Early M-Protein Immune Reconstitution after Autologous Hematopoietic Stem Cell Transplantation Is a Good Prognostic Marker for Patients with High-Risk Cytogenetic Multiple Myeloma

OBJECTIVE: The presence of transient abnormal protein banding (i.e. M-protein immune reconstitution) in serum immunofixation electrophoresis after autologous hematopoietic stem cell transplantation in patients with multiple myeloma has been reported, and patients with high-risk cytogenetics tend to have poor prognosis; the purpose of this paper is to investigate the impact of post-transplant M-protein immune reconstitution on the prognosis of patients with high-risk cytogenetic multiple myeloma;

METHODS: To retrospectively analyze the clinical data of 290 newly diagnosed multiple myeloma patients from August 1, 2008 to July 31, 2021 at the First Affiliated Hospital of Sun Yat-sen University, all of whom underwent sequential autologous hematopoietic stem cell transplantation after induction therapy, and to analyze and compare the clinical characteristics and prognostic survival of patients with and without M-protein immune reconstitution;

RESULTS: M-protein immune reconstitution was observed in 25.9% (75/290 patients), the most common type of immunoglobulin was IgG-λ. The median time to obtain M-protein immune reconstitution was 3 months (1-38 months) and the median duration was 4 months (1-39 months) after transplantation, and there were no statistical differences in disease stage, tumor load and cytogenetics between the M-protein immune reconstituted and non-M-protein immune reconstituted groups. The CR rate and MRD negativity were higher in the M-protein immune reconstitution group (85.3% vs 69.3%, p=0.013, 81.9% vs 66.5%, p=0.014), and although there were no statistical differences in PFS and OS between the M-protein immune reconstitution group and the group without M protein immune reconstruction, the overall median survival time was longer in the M protein immune reconstruction group (80 vs 72m, p=0.096. not reached vs 105m, p=0.344). Among patients in the cytogenetic high-risk group, access to M-protein immune reconstitution predicted better PFS and OS (80 vs 31m, p=0.010. not reached vs 79m, p=0.026). Also in R-ISS stage III patients, PFS and OS were better in patients who obtained M-protein immune reconstitution (80 vs 20m, p=0.034. 57 vs 32m, p=0.137).

CONCLUSION: Better prognosis in M-protein immune reconstitution patients may be associated with the acquisition of a deeper response, but in high-risk patients, early acquisition of M-protein immune reconstitution may suggest a better prognosis.