Plasma Exchange vs. Immunoadsorption: Effects on Immunological Markers and Predictive Value in Steroid-Refractory MS Attacks.

BACKGROUND: Evidence on neurochemical mechanisms underlying response to apheresis in steroid-refractory Multiple Sclerosis (MS) attacks is limited. OBJECTIVE: To examine the effect of immunoadsorption (IA) versus plasma exchange (PLEX) on serum immunological parameters [IgG, IgA, IgM, kappa- and lambda-immunoglobulin free light chains (κ-FLC, λ-FLC), CXCL13, CXCL12] and the predictive value of these parameters on response to apheresis. METHODS: Pre- and postprocedural serum samples of 38 participants (IA: n = 19, PLEX: n = 19) from the IAPEMS trial (NCT02671682), conducted in our tertiary centre, were examined. RESULTS: Serum immunoglobulins were strongly reduced after both procedures (IgG: IA median -96.04%; PLEX median -85.98%). κ-FLC levels were reduced after PLEX (median -34.74%), not affected by IA. Both procedures caused a decrease in λ-FLC levels. CXCL13 slightly increased after PLEX (median +24.16%), conversely decreased after IA (median -21.92%). CXCL12 levels were reduced after IA (median -45.69%), but not significantly altered after PLEX. None of the serum parameters evaluated showed predictive value for apheresis response. CONCLUSION: IA and PLEX have a differential effect on serum immunological parameters. IA appears to reduce B-cell derived inflammation more effectively. This finding requires further evaluation and comparative analysis with clinical outcomes, especially in the context of the efficacy of B-cell therapies in treating MS.