Figure 1.

Laboratory results and kidney biopsy findings are consistent with thrombotic microangiopathy involving the transplanted kidney. (A-D) Laboratory parameters show improvement after complement inhibition with eculizumab was initiated on postoperative day 5, with creatinine, hemoglobin, platelet, and lactate dehydrogenase (LDH) levels returning to normal range. Filled triangle marks the day of discontinuation of tacrolimus therapy, arrow marks the start of eculizumab therapy followed by the introduction of belatacept therapy on the following day. (E-F) Light microscopy of the kidney biopsy specimen (hematoxylin and eosin stain) is shown. Occluded arteriole (indicated by arrow) can be seen along with reactive endothelium and expanded subendothelial space. Red blood cell fragmentation can be seen beneath the endothelium. (G) Periodic acid–Schiff and (H) trichrome stain show similar findings.