Plasma Exchange for Severe Attacks in the Spectrum of Central Demyelinating Disorders

Plasma exchange (PLEX), which basically consists in the removal of the plasma out of the patient blood, is especially dedicated to target the humoral part of the inflammatory response based on the mechanistic knowledge of the disease physiopathology. In this chapter we will focus on the new indication of PLEX in the full spectrum of demyelinating disorders of central nervous system.

We will briefly review the spectrum of disorders (MS, NMO, ADEM, Balo) and demonstrate how the humoral part of inflammation, according to the underlying disease, is especially suitable to be eliminated by PLEX upstream the extravasation step. The strong link between pathology and treatment sensitivity will be clearly demonstrated with a special emphasis on NMO. We will describe the main technical aspects of PLEX and emphasize the kinetics of the targeted components since PLEX efficiency is strongly dependent on the clearance of the targeted components and the timing of the treatment in the dynamic of the inflammatory lesion. Safety concerns and risks will be developed.

We will assess all the relevant clinical results obtained in each disorder of the spectrum according to the type of the attacks (spinal, optical, brain), the specificity of each disorder and tricky clinical situations in this spectrum. Parameters influencing the outcome will be detailed with a specific emphasize of the strongly time-dependent effect of PLEX in NMO. Moreover we will try to delineate a long-term role of PLEX given for relapses. Finally we will give an overview of various experimental techniques in line with PLEX.

In conclusion, PLEX is safe and could be a major treatment in inflammatory disorders relapses, especially in NMO. Preliminary results suggest that PLEX may modify the short prognosis of some demyelinating relapses.

Keywords: Acute disseminated encephalomyelitis, Multiple sclerosis, Neuromyelitis optica, Plasma Exchange, Optic neuritis, Transverse myelitis.