Addition of ketamine to interleukin-4 granulocyte–monocyte colony-stimulating factor (IL-4&GM-CSF)-cultured monocytes results in perseverance of monocyte marker—CD14 (A). However, phagocytic activity of IL-4&GM-CSF-cultured monocytes stimulated with ketamine during differentiation process remains unchanged (B). 4&GM = interleukin-4 and granulocyte macrophage colony-stimulating factor stimulated; 4&G+Ket100 = interleukin-4 and granulocyte macrophage colony-stimulating factor + ketamine 100 µg/ml stimulated; 4&G+Ket10 = interleukin-4 and granulocyte macrophage colony-stimulating factor + ketamine 10 µg/ml stimulated; 4&G+Ket1 = interleukin-4 and granulocyte macrophage colony-stimulating factor + ketamine 1 µg/ml stimulated; MFI = mean fluorescent intensity.