Beneficial Plasma Exchange Response in Central Nervous System Inflammatory Demyelination

Background: Plasma exchange (PLEX) is a beneficial rescue therapy for acute, steroid-refractory central nervous system inflammatory demyelinating disease (CNS-IDD). Despite the approximately 45% PLEX response rate reported among patients with CNS-IDD, determinants of interindividual differences in PLEX response are not well characterized. Objective: To perform an exploratory analysis of clinical, radiographic, and serological features associated with beneficial PLEX response. Design: Historical cohort study. Setting: Neurology practice, Mayo Clinic College of Medicine, Rochester, Minnesota. Patients: All Mayo Clinic patients treated with PLEX between January 5, 1999, and November 12, 2007, for a steroid-refractory CNS-IDD attack. Main Outcome Measure: The PLEX response in attack-related, targeted neurological deficit(s) assessed within the 6-month period following PLEX. Results: We identified 153 patients treated with PLEX for a steroid-refractory CNS-IDD, of whom 90 (59%) exhibited moderate to marked functional neurological improvement within 6 months following treatment. Pre-PLEX clinical features associated with a beneficial PLEX response were shorter disease duration (P = .02) and preserved deep tendon reflexes (P = .001); post-PLEX variables included a diagnosis of relapsing-remitting multiple sclerosis (P = .008) and a lower Expanded Disability Status Scale score (P < .001) at last follow-up. Plasma exchange was less effective for patients with multiple sclerosis who subsequently developed a progressive disease course (P = .046). Radiographic features associated with a beneficial PLEX response were presence of ring-enhancing lesions (odds ratio = 4.00; P = .03) and/or mass effect (odds ratio = 3.00; P = .02). No association was found between neuromyelitis optica-IgG serostatus and PLEX response. Conclusions: We have identified clinical and radiographic features that may aid in identifying patients with fulminant, steroid-refractory CNS-IDD attacks who are more likely to respond to PLEX.