Evaluation of the Efficacy and Tolerance of Plasmapheresis by Double Cascade Filtration in a University Centre

A study is being carried out to evaluate the biological, technical and clinical/biological efficacy of this technique, the practice of which is standardized in the department, in order to evaluate our practices and to improve them if necessary. As part of this study, the investigators will ask all patients scheduled for this procedure to participate in this observational prospective study without changing usual practices.