Patients with multiple myeloma (MM) often relapse over time despite initially achieving a complete response without minimal residual disease following induction treatment, leaving questions about changes in the immune system and the prognosis of the disease.
New study findings are drawing a possible connection between the proportion of bone marrow (BM) lymphocyte subsets following autologous stem cell transplant (ASCT) and disease prognosis in patients with multiple myeloma (MM).
The results have important implications, as patients with MM often relapse over time despite initially achieving a complete response without minimal residual disease (MRD) following induction treatment, leaving questions about changes in the immune system and the prognosis of the disease.
The researchers collected data on 98 patients who were newly diagnosed with MM and received induction therapy before bridging to ASCT. A total of 12 BM lymphocytic subtypes were analyzed using multi-parametric flow cytometry.
The relative proportion of BM lymphocyte subtypes were linked to several indicators of disease prognosis, such as progression-free survival (PFS) and overall survival (OS).
For example, a higher relative proportion of memory B cells were associated with worse median PFS (hazard ratio [HR] 1.089; 95% CI, 1.023-1.160) and median OS (HR 1.170; 95% CI, 1.074-1.274).
“This finding is surprising, when in analysis published by Paiva et al., higher proportion of memory B cells was associated with better prognosis,” commented the researchers. “Differences between our and previously mentioned analysis could be explained by differences in timing of BM sampling. In Paiva’s analysis, patients were sampled at the time of maintenance treatment with IMIDs, but in our group of patients, there was a treatment-free interval of at least 3 months before BM sampling.”
The researchers also highlight another explanation of the results: in MM, memory B cells may be a source of clonotypic B cells that have the potential to change into MM cells.
They add that memory B cells may be difficult to use as prognostic markers in routine clinical practice because of the small differences in populations between responsive and non-responsive patients.
As a whole, the proportion of NK cells was no associated with OS, although the researchers did find that an increase in the proportion of CD56+ NK/NKT cells was significantly associated with worse median OS (HR, 1.057l; 95% CI, 1.009-1.108).
The researchers did not find any associations between specific lymphocyte sub-population or pattern with MRD-negative CR, although they note that more complex or continuous analyses should be done.
Stork M, Bezdekova R, Kralova R, et al. Prognostic significance of lymphocyte patterns in multiple myeloma patients after autologous transplant. Neoplasma. Published online February 23, 2021. doi:10.4149/neo_2021_200814N861