Impact of therapeutic and low volume plasma exchange on clinical laboratory parameters in patients treated for Alzheimer's disease from the AMBAR study

Introduction Little is known about the impact of plasma exchange (PE) on clinical laboratory parameters in Alzheimer's disease (AD) patients. Methods AD patients in the AMBAR trial (N = 322) received weekly therapeutic PE (TPE) for 6 weeks followed by monthly low‐volume PE (LVPE) for12 months. Treatment were placebo (sham PE), low‐albumin, low‐albumin + IVIG (i.e., albumin alternated with intravenous immunoglobulin) and high‐albumin + IVIG. Results Coagulation parameters transiently increased post‐TPE. Blood calcium, platelets, and albumin levels decreased but remained within the reference range. Leukocyte counts increased. Fibrinogen, hemoglobin, total protein, gamma globulin, and IgG, transiently dipped below the reference range. Hypogammaglobulinemia (7.2 g/L) persisted in pre‐TPE measurements. No changes were observed during the LVPE period. Cerebrospinal fluid parameters and vital signs were unchanged throughout. Conclusion Laboratory parameters of AD patients were affected by TPE similarly to effects of PE‐treatment for other pathologies. These effects were less pronounced or non‐existent for LVPE.