MRD contamination in peripheral blood autologous stem cell grafts: implications for relapse and prognosis in multiple myeloma

A large number of clinical studies have shown that the detection of contamination with clonal plasma cells (CPCs) in peripheral blood autologous stem cell grafts by flow cytometry, next-generation sequencing (NGS), next-generation flow cytometry (NGF), and other methods can reflect the residual tumor burden of multiple myeloma (MM) patients before autologous stem cell transplantation (ASCT). Despite the disadvantages of single-time and unsustainable monitoring, the MRD detection of stem cell grafts remains a negative prognostic factor that reduces overall survival. However, it must be acknowledged that MRD contamination in stem cell grafts is not a primary contributor to disease relapse. In clinical practice, MRD in grafts can be incorporated as a robust additional risk factor within a comprehensive and dynamic evaluation framework. For high-risk patients who are MRD-positive for the grafts, early intervention strategies such as preemptive or intensive therapy, and maintenance therapy with different novel agents may improve clinical outcomes.