Decreased Expression of CXCR4 Chemokine Receptor in Bone Marrow after Chemotherapy in Patients with Non-Hodgkin Lymphomas Is a Good Prognostic Factor

BACKGROUND CXCR4 chemokine receptor is constitutively expressed on normal and malignant B lymphocytes derived from patients with B-cell lymphoproliferative disorders and has a significant role in cell migration to lymph nodes and bone marrow. Non-Hodgkin's lymphomas (NHL) constitute a heterogeneous group of lymphoproliferative diseases, which can localize not only to lymph nodes, but also can migrate to peripheral blood and metastase to other organs, including bone marrow. AIM The purpose of this study was to determine CXCR4 gene expression in peripheral blood and bone marrow of NHL patients before and after treatment. METHODS Samples of lymphoma lymph nodes, peripheral blood and bone marrow aspirates of patients with B-cell NHL were taken at diagnosis and after chemotherapy. Gene expression was determined by the reverse transcription (RT)-polymerase chain reaction method. Expression was estimated from 0 AU (no amplificate signal) to 3 AU (maximal amplificate signal). RESULTS No significant difference in the level of CXCR4 expression was found in reactive lymph nodes compared to lymphoma samples We observed high level of CXCR4 expression in most patients before treatment: in bone marrow: 3 AU-10 pts, 2 AU-8 pts, 1 AU-2 pts. In peripheral blood: 3 AU-14 pts, 2 AU-4 pts, 1 AU-1 pts, 0 AU-1 pts. After chemotherapy, significant decrease in CXCR4 expression was observed. Bone marrow: 3 AU-5 pts, 2 AU-7 pts, 1 AU-5 pts, 0 AU-3 pts (p = 0.03). Peripheral blood: 3 AU-2 pts, 2 AU-6 pts, 1 AU-10 pts, 0 AU-2 pts (p = 0.0002). There was a good response to treatment in patients with significant decrease of CXCR4 expression in the bone marrow after treatment with 10-fold lower risk of death (p = 0.03). CONCLUSIONS Decrease in CXCR4 expression in the bone marrow of NHL patients after chemotherapy may be a good prognostic factor.