Monitoring of hematopoietic recovery after autologous stem cell transplantation by analysis of G alpha 16 mRNA and CD34 surface glycoprotein

Abstract

 The hematopoiesis-specific G protein alpha subunit Gα16 was shown to be expressed in early normal and malignant hematopoietic cell lines and has been suggested to play an important role in signal transduction of hematopoiesis. We previously demonstrated a strict correlation of Gα16 mRNA and CD34 antigen expression in peripheral blood stem cells (PBSC). In PBSC mobilization, both markers are detectable at the time of hematopoietic recovery and progenitor cell release. In this study the possible use of Gα16 determination in peripheral blood samples for monitoring patients undergoing stem cell transplantation was investigated. Normal peripheral blood is negative for Gα16 expression. In all five patients Gα16 mRNA expression appeared shortly before the time of blood cell recovery. When tested together with CD34 (three cases) a pattern different from CD34 antigen expression was found, reflecting a different mechanism of action. In two cases with different time points of leukocyte and platelet recovery Gα16 mRNA was detected at both time points but not in the interval, thus suggesting a role of Gα16 in multipotent precursor cells. CD34 mRNA tested in three patients was not detected at any time; this argues for different regulation of CD34 and Gα16 mRNA. Gα16 may be used as an indicator of hematopoietic recovery after autologous stem cell transplantation, suggesting that there are cell type-specific G protein-mediated signal transduction pathways of early hematopoiesis.