The Role of Microparticles as a Biomarker

The investigators propose to characterize MPs in aHUS and TTP both at the onset and throughout treatment. The investigators believe that the number, size, and cell origin of MPs will differ between these two diseases. The hypothesis is that endothelial derived MPs will be higher in number and comprise a larger portion of the MP population in aHUS and that platelet MPs will comprise a larger number and greater proportion of MPs in TTP. The investigators believe that MP identity and number can be used to reliably differentiate between aHUS and TTP at disease onset.