We report 2 complicated cases of thrombotic microangiopathy with chronic features and active components. The first case was a 36-yr-old woman with positive anti-DNA antibody and possible lupus cerebritis, who developed thrombotic microangiopathy secondary to a series of syndromes, including preeclampsia and anti-phospholipid antibody syndrome. Renal biopsy revealed no evidence of lupus nephritis and her renal function returned to normal 1 week after the biopsy. The second case was a 46-yr-old man who developed thrombotic microangiopathy of unknown etiology, which led to end-stage renal disease within 6 mo. The patient received a living related-donor transplant, but thrombotic microangiopathy recurred in the donor kidney only 40 days after the renal transplantation.