Development of TA-TMA prior to post-HCT day 100 is associated with poor OS. In patients surviving until post-HCT day 100, survival curves are shown dichotomized by patients who developed TA-TMA prior to day 100 and those who did not. There is clear separation of the curves beginning from day 100 through at least 3 years of follow-up demonstrating a significant survival advantage for patients who did not develop TA-TMA in the first 100 days after HCT.