Favorable Long-Term Outcomes of Umbilical Cord Blood Transplantation in Primary Hemophagocytic Lymphohistiocytosis: A 20-Year Institutional Review
Bibliographic record
Abstract
Background Primary Hemophagocytic Lymphohistiocytosis (pHLH) is a potentially fatal hyperinflammatory disorder. Allogeneic HCT remains the only curative treatment. Historically, umbilical cord blood grafts (UC) have been associated with concerns of inferior outcomes, primarily due to an increased risk of graft failure (GF) and mixed chimerism, which may contribute to HLH relapse. As a result, bone marrow grafts have traditionally been preferred in this disorder. Methods We conducted a retrospective review under an approved IRB protocol to evaluate twelve patients at Children's Healthcare of Atlanta who received a UC HCT for confirmed or presumed pHLH from 2004 to 2024. Results Patients median age at HCT was 10 months (range: 5 months to 14 years), with median follow-up 8.5 years (range 0.5 - 20 years). The majority received myeloablative conditioning (7/12), with 5 received reduced intensity conditioning . Four patients received 6/6 HLA-matched UC graft, 7 received 5/6 graft and 1 received 4/6 graft. All patients were in HLH remission prior to HCT, treated per HLH-2004 protocol or modified based on clinical status. Two patients had CNS HLH, both receiving intrathecal treatment prior to HCT. Pre-HCT, 5 patients had viremia (EBV=3, CMV=2), all were quiescent before HCT. Importantly, none had viral reactivation 6 months post-HCT. One patient developed SOS and was treated with defibrotide with no long term sequalae. Ten patients had long-term donor chimerism >90%, with one developing primary graft rejection (GR), and the other developing GF requiring a second HCT. Both patients with GR/GF had received RIC. Eight patients developed GVHD (n=3 had grade 2-4); all were steroid responsive (Figure 1). Both patients with CNS HLH had developmental delays , one required tracheostomy . At three years all patients were alive; one patient died 14 years after HCT secondary to tracheostomy-associated infection. Discussion In conclusion, our study demonstrates that UC graft is a viable option for allogeneic HCT in pHLH and it can achieve favorable long-term survival outcomes in pHLH, including high rates of sustained donor chimerism and low mortality, even in patients with prior viral infections and CNS involvement. Further studies with larger cohorts are needed to evaluate this stem cell source in pHLH.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".