Exploration of residual disease in stem cell products from mantle cell lymphoma using next-generation sequencing.

High-dose chemotherapy followed by autologous stem cell transplantation (ASCT) has become a treatment option for fit patients with mantle cell lymphoma (MCL). However, these patients often relapse within few years, potentially caused by contaminating lymphoma cells within the reinfused stem cell product (SCP). Studies have shown that measurable residual disease, also termed minimal residual disease (MRD), following ASCT predicts shorter survival. Using next-generation sequencing, we explore whether the diagnostic MCL clonotype is present within the infused SCP. MRD was detected in 4/17 of the SCPs, ranging 4-568 clonal cells/100,000 cells. With a median survival of 17 months, 3/4 of patients with MRD+ graft succumbed from MCL relapse versus 2/13 in the MRD- fraction. Patients receiving MRD+ grafts had increased risk of mortality, and thus screening of SCPs may be important for clinical decision-making.