Efficacy of Substance Removal by Immunoadsorption With a Selective Plasma Separator

Abstract

Immunoadsorption with a tryptophan-conjugated column has a limited capacity and reduces fibrinogen. We speculated that immunoadsorption with a selective plasma separator has higher efficiency in removing immunoglobulins than ordinary immunoadsorption without affecting coagulation factors. This study investigated the efficacy of immunoadsorption with a selective plasma separator in vitro. The sieving coefficients, the pool concentration, and the adsorbed amount were investigated serially with up to 5 L of processed plasma. The sieving coefficients of the selective plasma separator were 0.8, 0.5, and 0.1 for albumin, immunoglobulin G (IgG), and factor 13, respectively. The trend of concentrations for the ordinary plasma separator in the pool reached its nadir at 1.5 L and 3.5 L of plasma processed for IgG, IgG1, or IgG2, and IgG3, respectively. However, the volume was doubled for the selective plasma separator. The trends of fibrinogen and factor 13 concentrations differed significantly between two plasma separators. The trends of the absorbed amount were mirror images of the concentration in the pool. Comparison of the peak amount absorbed indicated that the amounts were almost identical between the two separators for IgG, IgG1, and IgG2. On the other hand, the peak amounts were less for albumin, fibrinogen, and IgG3 with the selective plasma separator than with the ordinary separator. Although further investigations about bradykinin are required, immunoadsorption with the selective plasma separator supports the administration of more frequent and intensive treatments to remove IgG1 or IgG2 without affecting coagulation factors.

Removal Characteristics of Immunoadsorption with the Tryptophan‐Immobilized Column Using Conventional and Selective Plasma Separators in the Treatment of Myasthenia Gravis

“…The plasma concentrations of IgGs before IM‐TR in SeIA can be reduced to half of those in IA. The maximal amounts of adsorbed IgGs except for IgG3 might be nearly similar in IA and SeIA as observed in the previous in vitro study . However, the previous report showed that the maximal amounts of adsorbed IgG3 were smaller in SeIA than in IA .…”

“…In contrast, IM-TR semiselectively adsorbs due to electrostatic and hydrophobic interactions and involves a low-cost, single-use column (1,12). The PPV is normally limited to 1.5-2 L in one session of IA due to IgG detachment (12). In the present study, IM-TR approximately achieved a 26.5% reduction of IgG after a single IA, and the IgG reduction rate by IM-TR was lower than that by high-affinity IgG adsorbers.…”

Immunoadsorption With a Tryptophan‐Immobilized Column Using Conventional and Selective Plasma Separators in the Treatment of Myasthenia Gravis

“…Autoimmune neurological diseases are often treated by immunoadsorption (IA) using a conventional plasma separator and tryptophan-immobilized column (1). Recently, in vitro studies revealed that immunoadsorption by tryptophan-immobilized column using a selective plasma separator (SeIA) could eliminate IgG to a degree similar to that in IA while retaining fibrinogen (2,3). However, no previous reports have evaluated treatment with SeIA in clinical practice.…”

“…IA was performed by Immusorba TR-350 column (IM-TR; Asahi Kasei Medical, Tokyo, Japan) using OP-05 W (Asahi Kasei Medical) as a conventional plasma separator, and SeIA was performed by IM-TR using Evacure plus EC-4A10 (EC-4A; Kawasumi Laboratories) as a selective plasma separator (2,3). The sieving coefficients of IgG, factor XIII (FXIII), and fibrinogen using EC-4A were 0.5, 0.17, and 0, respectively (4).…”

“…© 2017 International Society for Apheresis, Japanese Society for Apheresis, and Japanese Society for Dialysis Therapy Ther Apher Dial, Vol. 22, No 3,. 2018 Letters to the Editor…”