Impact of TA-TMA Therapies on Illness Severity and Survival in Pediatric HSCT PICU Patients

Monday, March 23, 2026

11:30 AM - 12:30 PM Central Time

Location: Connections Central - RST 04

Haitham Al-Khatib, MD (he/him/his)

Baylor College of Medicine Texas Children's Hospital, Texas

Disclosure(s): No relevant financial relationship(s) to disclose.
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Taylor Luckie, MD

Dr.
Baylor College of Medicine Texas Children's Hospital

Disclosure information not submitted.
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Andrew Wahba, MD

Dr.
Baylor College of Medicine Texas Children's Hospital

Disclosure information not submitted.
JF

Josaura Fernandez Sanchez, MD

Dr.
Baylor College of Medicine Texas Children's Hospital

Disclosure information not submitted.
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Baheyeldin Salem, MD

Dr.
Baylor College of Medicine Texas Children's Hospital

Disclosure information not submitted.
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Dalia A. Bashir, MD

Assistant Professor of Pediatrics
Baylor College of Medicine/ Texas Children's Hospital

Disclosure information not submitted.
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Poyyapakkam Srivaths, MD, FAAP

Dr.
Baylor College of Medicine Texas Children's Hospital

Disclosure information not submitted.
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Sarah Sartain, MD

Dr.
Baylor College of Medicine Texas Children's Hospital

Disclosure information not submitted.
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Saleh Bhar, MD

Dr.
Baylor College of Medicine Texas Children's Hospital

Disclosure information not submitted.

Introduction: Transplant-associated thrombotic microangiopathy (TA-TMA) is a life-threatening complication following hematopoietic stem cell transplant (HSCT), often resulting in multiorgan dysfunction and requiring PICU-level care. Data on how treatment strategies influence critical illness severity and outcomes in this population remain limited.

Methods: We performed a retrospective analysis of pediatric patients (0-22 years) who underwent allogeneic or autologous HSCT at Texas Children’s Hospital and diagnosed with TA-TMA (2011-2024). Diagnosis was made by treating teams; harmonized criteria and high-risk features were applied retrospectively per Schoettler et al., 2023. High-risk disease was defined by ≥1 of the following: rUPCR ≥1 mg/mg, sC5b-9 > ULN, LDH >2× ULN, grade 2–4 GVHD, infection, or organ dysfunction. Patients were grouped by treatment: none, eculizumab, therapeutic plasma exchange (TPE), or both. Outcomes included ICU interventions and survival.

Results: Among 110 TA-TMA patients, 41 (37%) required PICU admission. Median age was 8 years; 61% male, 55% Hispanic. Most received allogeneic HSCT (96%) for malignancy (69%) with myeloablative conditioning (89%). Consensus diagnostic criteria were met in 93%; 27% had biopsy-confirmed disease. High-risk features included LDH >2× ULN (94%), proteinuria (40%), and elevated sC5b-9 (39%).
Patients treated with both eculizumab and TPE had the highest burden of high-risk features—renal dysfunction (97%, p=0.003), proteinuria (77%, p=0.007), and elevated sC5b-9 (63%, p=0.002)—and required more intensive PICU support: mechanical ventilation (87%, p=0.024), renal replacement therapy (70%, p< 0.001), and prolonged ICU stay (median 36 days, p=0.040). Survival was lowest in those treated with TPE ± eculizumab and highest in those who received no TA-TMA-targeted therapy, likely reflecting baseline severity rather than treatment effect.

Conclusions: In pediatric HSCT patients, high-risk TA-TMA features correlate with critical illness severity and resource utilization. Eculizumab and/or TPE were more frequently used in sicker patients, reflecting clinical acuity. Early recognition of high-risk features may support timely interventions. Prospective studies are needed to define optimal treatment timing in this population.