The investigation has demonstrated that there is a high association of the secretion of monoclonal paraproteins with bone marrow involvement in DLBCL (p<0.001). The intensified therapy using the mNHL-BFM-90 and R-DA-EPOCH/R-HMA programs involving autologous hematopoietic stem cell transplantation also permits the patients with Ig-secreting DLBCL to achieve long-term sustained remissions in not all cases.