PSME3 and myeloid sarcoma: This may have several possible interpretations, including, but not limited to (1) the effect of a relapse on Ki is delayed or lasts longer than 3 months, (2) subjects with an intrinsic aggressive MS phenotype show a persistently elevated Ki irrespective of current relapse activity, or (3) subjects currently receiving a suboptimal disease-modifying treatment have persistently elevated Ki.