Bone marrow lymphocytes reconstructive pattern in multiple myeloma patients after autologous transplant has no prognostic significance

In the last 20 years, the modern anti-myeloma drugs and autologous stem cell transplant (ASCT) significantly improved prognosis of multiple myeloma (MM) patients. Despite high efficiency of current induction regimens, most patients relapse over time. The link between changes in the immune system and prognosis of the disease is still not entirely clear. Therefore, we analyzed whether the reconstructive pattern of bone marrow (BM) lymphocytes during routine BM examination after ASCT is related to disease prognosis and whether there is a typical reconstructive pattern in patients with MRD negative complete remission. From September 2009 to October 2018, 98 MM patients underwent routine BM testing after the first ASCT at the Department of Internal medicine, Hematology and Oncology, University Hospital Brno in the Czech Republic. By multi-parametric flowcytometry, four BM lymphocyte subtypes were analyzed - T cells (CD19-CD5+), mature B cells (CD19+CD20+) immature B cells (CD19+CD20-) and NK cells (CD19-CD5-CD56+). In 60% of patients who achieved complete response (CR), MRD by flowcytometric analysis (sensitivity threshold 10-5) was evaluated. We analyzed correlation of changes in BM lymphocyte populations to length of progression free survival (PFS) and overall survival (OS) or minimal residual disease (MRD) negativity achievement. Changes in counts of any lymphocyte subtypes were not associated with significant PFS or OS benefit. No significant association of BM lymphocyte subtypes count with MRD negative status was found. Our results showed that the reconstructive post-transplant BM lymphocyte pattern is not connected to further newly diagnosed MM patients` prognosis after intensive treatment including ASCT.