ИММУНОФЕНОТИП ПЛАЗМАТИЧЕСКИХ КЛЕТОК КОСТНОГО МОЗГА БОЛЬНЫХ МНОЖЕСТВЕННОЙ МИЕЛОМОЙ НА ФОНЕ ВЫСОКОДОЗНОЙ ХИМИОТЕРАПИИ И ПОСЛЕ ТРАНСПЛАНТАЦИИ АУТОЛОГИЧНЫХ ГЕМОПОЭТИЧЕСКИХ СТВОЛОВЫХ КЛЕТОК

Abstract

The aim of the study is to investigate the immunophenotype of bone marrow plasma cells in patients with multiple myeloma (MM) before and after the transplantation of autologous hematopoietic stem cells (autologous HSCT), and to assess response to the treatment determine the frequency of the lack of achievement of minimal residual disease (MRD) negativity as a result of the treatment. Material and methods. Immunophenotyping of marrow plasma cells was performed in 17 MM patients aged from 43 to 62 years (median age 55 years). Four color flow cytometry (Cytomics FC unit 500, Beckman Coulter, USA) and the panel of monoclonal antibodies CD138/CD38/CD45/CD19/CD117/CD56 were used. In total, there were estimated 200,000--500,000 events in the initial Gate for forward scatter (FS) vs side scatter (SS). Plasma cells were isolated in Gate CD138/CD38. MRD-negativity was determined as the achievement of threshold value less than 0.01%. 37 bone marrow samples from 17 patients were analyzed. Immunophenotyping was performed before the 1st autologous HSCT, after the 1st autologous HSCT and after the 2nd autologous HSCT. Results and discussion. In all samples bone marrow plasma cells were characterized by the expression of both CD138/CD38 markers and weak expression or absence of expression of CD45 (CD45dim/neg-). The immunophenotype of plasma cells was presented by three markers CD19, CD117, CD56 and varied at different stages of the treatment. The analysis of the quantitative expression of aberrant markers before and after the 1st autologous HSCT revealed a statistically significant reduction of aberrant plasma cells. In 6 (35.3%) of 17 patients MRD-negativity was successfully achieved after the 1st autologous HSCT. Conclusion. Immunophenotyping by flow cytometry is a highly sensitive method. It permit to detect the expression of aberrant markers of plasma cells, to obtain their changes during the therapy. The efficacy of high-dose chemotherapy with following autologous HSCT was confirmed. The heterogeneity of aberrant expression of plasma cells was found.