Abstract: SA-PO1036
Delayed Onset Transplant-Associated Thrombotic Microangiopathy
Session Information
- Transplantation: Clinical - Postkidney Transplant Outcomes and Potpourri
November 08, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Transplantation
- 2102 Transplantation: Clinical
Authors
- Ahmed, Muhammad, United Health Services Hospitals Inc, Binghamton, New York, United States
- Quasem, Mohammad A., United Health Services Hospitals Inc, Binghamton, New York, United States
- Suo, Liye, SUNY Upstate Medical University, Syracuse, New York, United States
- Amin, Mehreen, The Wright Center for Graduate Medical Education, Scranton, Pennsylvania, United States
Introduction
Globally, around 50,000 allogeneic hematopoietic stem cell transplants (allo-HSCTs) are performed annually to treat both malignant and non-malignant diseases. Here, we are reporting a unique case of delayed-onset TA-TMA.
Case Description
61-year-old Caucasian female with a history of Acute myeloid leukemia underwent a matched unrelated allo-HSCT at our institution. On day +77, the patient developed acute kidney injury (AKI), attributed to tacrolimus nephrotoxicity. Tacrolimus was temporarily held and later reintroduced, followed by a successful taper completed by day +314. At day +531 post-transplant, the patient presented with progressive renal dysfunction and was admitted for initiation of dialysis. Laboratory evaluation revealed a serum creatinine of 3.6 mg/dL. Urinalysis demonstrated significant proteinuria. Additional findings included macrocytic anemia, normal platelet count, and elevated immature reticulocyte count. Haptoglobin was mildly elevated (203 mg/dL), lactate dehydrogenase (LDH) was within normal limits, and direct Coombs test was negative. A comprehensive work-up for infectious and autoimmune causes, including hepatitis B and C serologies, complement levels, ANA, and ANCA, was normal. Given the unclear etiology of renal deterioration, a kidney biopsy was performed, which revealed features of both acute and chronic thrombotic microangiopathy (TMA). ADAMTS13 activity was found to be reduced at 54%. The patient was discharged with a plan to continue dialysis. As of over six months post-TMA diagnosis, the patient remains clinically stable, off immunosuppression, and without recurrence of TMA-related symptoms.
Discussion
Common risk factors for TA-TMA include using Calcineurin inhibitors (CNIs), acute or chronic GVHD, and post-transplant infections. TA-TMA usually manifests within the first 100 days of post-transplant in the presence of the mentioned risk factors. The delayed manifestation of TA-TMA, lack of classic diagnostic criteria, and risk factors are the unique features of this case. Although there are cases of TA-TMA reported in the absence of cardinal features like our case, but given the high index of suspicion, we pursued kidney biopsy with favorable outcomes. In summary, this case illustrated an atypical presentation of TA-TMA. Definitive diagnosis with a kidney biopsy can avoid morbidity and mortality in patients with atypical presentations.