Granulocyte‐colony‐stimulating factor induces increased serum levels of soluble interleukin 2 receptors preceding engraftment in autologous bone marrow transplantation

Abstract

Summary The serum levels of soluble interleukin 2 receptors (sIL‐2R) were determined in 19 patients who received highdose chemotherapy and an autologous or syngeneic bone marrow transplant (BMT) for treatment of Hodgkin's disease (n= 18) or non‐Hodgkin's lymphoma (n= 1). Twelve patients received granulocyte colony‐stimulating factor (G‐CSF) from day 0 or day +1 after autologous BMT until the white blood cell count had been stable for 9 d above 1 × 10⁹/1, the remaining seven patients did not receive growth factors, In all G‐CSF‐treated patients the sIL‐2R levels increased steadily in the early post‐transplant course, even in the absence of infection. This increase was statistically significant 2‐4 d prior to the appearance of leucocytes in the peripheral blood (median 340 pm versus median 256 pm immediately after BMT, PP<0.001). Cessation of G‐CSF administration resulted in a decline of sIL‐2R levels. In contrast, five of seven patients without G‐CSF treatment did not exhibit an sIL‐2R increase before or at the time of engraftment. Infection was associated with a rise of sIL‐2R levels. A correlation between sIL‐2R levels and total leucocyte count, lymphocyte count, or CD25 + lymphocyte count was not evident. These data suggest that after autologous BMT G‐CSF induces increased sIL‐2R levels, which occur independent of lymphocyte activation. This may be compatible with involvement of immature bone marrow cells in G‐CSF‐induced sIL‐2R release.