [13].…”