CXCR4 (CD184) expression on stem cell harvest and CD34+ cells post-transplant

Abstract

Objectives/backgroundCXCR4 is a receptor for stromal-derived factor-1 (SDF-1), a molecule that has a chemotactic activity for lymphocytes and is important in homing of hematopoietic stem cells to their adult marrow. We evaluated the CXCR4 (CD184) expression in the harvest cells and in the post-transplant bone marrow (BM) and its relation to engraftment, as determined by the consensus criteria and chimerism. MethodsThis is a prospective study which included 30 patients undergoing hematopoietic stem cell transplantation; 15 patients received autograft and 15 patients received allograft on dates between January 2012 and May 2014. We assessed CD184 (CXCR4) using flow cytometry in the harvest cells together with post-transplant BM assessment on Day 28 and Day 90 for complete morphologic, molecular studies, and detection of CD184 expression on CD34+ cells with chimerism studies on total peripheral blood mononuclear cells. ResultsDiagnoses of the enrolled patients were as follows: seven (24.1%) with acute myeloid leukemia, eight (27.6%) with multiple myeloma, four (13.8%) with acute lymphoblastic leukemia, three (10.3%) with non-Hodgkin lymphoma, two (6.9%) with myelodysplastic syndromes, two (6.9%) with aplastic anemia, two (6.9%) with chronic myeloid leukemia, one (3.4%) with Hodgkin lymphoma, and one (3.4%) with plasmacytomas. One patient died and was excluded from the study because there were not enough data about engraftment. There was no statistical significance between the level of CD184 in stem cell harvest and the prediction of successful engraftment (p>0.05) as well as in Day 28 BM sample (p>0.05), whereas there was a statistical significance between the level of CD184 in Day 90 BM sample and the occurrence of successful engraftment (p=0.002). ConclusionSDF-1/CXCR4 axis plays a crucial role in engraftment; however, more studies are warranted to assess their expression post-transplant. Evaluating the ligand (chemokine, SDF-1) or its receptor (CXCR4) may serve as potential surrogate markers for assessment of engraftment.