rhG-CSF effect on mixed lymphocyte cultures and circulating soluble HLA antigen levels in volunteer stem cell donors

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) is a cytokine widely used in the procurement of peripheral blood stem cells (PBSC) from donors for allogeneic hematopoietic cell transplantation. Therefore, we were interested in its immediate and long-term effects on cellular and soluble factors known to be involved in the immune response.

We studied 35 PBSC donors by mixed lymphocyte culture (MLC) and lymphocyte transformation test (LTT), and 41 for soluble plasma factors (soluble human leukocyte antigen [sHLA]-G, -class I, -DR, and interleukin [IL]-10) pre and 5 days post initial rhG-CSF administration, respectively. In addition, 10 donors were reexamined at an average of 2 months (3-16 weeks) post-rhG-CSF.

At 5 days post-rhG-CSF the donors presented a significant (p < 0.05) decrease of MLC, LTT mitogen, and recall antigen reactions. Plasma levels of sHLA-G, -class I, -DR, and IL-10 (p < 0.005 each) were significantly increased. The changes in IL-10 but not in sHLA were significantly (p < 0.05) correlated with LTT responses. In the 2-month follow-up there was no significant difference in alloreactivity and LTT reactions as compared to the pre-rhG-CSF results. The results generated after 3 to 16 weeks did not depend on the time point of investigation. Consistently, soluble factors decreased to pre-rhG-CSF levels.

rhG-CSF administration suppresses cellular immune functions within 5 days and increases sHLA and IL-10 plasma levels. These immunomodulatory effects appear to be short-term only and vanished at an average of 2 months after rhG-CSF application.