Phenotypic and functional comparison of monocytes from cord blood and granulocyte colony-stimulating factor–mobilized apheresis products

Objective It is well established that T cells are effector cells in graft-vs-host disease (GVHD), yet the contribution of graft monocytes is less well characterized. Therefore, monocytes in cord blood (CB) and granulocyte colony-stimulating factor–mobilized apheresis products (G-AP), two stem cell grafts associated with reduction of acute and chronic GVHD and relative reduction of acute GVHD, respectively, were compared phenotypically and functionally. Materials and Methods The frequencies, phenotypes, and pinocytosis activities of monocytes from CB and G-AP were determined by flow cytometry and their allostimulatory potential in a primary mixed leukocyte reaction. Results G-AP contained significantly more monocytes than CB (24.9% ± 7.1% vs 8.8% ± 1.5% CD14+ and 62.4 ± 27.5 × 106 vs 0.9 ± 0.2 × 106 CD14+ cells/mL). Monocytes from both sources revealed similar phenotypes. They expressed CD4, CD11a, CD11b, CD11c, CD18, CD32, CD33, CD45R0, CD48, CD50, CD54, CD58, CD64, CD86, CD102, CD116, CD123, and HLA-DR; showed no expression of CD1a and CD83; and weak expression of CD16, CD45RA, and CD80. The levels of CD80 and CD86 expression were comparable; however, in contrast to G-AP monocytes, CB monocytes lacked CD40. There was no difference in pinocytosis activity and allostimulatory capacity of CB and G-AP monocytes. Conclusions Monocytes in CB and G-AP are phenotypically and functionally comparable. The only difference observed is the lack of CD40 on CB monocytes