At the 2026 European Hematology Association (EHA) Annual Meeting, Professor Todd Knepper from Moffitt Cancer Center shared a thematic report on "Post-Transplant Molecular Surveillance Reveals Divergent Clinical Trajectories of Donor-Derived Clonal Hematopoiesis (DD-CHIP)." Through high-throughput sequencing (NGS) technology, this study explored the incidence, molecular landscape, and differentiated impact of DD-CHIP on clinical outcomes in recipients of transplants for myeloid malignancies.01 Background and Challenges: NGS Opens a New Dimension of Post-Transplant Molecular Surveillance
In the treatment of myeloid malignancies, allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a critical means of achieving long-term survival. Post-transplant monitoring for disease relapse traditionally relies on flow cytometry, cytogenetics, and minimal residual disease (MRD) testing. However, the introduction of NGS in recent years has significantly enhanced monitoring sensitivity, particularly in capturing mutations at low allele frequencies.
Professor Todd Knepper pointed out that panel-based NGS monitoring not only tracks mutations from the primary disease but also reveals de novo mutations not present before the transplant. This deep insight at the “molecular level” brings a new clinical proposition: how to distinguish between residual disease, germline alterations, and de novo donor-derived clonal hematopoiesis (DD-CHIP)? What differentiated clinical prognoses correspond to different molecular evolutionary trajectories? This is the core focus of this study.
02 Study Design: Deep Review of a Large Cohort of 822 Recipients
To objectively evaluate the clinical significance of DD-CHIP, the research team conducted this single-center retrospective study based on a real-world patient cohort established by the internal Molecular Tumor Board (MTB). The study included 822 patients with myeloid malignancies who underwent allo-HSCT.
Workflow and Methodology:
- Multidimensional Calibration: Integrated evaluation of current NGS monitoring results with pre- and post-transplant sequencing results, chimerism testing, and bone marrow reports.
- Definition of DD-CHIP: Detection of potentially pathogenic somatic mutations not present in the patient pre-transplant, within the context of full donor chimerism.
- Evaluation Indicators: Focused on recipient survival rates, disease relapse rates, and the risk of developing donor-derived myeloid neoplasms (DD-MN).
03 Incidence and Risk Factors: Impact of Donor Age and Kinship
Among the 822 recipients, a total of 28 cases (3.4%) were confirmed as suspected DD-CHIP. Further analysis of donor characteristics revealed significant distributional differences:
- Impact of Donor Type: The incidence of DD-CHIP was as high as 13.4% among matched related donors; in contrast, the incidence among matched unrelated donors was only 1.4%.
- Age-Driven Effect: This difference is likely driven by donor age. The median age of donors in the DD-CHIP group was 58 years, compared to 28 years for the group without DD-CHIP. This conclusion is consistent with the biological characteristic that clonal hematopoiesis increases with age.
- Genetic Profile Characteristics: Consistent with the distribution of CHIP in the general population, DNMT3A was the most frequently mutated gene in recipients, followed by ASXL1 and TP53.
04 Clinical Trajectory I: DD-CHIP Associated with Favorable Overall Survival Benefit
Although DD-CHIP represents a clonal evolution of donor hematopoietic stem cells, its manifestation in recipients is not always negative. Study data showed that the overall prognosis for DD-CHIP recipients in this cohort was favorable:
- Survival Data: With a median follow-up of 3.3 years, the 2-year overall survival (OS) rate reached 92% (excluding surviving recipients who had not yet reached 2 years of follow-up).
- Relapse Risk and GVHD: The study specifically focused on DD-CHIP with DNMT3A mutations. Although limited by small numbers, preliminary analysis did not observe a significant difference in relapse rates based on DNMT3A mutation status. While a higher rate of chronic GVHD was observed among patients with DNMT3A mutations who received GVHD prophylaxis without PT-Cy (post-transplant cyclophosphamide), this was also true for the entire cohort, suggesting that DD-CHIP is not an independent factor promoting GVHD.
05 Clinical Trajectory II: High-Risk Mutations Evolving into Donor-Derived Myeloid Neoplasms (DD-MN)
While most DD-CHIP remained stable, the research team identified a few evolutionary trajectories toward malignant transformation. Professor Todd Knepper detailed three typical cases that evolved into DD-MN, revealing the following high-risk molecular signals:
- Mutation Types: TP53 mutations and splicing factor mutations (such as SRSF2, U2AF1, and SF3B1) were key warning signals for transformation to DD-MN.
- Dynamic Expansion: Cases evolving into DD-MN all demonstrated the persistence and continuous expansion of the aforementioned high-risk mutations (increasing VAF) following transplantation.
- Transformation Features: The progression to DD-MN did not necessarily require the acquisition of additional mutations beyond those already present. In several cases, high-risk DD-CHIP mutations detected early directly expanded under conditions of full donor chimerism, ultimately leading to donor-derived leukemia or myelodysplastic syndromes.
06 Conclusion and Outlook: Constructing a Precise Post-Transplant Molecular Management Strategy
In summary, Professor Todd Knepper emphasized that post-transplant DD-CHIP is a biologically and clinically relevant phenomenon.
Core Conclusions:
- Ubiquity and Heterogeneity: DD-CHIP can occur across all donor types, with a higher incidence observed in older matched related donors.
- Clinical Uncertainty: The detection of DD-CHIP complicates post-transplant molecular assessment, and clinicians must carefully distinguish it from disease relapse.
- Stratified Management: Recipients with low-risk mutations such as DNMT3A can usually maintain long-term remission; however, those with TP53 or splicing factor mutations face a higher risk of DD-MN and require more frequent monitoring.
Statement of Limitations:As this was a retrospective real-world study, it lacked paired donor NGS samples for definitive confirmation, and the DD-CHIP group sample size was relatively small (n=28). Some statistical conclusions still require further validation through large-scale prospective clinical studies.
Future Vision:Future post-transplant management should integrate NGS monitoring results to establish more refined risk-stratification models. For patients identified with DD-CHIP, attention should be paid not only to the prevention and control of the primary disease but also to preventing the risk of malignant clonal evolution from the donor through dynamic molecular monitoring, thereby truly achieving individualized precision management after allo-HSCT.
