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.

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 without 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. Plasmapheresis supposedly removes toxic agents like antibodies from plasma but it is uncertain whether it has an immune-modulating 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 plasmapheresis 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 plasma will be removed from the patient with a plasma separator membrane, then processed via a fractionator membrane to remove molecules of a greater size than albumin before returning it to the patient. This technique requires no substitution solutes, only 20 g of albumin to replace what would normally be lost during a session. The primary outcome is the difference between the two plasmapheresis techniques in the variation of the TH1/TH17 ratio over the period D0H0-D0H3 and D0H0-D7. Secondary outcomes include the variation in lymphocyte subpopulations at each session and between therapeutic plasmapheresis techniques, the clinical evolution, tolerance and cost of treatments. DISCUSSION: Understanding the action mechanisms of single plasma exchange and DFPP will help us to offer the right treatment to each patient with CIPD according to efficacy, tolerance and cost. TRIAL REGISTRATION: ClinicalTrials.gov under the no. NCT04742374 and date of registration 10 December 2020.

Tandem hemodialysis and DFPP: Procedure, safety and cost-effectiveness in patients requiring chronic hemodialysis and lipid apheresis.

INTRODUCTION: Certain patients require simultaneous lipoprotein apheresis (LA) and intermittent hemodialysis (HD). Instead of undergoing 2 consecutive treatment sessions, a double filtration plasmapheresis (DFPP) and HD tandem procedure could be offered to reduce treatment times and costs. Our study evaluated the performance, safety and cost of this tandem procedure. MATERIAL AND METHODS: Three patients underwent 168 HD and DFPP tandem sessions in a tertiary center from August 2018 to November 2020, using a Fresenius 5008 generator for HD and an InfomedHF440 for DFPP. The system's efficacy was assessed by lipid subtraction performance for DFPP. Efficacy of 2 blood line connection configurations (parallel or sequential) was compared in terms of Kt/V and matched against an HD control session for each patient. Clinical and biological safety and the differential cost between tandem and consecutive procedures were evaluated. RESULTS: Throughout the tandem sessions, DFPP lasted 85 to 120 minutes, overlapping the 240-minute HD. Blood flow for HD and Kt/V were significantly lower during the tandem procedure with a parallel configuration compared to sequential or control paired HD. DFPP efficacy was comparable between all groups: over 60% reduction in cholesterol and over 50% for triglycerides. Symptomatic hypotension depended on the patients, not the procedure. The tandem procedure revealed an acceptable benefit-cost ratio. CONCLUSION: HD-DFPP tandem with a sequential blood line connecting system (derivation installed on the HD venous line) is effective and well-tolerated with a good cost-benefit ratio. Tandem reduces hospitalization and treatment session times and can be offered to patients requiring simultaneous HD and DFPP.