Thromboembolism Induced by Umbilical Cord Mesenchymal Stem Cell Infusion: A Report of Two Cases and Literature Review

To investigate the thromboembolism induced by blood-mediated inflammatory reactions against infused cells during the clinical application of stem cells.Two patients with renal transplantation and chronic kidney disease, respectively, experienced thromboembolism after umbilical cord mesenchymal stem cell (UCMSC) infusion. The clinical manifestations and the laboratory test results were collected and analyzed.The patients received stem cell infusion through the peripheral veins and presented with a swollen and painful forearm postinfusion. Doppler ultrasound showed venous clots at the proximal end of the puncture site. Urokinase and warfarin were used for thrombolytic therapy. The swelling and pain were relieved and cured.Safety concerns are still a primary hurdle for stem cell therapy, and thromboembolism as a critical complication should be prevented appropriately.