Moranne et al. BMC Neurology (2022) 22:293 https://doi.org/10.1186/s12883-022-02816-w STUDY PROTOCOL Protocol of comparison of the effects of single plasma exchange and double filtration plasmapheresis on peripheral lymphocyte phenotypes in patients with Chronic Inflammatory Demyelinating Polyradiculoneuropathy: a monocentric prospective study with single-case experimental design O. Moranne 1,2* , IM. Ion 3 , R. Cezar 4 , Z. Messikh 1 , C. Prelipcean 1 , S. Chkair 5 , E. Thouvenot 3,6 , Tu Anh Tran 7 , P. Corbeau 8 and T. Chevallier 2,5 Abstract Background: Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP), a rare disorder affecting young adults, causes gradual weakness of the limbs, areflexia and impaired sensory function. New CIDP phenotypes with- out pathogenic antibodies but with modified cell profiles have been described. Treatments include corticotherapy, intravenous immunoglobulins, and plasmapheresis but the latter’s action mechanisms remain unclear. Plasmapher- esis supposedly removes toxic agents like antibodies from plasma but it is uncertain whether it has an immune-mod- ulating effect. Also, the refining mechanisms of the two main plasmapheresis techniques—single plasma exchange and double filtration plasmapheresis (DFPP) – are different and unclear. This study aims to compare the evolution of peripheral lymphocyte profiles in patients with CIDP according to their treatment (single centrifugation plasmapher- esis or DFPP) to better grasp the action mechanisms of both techniques. Method: In this proof-of-concept, monocentric, prospective, Single-Case Experimental Design study, 5 patients are evaluated by alternating their treatment type (single plasma exchange or DFPP) for 6 courses of treatment after randomization to their first treatment type. Each course of treatment lasts 2–4 weeks. For single plasma exchange, 60 ml/kg plasma will be removed from the patient and replaced with albumin solutes, with a centrifugation method to avoid the immunological reaction caused by the membrane used with the filtration method. For DFPP, 60 ml/kg © The Author(s) 2022. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativeco mmons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Open Access *Correspondence: Olivier.moranne@chu-nimes.fr 1 Service de Nephrologie Dialyse Apherese, Hôpital Universitaire de Nîmes, Nîmes, France Full list of author information is available at the end of the article