Cell free DNA profiling as a tool to monitor clinically-relevant events in allogeneic hematopoietic stem cell transplantation - Finanziato dall’Unione europea – Next Generation EU

Allogeneic hematopoietic stem cell transplantation (HSCT) represents the best therapeutic option available for patients with high-risk hematological diseases. However, HSCT is burdened by significant and potentially life-threatening side effects, including graft-versus-host disease (GVHD), as well as engraftment failure, endothelial complications, reactivation of dormant viruses and recurrence of the disease. GVHD is a challenging complication for both early diagnosis and treatment. It occurs in up to 50% in the acute form and 35% in the chronic form, affecting potentially every organ (skin, liver, gastrointestinal tract – GI -, lung, eyes, muscles, mucosae etc). The diagnosis is essentially clinical due to absence of markers available in daily practice. Infections due to reactivation of dormant viruses are relatively common and are monitored through conventional virus-specific molecular tests. Lastly, minimal residual disease (MRD) and chimerism analysis can also provide significant prognostic information regarding relapse of disease, thus influencing clinical decisions. Currently, MRD is performed by monitoring the presence of genetic lesions of the tumor in blood or bone marrow of the patient. Cell free DNA (cfDNA) are DNA fragments (50-200 bp) normally present in biological fluids and deriving from cellular turnover. Analysis of cfDNA has proven of enormous importance in cancer in tracing genetic lesions typical of the tumor (a process known as liquid biopsy) and allowing disease monitoring and early detection of relapse. cfDNA measurement has also revolutionized the field of prenatal diagnosis in that it allows detection of genetic anomalies in the fetus without invasive procedures. A third field of application for cfDNA measurement is solid organ transplantation, where determination of the relative amount of cfDNA coming from the donor is a proxy of organ damage. Recent data indicate that periodic measurement of cfDNA can be useful in monitoring rejection episodes, decreasing the number of biopsies. In HSCT the clinical usefulness of measuring cfDNA from plasma of transplanted patients is scarce, indicating the need for pilot studies. This proposal is aimed at providing proof-of-principle of the validity of cfDNA Whole Genome Bisulfite Sequencing (WGBS) as a marker of acute GVHD (primary endpoint), as well as ii) infections, iii) engraftment, iv) disease relapse, v) transplant associated microangiopathy or sinusoidal obstruction syndrome and vi) chronic GvHD (secondary endpoints). To do so, we will recruit a prospective cohort of 25-30 patients undergoing allogeneic HSCT and will follow them for 12 months following HSCT. cfDNA WGBS analyses will be compared to currently performed routine tests, to understand its diagnostic potential for the various complications arising post-transplant. This is a pilot study exploring a novel area in hematology with important consequences for transplant monitoring in patients undergoing HSCT.