HSP90B1 and systemic lupus erythematosus: SLE-MPs do display high levels of some of the putative ectosome-specific proteins such as TKT, Rab8B, and GSTP1 and the recently proposed marker of medium sized EVs, actinin-4, but other markers, such as mitofilin and GP96, are drastically decreased and unaltered, respectively [32, 43].