To do or not to do? Plasma exchange and timing of steroid administration in PML

ABSTRACT

Objective: To retrospectively analyze the effect of plasma exchange (PLEX, yes=PLEX+, no=PLEX-) and steroids administration timing (prophylactically –proST- or therapeutically –therST-) on the longitudinal clinical course of patients with natalizumab related progressive multifocal leukoencephalopathy (PML) and full blown immune reconstitution inflammatory syndrome (PML-IRIS).

Methods: Clinical and radiological data of 42 Italian patients with PML were analyzed. Patient's data are available until 12 months after PML diagnosis. PLEX and steroids treatment as time-dependent covariates were entered in: i) a Cox model to investigate their impact on full blown PML-IRIS latency; ii) an ANOVA to investigate their impact on IRIS duration; iii) a linear mixed model to assess their impact on the longitudinal clinical course (measured by means of EDSS).

Results: Treatment with PLEX was not associated to PML-IRIS latency (HR=1.05, p=0.92), but once IRIS emerged, its duration was significantly longer in patients who underwent PLEX (101 vs 54 days in PLEX+ and PLEX- patients, p=0.028). Receiving proST vs therST was not associated to IRIS latency (HR=0.67, p=0.39) or duration (p=0.95). Patients who underwent proST had a significant higher EDSS increase during PML (0.09 EDSS points per month, p=0.04) as compared to those who had therST.

Interpretation: this study highlights that: i) caution on the use of PLEX should be considered as the current data do not support a beneficial effect of PLEX; ii) caution on the early use of steroids is suggested since their prophylactic use to prevent full blown PML-IRIS seems to negatively impact on the longitudinal disability course. This article is protected by copyright. All rights reserved.

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