INTERLEUKIN-10 Production and monocyte maturity in g-csf-mobilized peripheral blood stem cell transplants correlate with graft-versus host disease

Abstract Despite an increased number of donor T cells in peripheral blood stem cell (PBSC) collections mobilized with G-CSF, the incidence of severe acute graft-versus-host disease (GVHD) is not increased compared to bone marrow transplant (BMT) recipients. However, the incidence of chronic GVHD has been reported to be higher with PBSC than BMT, and this may be due to the balance of cytokines produced by the graft. Here we have examined monocyte phenotype and cytokine production in the PBSC grafts of 27 patients that have undergone allogeneic PBSC grafting for haematologic malignancy. Monocytes in PBSC grafts appeared to be immature with a significantly lower CD14 expression by CD64 + cells within 22/27 PBSC collections. The presence of immature monocytes was significantly correlated (p = 0.0361) with absent or low acute GVHD (grade 1), while monocytes of a more normal phenotype were contained in the grafts of those developing severe acute GVHD (grades 2–4). Furthermore, monocytes in PBSC grafts showed a significantly increased spontaneous production of IL-10 compared to non-mobilized controls (p